// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------

//! \addtogroup diskio
//! @{

//! Generate the first line of the header used for saving matrices in text format.
//! Format: "ARMA_MAT_TXT_ABXYZ".
//! A is one of: I (for integral types) or F (for floating point types).
//! B is one of: U (for unsigned types), S (for signed types), N (for not applicable) or C
//! (for complex types). XYZ specifies the width of each element in terms of bytes, eg.
//! "008" indicates eight bytes.
template <typename eT>
inline std::string diskio::gen_txt_header(const Mat<eT>&) {
  arma_type_check((is_supported_elem_type<eT>::value == false));

  const char* ARMA_MAT_TXT_IU001 = "ARMA_MAT_TXT_IU001";
  const char* ARMA_MAT_TXT_IS001 = "ARMA_MAT_TXT_IS001";
  const char* ARMA_MAT_TXT_IU002 = "ARMA_MAT_TXT_IU002";
  const char* ARMA_MAT_TXT_IS002 = "ARMA_MAT_TXT_IS002";
  const char* ARMA_MAT_TXT_IU004 = "ARMA_MAT_TXT_IU004";
  const char* ARMA_MAT_TXT_IS004 = "ARMA_MAT_TXT_IS004";
  const char* ARMA_MAT_TXT_IU008 = "ARMA_MAT_TXT_IU008";
  const char* ARMA_MAT_TXT_IS008 = "ARMA_MAT_TXT_IS008";
  const char* ARMA_MAT_TXT_FN004 = "ARMA_MAT_TXT_FN004";
  const char* ARMA_MAT_TXT_FN008 = "ARMA_MAT_TXT_FN008";
  const char* ARMA_MAT_TXT_FC008 = "ARMA_MAT_TXT_FC008";
  const char* ARMA_MAT_TXT_FC016 = "ARMA_MAT_TXT_FC016";

  char* header = nullptr;

  if (is_u8<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IU001);
  } else if (is_s8<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IS001);
  } else if (is_u16<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IU002);
  } else if (is_s16<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IS002);
  } else if (is_u32<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IU004);
  } else if (is_s32<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IS004);
  } else if (is_u64<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IU008);
  } else if (is_s64<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IS008);
  } else if (is_ulng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IU004);
  } else if (is_slng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IS004);
  } else if (is_ulng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IU008);
  } else if (is_slng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_IS008);
  } else if (is_float<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_FN004);
  } else if (is_double<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_FN008);
  } else if (is_cx_float<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_FC008);
  } else if (is_cx_double<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_TXT_FC016);
  }

  return std::string(header);
}

//! Generate the first line of the header used for saving matrices in binary format.
//! Format: "ARMA_MAT_BIN_ABXYZ".
//! A is one of: I (for integral types) or F (for floating point types).
//! B is one of: U (for unsigned types), S (for signed types), N (for not applicable) or C
//! (for complex types). XYZ specifies the width of each element in terms of bytes, eg.
//! "008" indicates eight bytes.
template <typename eT>
inline std::string diskio::gen_bin_header(const Mat<eT>&) {
  arma_type_check((is_supported_elem_type<eT>::value == false));

  const char* ARMA_MAT_BIN_IU001 = "ARMA_MAT_BIN_IU001";
  const char* ARMA_MAT_BIN_IS001 = "ARMA_MAT_BIN_IS001";
  const char* ARMA_MAT_BIN_IU002 = "ARMA_MAT_BIN_IU002";
  const char* ARMA_MAT_BIN_IS002 = "ARMA_MAT_BIN_IS002";
  const char* ARMA_MAT_BIN_IU004 = "ARMA_MAT_BIN_IU004";
  const char* ARMA_MAT_BIN_IS004 = "ARMA_MAT_BIN_IS004";
  const char* ARMA_MAT_BIN_IU008 = "ARMA_MAT_BIN_IU008";
  const char* ARMA_MAT_BIN_IS008 = "ARMA_MAT_BIN_IS008";
  const char* ARMA_MAT_BIN_FN004 = "ARMA_MAT_BIN_FN004";
  const char* ARMA_MAT_BIN_FN008 = "ARMA_MAT_BIN_FN008";
  const char* ARMA_MAT_BIN_FC008 = "ARMA_MAT_BIN_FC008";
  const char* ARMA_MAT_BIN_FC016 = "ARMA_MAT_BIN_FC016";

  char* header = nullptr;

  if (is_u8<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IU001);
  } else if (is_s8<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IS001);
  } else if (is_u16<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IU002);
  } else if (is_s16<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IS002);
  } else if (is_u32<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IU004);
  } else if (is_s32<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IS004);
  } else if (is_u64<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IU008);
  } else if (is_s64<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IS008);
  } else if (is_ulng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IU004);
  } else if (is_slng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IS004);
  } else if (is_ulng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IU008);
  } else if (is_slng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_IS008);
  } else if (is_float<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_FN004);
  } else if (is_double<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_FN008);
  } else if (is_cx_float<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_FC008);
  } else if (is_cx_double<eT>::value) {
    header = const_cast<char*>(ARMA_MAT_BIN_FC016);
  }

  return std::string(header);
}

//! Generate the first line of the header used for saving matrices in binary format.
//! Format: "ARMA_SPM_BIN_ABXYZ".
//! A is one of: I (for integral types) or F (for floating point types).
//! B is one of: U (for unsigned types), S (for signed types), N (for not applicable) or C
//! (for complex types). XYZ specifies the width of each element in terms of bytes, eg.
//! "008" indicates eight bytes.
template <typename eT>
inline std::string diskio::gen_bin_header(const SpMat<eT>&) {
  arma_type_check((is_supported_elem_type<eT>::value == false));

  const char* ARMA_SPM_BIN_IU001 = "ARMA_SPM_BIN_IU001";
  const char* ARMA_SPM_BIN_IS001 = "ARMA_SPM_BIN_IS001";
  const char* ARMA_SPM_BIN_IU002 = "ARMA_SPM_BIN_IU002";
  const char* ARMA_SPM_BIN_IS002 = "ARMA_SPM_BIN_IS002";
  const char* ARMA_SPM_BIN_IU004 = "ARMA_SPM_BIN_IU004";
  const char* ARMA_SPM_BIN_IS004 = "ARMA_SPM_BIN_IS004";
  const char* ARMA_SPM_BIN_IU008 = "ARMA_SPM_BIN_IU008";
  const char* ARMA_SPM_BIN_IS008 = "ARMA_SPM_BIN_IS008";
  const char* ARMA_SPM_BIN_FN004 = "ARMA_SPM_BIN_FN004";
  const char* ARMA_SPM_BIN_FN008 = "ARMA_SPM_BIN_FN008";
  const char* ARMA_SPM_BIN_FC008 = "ARMA_SPM_BIN_FC008";
  const char* ARMA_SPM_BIN_FC016 = "ARMA_SPM_BIN_FC016";

  char* header = nullptr;

  if (is_u8<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IU001);
  } else if (is_s8<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IS001);
  } else if (is_u16<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IU002);
  } else if (is_s16<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IS002);
  } else if (is_u32<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IU004);
  } else if (is_s32<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IS004);
  } else if (is_u64<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IU008);
  } else if (is_s64<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IS008);
  } else if (is_ulng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IU004);
  } else if (is_slng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IS004);
  } else if (is_ulng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IU008);
  } else if (is_slng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_IS008);
  } else if (is_float<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_FN004);
  } else if (is_double<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_FN008);
  } else if (is_cx_float<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_FC008);
  } else if (is_cx_double<eT>::value) {
    header = const_cast<char*>(ARMA_SPM_BIN_FC016);
  }

  return std::string(header);
}

//! Generate the first line of the header used for saving cubes in text format.
//! Format: "ARMA_CUB_TXT_ABXYZ".
//! A is one of: I (for integral types) or F (for floating point types).
//! B is one of: U (for unsigned types), S (for signed types), N (for not applicable) or C
//! (for complex types). XYZ specifies the width of each element in terms of bytes, eg.
//! "008" indicates eight bytes.
template <typename eT>
inline std::string diskio::gen_txt_header(const Cube<eT>&) {
  arma_type_check((is_supported_elem_type<eT>::value == false));

  const char* ARMA_CUB_TXT_IU001 = "ARMA_CUB_TXT_IU001";
  const char* ARMA_CUB_TXT_IS001 = "ARMA_CUB_TXT_IS001";
  const char* ARMA_CUB_TXT_IU002 = "ARMA_CUB_TXT_IU002";
  const char* ARMA_CUB_TXT_IS002 = "ARMA_CUB_TXT_IS002";
  const char* ARMA_CUB_TXT_IU004 = "ARMA_CUB_TXT_IU004";
  const char* ARMA_CUB_TXT_IS004 = "ARMA_CUB_TXT_IS004";
  const char* ARMA_CUB_TXT_IU008 = "ARMA_CUB_TXT_IU008";
  const char* ARMA_CUB_TXT_IS008 = "ARMA_CUB_TXT_IS008";
  const char* ARMA_CUB_TXT_FN004 = "ARMA_CUB_TXT_FN004";
  const char* ARMA_CUB_TXT_FN008 = "ARMA_CUB_TXT_FN008";
  const char* ARMA_CUB_TXT_FC008 = "ARMA_CUB_TXT_FC008";
  const char* ARMA_CUB_TXT_FC016 = "ARMA_CUB_TXT_FC016";

  char* header = nullptr;

  if (is_u8<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IU001);
  } else if (is_s8<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IS001);
  } else if (is_u16<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IU002);
  } else if (is_s16<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IS002);
  } else if (is_u32<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IU004);
  } else if (is_s32<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IS004);
  } else if (is_u64<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IU008);
  } else if (is_s64<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IS008);
  } else if (is_ulng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IU004);
  } else if (is_slng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IS004);
  } else if (is_ulng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IU008);
  } else if (is_slng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_IS008);
  } else if (is_float<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_FN004);
  } else if (is_double<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_FN008);
  } else if (is_cx_float<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_FC008);
  } else if (is_cx_double<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_TXT_FC016);
  }

  return std::string(header);
}

//! Generate the first line of the header used for saving cubes in binary format.
//! Format: "ARMA_CUB_BIN_ABXYZ".
//! A is one of: I (for integral types) or F (for floating point types).
//! B is one of: U (for unsigned types), S (for signed types), N (for not applicable) or C
//! (for complex types). XYZ specifies the width of each element in terms of bytes, eg.
//! "008" indicates eight bytes.
template <typename eT>
inline std::string diskio::gen_bin_header(const Cube<eT>&) {
  arma_type_check((is_supported_elem_type<eT>::value == false));

  const char* ARMA_CUB_BIN_IU001 = "ARMA_CUB_BIN_IU001";
  const char* ARMA_CUB_BIN_IS001 = "ARMA_CUB_BIN_IS001";
  const char* ARMA_CUB_BIN_IU002 = "ARMA_CUB_BIN_IU002";
  const char* ARMA_CUB_BIN_IS002 = "ARMA_CUB_BIN_IS002";
  const char* ARMA_CUB_BIN_IU004 = "ARMA_CUB_BIN_IU004";
  const char* ARMA_CUB_BIN_IS004 = "ARMA_CUB_BIN_IS004";
  const char* ARMA_CUB_BIN_IU008 = "ARMA_CUB_BIN_IU008";
  const char* ARMA_CUB_BIN_IS008 = "ARMA_CUB_BIN_IS008";
  const char* ARMA_CUB_BIN_FN004 = "ARMA_CUB_BIN_FN004";
  const char* ARMA_CUB_BIN_FN008 = "ARMA_CUB_BIN_FN008";
  const char* ARMA_CUB_BIN_FC008 = "ARMA_CUB_BIN_FC008";
  const char* ARMA_CUB_BIN_FC016 = "ARMA_CUB_BIN_FC016";

  char* header = nullptr;

  if (is_u8<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IU001);
  } else if (is_s8<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IS001);
  } else if (is_u16<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IU002);
  } else if (is_s16<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IS002);
  } else if (is_u32<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IU004);
  } else if (is_s32<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IS004);
  } else if (is_u64<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IU008);
  } else if (is_s64<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IS008);
  } else if (is_ulng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IU004);
  } else if (is_slng_t_32<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IS004);
  } else if (is_ulng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IU008);
  } else if (is_slng_t_64<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_IS008);
  } else if (is_float<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_FN004);
  } else if (is_double<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_FN008);
  } else if (is_cx_float<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_FC008);
  } else if (is_cx_double<eT>::value) {
    header = const_cast<char*>(ARMA_CUB_BIN_FC016);
  }

  return std::string(header);
}

inline file_type diskio::guess_file_type(std::istream& f) {
  arma_extra_debug_sigprint();

  return diskio::guess_file_type_internal(f);
}

inline file_type diskio::guess_file_type_internal(std::istream& f) {
  arma_extra_debug_sigprint();

  f.clear();
  const std::fstream::pos_type pos1 = f.tellg();

  f.clear();
  f.seekg(0, ios::end);

  f.clear();
  const std::fstream::pos_type pos2 = f.tellg();

  const uword N_max =
      ((pos1 >= 0) && (pos2 >= 0) && (pos2 > pos1)) ? uword(pos2 - pos1) : uword(0);

  f.clear();
  f.seekg(pos1);

  if (N_max == 0) {
    return file_type_unknown;
  }

  const uword N_use = (std::min)(N_max, uword(4096));

  podarray<unsigned char> data(N_use);
  data.zeros();

  unsigned char* data_mem = data.memptr();

  f.clear();
  f.read(reinterpret_cast<char*>(data_mem), std::streamsize(N_use));

  const bool load_okay = f.good();

  f.clear();
  f.seekg(pos1);

  if (load_okay == false) {
    return file_type_unknown;
  }

  bool has_binary = false;
  bool has_bracket = false;
  bool has_comma = false;
  bool has_semicolon = false;

  for (uword i = 0; i < N_use; ++i) {
    const unsigned char val = data_mem[i];

    if ((val <= 8) || (val >= 123)) {
      has_binary = true;
      break;
    }  // the range checking can be made more elaborate

    if ((val == '(') || (val == ')')) {
      has_bracket = true;
    }

    if ((val == ';')) {
      has_semicolon = true;
    }

    if ((val == ',')) {
      has_comma = true;
    }
  }

  if (has_binary) {
    return raw_binary;
  }

  // ssv_ascii has to be before csv_ascii;
  // if the data has semicolons, it suggests a CSV file with semicolon as the separating
  // character; the semicolon may be used to allow the comma character to represent the
  // decimal seperator (eg. 1,2345 vs 1.2345)

  if (has_semicolon && (has_bracket == false)) {
    return ssv_ascii;
  }

  if (has_comma && (has_bracket == false)) {
    return csv_ascii;
  }

  return raw_ascii;
}

//! Append a quasi-random string to the given filename.
//! Avoiding use of rand() to preserve its state.
inline std::string diskio::gen_tmp_name(const std::string& x) {
  union {
    uword val;
    void* ptr;
  } u;

  u.val = uword(0);
  u.ptr = const_cast<std::string*>(&x);

  const u16 a = u16((u.val >> 8) & 0xFFFF);
  const u16 b = u16((std::clock()) & 0xFFFF);

  std::ostringstream ss;

  ss << x << ".tmp_";

  ss.setf(std::ios_base::hex, std::ios_base::basefield);

  ss.width(4);
  ss.fill('0');
  ss << a;

  ss.width(4);
  ss.fill('0');
  ss << b;

  return ss.str();
}

//! Safely rename a file.
//! Before renaming, test if we can write to the final file.
//! This should prevent:
//! (i)  overwriting files that are write protected,
//! (ii) overwriting directories.
inline bool diskio::safe_rename(const std::string& old_name,
                                const std::string& new_name) {
  const char* new_name_c_str = new_name.c_str();

  std::fstream f(new_name_c_str, std::fstream::out | std::fstream::app);
  f.put(' ');

  if (f.good()) {
    f.close();
  } else {
    return false;
  }

  if (std::remove(new_name_c_str) != 0) {
    return false;
  }
  if (std::rename(old_name.c_str(), new_name_c_str) != 0) {
    return false;
  }

  return true;
}

inline bool diskio::is_readable(const std::string& name) {
  std::ifstream f;

  f.open(name, std::fstream::binary);

  // std::ifstream destructor will close the file

  return (f.is_open());
}

inline void diskio::sanitise_token(std::string& token) {
  // remove spaces, tabs, carriage returns

  if (token.length() == 0) {
    return;
  }

  const char c_front = token.front();
  const char c_back = token.back();

  if ((c_front == ' ') || (c_front == '\t') || (c_front == '\r') || (c_back == ' ') ||
      (c_back == '\t') || (c_back == '\r')) {
    token.erase(
        std::remove_if(token.begin(), token.end(),
                       [](char c) { return ((c == ' ') || (c == '\t') || (c == '\r')); }),
        token.end());
  }
}

template <typename eT>
inline bool diskio::convert_token(eT& val, const std::string& token) {
  const size_t N = size_t(token.length());

  const char* str = token.c_str();

  if ((N == 0) || ((N == 1) && (str[0] == '0'))) {
    val = eT(0);
    return true;
  }

  if ((N == 3) || (N == 4)) {
    const bool neg = (str[0] == '-');
    const bool pos = (str[0] == '+');

    const size_t offset = ((neg || pos) && (N == 4)) ? 1 : 0;

    const char sig_a = str[offset];
    const char sig_b = str[offset + 1];
    const char sig_c = str[offset + 2];

    if (((sig_a == 'i') || (sig_a == 'I')) && ((sig_b == 'n') || (sig_b == 'N')) &&
        ((sig_c == 'f') || (sig_c == 'F'))) {
      val =
          neg ? cond_rel<is_signed<eT>::value>::make_neg(Datum<eT>::inf) : Datum<eT>::inf;

      return true;
    } else if (((sig_a == 'n') || (sig_a == 'N')) && ((sig_b == 'a') || (sig_b == 'A')) &&
               ((sig_c == 'n') || (sig_c == 'N'))) {
      val = Datum<eT>::nan;

      return true;
    }
  }

  // #if (defined(ARMA_HAVE_CXX17) && (__cpp_lib_to_chars >= 201611L))
  //   {
  //   // std::from_chars() doesn't handle leading whitespace
  //   // std::from_chars() doesn't handle leading + sign
  //   // std::from_chars() handles only the decimal point (.) as the decimal seperator
  //
  //   const char str0     = str[0];
  //   const bool start_ok = ((str0 != ' ') && (str0 != '\t') && (str0 != '+'));
  //
  //   bool has_comma = false;
  //   for(uword i=0; i<N; ++i)  { if(str[i] == ',')  { has_comma = true; break; } }
  //
  //   if(start_ok && (has_comma == false))
  //     {
  //     eT result_val = eT(0);
  //
  //     const std::from_chars_result result_state = std::from_chars(str, str+N,
  //     result_val);
  //
  //     if( (result_state.ptr != str) && (result_state.ec == std::errc()) )
  //       {
  //       val = result_val;
  //       return true;
  //       }
  //     }
  //
  //   // fallthrough if std::from_chars() failed
  //   }
  // #endif

  char* endptr = nullptr;

  if (is_real<eT>::value) {
    val = eT(std::strtod(str, &endptr));
  } else {
    if (is_signed<eT>::value) {
      // signed integer

      val = eT(std::strtoll(str, &endptr, 10));
    } else {
      // unsigned integer

      if ((str[0] == '-') && (N >= 2)) {
        val = eT(0);

        if ((str[1] == '-') || (str[1] == '+')) {
          return false;
        }

        const char* str_offset1 = &(str[1]);

        std::strtoull(str_offset1, &endptr, 10);

        if (str_offset1 == endptr) {
          return false;
        }

        return true;
      }

      val = eT(std::strtoull(str, &endptr, 10));
    }
  }

  if (str == endptr) {
    return false;
  }

  return true;
}

template <typename T>
inline bool diskio::convert_token(std::complex<T>& val, const std::string& token) {
  const size_t N = size_t(token.length());
  const size_t Nm1 = N - 1;

  if (N == 0) {
    val = std::complex<T>(0);
    return true;
  }

  const char* str = token.c_str();

  // valid complex number formats:
  // (real,imag)
  // (real)
  // ()

  if ((token[0] != '(') || (token[Nm1] != ')')) {
    // no brackets, so treat the token as a non-complex number

    T val_real;

    const bool state = diskio::convert_token(
        val_real, token);  // use the non-complex version of this function

    val = std::complex<T>(val_real);

    return state;
  }

  // does the token contain only the () brackets?
  if (N <= 2) {
    val = std::complex<T>(0);
    return true;
  }

  size_t comma_loc = 0;
  bool comma_found = false;

  for (size_t i = 0; i < N; ++i) {
    if (str[i] == ',') {
      comma_loc = i;
      comma_found = true;
      break;
    }
  }

  bool state = false;

  if (comma_found == false) {
    // only the real part is available

    const std::string token_real(&(str[1]), (Nm1 - 1));

    T val_real;

    state = diskio::convert_token(
        val_real, token_real);  // use the non-complex version of this function

    val = std::complex<T>(val_real);
  } else {
    const std::string token_real(&(str[1]), (comma_loc - 1));
    const std::string token_imag(&(str[comma_loc + 1]), (Nm1 - 1 - comma_loc));

    T val_real;
    T val_imag;

    const bool state_real = diskio::convert_token(val_real, token_real);
    const bool state_imag = diskio::convert_token(val_imag, token_imag);

    state = (state_real && state_imag);

    val = std::complex<T>(val_real, val_imag);
  }

  return state;
}

template <typename eT>
inline bool diskio::convert_token_strict(eT& val, const std::string& token) {
  const size_t N = size_t(token.length());

  const bool status = (N > 0) ? diskio::convert_token(val, token) : false;

  if (status == false) {
    val = Datum<eT>::nan;
  }

  return status;
}

template <typename eT>
inline std::streamsize diskio::prepare_stream(std::ostream& f) {
  std::streamsize cell_width = f.width();

  if (is_real<eT>::value) {
    f.unsetf(ios::fixed);
    f.setf(ios::scientific);
    f.fill(' ');

    f.precision(16);
    cell_width = 24;

    // NOTE: for 'float' the optimum settings are f.precision(8) and cell_width = 15
    // NOTE: however, to avoid introducing errors in case single precision data is loaded
    // as double precision, NOTE: the same settings must be used for both 'float' and
    // 'double'
  } else if (is_cx<eT>::value) {
    f.unsetf(ios::fixed);
    f.setf(ios::scientific);

    f.precision(16);
  }

  return cell_width;
}

//! Save a matrix as raw text (no header, human readable).
//! Matrices can be loaded in Matlab and Octave, as long as they don't have complex
//! elements.
template <typename eT>
inline bool diskio::save_raw_ascii(const Mat<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f;

  (arma_config::text_as_binary) ? f.open(tmp_name, std::fstream::binary)
                                : f.open(tmp_name);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_raw_ascii(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

//! Save a matrix as raw text (no header, human readable).
//! Matrices can be loaded in Matlab and Octave, as long as they don't have complex
//! elements.
template <typename eT>
inline bool diskio::save_raw_ascii(const Mat<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  const arma_ostream_state stream_state(f);

  const std::streamsize cell_width = diskio::prepare_stream<eT>(f);

  for (uword row = 0; row < x.n_rows; ++row) {
    for (uword col = 0; col < x.n_cols; ++col) {
      f.put(' ');

      if (is_real<eT>::value) {
        f.width(cell_width);
      }

      arma_ostream::raw_print_elem(f, x.at(row, col));
    }

    f.put('\n');
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

//! Save a matrix as raw binary (no header)
template <typename eT>
inline bool diskio::save_raw_binary(const Mat<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f(tmp_name, std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_raw_binary(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

template <typename eT>
inline bool diskio::save_raw_binary(const Mat<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  f.write(reinterpret_cast<const char*>(x.mem), std::streamsize(x.n_elem * sizeof(eT)));

  return f.good();
}

//! Save a matrix in text format (human readable),
//! with a header that indicates the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_ascii(const Mat<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f;

  (arma_config::text_as_binary) ? f.open(tmp_name, std::fstream::binary)
                                : f.open(tmp_name);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_arma_ascii(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

//! Save a matrix in text format (human readable),
//! with a header that indicates the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_ascii(const Mat<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  const arma_ostream_state stream_state(f);

  f << diskio::gen_txt_header(x) << '\n';
  f << x.n_rows << ' ' << x.n_cols << '\n';

  const std::streamsize cell_width = diskio::prepare_stream<eT>(f);

  for (uword row = 0; row < x.n_rows; ++row) {
    for (uword col = 0; col < x.n_cols; ++col) {
      f.put(' ');

      if (is_real<eT>::value) {
        f.width(cell_width);
      }

      arma_ostream::raw_print_elem(f, x.at(row, col));
    }

    f.put('\n');
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

//! Save a matrix in CSV text format (human readable)
template <typename eT>
inline bool diskio::save_csv_ascii(const Mat<eT>& x, const std::string& final_name,
                                   const field<std::string>& header,
                                   const bool with_header, const char separator) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f;

  (arma_config::text_as_binary) ? f.open(tmp_name, std::fstream::binary)
                                : f.open(tmp_name);

  bool save_okay = f.is_open();

  if (save_okay == false) {
    return false;
  }

  if (with_header) {
    arma_extra_debug_print("diskio::save_csv_ascii(): writing header");

    for (uword i = 0; i < header.n_elem; ++i) {
      f << header.at(i);

      if (i != (header.n_elem - 1)) {
        f.put(separator);
      }
    }

    f.put('\n');

    save_okay = f.good();
  }

  if (save_okay) {
    save_okay = diskio::save_csv_ascii(x, f, separator);
  }

  f.flush();
  f.close();

  if (save_okay) {
    save_okay = diskio::safe_rename(tmp_name, final_name);
  }

  return save_okay;
}

//! Save a matrix in CSV text format (human readable)
template <typename eT>
inline bool diskio::save_csv_ascii(const Mat<eT>& x, std::ostream& f,
                                   const char separator) {
  arma_extra_debug_sigprint();

  const arma_ostream_state stream_state(f);

  diskio::prepare_stream<eT>(f);

  uword x_n_rows = x.n_rows;
  uword x_n_cols = x.n_cols;

  for (uword row = 0; row < x_n_rows; ++row) {
    for (uword col = 0; col < x_n_cols; ++col) {
      arma_ostream::raw_print_elem(f, x.at(row, col));

      if (col < (x_n_cols - 1)) {
        f.put(separator);
      }
    }

    f.put('\n');
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

//! Save a matrix in CSV text format (human readable); complex numbers stored in "a+bi"
//! format
template <typename T>
inline bool diskio::save_csv_ascii(const Mat<std::complex<T> >& x, std::ostream& f,
                                   const char separator) {
  arma_extra_debug_sigprint();

  typedef typename std::complex<T> eT;

  const arma_ostream_state stream_state(f);

  diskio::prepare_stream<eT>(f);

  uword x_n_rows = x.n_rows;
  uword x_n_cols = x.n_cols;

  for (uword row = 0; row < x_n_rows; ++row) {
    for (uword col = 0; col < x_n_cols; ++col) {
      const eT& val = x.at(row, col);

      const T tmp_r = std::real(val);
      const T tmp_i = std::imag(val);
      const T tmp_i_abs = (tmp_i < T(0)) ? T(-tmp_i) : T(tmp_i);
      const char tmp_sign = (tmp_i < T(0)) ? char('-') : char('+');

      arma_ostream::raw_print_elem(f, tmp_r);
      f.put(tmp_sign);
      arma_ostream::raw_print_elem(f, tmp_i_abs);
      f.put('i');

      if (col < (x_n_cols - 1)) {
        f.put(separator);
      }
    }

    f.put('\n');
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

template <typename eT>
inline bool diskio::save_coord_ascii(const Mat<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f;

  (arma_config::text_as_binary) ? f.open(tmp_name, std::fstream::binary)
                                : f.open(tmp_name);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_coord_ascii(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

template <typename eT>
inline bool diskio::save_coord_ascii(const Mat<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  const arma_ostream_state stream_state(f);

  diskio::prepare_stream<eT>(f);

  for (uword col = 0; col < x.n_cols; ++col)
    for (uword row = 0; row < x.n_rows; ++row) {
      const eT val = x.at(row, col);

      if (val != eT(0)) {
        f << row << ' ' << col << ' ' << val << '\n';
      }
    }

  // make sure it's possible to figure out the matrix size later
  if ((x.n_rows > 0) && (x.n_cols > 0)) {
    const uword max_row = (x.n_rows > 0) ? x.n_rows - 1 : 0;
    const uword max_col = (x.n_cols > 0) ? x.n_cols - 1 : 0;

    if (x.at(max_row, max_col) == eT(0)) {
      f << max_row << ' ' << max_col << " 0\n";
    }
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

template <typename T>
inline bool diskio::save_coord_ascii(const Mat<std::complex<T> >& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  typedef typename std::complex<T> eT;

  const arma_ostream_state stream_state(f);

  diskio::prepare_stream<eT>(f);

  const eT eT_zero = eT(0);

  for (uword col = 0; col < x.n_cols; ++col)
    for (uword row = 0; row < x.n_rows; ++row) {
      const eT& val = x.at(row, col);

      if (val != eT_zero) {
        f << row << ' ' << col << ' ' << val.real() << ' ' << val.imag() << '\n';
      }
    }

  // make sure it's possible to figure out the matrix size later
  if ((x.n_rows > 0) && (x.n_cols > 0)) {
    const uword max_row = (x.n_rows > 0) ? x.n_rows - 1 : 0;
    const uword max_col = (x.n_cols > 0) ? x.n_cols - 1 : 0;

    if (x.at(max_row, max_col) == eT_zero) {
      f << max_row << ' ' << max_col << " 0 0\n";
    }
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

//! Save a matrix in binary format,
//! with a header that stores the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_binary(const Mat<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f(tmp_name, std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_arma_binary(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

//! Save a matrix in binary format,
//! with a header that stores the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_binary(const Mat<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  f << diskio::gen_bin_header(x) << '\n';
  f << x.n_rows << ' ' << x.n_cols << '\n';

  f.write(reinterpret_cast<const char*>(x.mem), std::streamsize(x.n_elem * sizeof(eT)));

  return f.good();
}

//! Save a matrix as a PGM greyscale image
template <typename eT>
inline bool diskio::save_pgm_binary(const Mat<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::fstream f(tmp_name, std::fstream::out | std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_pgm_binary(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

//! Save a matrix as a PGM greyscale image
template <typename eT>
inline bool diskio::save_pgm_binary(const Mat<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  f << "P5" << '\n';
  f << x.n_cols << ' ' << x.n_rows << '\n';
  f << 255 << '\n';

  const uword n_elem = x.n_rows * x.n_cols;
  podarray<u8> tmp(n_elem);

  uword i = 0;

  for (uword row = 0; row < x.n_rows; ++row)
    for (uword col = 0; col < x.n_cols; ++col) {
      tmp[i] = u8(x.at(row, col));  // TODO: add round() ?
      ++i;
    }

  f.write(reinterpret_cast<const char*>(tmp.mem), std::streamsize(n_elem));

  return f.good();
}

//! Save a matrix as a PGM greyscale image
template <typename T>
inline bool diskio::save_pgm_binary(const Mat<std::complex<T> >& x,
                                    const std::string& final_name) {
  arma_extra_debug_sigprint();

  const uchar_mat tmp = conv_to<uchar_mat>::from(x);

  return diskio::save_pgm_binary(tmp, final_name);
}

//! Save a matrix as a PGM greyscale image
template <typename T>
inline bool diskio::save_pgm_binary(const Mat<std::complex<T> >& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  const uchar_mat tmp = conv_to<uchar_mat>::from(x);

  return diskio::save_pgm_binary(tmp, f);
}

//! Save a matrix as part of a HDF5 file
template <typename eT>
inline bool diskio::save_hdf5_binary(const Mat<eT>& x, const hdf5_name& spec,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

#if defined(ARMA_USE_HDF5)
  {
    hdf5_misc::hdf5_suspend_printing_errors hdf5_print_suspender;

    bool save_okay = false;

    const bool append = bool(spec.opts.flags & hdf5_opts::flag_append);
    const bool replace = bool(spec.opts.flags & hdf5_opts::flag_replace);

    const bool use_existing_file =
        ((append || replace) && (H5Fis_hdf5(spec.filename.c_str()) > 0));

    const std::string tmp_name =
        (use_existing_file) ? std::string() : diskio::gen_tmp_name(spec.filename);

    // Set up the file according to HDF5's preferences
    hid_t file =
        (use_existing_file)
            ? H5Fopen(spec.filename.c_str(), H5F_ACC_RDWR, H5P_DEFAULT)
            : H5Fcreate(tmp_name.c_str(), H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);

    if (file < 0) {
      return false;
    }

    // We need to create a dataset, datatype, and dataspace
    hsize_t dims[2];
    dims[1] = x.n_rows;
    dims[0] = x.n_cols;

    hid_t dataspace =
        H5Screate_simple(2, dims, NULL);  // treat the matrix as a 2d array dataspace
    hid_t datatype = hdf5_misc::get_hdf5_type<eT>();

    // If this returned something invalid, well, it's time to crash.
    arma_check(datatype == -1, "Mat::save(): unknown datatype for HDF5");

    // MATLAB forces the users to specify a name at save time for HDF5;
    // Octave will use the default of 'dataset' unless otherwise specified.
    // If the user hasn't specified a dataset name, we will use 'dataset'
    // We may have to split out the group name from the dataset name.
    std::vector<hid_t> groups;
    std::string full_name = spec.dsname;
    size_t loc;
    while ((loc = full_name.find("/")) != std::string::npos) {
      // Create another group...
      if (loc != 0)  // Ignore the first /, if there is a leading /.
      {
        hid_t gid = H5Gcreate((groups.size() == 0) ? file : groups[groups.size() - 1],
                              full_name.substr(0, loc).c_str(), H5P_DEFAULT, H5P_DEFAULT,
                              H5P_DEFAULT);

        if ((gid < 0) && use_existing_file) {
          gid = H5Gopen((groups.size() == 0) ? file : groups[groups.size() - 1],
                        full_name.substr(0, loc).c_str(), H5P_DEFAULT);
        }

        groups.push_back(gid);
      }

      full_name = full_name.substr(loc + 1);
    }

    const std::string dataset_name =
        full_name.empty() ? std::string("dataset") : full_name;

    const hid_t last_group = (groups.size() == 0) ? file : groups[groups.size() - 1];

    if (use_existing_file && replace) {
      H5Ldelete(last_group, dataset_name.c_str(), H5P_DEFAULT);
      // NOTE: H5Ldelete() in HDF5 v1.8 doesn't reclaim the deleted space; use h5repack to
      // reclaim space: h5repack oldfile.h5 newfile.h5 NOTE: has this behaviour changed in
      // HDF5 1.10 ? NOTE:
      // https://lists.hdfgroup.org/pipermail/hdf-forum_lists.hdfgroup.org/2017-August/010482.html
      // NOTE:
      // https://lists.hdfgroup.org/pipermail/hdf-forum_lists.hdfgroup.org/2017-August/010486.html
    }

    hid_t dataset = H5Dcreate(last_group, dataset_name.c_str(), datatype, dataspace,
                              H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);

    if (dataset < 0) {
      save_okay = false;

      err_msg = "failed to create dataset";
    } else {
      save_okay =
          (H5Dwrite(dataset, datatype, H5S_ALL, H5S_ALL, H5P_DEFAULT, x.mem) >= 0);

      H5Dclose(dataset);
    }

    H5Tclose(datatype);
    H5Sclose(dataspace);
    for (size_t i = 0; i < groups.size(); ++i) {
      H5Gclose(groups[i]);
    }
    H5Fclose(file);

    if ((use_existing_file == false) && (save_okay == true)) {
      save_okay = diskio::safe_rename(tmp_name, spec.filename);
    }

    return save_okay;
  }
#else
  {
    arma_ignore(x);
    arma_ignore(spec);
    arma_ignore(err_msg);

    arma_stop_logic_error("Mat::save(): use of HDF5 must be enabled");

    return false;
  }
#endif
}

//! Load a matrix as raw text (no header, human readable).
//! Can read matrices saved as text in Matlab and Octave.
//! NOTE: this is much slower than reading a file with a header.
template <typename eT>
inline bool diskio::load_raw_ascii(Mat<eT>& x, const std::string& name,
                                   std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;

  (arma_config::text_as_binary) ? f.open(name, std::fstream::binary) : f.open(name);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_raw_ascii(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

//! Load a matrix as raw text (no header, human readable).
//! Can read matrices saved as text in Matlab and Octave.
//! NOTE: this is much slower than reading a file with a header.
template <typename eT>
inline bool diskio::load_raw_ascii(Mat<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  bool load_okay = f.good();

  f.clear();
  const std::fstream::pos_type pos1 = f.tellg();

  //
  // work out the size

  uword f_n_rows = 0;
  uword f_n_cols = 0;

  bool f_n_cols_found = false;

  std::string line_string;
  std::stringstream line_stream;

  std::string token;

  while (f.good() && load_okay) {
    std::getline(f, line_string);

    // TODO: does it make sense to stop processing the file if an empty line is found ?
    if (line_string.size() == 0) {
      break;
    }

    line_stream.clear();
    line_stream.str(line_string);

    uword line_n_cols = 0;

    while (line_stream >> token) {
      ++line_n_cols;
    }

    if (f_n_cols_found == false) {
      f_n_cols = line_n_cols;
      f_n_cols_found = true;
    } else {
      if (line_n_cols != f_n_cols) {
        load_okay = false;
        err_msg = "inconsistent number of columns";
      }
    }

    ++f_n_rows;
  }

  if (load_okay) {
    f.clear();
    f.seekg(pos1);

    if (f.fail() || (f.tellg() != pos1)) {
      err_msg = "seek failure";
      return false;
    }

    try {
      x.set_size(f_n_rows, f_n_cols);
    } catch (...) {
      err_msg = "not enough memory";
      return false;
    }

    for (uword row = 0; ((row < x.n_rows) && load_okay); ++row)
      for (uword col = 0; ((col < x.n_cols) && load_okay); ++col) {
        f >> token;

        if (diskio::convert_token(x.at(row, col), token) == false) {
          load_okay = false;
          err_msg = "data interpretation failure";
        }
      }
  }

  // an empty file indicates an empty matrix
  if ((f_n_cols_found == false) && (load_okay == true)) {
    x.reset();
  }

  return load_okay;
}

//! Load a matrix in binary format (no header);
//! the matrix is assumed to have one column
template <typename eT>
inline bool diskio::load_raw_binary(Mat<eT>& x, const std::string& name,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;
  f.open(name, std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_raw_binary(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

template <typename eT>
inline bool diskio::load_raw_binary(Mat<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  f.clear();
  const std::streampos pos1 = f.tellg();

  f.clear();
  f.seekg(0, ios::end);

  f.clear();
  const std::streampos pos2 = f.tellg();

  const uword N = ((pos1 >= 0) && (pos2 >= 0)) ? uword(pos2 - pos1) : 0;

  f.clear();
  // f.seekg(0, ios::beg);
  f.seekg(pos1);

  if (f.fail() || (f.tellg() != pos1)) {
    err_msg = "seek failure";
    return false;
  }

  try {
    x.set_size(N / uword(sizeof(eT)), 1);
  } catch (...) {
    err_msg = "not enough memory";
    return false;
  }

  f.clear();
  f.read(reinterpret_cast<char*>(x.memptr()),
         std::streamsize(x.n_elem * uword(sizeof(eT))));

  return f.good();
}

//! Load a matrix in text format (human readable),
//! with a header that indicates the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::load_arma_ascii(Mat<eT>& x, const std::string& name,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;

  (arma_config::text_as_binary) ? f.open(name, std::fstream::binary) : f.open(name);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_arma_ascii(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

//! Load a matrix in text format (human readable),
//! with a header that indicates the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::load_arma_ascii(Mat<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::streampos pos = f.tellg();

  bool load_okay = true;

  std::string f_header;
  uword f_n_rows;
  uword f_n_cols;

  f >> f_header;
  f >> f_n_rows;
  f >> f_n_cols;

  if (f_header == diskio::gen_txt_header(x)) {
    try {
      x.zeros(f_n_rows, f_n_cols);
    } catch (...) {
      err_msg = "not enough memory";
      return false;
    }

    std::string token;

    for (uword row = 0; row < x.n_rows; ++row)
      for (uword col = 0; col < x.n_cols; ++col) {
        f >> token;

        diskio::convert_token(x.at(row, col), token);
      }

    load_okay = f.good();
  } else {
    load_okay = false;
    err_msg = "incorrect header";
  }

  // allow automatic conversion of u32/s32 matrices into u64/s64 matrices

  if (load_okay == false) {
    if ((sizeof(eT) == 8) && is_same_type<uword, eT>::yes) {
      Mat<u32> tmp;
      std::string junk;

      f.clear();
      f.seekg(pos);

      load_okay = diskio::load_arma_ascii(tmp, f, junk);

      if (load_okay) {
        x = conv_to<Mat<eT> >::from(tmp);
      }
    } else if ((sizeof(eT) == 8) && is_same_type<sword, eT>::yes) {
      Mat<s32> tmp;
      std::string junk;

      f.clear();
      f.seekg(pos);

      load_okay = diskio::load_arma_ascii(tmp, f, junk);

      if (load_okay) {
        x = conv_to<Mat<eT> >::from(tmp);
      }
    }
  }

  return load_okay;
}

//! Load a matrix in CSV text format (human readable)
template <typename eT>
inline bool diskio::load_csv_ascii(Mat<eT>& x, const std::string& name,
                                   std::string& err_msg, field<std::string>& header,
                                   const bool with_header, const char separator,
                                   const bool strict) {
  arma_extra_debug_sigprint();

  std::ifstream f;

  (arma_config::text_as_binary) ? f.open(name, std::fstream::binary) : f.open(name);

  bool load_okay = f.is_open();

  if (load_okay == false) {
    return false;
  }

  if (with_header) {
    arma_extra_debug_print("diskio::load_csv_ascii(): reading header");

    std::string header_line;
    std::stringstream header_stream;
    std::vector<std::string> header_tokens;

    std::getline(f, header_line);

    load_okay = f.good();

    if (load_okay) {
      std::string token;

      header_stream.clear();
      header_stream.str(header_line);

      uword header_n_tokens = 0;

      while (header_stream.good()) {
        std::getline(header_stream, token, separator);

        diskio::sanitise_token(token);

        ++header_n_tokens;

        header_tokens.push_back(token);
      }

      if (header_n_tokens == uword(0)) {
        header.reset();
      } else {
        header.set_size(1, header_n_tokens);

        for (uword i = 0; i < header_n_tokens; ++i) {
          header.at(i) = header_tokens[i];
        }
      }
    }
  }

  if (load_okay) {
    load_okay = diskio::load_csv_ascii(x, f, err_msg, separator, strict);
  }

  f.close();

  return load_okay;
}

//! Load a matrix in CSV text format (human readable)
template <typename eT>
inline bool diskio::load_csv_ascii(Mat<eT>& x, std::istream& f, std::string& err_msg,
                                   const char separator, const bool strict) {
  arma_extra_debug_sigprint();

  // TODO: replace with more efficient implementation

  if (f.good() == false) {
    return false;
  }

  f.clear();
  const std::fstream::pos_type pos1 = f.tellg();

  //
  // work out the size

  uword f_n_rows = 0;
  uword f_n_cols = 0;

  std::string line_string;
  std::stringstream line_stream;

  std::string token;

  while (f.good()) {
    std::getline(f, line_string);

    if (line_string.size() == 0) {
      break;
    }

    line_stream.clear();
    line_stream.str(line_string);

    uword line_n_cols = 0;

    while (line_stream.good()) {
      std::getline(line_stream, token, separator);
      ++line_n_cols;
    }

    if (f_n_cols < line_n_cols) {
      f_n_cols = line_n_cols;
    }

    ++f_n_rows;
  }

  f.clear();
  f.seekg(pos1);

  if (f.fail() || (f.tellg() != pos1)) {
    err_msg = "seek failure";
    return false;
  }

  try {
    x.zeros(f_n_rows, f_n_cols);
  } catch (...) {
    err_msg = "not enough memory";
    return false;
  }

  if (strict) {
    x.fill(Datum<eT>::nan);
  }  // take into account that each row may have a unique number of columns

  const bool use_mp = (arma_config::openmp) && (f_n_rows >= 2) && (f_n_cols >= 64);

  field<std::string> token_array;

  bool token_array_ok = false;

  if (use_mp) {
    try {
      token_array.set_size(f_n_cols);

      for (uword i = 0; i < f_n_cols; ++i) {
        token_array(i).reserve(32);
      }

      token_array_ok = true;
    } catch (...) {
      token_array.reset();
    }
  }

  if (use_mp && token_array_ok) {
#if defined(ARMA_USE_OPENMP)
    {
      uword row = 0;

      while (f.good()) {
        std::getline(f, line_string);

        if (line_string.size() == 0) {
          break;
        }

        line_stream.clear();
        line_stream.str(line_string);

        for (uword i = 0; i < f_n_cols; ++i) {
          token_array(i).clear();
        }

        uword line_stream_col = 0;

        while (line_stream.good()) {
          std::getline(line_stream, token_array(line_stream_col), separator);

          ++line_stream_col;
        }

        const int n_threads = mp_thread_limit::get();

#pragma omp parallel for schedule(static) num_threads(n_threads)
        for (uword col = 0; col < line_stream_col; ++col) {
          eT& out_val = x.at(row, col);

          (strict) ? diskio::convert_token_strict(out_val, token_array(col))
                   : diskio::convert_token(out_val, token_array(col));
        }

        ++row;
      }
    }
#endif
  } else  // serial implementation
  {
    uword row = 0;

    while (f.good()) {
      std::getline(f, line_string);

      if (line_string.size() == 0) {
        break;
      }

      line_stream.clear();
      line_stream.str(line_string);

      uword col = 0;

      while (line_stream.good()) {
        std::getline(line_stream, token, separator);

        eT& out_val = x.at(row, col);

        (strict) ? diskio::convert_token_strict(out_val, token)
                 : diskio::convert_token(out_val, token);

        ++col;
      }

      ++row;
    }
  }

  return true;
}

//! Load a matrix in CSV text format (human readable); complex numbers stored in "a+bi"
//! format
template <typename T>
inline bool diskio::load_csv_ascii(Mat<std::complex<T> >& x, std::istream& f,
                                   std::string& err_msg, const char separator,
                                   const bool strict) {
  arma_extra_debug_sigprint();

  // TODO: replace with more efficient implementation

  if (f.good() == false) {
    return false;
  }

  f.clear();
  const std::fstream::pos_type pos1 = f.tellg();

  //
  // work out the size

  uword f_n_rows = 0;
  uword f_n_cols = 0;

  std::string line_string;
  std::stringstream line_stream;

  std::string token;

  while (f.good()) {
    std::getline(f, line_string);

    if (line_string.size() == 0) {
      break;
    }

    line_stream.clear();
    line_stream.str(line_string);

    uword line_n_cols = 0;

    while (line_stream.good()) {
      std::getline(line_stream, token, separator);
      ++line_n_cols;
    }

    if (f_n_cols < line_n_cols) {
      f_n_cols = line_n_cols;
    }

    ++f_n_rows;
  }

  f.clear();
  f.seekg(pos1);

  if (f.fail() || (f.tellg() != pos1)) {
    err_msg = "seek failure";
    return false;
  }

  try {
    x.zeros(f_n_rows, f_n_cols);
  } catch (...) {
    err_msg = "not enough memory";
    return false;
  }

  if (strict) {
    x.fill(Datum<std::complex<T> >::nan);
  }  // take into account that each row may have a unique number of columns

  uword row = 0;

  std::string str_real;
  std::string str_imag;

  while (f.good()) {
    std::getline(f, line_string);

    if (line_string.size() == 0) {
      break;
    }

    line_stream.clear();
    line_stream.str(line_string);

    uword col = 0;

    while (line_stream.good()) {
      std::getline(line_stream, token, separator);

      diskio::sanitise_token(token);

      const size_t token_len = size_t(token.length());

      if (token_len == 0) {
        col++;
        continue;
      }

      // handle special cases: inf and nan, without the imaginary part
      if ((token_len == 3) || (token_len == 4)) {
        const char* str = token.c_str();

        const bool neg = (str[0] == '-');
        const bool pos = (str[0] == '+');

        const size_t offset = ((neg || pos) && (token_len == 4)) ? 1 : 0;

        const char sig_a = str[offset];
        const char sig_b = str[offset + 1];
        const char sig_c = str[offset + 2];

        bool found_val_real = false;
        T val_real = T(0);

        if (((sig_a == 'i') || (sig_a == 'I')) && ((sig_b == 'n') || (sig_b == 'N')) &&
            ((sig_c == 'f') || (sig_c == 'F'))) {
          val_real = (neg) ? -(Datum<T>::inf) : Datum<T>::inf;

          found_val_real = true;
        } else if (((sig_a == 'n') || (sig_a == 'N')) &&
                   ((sig_b == 'a') || (sig_b == 'A')) &&
                   ((sig_c == 'n') || (sig_c == 'N'))) {
          val_real = Datum<T>::nan;

          found_val_real = true;
        }

        if (found_val_real) {
          const T val_imag = (strict) ? T(Datum<T>::nan) : T(0);

          x.at(row, col) = std::complex<T>(val_real, val_imag);

          col++;
          continue;  // get next token
        }
      }

      bool found_x = false;
      std::string::size_type loc_x =
          0;  // location of the separator (+ or -) between the real and imaginary part

      std::string::size_type loc_i =
          token.find_last_of('i');  // location of the imaginary part indicator

      if (loc_i == std::string::npos) {
        str_real = token;
        str_imag.clear();
      } else {
        bool found_plus = false;
        bool found_minus = false;

        std::string::size_type loc_plus = token.find_last_of('+');

        if (loc_plus != std::string::npos) {
          if (loc_plus >= 1) {
            const char prev_char = token.at(loc_plus - 1);

            // make sure we're not looking at the sign of the exponent
            if ((prev_char != 'e') && (prev_char != 'E')) {
              found_plus = true;
            } else {
              // search again, omitting the exponent
              loc_plus = token.find_last_of('+', loc_plus - 1);

              if (loc_plus != std::string::npos) {
                found_plus = true;
              }
            }
          } else {
            // loc_plus == 0, meaning we're at the start of the string
            found_plus = true;
          }
        }

        std::string::size_type loc_minus = token.find_last_of('-');

        if (loc_minus != std::string::npos) {
          if (loc_minus >= 1) {
            const char prev_char = token.at(loc_minus - 1);

            // make sure we're not looking at the sign of the exponent
            if ((prev_char != 'e') && (prev_char != 'E')) {
              found_minus = true;
            } else {
              // search again, omitting the exponent
              loc_minus = token.find_last_of('-', loc_minus - 1);

              if (loc_minus != std::string::npos) {
                found_minus = true;
              }
            }
          } else {
            // loc_minus == 0, meaning we're at the start of the string
            found_minus = true;
          }
        }

        if (found_plus && found_minus) {
          if ((loc_i > loc_plus) && (loc_i > loc_minus)) {
            // choose the sign closest to the "i" to be the separator between the real and
            // imaginary part
            loc_x = ((loc_i - loc_plus) < (loc_i - loc_minus)) ? loc_plus : loc_minus;
            found_x = true;
          }
        } else if (found_plus) {
          loc_x = loc_plus;
          found_x = true;
        } else if (found_minus) {
          loc_x = loc_minus;
          found_x = true;
        }

        if (found_x) {
          if (loc_x > 0) {
            str_real = token.substr(0, loc_x);
          } else {
            str_real.clear();
          }
          if ((loc_x + 1) < token.size()) {
            str_imag = token.substr(loc_x, token.size() - loc_x - 1);
          } else {
            str_imag.clear();
          }
        } else {
          str_real.clear();
          str_imag.clear();
        }
      }

      T val_real = T(0);
      T val_imag = T(0);

      (strict) ? diskio::convert_token_strict(val_real, str_real)
               : diskio::convert_token(val_real, str_real);
      (strict) ? diskio::convert_token_strict(val_imag, str_imag)
               : diskio::convert_token(val_imag, str_imag);

      x.at(row, col) = std::complex<T>(val_real, val_imag);

      ++col;
    }

    ++row;
  }

  return true;
}

template <typename eT>
inline bool diskio::load_coord_ascii(Mat<eT>& x, const std::string& name,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;

  (arma_config::text_as_binary) ? f.open(name, std::fstream::binary) : f.open(name);

  bool load_okay = f.is_open();

  if (load_okay == false) {
    return false;
  }

  if (load_okay) {
    load_okay = diskio::load_coord_ascii(x, f, err_msg);
  }

  f.close();

  return load_okay;
}

//! Load a matrix in CSV text format (human readable)
template <typename eT>
inline bool diskio::load_coord_ascii(Mat<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  if (f.good() == false) {
    return false;
  }

  f.clear();
  const std::fstream::pos_type pos1 = f.tellg();

  // work out the size

  uword f_n_rows = 0;
  uword f_n_cols = 0;

  bool size_found = false;

  std::string line_string;
  std::stringstream line_stream;

  std::string token;

  while (f.good()) {
    std::getline(f, line_string);

    if (line_string.size() == 0) {
      break;
    }

    line_stream.clear();
    line_stream.str(line_string);

    uword line_row = 0;
    uword line_col = 0;

    // a valid line in co-ord format has at least 2 entries

    line_stream >> line_row;

    if (line_stream.good() == false) {
      err_msg = "incorrect format";
      return false;
    }

    line_stream >> line_col;

    size_found = true;

    if (f_n_rows < line_row) {
      f_n_rows = line_row;
    }
    if (f_n_cols < line_col) {
      f_n_cols = line_col;
    }
  }

  // take into account that indices start at 0
  if (size_found) {
    ++f_n_rows;
    ++f_n_cols;
  }

  f.clear();
  f.seekg(pos1);

  if (f.fail() || (f.tellg() != pos1)) {
    err_msg = "seek failure";
    return false;
  }

  try {
    Mat<eT> tmp(f_n_rows, f_n_cols, arma_zeros_indicator());

    while (f.good()) {
      std::getline(f, line_string);

      if (line_string.size() == 0) {
        break;
      }

      line_stream.clear();
      line_stream.str(line_string);

      uword line_row = 0;
      uword line_col = 0;

      line_stream >> line_row;
      line_stream >> line_col;

      eT val = eT(0);

      line_stream >> token;

      if (line_stream.fail() == false) {
        diskio::convert_token(val, token);
      }

      if (val != eT(0)) {
        tmp(line_row, line_col) = val;
      }
    }

    x.steal_mem(tmp);
  } catch (...) {
    err_msg = "not enough memory";
    return false;
  }

  return true;
}

template <typename T>
inline bool diskio::load_coord_ascii(Mat<std::complex<T> >& x, std::istream& f,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  if (f.good() == false) {
    return false;
  }

  f.clear();
  const std::fstream::pos_type pos1 = f.tellg();

  // work out the size

  uword f_n_rows = 0;
  uword f_n_cols = 0;

  bool size_found = false;

  std::string line_string;
  std::stringstream line_stream;

  std::string token_real;
  std::string token_imag;

  while (f.good()) {
    std::getline(f, line_string);

    if (line_string.size() == 0) {
      break;
    }

    line_stream.clear();
    line_stream.str(line_string);

    uword line_row = 0;
    uword line_col = 0;

    // a valid line in co-ord format has at least 2 entries

    line_stream >> line_row;

    if (line_stream.good() == false) {
      err_msg = "incorrect format";
      return false;
    }

    line_stream >> line_col;

    size_found = true;

    if (f_n_rows < line_row) f_n_rows = line_row;
    if (f_n_cols < line_col) f_n_cols = line_col;
  }

  // take into account that indices start at 0
  if (size_found) {
    ++f_n_rows;
    ++f_n_cols;
  }

  f.clear();
  f.seekg(pos1);

  if (f.fail() || (f.tellg() != pos1)) {
    err_msg = "seek failure";
    return false;
  }

  try {
    Mat<std::complex<T> > tmp(f_n_rows, f_n_cols, arma_zeros_indicator());

    while (f.good()) {
      std::getline(f, line_string);

      if (line_string.size() == 0) {
        break;
      }

      line_stream.clear();
      line_stream.str(line_string);

      uword line_row = 0;
      uword line_col = 0;

      line_stream >> line_row;
      line_stream >> line_col;

      T val_real = T(0);
      T val_imag = T(0);

      line_stream >> token_real;

      if (line_stream.fail() == false) {
        diskio::convert_token(val_real, token_real);
      }

      line_stream >> token_imag;

      if (line_stream.fail() == false) {
        diskio::convert_token(val_imag, token_imag);
      }

      if ((val_real != T(0)) || (val_imag != T(0))) {
        tmp(line_row, line_col) = std::complex<T>(val_real, val_imag);
      }
    }

    x.steal_mem(tmp);
  } catch (...) {
    err_msg = "not enough memory";
    return false;
  }

  return true;
}

//! Load a matrix in binary format,
//! with a header that indicates the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::load_arma_binary(Mat<eT>& x, const std::string& name,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;
  f.open(name, std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_arma_binary(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

template <typename eT>
inline bool diskio::load_arma_binary(Mat<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::streampos pos = f.tellg();

  bool load_okay = true;

  std::string f_header;
  uword f_n_rows;
  uword f_n_cols;

  f >> f_header;
  f >> f_n_rows;
  f >> f_n_cols;

  if (f_header == diskio::gen_bin_header(x)) {
    // f.seekg(1, ios::cur);  // NOTE: this may not be portable, as on a Windows machine a
    // newline could be two characters
    f.get();

    try {
      x.set_size(f_n_rows, f_n_cols);
    } catch (...) {
      err_msg = "not enough memory";
      return false;
    }

    f.read(reinterpret_cast<char*>(x.memptr()), std::streamsize(x.n_elem * sizeof(eT)));

    load_okay = f.good();
  } else {
    load_okay = false;
    err_msg = "incorrect header";
  }

  // allow automatic conversion of u32/s32 matrices into u64/s64 matrices

  if (load_okay == false) {
    if ((sizeof(eT) == 8) && is_same_type<uword, eT>::yes) {
      Mat<u32> tmp;
      std::string junk;

      f.clear();
      f.seekg(pos);

      load_okay = diskio::load_arma_binary(tmp, f, junk);

      if (load_okay) {
        x = conv_to<Mat<eT> >::from(tmp);
      }
    } else if ((sizeof(eT) == 8) && is_same_type<sword, eT>::yes) {
      Mat<s32> tmp;
      std::string junk;

      f.clear();
      f.seekg(pos);

      load_okay = diskio::load_arma_binary(tmp, f, junk);

      if (load_okay) {
        x = conv_to<Mat<eT> >::from(tmp);
      }
    }
  }

  return load_okay;
}

inline void diskio::pnm_skip_comments(std::istream& f) {
  while (isspace(f.peek())) {
    while (isspace(f.peek())) {
      f.get();
    }

    if (f.peek() == '#') {
      while ((f.peek() != '\r') && (f.peek() != '\n')) {
        f.get();
      }
    }
  }
}

//! Load a PGM greyscale image as a matrix
template <typename eT>
inline bool diskio::load_pgm_binary(Mat<eT>& x, const std::string& name,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::fstream f;
  f.open(name, std::fstream::in | std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_pgm_binary(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

//! Load a PGM greyscale image as a matrix
template <typename eT>
inline bool diskio::load_pgm_binary(Mat<eT>& x, std::istream& f, std::string& err_msg) {
  bool load_okay = true;

  std::string f_header;

  f >> f_header;

  if (f_header == "P5") {
    uword f_n_rows = 0;
    uword f_n_cols = 0;
    int f_maxval = 0;

    diskio::pnm_skip_comments(f);

    f >> f_n_cols;
    diskio::pnm_skip_comments(f);

    f >> f_n_rows;
    diskio::pnm_skip_comments(f);

    f >> f_maxval;
    f.get();

    if ((f_maxval > 0) && (f_maxval <= 65535)) {
      try {
        x.set_size(f_n_rows, f_n_cols);
      } catch (...) {
        err_msg = "not enough memory";
        return false;
      }

      if (f_maxval <= 255) {
        const uword n_elem = f_n_cols * f_n_rows;
        podarray<u8> tmp(n_elem);

        f.read(reinterpret_cast<char*>(tmp.memptr()), std::streamsize(n_elem));

        uword i = 0;

        // cout << "f_n_cols = " << f_n_cols << endl;
        // cout << "f_n_rows = " << f_n_rows << endl;

        for (uword row = 0; row < f_n_rows; ++row)
          for (uword col = 0; col < f_n_cols; ++col) {
            x.at(row, col) = eT(tmp[i]);
            ++i;
          }
      } else {
        const uword n_elem = f_n_cols * f_n_rows;
        podarray<u16> tmp(n_elem);

        f.read(reinterpret_cast<char*>(tmp.memptr()), std::streamsize(n_elem * 2));

        uword i = 0;

        for (uword row = 0; row < f_n_rows; ++row)
          for (uword col = 0; col < f_n_cols; ++col) {
            x.at(row, col) = eT(tmp[i]);
            ++i;
          }
      }
    } else {
      load_okay = false;
      err_msg = "functionality unimplemented";
    }

    if (f.good() == false) {
      load_okay = false;
    }
  } else {
    load_okay = false;
    err_msg = "unsupported header";
  }

  return load_okay;
}

//! Load a PGM greyscale image as a matrix
template <typename T>
inline bool diskio::load_pgm_binary(Mat<std::complex<T> >& x, const std::string& name,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  uchar_mat tmp;
  const bool load_okay = diskio::load_pgm_binary(tmp, name, err_msg);

  x = conv_to<Mat<std::complex<T> > >::from(tmp);

  return load_okay;
}

//! Load a PGM greyscale image as a matrix
template <typename T>
inline bool diskio::load_pgm_binary(Mat<std::complex<T> >& x, std::istream& is,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  uchar_mat tmp;
  const bool load_okay = diskio::load_pgm_binary(tmp, is, err_msg);

  x = conv_to<Mat<std::complex<T> > >::from(tmp);

  return load_okay;
}

//! Load a HDF5 file as a matrix
template <typename eT>
inline bool diskio::load_hdf5_binary(Mat<eT>& x, const hdf5_name& spec,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

#if defined(ARMA_USE_HDF5)
  {
    if (diskio::is_readable(spec.filename) == false) {
      return false;
    }

    hdf5_misc::hdf5_suspend_printing_errors hdf5_print_suspender;

    bool load_okay = false;

    hid_t fid = H5Fopen(spec.filename.c_str(), H5F_ACC_RDONLY, H5P_DEFAULT);

    if (fid >= 0) {
      // MATLAB HDF5 dataset names are user-specified;
      // Octave tends to store the datasets in a group, with the actual dataset being
      // referred to as "value". If the user hasn't specified a dataset, we will search
      // for "dataset" and "value", and if those are not found we will take the first
      // dataset we do find.

      std::vector<std::string> searchNames;

      const bool exact = (spec.dsname.empty() == false);

      if (exact) {
        searchNames.push_back(spec.dsname);
      } else {
        searchNames.push_back("dataset");
        searchNames.push_back("value");
      }

      hid_t dataset = hdf5_misc::search_hdf5_file(searchNames, fid, 2, exact);

      if (dataset >= 0) {
        hid_t filespace = H5Dget_space(dataset);

        // This must be <= 2 due to our search rules.
        const int ndims = H5Sget_simple_extent_ndims(filespace);

        hsize_t dims[2];
        const herr_t query_status = H5Sget_simple_extent_dims(filespace, dims, NULL);

        // arma_check(query_status < 0, "Mat::load(): cannot get size of HDF5 dataset");
        if (query_status < 0) {
          err_msg = "cannot get size of HDF5 dataset";

          H5Sclose(filespace);
          H5Dclose(dataset);
          H5Fclose(fid);

          return false;
        }

        if (ndims == 1) {
          dims[1] = 1;
        }  // Vector case; fake second dimension (one column).

        try {
          x.set_size(dims[1], dims[0]);
        } catch (...) {
          err_msg = "not enough memory";
          return false;
        }

        // Now we have to see what type is stored to figure out how to load it.
        hid_t datatype = H5Dget_type(dataset);
        hid_t mat_type = hdf5_misc::get_hdf5_type<eT>();

        // If these are the same type, it is simple.
        if (H5Tequal(datatype, mat_type) > 0) {
          // Load directly; H5S_ALL used so that we load the entire dataset.
          hid_t read_status = H5Dread(dataset, datatype, H5S_ALL, H5S_ALL, H5P_DEFAULT,
                                      void_ptr(x.memptr()));

          if (read_status >= 0) {
            load_okay = true;
          }
        } else {
          // Load into another array and convert its type accordingly.
          hid_t read_status =
              hdf5_misc::load_and_convert_hdf5(x.memptr(), dataset, datatype, x.n_elem);

          if (read_status >= 0) {
            load_okay = true;
          }
        }

        // Now clean up.
        H5Tclose(datatype);
        H5Tclose(mat_type);
        H5Sclose(filespace);
      }

      H5Dclose(dataset);

      H5Fclose(fid);

      if (load_okay == false) {
        err_msg = "unsupported or missing HDF5 data";
      }
    } else {
      err_msg = "cannot open";
    }

    return load_okay;
  }
#else
  {
    arma_ignore(x);
    arma_ignore(spec);
    arma_ignore(err_msg);

    arma_stop_logic_error("Mat::load(): use of HDF5 must be enabled");

    return false;
  }
#endif
}

//! Try to load a matrix by automatically determining its type
template <typename eT>
inline bool diskio::load_auto_detect(Mat<eT>& x, const std::string& name,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  if (diskio::is_readable(name) == false) {
    return false;
  }

#if defined(ARMA_USE_HDF5)
  // We're currently using the C bindings for the HDF5 library, which don't support C++
  // streams
  if (H5Fis_hdf5(name.c_str())) {
    return load_hdf5_binary(x, name, err_msg);
  }
#endif

  std::fstream f;
  f.open(name, std::fstream::in | std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_auto_detect(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

//! Try to load a matrix by automatically determining its type
template <typename eT>
inline bool diskio::load_auto_detect(Mat<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  const char* ARMA_MAT_TXT_str = "ARMA_MAT_TXT";
  const char* ARMA_MAT_BIN_str = "ARMA_MAT_BIN";
  const char* P5_str = "P5";

  const uword ARMA_MAT_TXT_len = uword(12);
  const uword ARMA_MAT_BIN_len = uword(12);
  const uword P5_len = uword(2);

  podarray<char> header(ARMA_MAT_TXT_len + 1);

  char* header_mem = header.memptr();

  std::streampos pos = f.tellg();

  f.read(header_mem, std::streamsize(ARMA_MAT_TXT_len));
  f.clear();
  f.seekg(pos);

  header_mem[ARMA_MAT_TXT_len] = '\0';

  if (std::strncmp(ARMA_MAT_TXT_str, header_mem, size_t(ARMA_MAT_TXT_len)) == 0) {
    return load_arma_ascii(x, f, err_msg);
  } else if (std::strncmp(ARMA_MAT_BIN_str, header_mem, size_t(ARMA_MAT_BIN_len)) == 0) {
    return load_arma_binary(x, f, err_msg);
  } else if (std::strncmp(P5_str, header_mem, size_t(P5_len)) == 0) {
    return load_pgm_binary(x, f, err_msg);
  } else {
    const file_type ft = guess_file_type_internal(f);

    switch (ft) {
      case csv_ascii:
        return load_csv_ascii(x, f, err_msg, char(','), false);
        break;

      case ssv_ascii:
        return load_csv_ascii(x, f, err_msg, char(';'), false);
        break;

      case raw_binary:
        return load_raw_binary(x, f, err_msg);
        break;

      case raw_ascii:
        return load_raw_ascii(x, f, err_msg);
        break;

      default:
        err_msg = "unknown data";
        return false;
    }
  }

  return false;
}

//
// sparse matrices
//

//! Save a sparse matrix in CSV format
template <typename eT>
inline bool diskio::save_csv_ascii(const SpMat<eT>& x, const std::string& final_name,
                                   const field<std::string>& header,
                                   const bool with_header, const char separator) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f;

  (arma_config::text_as_binary) ? f.open(tmp_name, std::fstream::binary)
                                : f.open(tmp_name);

  bool save_okay = f.is_open();

  if (save_okay == false) {
    return false;
  }

  if (with_header) {
    arma_extra_debug_print("diskio::save_csv_ascii(): writing header");

    for (uword i = 0; i < header.n_elem; ++i) {
      f << header(i);

      if (i != (header.n_elem - 1)) {
        f.put(separator);
      }
    }

    f.put('\n');

    save_okay = f.good();
  }

  if (save_okay) {
    save_okay = diskio::save_csv_ascii(x, f, separator);
  }

  f.flush();
  f.close();

  if (save_okay) {
    save_okay = diskio::safe_rename(tmp_name, final_name);
  }

  return save_okay;
}

//! Save a sparse matrix in CSV format
template <typename eT>
inline bool diskio::save_csv_ascii(const SpMat<eT>& x, std::ostream& f,
                                   const char separator) {
  arma_extra_debug_sigprint();

  const arma_ostream_state stream_state(f);

  diskio::prepare_stream<eT>(f);

  x.sync();

  uword x_n_rows = x.n_rows;
  uword x_n_cols = x.n_cols;

  const eT eT_zero = eT(0);

  for (uword row = 0; row < x_n_rows; ++row) {
    for (uword col = 0; col < x_n_cols; ++col) {
      const eT val = x.at(row, col);

      if (val == eT_zero) {
        f.put('0');
      } else {
        arma_ostream::raw_print_elem(f, val);
      }

      if (col < (x_n_cols - 1)) {
        f.put(separator);
      }
    }

    f.put('\n');
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

//! Save a sparse matrix in CSV format (complex numbers)
template <typename T>
inline bool diskio::save_csv_ascii(const SpMat<std::complex<T> >& x, std::ostream& f,
                                   const char separator) {
  arma_extra_debug_sigprint();

  arma_ignore(x);
  arma_ignore(f);
  arma_ignore(separator);

  arma_debug_warn_level(
      1, "saving complex sparse matrices as csv_ascii not yet implemented");

  return false;
}

//! Save a matrix in ASCII coord format
template <typename eT>
inline bool diskio::save_coord_ascii(const SpMat<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f;

  (arma_config::text_as_binary) ? f.open(tmp_name, std::fstream::binary)
                                : f.open(tmp_name);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_coord_ascii(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

//! Save a matrix in ASCII coord format
template <typename eT>
inline bool diskio::save_coord_ascii(const SpMat<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  const arma_ostream_state stream_state(f);

  diskio::prepare_stream<eT>(f);

  typename SpMat<eT>::const_iterator iter = x.begin();
  typename SpMat<eT>::const_iterator iter_end = x.end();

  for (; iter != iter_end; ++iter) {
    const eT val = (*iter);

    f << iter.row() << ' ' << iter.col() << ' ' << val << '\n';
  }

  // make sure it's possible to figure out the matrix size later
  if ((x.n_rows > 0) && (x.n_cols > 0)) {
    const uword max_row = (x.n_rows > 0) ? x.n_rows - 1 : 0;
    const uword max_col = (x.n_cols > 0) ? x.n_cols - 1 : 0;

    if (x.at(max_row, max_col) == eT(0)) {
      f << max_row << ' ' << max_col << " 0\n";
    }
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

//! Save a matrix in ASCII coord format (complex numbers)
template <typename T>
inline bool diskio::save_coord_ascii(const SpMat<std::complex<T> >& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  typedef typename std::complex<T> eT;

  const arma_ostream_state stream_state(f);

  diskio::prepare_stream<eT>(f);

  typename SpMat<eT>::const_iterator iter = x.begin();
  typename SpMat<eT>::const_iterator iter_end = x.end();

  for (; iter != iter_end; ++iter) {
    const eT val = (*iter);

    f << iter.row() << ' ' << iter.col() << ' ' << val.real() << ' ' << val.imag()
      << '\n';
  }

  // make sure it's possible to figure out the matrix size later
  if ((x.n_rows > 0) && (x.n_cols > 0)) {
    const uword max_row = (x.n_rows > 0) ? x.n_rows - 1 : 0;
    const uword max_col = (x.n_cols > 0) ? x.n_cols - 1 : 0;

    if (x.at(max_row, max_col) == eT(0)) {
      f << max_row << ' ' << max_col << " 0 0\n";
    }
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

//! Save a matrix in binary format,
//! with a header that stores the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_binary(const SpMat<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f(tmp_name, std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_arma_binary(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

//! Save a matrix in binary format,
//! with a header that stores the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_binary(const SpMat<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  f << diskio::gen_bin_header(x) << '\n';
  f << x.n_rows << ' ' << x.n_cols << ' ' << x.n_nonzero << '\n';

  f.write(reinterpret_cast<const char*>(x.values),
          std::streamsize(x.n_nonzero * sizeof(eT)));
  f.write(reinterpret_cast<const char*>(x.row_indices),
          std::streamsize(x.n_nonzero * sizeof(uword)));
  f.write(reinterpret_cast<const char*>(x.col_ptrs),
          std::streamsize((x.n_cols + 1) * sizeof(uword)));

  return f.good();
}

template <typename eT>
inline bool diskio::load_csv_ascii(SpMat<eT>& x, const std::string& name,
                                   std::string& err_msg, field<std::string>& header,
                                   const bool with_header, const char separator) {
  arma_extra_debug_sigprint();

  std::ifstream f;

  (arma_config::text_as_binary) ? f.open(name, std::fstream::binary) : f.open(name);

  bool load_okay = f.is_open();

  if (load_okay == false) {
    return false;
  }

  if (with_header) {
    arma_extra_debug_print("diskio::load_csv_ascii(): reading header");

    std::string header_line;
    std::stringstream header_stream;
    std::vector<std::string> header_tokens;

    std::getline(f, header_line);

    load_okay = f.good();

    if (load_okay) {
      std::string token;

      header_stream.clear();
      header_stream.str(header_line);

      uword header_n_tokens = 0;

      while (header_stream.good()) {
        std::getline(header_stream, token, separator);

        diskio::sanitise_token(token);

        ++header_n_tokens;

        header_tokens.push_back(token);
      }

      if (header_n_tokens == uword(0)) {
        header.reset();
      } else {
        header.set_size(1, header_n_tokens);

        for (uword i = 0; i < header_n_tokens; ++i) {
          header.at(i) = header_tokens[i];
        }
      }
    }
  }

  if (load_okay) {
    load_okay = diskio::load_csv_ascii(x, f, err_msg, separator);
  }

  f.close();

  return load_okay;
}

template <typename eT>
inline bool diskio::load_csv_ascii(SpMat<eT>& x, std::istream& f, std::string& err_msg,
                                   const char separator) {
  arma_extra_debug_sigprint();

  // TODO: replace with more efficient implementation

  if (f.good() == false) {
    return false;
  }

  f.clear();
  const std::fstream::pos_type pos1 = f.tellg();

  //
  // work out the size

  uword f_n_rows = 0;
  uword f_n_cols = 0;

  std::string line_string;
  std::stringstream line_stream;

  std::string token;

  while (f.good()) {
    std::getline(f, line_string);

    if (line_string.size() == 0) {
      break;
    }

    line_stream.clear();
    line_stream.str(line_string);

    uword line_n_cols = 0;

    while (line_stream.good()) {
      std::getline(line_stream, token, separator);
      ++line_n_cols;
    }

    if (f_n_cols < line_n_cols) {
      f_n_cols = line_n_cols;
    }

    ++f_n_rows;
  }

  f.clear();
  f.seekg(pos1);

  if (f.fail() || (f.tellg() != pos1)) {
    err_msg = "seek failure";
    return false;
  }

  try {
    MapMat<eT> tmp(f_n_rows, f_n_cols);

    uword row = 0;

    while (f.good()) {
      std::getline(f, line_string);

      if (line_string.size() == 0) {
        break;
      }

      line_stream.clear();
      line_stream.str(line_string);

      uword col = 0;

      while (line_stream.good()) {
        std::getline(line_stream, token, separator);

        eT val = eT(0);

        diskio::convert_token(val, token);

        if (val != eT(0)) {
          tmp(row, col) = val;
        }

        ++col;
      }

      ++row;
    }

    x = tmp;
  } catch (...) {
    err_msg = "not enough memory";
    return false;
  }

  return true;
}

template <typename T>
inline bool diskio::load_csv_ascii(SpMat<std::complex<T> >& x, std::istream& f,
                                   std::string& err_msg, const char separator) {
  arma_extra_debug_sigprint();

  arma_ignore(x);
  arma_ignore(f);
  arma_ignore(err_msg);
  arma_ignore(separator);

  arma_debug_warn_level(
      1, "loading complex sparse matrices as csv_ascii not yet implemented");

  return false;
}

template <typename eT>
inline bool diskio::load_coord_ascii(SpMat<eT>& x, const std::string& name,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;

  (arma_config::text_as_binary) ? f.open(name, std::fstream::binary) : f.open(name);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_coord_ascii(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

template <typename eT>
inline bool diskio::load_coord_ascii(SpMat<eT>& x, std::istream& f,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  if (f.good() == false) {
    return false;
  }

  f.clear();
  const std::fstream::pos_type pos1 = f.tellg();

  // work out the size

  uword f_n_rows = 0;
  uword f_n_cols = 0;

  bool size_found = false;

  std::string line_string;
  std::stringstream line_stream;

  std::string token;

  while (f.good()) {
    std::getline(f, line_string);

    if (line_string.size() == 0) {
      break;
    }

    line_stream.clear();
    line_stream.str(line_string);

    uword line_row = 0;
    uword line_col = 0;

    // a valid line in co-ord format has at least 2 entries

    line_stream >> line_row;

    if (line_stream.good() == false) {
      err_msg = "incorrect format";
      return false;
    }

    line_stream >> line_col;

    size_found = true;

    if (f_n_rows < line_row) {
      f_n_rows = line_row;
    }
    if (f_n_cols < line_col) {
      f_n_cols = line_col;
    }
  }

  // take into account that indices start at 0
  if (size_found) {
    ++f_n_rows;
    ++f_n_cols;
  }

  f.clear();
  f.seekg(pos1);

  if (f.fail() || (f.tellg() != pos1)) {
    err_msg = "seek failure";
    return false;
  }

  try {
    MapMat<eT> tmp(f_n_rows, f_n_cols);

    while (f.good()) {
      std::getline(f, line_string);

      if (line_string.size() == 0) {
        break;
      }

      line_stream.clear();
      line_stream.str(line_string);

      uword line_row = 0;
      uword line_col = 0;

      line_stream >> line_row;
      line_stream >> line_col;

      eT val = eT(0);

      line_stream >> token;

      if (line_stream.fail() == false) {
        diskio::convert_token(val, token);
      }

      if (val != eT(0)) {
        tmp(line_row, line_col) = val;
      }
    }

    x = tmp;
  } catch (...) {
    err_msg = "not enough memory";
    return false;
  }

  return true;
}

template <typename T>
inline bool diskio::load_coord_ascii(SpMat<std::complex<T> >& x, std::istream& f,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  if (f.good() == false) {
    return false;
  }

  f.clear();
  const std::fstream::pos_type pos1 = f.tellg();

  // work out the size

  uword f_n_rows = 0;
  uword f_n_cols = 0;

  bool size_found = false;

  std::string line_string;
  std::stringstream line_stream;

  std::string token_real;
  std::string token_imag;

  while (f.good()) {
    std::getline(f, line_string);

    if (line_string.size() == 0) {
      break;
    }

    line_stream.clear();
    line_stream.str(line_string);

    uword line_row = 0;
    uword line_col = 0;

    // a valid line in co-ord format has at least 2 entries

    line_stream >> line_row;

    if (line_stream.good() == false) {
      err_msg = "incorrect format";
      return false;
    }

    line_stream >> line_col;

    size_found = true;

    if (f_n_rows < line_row) f_n_rows = line_row;
    if (f_n_cols < line_col) f_n_cols = line_col;
  }

  // take into account that indices start at 0
  if (size_found) {
    ++f_n_rows;
    ++f_n_cols;
  }

  f.clear();
  f.seekg(pos1);

  if (f.fail() || (f.tellg() != pos1)) {
    err_msg = "seek failure";
    return false;
  }

  try {
    MapMat<std::complex<T> > tmp(f_n_rows, f_n_cols);

    while (f.good()) {
      std::getline(f, line_string);

      if (line_string.size() == 0) {
        break;
      }

      line_stream.clear();
      line_stream.str(line_string);

      uword line_row = 0;
      uword line_col = 0;

      line_stream >> line_row;
      line_stream >> line_col;

      T val_real = T(0);
      T val_imag = T(0);

      line_stream >> token_real;

      if (line_stream.fail() == false) {
        diskio::convert_token(val_real, token_real);
      }

      line_stream >> token_imag;

      if (line_stream.fail() == false) {
        diskio::convert_token(val_imag, token_imag);
      }

      if ((val_real != T(0)) || (val_imag != T(0))) {
        tmp(line_row, line_col) = std::complex<T>(val_real, val_imag);
      }
    }

    x = tmp;
  } catch (...) {
    err_msg = "not enough memory";
    return false;
  }

  return true;
}

//! Load a matrix in binary format,
//! with a header that indicates the matrix type as well as its dimensions
template <typename eT>
inline bool diskio::load_arma_binary(SpMat<eT>& x, const std::string& name,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;
  f.open(name, std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_arma_binary(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

template <typename eT>
inline bool diskio::load_arma_binary(SpMat<eT>& x, std::istream& f,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  bool load_okay = true;

  std::string f_header;

  f >> f_header;

  if (f_header == diskio::gen_bin_header(x)) {
    uword f_n_rows;
    uword f_n_cols;
    uword f_n_nz;

    f >> f_n_rows;
    f >> f_n_cols;
    f >> f_n_nz;

    // f.seekg(1, ios::cur);  // NOTE: this may not be portable, as on a Windows machine a
    // newline could be two characters
    f.get();

    try {
      x.reserve(f_n_rows, f_n_cols, f_n_nz);
    } catch (...) {
      err_msg = "not enough memory";
      return false;
    }

    f.read(reinterpret_cast<char*>(access::rwp(x.values)),
           std::streamsize(x.n_nonzero * sizeof(eT)));

    std::streampos pos = f.tellg();

    f.read(reinterpret_cast<char*>(access::rwp(x.row_indices)),
           std::streamsize(x.n_nonzero * sizeof(uword)));
    f.read(reinterpret_cast<char*>(access::rwp(x.col_ptrs)),
           std::streamsize((x.n_cols + 1) * sizeof(uword)));

    bool check1 = true;
    for (uword i = 0; i < x.n_nonzero; ++i) {
      if (x.values[i] == eT(0)) {
        check1 = false;
        break;
      }
    }
    bool check2 = true;
    for (uword i = 0; i < x.n_cols; ++i) {
      if (x.col_ptrs[i + 1] < x.col_ptrs[i]) {
        check2 = false;
        break;
      }
    }
    bool check3 = (x.col_ptrs[x.n_cols] == x.n_nonzero);

    if ((check1 == true) && ((check2 == false) || (check3 == false))) {
      if (sizeof(uword) == 8) {
        arma_extra_debug_print(
            "detected inconsistent data while loading; re-reading integer parts as u32");

        // inconstency could be due to a different uword size used during saving,
        // so try loading the row_indices and col_ptrs under the assumption of 32 bit
        // unsigned integers

        f.clear();
        f.seekg(pos);

        podarray<u32> tmp_a(x.n_nonzero);
        tmp_a.zeros();
        podarray<u32> tmp_b(x.n_cols + 1);
        tmp_b.zeros();

        f.read(reinterpret_cast<char*>(tmp_a.memptr()),
               std::streamsize(x.n_nonzero * sizeof(u32)));
        f.read(reinterpret_cast<char*>(tmp_b.memptr()),
               std::streamsize((x.n_cols + 1) * sizeof(u32)));

        check2 = true;
        for (uword i = 0; i < x.n_cols; ++i) {
          if (tmp_b[i + 1] < tmp_b[i]) {
            check2 = false;
            break;
          }
        }
        check3 = (tmp_b[x.n_cols] == x.n_nonzero);

        load_okay = f.good();

        if (load_okay && (check2 == true) && (check3 == true)) {
          arma_extra_debug_print("reading integer parts as u32 succeeded");

          arrayops::convert(access::rwp(x.row_indices), tmp_a.memptr(), x.n_nonzero);
          arrayops::convert(access::rwp(x.col_ptrs), tmp_b.memptr(), x.n_cols + 1);
        } else {
          arma_extra_debug_print("reading integer parts as u32 failed");
        }
      }
    }

    if ((check1 == false) || (check2 == false) || (check3 == false)) {
      load_okay = false;
      err_msg = "inconsistent data";
    } else {
      load_okay = f.good();
    }
  } else {
    load_okay = false;
    err_msg = "incorrect header";
  }

  return load_okay;
}

// cubes

//! Save a cube as raw text (no header, human readable).
template <typename eT>
inline bool diskio::save_raw_ascii(const Cube<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f;

  (arma_config::text_as_binary) ? f.open(tmp_name, std::fstream::binary)
                                : f.open(tmp_name);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = save_raw_ascii(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

//! Save a cube as raw text (no header, human readable).
template <typename eT>
inline bool diskio::save_raw_ascii(const Cube<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  const arma_ostream_state stream_state(f);

  const std::streamsize cell_width = diskio::prepare_stream<eT>(f);

  for (uword slice = 0; slice < x.n_slices; ++slice) {
    for (uword row = 0; row < x.n_rows; ++row) {
      for (uword col = 0; col < x.n_cols; ++col) {
        f.put(' ');

        if (is_real<eT>::value) {
          f.width(cell_width);
        }

        arma_ostream::raw_print_elem(f, x.at(row, col, slice));
      }

      f.put('\n');
    }
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

//! Save a cube as raw binary (no header)
template <typename eT>
inline bool diskio::save_raw_binary(const Cube<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f(tmp_name, std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_raw_binary(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

template <typename eT>
inline bool diskio::save_raw_binary(const Cube<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  f.write(reinterpret_cast<const char*>(x.mem), std::streamsize(x.n_elem * sizeof(eT)));

  return f.good();
}

//! Save a cube in text format (human readable),
//! with a header that indicates the cube type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_ascii(const Cube<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f;

  (arma_config::text_as_binary) ? f.open(tmp_name, std::fstream::binary)
                                : f.open(tmp_name);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_arma_ascii(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

//! Save a cube in text format (human readable),
//! with a header that indicates the cube type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_ascii(const Cube<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  const arma_ostream_state stream_state(f);

  f << diskio::gen_txt_header(x) << '\n';
  f << x.n_rows << ' ' << x.n_cols << ' ' << x.n_slices << '\n';

  const std::streamsize cell_width = diskio::prepare_stream<eT>(f);

  for (uword slice = 0; slice < x.n_slices; ++slice) {
    for (uword row = 0; row < x.n_rows; ++row) {
      for (uword col = 0; col < x.n_cols; ++col) {
        f.put(' ');

        if (is_real<eT>::value) {
          f.width(cell_width);
        }

        arma_ostream::raw_print_elem(f, x.at(row, col, slice));
      }

      f.put('\n');
    }
  }

  const bool save_okay = f.good();

  stream_state.restore(f);

  return save_okay;
}

//! Save a cube in binary format,
//! with a header that stores the cube type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_binary(const Cube<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f(tmp_name, std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_arma_binary(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

//! Save a cube in binary format,
//! with a header that stores the cube type as well as its dimensions
template <typename eT>
inline bool diskio::save_arma_binary(const Cube<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  f << diskio::gen_bin_header(x) << '\n';
  f << x.n_rows << ' ' << x.n_cols << ' ' << x.n_slices << '\n';

  f.write(reinterpret_cast<const char*>(x.mem), std::streamsize(x.n_elem * sizeof(eT)));

  return f.good();
}

//! Save a cube as part of a HDF5 file
template <typename eT>
inline bool diskio::save_hdf5_binary(const Cube<eT>& x, const hdf5_name& spec,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

#if defined(ARMA_USE_HDF5)
  {
    hdf5_misc::hdf5_suspend_printing_errors hdf5_print_suspender;

    bool save_okay = false;

    const bool append = bool(spec.opts.flags & hdf5_opts::flag_append);
    const bool replace = bool(spec.opts.flags & hdf5_opts::flag_replace);

    const bool use_existing_file =
        ((append || replace) && (H5Fis_hdf5(spec.filename.c_str()) > 0));

    const std::string tmp_name =
        (use_existing_file) ? std::string() : diskio::gen_tmp_name(spec.filename);

    // Set up the file according to HDF5's preferences
    hid_t file =
        (use_existing_file)
            ? H5Fopen(spec.filename.c_str(), H5F_ACC_RDWR, H5P_DEFAULT)
            : H5Fcreate(tmp_name.c_str(), H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);

    if (file < 0) {
      return false;
    }

    // We need to create a dataset, datatype, and dataspace
    hsize_t dims[3];
    dims[2] = x.n_rows;
    dims[1] = x.n_cols;
    dims[0] = x.n_slices;

    hid_t dataspace =
        H5Screate_simple(3, dims, NULL);  // treat the cube as a 3d array dataspace
    hid_t datatype = hdf5_misc::get_hdf5_type<eT>();

    // If this returned something invalid, well, it's time to crash.
    arma_check(datatype == -1, "Cube::save(): unknown datatype for HDF5");

    // MATLAB forces the users to specify a name at save time for HDF5;
    // Octave will use the default of 'dataset' unless otherwise specified.
    // If the user hasn't specified a dataset name, we will use 'dataset'
    // We may have to split out the group name from the dataset name.
    std::vector<hid_t> groups;
    std::string full_name = spec.dsname;
    size_t loc;
    while ((loc = full_name.find("/")) != std::string::npos) {
      // Create another group...
      if (loc != 0)  // Ignore the first /, if there is a leading /.
      {
        hid_t gid = H5Gcreate((groups.size() == 0) ? file : groups[groups.size() - 1],
                              full_name.substr(0, loc).c_str(), H5P_DEFAULT, H5P_DEFAULT,
                              H5P_DEFAULT);

        if ((gid < 0) && use_existing_file) {
          gid = H5Gopen((groups.size() == 0) ? file : groups[groups.size() - 1],
                        full_name.substr(0, loc).c_str(), H5P_DEFAULT);
        }

        groups.push_back(gid);
      }

      full_name = full_name.substr(loc + 1);
    }

    const std::string dataset_name =
        full_name.empty() ? std::string("dataset") : full_name;

    const hid_t last_group = (groups.size() == 0) ? file : groups[groups.size() - 1];

    if (use_existing_file && replace) {
      H5Ldelete(last_group, dataset_name.c_str(), H5P_DEFAULT);
      // NOTE: H5Ldelete() in HDF5 v1.8 doesn't reclaim the deleted space; use h5repack to
      // reclaim space: h5repack oldfile.h5 newfile.h5 NOTE: has this behaviour changed in
      // HDF5 1.10 ? NOTE:
      // https://lists.hdfgroup.org/pipermail/hdf-forum_lists.hdfgroup.org/2017-August/010482.html
      // NOTE:
      // https://lists.hdfgroup.org/pipermail/hdf-forum_lists.hdfgroup.org/2017-August/010486.html
    }

    hid_t dataset = H5Dcreate(last_group, dataset_name.c_str(), datatype, dataspace,
                              H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);

    if (dataset < 0) {
      save_okay = false;

      err_msg = "failed to create dataset";
    } else {
      save_okay =
          (H5Dwrite(dataset, datatype, H5S_ALL, H5S_ALL, H5P_DEFAULT, x.mem) >= 0);

      H5Dclose(dataset);
    }

    H5Tclose(datatype);
    H5Sclose(dataspace);
    for (size_t i = 0; i < groups.size(); ++i) {
      H5Gclose(groups[i]);
    }
    H5Fclose(file);

    if ((use_existing_file == false) && (save_okay == true)) {
      save_okay = diskio::safe_rename(tmp_name, spec.filename);
    }

    return save_okay;
  }
#else
  {
    arma_ignore(x);
    arma_ignore(spec);
    arma_ignore(err_msg);

    arma_stop_logic_error("Cube::save(): use of HDF5 must be enabled");

    return false;
  }
#endif
}

//! Load a cube as raw text (no header, human readable).
//! NOTE: this is much slower than reading a file with a header.
template <typename eT>
inline bool diskio::load_raw_ascii(Cube<eT>& x, const std::string& name,
                                   std::string& err_msg) {
  arma_extra_debug_sigprint();

  Mat<eT> tmp;
  const bool load_okay = diskio::load_raw_ascii(tmp, name, err_msg);

  if (load_okay) {
    if (tmp.is_empty() == false) {
      try {
        x.set_size(tmp.n_rows, tmp.n_cols, 1);
      } catch (...) {
        err_msg = "not enough memory";
        return false;
      }

      x.slice(0) = tmp;
    } else {
      x.reset();
    }
  }

  return load_okay;
}

//! Load a cube as raw text (no header, human readable).
//! NOTE: this is much slower than reading a file with a header.
template <typename eT>
inline bool diskio::load_raw_ascii(Cube<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  Mat<eT> tmp;
  const bool load_okay = diskio::load_raw_ascii(tmp, f, err_msg);

  if (load_okay) {
    if (tmp.is_empty() == false) {
      try {
        x.set_size(tmp.n_rows, tmp.n_cols, 1);
      } catch (...) {
        err_msg = "not enough memory";
        return false;
      }

      x.slice(0) = tmp;
    } else {
      x.reset();
    }
  }

  return load_okay;
}

//! Load a cube in binary format (no header);
//! the cube is assumed to have one slice with one column
template <typename eT>
inline bool diskio::load_raw_binary(Cube<eT>& x, const std::string& name,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;
  f.open(name, std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_raw_binary(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

template <typename eT>
inline bool diskio::load_raw_binary(Cube<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  f.clear();
  const std::streampos pos1 = f.tellg();

  f.clear();
  f.seekg(0, ios::end);

  f.clear();
  const std::streampos pos2 = f.tellg();

  const uword N = ((pos1 >= 0) && (pos2 >= 0)) ? uword(pos2 - pos1) : 0;

  f.clear();
  // f.seekg(0, ios::beg);
  f.seekg(pos1);

  try {
    x.set_size(N / uword(sizeof(eT)), 1, 1);
  } catch (...) {
    err_msg = "not enough memory";
    return false;
  }

  f.clear();
  f.read(reinterpret_cast<char*>(x.memptr()),
         std::streamsize(x.n_elem * uword(sizeof(eT))));

  return f.good();
}

//! Load a cube in text format (human readable),
//! with a header that indicates the cube type as well as its dimensions
template <typename eT>
inline bool diskio::load_arma_ascii(Cube<eT>& x, const std::string& name,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;

  (arma_config::text_as_binary) ? f.open(name, std::fstream::binary) : f.open(name);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_arma_ascii(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

//! Load a cube in text format (human readable),
//! with a header that indicates the cube type as well as its dimensions
template <typename eT>
inline bool diskio::load_arma_ascii(Cube<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::streampos pos = f.tellg();

  bool load_okay = true;

  std::string f_header;
  uword f_n_rows;
  uword f_n_cols;
  uword f_n_slices;

  f >> f_header;
  f >> f_n_rows;
  f >> f_n_cols;
  f >> f_n_slices;

  if (f_header == diskio::gen_txt_header(x)) {
    try {
      x.set_size(f_n_rows, f_n_cols, f_n_slices);
    } catch (...) {
      err_msg = "not enough memory";
      return false;
    }

    for (uword slice = 0; slice < x.n_slices; ++slice)
      for (uword row = 0; row < x.n_rows; ++row)
        for (uword col = 0; col < x.n_cols; ++col) {
          f >> x.at(row, col, slice);
        }

    load_okay = f.good();
  } else {
    load_okay = false;
    err_msg = "incorrect header";
  }

  // allow automatic conversion of u32/s32 cubes into u64/s64 cubes

  if (load_okay == false) {
    if ((sizeof(eT) == 8) && is_same_type<uword, eT>::yes) {
      Cube<u32> tmp;
      std::string junk;

      f.clear();
      f.seekg(pos);

      load_okay = diskio::load_arma_ascii(tmp, f, junk);

      if (load_okay) {
        x = conv_to<Cube<eT> >::from(tmp);
      }
    } else if ((sizeof(eT) == 8) && is_same_type<sword, eT>::yes) {
      Cube<s32> tmp;
      std::string junk;

      f.clear();
      f.seekg(pos);

      load_okay = diskio::load_arma_ascii(tmp, f, junk);

      if (load_okay) {
        x = conv_to<Cube<eT> >::from(tmp);
      }
    }
  }

  return load_okay;
}

//! Load a cube in binary format,
//! with a header that indicates the cube type as well as its dimensions
template <typename eT>
inline bool diskio::load_arma_binary(Cube<eT>& x, const std::string& name,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f;
  f.open(name, std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_arma_binary(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

template <typename eT>
inline bool diskio::load_arma_binary(Cube<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::streampos pos = f.tellg();

  bool load_okay = true;

  std::string f_header;
  uword f_n_rows;
  uword f_n_cols;
  uword f_n_slices;

  f >> f_header;
  f >> f_n_rows;
  f >> f_n_cols;
  f >> f_n_slices;

  if (f_header == diskio::gen_bin_header(x)) {
    // f.seekg(1, ios::cur);  // NOTE: this may not be portable, as on a Windows machine a
    // newline could be two characters
    f.get();

    try {
      x.set_size(f_n_rows, f_n_cols, f_n_slices);
    } catch (...) {
      err_msg = "not enough memory";
      return false;
    }

    f.read(reinterpret_cast<char*>(x.memptr()), std::streamsize(x.n_elem * sizeof(eT)));

    load_okay = f.good();
  } else {
    load_okay = false;
    err_msg = "incorrect header";
  }

  // allow automatic conversion of u32/s32 cubes into u64/s64 cubes

  if (load_okay == false) {
    if ((sizeof(eT) == 8) && is_same_type<uword, eT>::yes) {
      Cube<u32> tmp;
      std::string junk;

      f.clear();
      f.seekg(pos);

      load_okay = diskio::load_arma_binary(tmp, f, junk);

      if (load_okay) {
        x = conv_to<Cube<eT> >::from(tmp);
      }
    } else if ((sizeof(eT) == 8) && is_same_type<sword, eT>::yes) {
      Cube<s32> tmp;
      std::string junk;

      f.clear();
      f.seekg(pos);

      load_okay = diskio::load_arma_binary(tmp, f, junk);

      if (load_okay) {
        x = conv_to<Cube<eT> >::from(tmp);
      }
    }
  }

  return load_okay;
}

//! Load a HDF5 file as a cube
template <typename eT>
inline bool diskio::load_hdf5_binary(Cube<eT>& x, const hdf5_name& spec,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

#if defined(ARMA_USE_HDF5)
  {
    if (diskio::is_readable(spec.filename) == false) {
      return false;
    }

    hdf5_misc::hdf5_suspend_printing_errors hdf5_print_suspender;

    bool load_okay = false;

    hid_t fid = H5Fopen(spec.filename.c_str(), H5F_ACC_RDONLY, H5P_DEFAULT);

    if (fid >= 0) {
      // MATLAB HDF5 dataset names are user-specified;
      // Octave tends to store the datasets in a group, with the actual dataset being
      // referred to as "value". If the user hasn't specified a dataset, we will search
      // for "dataset" and "value", and if those are not found we will take the first
      // dataset we do find.

      std::vector<std::string> searchNames;

      const bool exact = (spec.dsname.empty() == false);

      if (exact) {
        searchNames.push_back(spec.dsname);
      } else {
        searchNames.push_back("dataset");
        searchNames.push_back("value");
      }

      hid_t dataset = hdf5_misc::search_hdf5_file(searchNames, fid, 3, exact);

      if (dataset >= 0) {
        hid_t filespace = H5Dget_space(dataset);

        // This must be <= 3 due to our search rules.
        const int ndims = H5Sget_simple_extent_ndims(filespace);

        hsize_t dims[3];
        const herr_t query_status = H5Sget_simple_extent_dims(filespace, dims, NULL);

        // arma_check(query_status < 0, "Cube::load(): cannot get size of HDF5 dataset");
        if (query_status < 0) {
          err_msg = "cannot get size of HDF5 dataset";

          H5Sclose(filespace);
          H5Dclose(dataset);
          H5Fclose(fid);

          return false;
        }

        if (ndims == 1) {
          dims[1] = 1;
          dims[2] = 1;
        }  // Vector case; one row/colum, several slices
        if (ndims == 2) {
          dims[2] = 1;
        }  // Matrix case; one column, several rows/slices

        try {
          x.set_size(dims[2], dims[1], dims[0]);
        } catch (...) {
          err_msg = "not enough memory";
          return false;
        }

        // Now we have to see what type is stored to figure out how to load it.
        hid_t datatype = H5Dget_type(dataset);
        hid_t mat_type = hdf5_misc::get_hdf5_type<eT>();

        // If these are the same type, it is simple.
        if (H5Tequal(datatype, mat_type) > 0) {
          // Load directly; H5S_ALL used so that we load the entire dataset.
          hid_t read_status = H5Dread(dataset, datatype, H5S_ALL, H5S_ALL, H5P_DEFAULT,
                                      void_ptr(x.memptr()));

          if (read_status >= 0) {
            load_okay = true;
          }
        } else {
          // Load into another array and convert its type accordingly.
          hid_t read_status =
              hdf5_misc::load_and_convert_hdf5(x.memptr(), dataset, datatype, x.n_elem);

          if (read_status >= 0) {
            load_okay = true;
          }
        }

        // Now clean up.
        H5Tclose(datatype);
        H5Tclose(mat_type);
        H5Sclose(filespace);
      }

      H5Dclose(dataset);

      H5Fclose(fid);

      if (load_okay == false) {
        err_msg = "unsupported or missing HDF5 data";
      }
    } else {
      err_msg = "cannot open";
    }

    return load_okay;
  }
#else
  {
    arma_ignore(x);
    arma_ignore(spec);
    arma_ignore(err_msg);

    arma_stop_logic_error("Cube::load(): use of HDF5 must be enabled");

    return false;
  }
#endif
}

//! Try to load a cube by automatically determining its type
template <typename eT>
inline bool diskio::load_auto_detect(Cube<eT>& x, const std::string& name,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  if (diskio::is_readable(name) == false) {
    return false;
  }

#if defined(ARMA_USE_HDF5)
  // We're currently using the C bindings for the HDF5 library, which don't support C++
  // streams
  if (H5Fis_hdf5(name.c_str())) {
    return load_hdf5_binary(x, name, err_msg);
  }
#endif

  std::fstream f;
  f.open(name, std::fstream::in | std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_auto_detect(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

//! Try to load a cube by automatically determining its type
template <typename eT>
inline bool diskio::load_auto_detect(Cube<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  const char* ARMA_CUB_TXT_str = "ARMA_CUB_TXT";
  const char* ARMA_CUB_BIN_str = "ARMA_CUB_BIN";
  const char* P6_str = "P6";

  const uword ARMA_CUB_TXT_len = uword(12);
  const uword ARMA_CUB_BIN_len = uword(12);
  const uword P6_len = uword(2);

  podarray<char> header(ARMA_CUB_TXT_len + 1);

  char* header_mem = header.memptr();

  std::streampos pos = f.tellg();

  f.read(header_mem, std::streamsize(ARMA_CUB_TXT_len));
  f.clear();
  f.seekg(pos);

  header_mem[ARMA_CUB_TXT_len] = '\0';

  if (std::strncmp(ARMA_CUB_TXT_str, header_mem, size_t(ARMA_CUB_TXT_len)) == 0) {
    return load_arma_ascii(x, f, err_msg);
  } else if (std::strncmp(ARMA_CUB_BIN_str, header_mem, size_t(ARMA_CUB_BIN_len)) == 0) {
    return load_arma_binary(x, f, err_msg);
  } else if (std::strncmp(P6_str, header_mem, size_t(P6_len)) == 0) {
    return load_ppm_binary(x, f, err_msg);
  } else {
    const file_type ft = guess_file_type_internal(f);

    switch (ft) {
        // case csv_ascii:
        //   return load_csv_ascii(x, f, err_msg);
        //   break;

      case raw_binary:
        return load_raw_binary(x, f, err_msg);
        break;

      case raw_ascii:
        return load_raw_ascii(x, f, err_msg);
        break;

      default:
        err_msg = "unknown data";
        return false;
    }
  }

  return false;
}

// fields

template <typename T1>
inline bool diskio::save_arma_binary(const field<T1>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f(tmp_name, std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_arma_binary(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

template <typename T1>
inline bool diskio::save_arma_binary(const field<T1>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  arma_type_check(((is_Mat<T1>::value == false) && (is_Cube<T1>::value == false)));

  if (x.n_slices <= 1) {
    f << "ARMA_FLD_BIN" << '\n';
    f << x.n_rows << '\n';
    f << x.n_cols << '\n';
  } else {
    f << "ARMA_FL3_BIN" << '\n';
    f << x.n_rows << '\n';
    f << x.n_cols << '\n';
    f << x.n_slices << '\n';
  }

  bool save_okay = true;

  for (uword i = 0; i < x.n_elem; ++i) {
    save_okay = diskio::save_arma_binary(x[i], f);

    if (save_okay == false) {
      break;
    }
  }

  return save_okay;
}

template <typename T1>
inline bool diskio::load_arma_binary(field<T1>& x, const std::string& name,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f(name, std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_arma_binary(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

template <typename T1>
inline bool diskio::load_arma_binary(field<T1>& x, std::istream& f,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  arma_type_check(((is_Mat<T1>::value == false) && (is_Cube<T1>::value == false)));

  bool load_okay = true;

  std::string f_type;
  f >> f_type;

  if (f_type == "ARMA_FLD_BIN") {
    uword f_n_rows;
    uword f_n_cols;

    f >> f_n_rows;
    f >> f_n_cols;

    try {
      x.set_size(f_n_rows, f_n_cols);
    } catch (...) {
      err_msg = "not enough memory";
      return false;
    }

    f.get();

    for (uword i = 0; i < x.n_elem; ++i) {
      load_okay = diskio::load_arma_binary(x[i], f, err_msg);

      if (load_okay == false) {
        break;
      }
    }
  } else if (f_type == "ARMA_FL3_BIN") {
    uword f_n_rows;
    uword f_n_cols;
    uword f_n_slices;

    f >> f_n_rows;
    f >> f_n_cols;
    f >> f_n_slices;

    try {
      x.set_size(f_n_rows, f_n_cols, f_n_slices);
    } catch (...) {
      err_msg = "not enough memory";
      return false;
    }

    f.get();

    for (uword i = 0; i < x.n_elem; ++i) {
      load_okay = diskio::load_arma_binary(x[i], f, err_msg);

      if (load_okay == false) {
        break;
      }
    }
  } else {
    load_okay = false;
    err_msg = "unsupported field type";
  }

  return load_okay;
}

inline bool diskio::save_std_string(const field<std::string>& x,
                                    const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f(tmp_name, std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_std_string(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

inline bool diskio::save_std_string(const field<std::string>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  for (uword row = 0; row < x.n_rows; ++row)
    for (uword col = 0; col < x.n_cols; ++col) {
      f << x.at(row, col);

      if (col < x.n_cols - 1) {
        f << ' ';
      } else {
        f << '\n';
      }
    }

  return f.good();
}

inline bool diskio::load_std_string(field<std::string>& x, const std::string& name,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::ifstream f(name);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_std_string(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

inline bool diskio::load_std_string(field<std::string>& x, std::istream& f,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  bool load_okay = true;

  //
  // work out the size

  uword f_n_rows = 0;
  uword f_n_cols = 0;

  bool f_n_cols_found = false;

  std::string line_string;
  std::string token;

  while (f.good() && load_okay) {
    std::getline(f, line_string);

    if (line_string.size() == 0) {
      break;
    }

    std::stringstream line_stream(line_string);

    uword line_n_cols = 0;

    while (line_stream >> token) {
      line_n_cols++;
    }

    if (f_n_cols_found == false) {
      f_n_cols = line_n_cols;
      f_n_cols_found = true;
    } else {
      if (line_n_cols != f_n_cols) {
        load_okay = false;
        err_msg = "inconsistent number of columns";
      }
    }

    ++f_n_rows;
  }

  if (load_okay) {
    f.clear();
    f.seekg(0, ios::beg);
    // f.seekg(start);

    try {
      x.set_size(f_n_rows, f_n_cols);
    } catch (...) {
      err_msg = "not enough memory";
      return false;
    }

    for (uword row = 0; row < x.n_rows; ++row)
      for (uword col = 0; col < x.n_cols; ++col) {
        f >> x.at(row, col);
      }
  }

  if (f.good() == false) {
    load_okay = false;
  }

  return load_okay;
}

//! Try to load a field by automatically determining its type
template <typename T1>
inline bool diskio::load_auto_detect(field<T1>& x, const std::string& name,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::fstream f;
  f.open(name, std::fstream::in | std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_auto_detect(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

//! Try to load a field by automatically determining its type
template <typename T1>
inline bool diskio::load_auto_detect(field<T1>& x, std::istream& f,
                                     std::string& err_msg) {
  arma_extra_debug_sigprint();

  arma_type_check((is_Mat<T1>::value == false));

  static const std::string ARMA_FLD_BIN = "ARMA_FLD_BIN";
  static const std::string ARMA_FL3_BIN = "ARMA_FL3_BIN";
  static const std::string P6 = "P6";

  podarray<char> raw_header(uword(ARMA_FLD_BIN.length()) + 1);

  std::streampos pos = f.tellg();

  f.read(raw_header.memptr(), std::streamsize(ARMA_FLD_BIN.length()));

  f.clear();
  f.seekg(pos);

  raw_header[uword(ARMA_FLD_BIN.length())] = '\0';

  const std::string header = raw_header.mem;

  if (ARMA_FLD_BIN == header.substr(0, ARMA_FLD_BIN.length())) {
    return load_arma_binary(x, f, err_msg);
  } else if (ARMA_FL3_BIN == header.substr(0, ARMA_FL3_BIN.length())) {
    return load_arma_binary(x, f, err_msg);
  } else if (P6 == header.substr(0, P6.length())) {
    return load_ppm_binary(x, f, err_msg);
  } else {
    err_msg = "unsupported header";
    return false;
  }
}

//
// handling of PPM images by cubes

template <typename eT>
inline bool diskio::load_ppm_binary(Cube<eT>& x, const std::string& name,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::fstream f;
  f.open(name, std::fstream::in | std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_ppm_binary(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

template <typename eT>
inline bool diskio::load_ppm_binary(Cube<eT>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  bool load_okay = true;

  std::string f_header;

  f >> f_header;

  if (f_header == "P6") {
    uword f_n_rows = 0;
    uword f_n_cols = 0;
    int f_maxval = 0;

    diskio::pnm_skip_comments(f);

    f >> f_n_cols;
    diskio::pnm_skip_comments(f);

    f >> f_n_rows;
    diskio::pnm_skip_comments(f);

    f >> f_maxval;
    f.get();

    if ((f_maxval > 0) && (f_maxval <= 65535)) {
      try {
        x.set_size(f_n_rows, f_n_cols, 3);
      } catch (...) {
        err_msg = "not enough memory";
        return false;
      }

      if (f_maxval <= 255) {
        const uword n_elem = 3 * f_n_cols * f_n_rows;
        podarray<u8> tmp(n_elem);

        f.read(reinterpret_cast<char*>(tmp.memptr()), std::streamsize(n_elem));

        uword i = 0;

        // cout << "f_n_cols = " << f_n_cols << endl;
        // cout << "f_n_rows = " << f_n_rows << endl;

        for (uword row = 0; row < f_n_rows; ++row)
          for (uword col = 0; col < f_n_cols; ++col) {
            x.at(row, col, 0) = eT(tmp[i + 0]);
            x.at(row, col, 1) = eT(tmp[i + 1]);
            x.at(row, col, 2) = eT(tmp[i + 2]);
            i += 3;
          }
      } else {
        const uword n_elem = 3 * f_n_cols * f_n_rows;
        podarray<u16> tmp(n_elem);

        f.read(reinterpret_cast<char*>(tmp.memptr()), std::streamsize(2 * n_elem));

        uword i = 0;

        for (uword row = 0; row < f_n_rows; ++row)
          for (uword col = 0; col < f_n_cols; ++col) {
            x.at(row, col, 0) = eT(tmp[i + 0]);
            x.at(row, col, 1) = eT(tmp[i + 1]);
            x.at(row, col, 2) = eT(tmp[i + 2]);
            i += 3;
          }
      }
    } else {
      load_okay = false;
      err_msg = "functionality unimplemented";
    }

    if (f.good() == false) {
      load_okay = false;
    }
  } else {
    load_okay = false;
    err_msg = "unsupported header";
  }

  return load_okay;
}

template <typename eT>
inline bool diskio::save_ppm_binary(const Cube<eT>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);

  std::ofstream f(tmp_name, std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_ppm_binary(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

template <typename eT>
inline bool diskio::save_ppm_binary(const Cube<eT>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  arma_debug_check((x.n_slices != 3),
                   "diskio::save_ppm_binary(): given cube must have exactly 3 slices");

  const uword n_elem = 3 * x.n_rows * x.n_cols;
  podarray<u8> tmp(n_elem);

  uword i = 0;
  for (uword row = 0; row < x.n_rows; ++row) {
    for (uword col = 0; col < x.n_cols; ++col) {
      tmp[i + 0] = u8(access::tmp_real(x.at(row, col, 0)));
      tmp[i + 1] = u8(access::tmp_real(x.at(row, col, 1)));
      tmp[i + 2] = u8(access::tmp_real(x.at(row, col, 2)));

      i += 3;
    }
  }

  f << "P6" << '\n';
  f << x.n_cols << '\n';
  f << x.n_rows << '\n';
  f << 255 << '\n';

  f.write(reinterpret_cast<const char*>(tmp.mem), std::streamsize(n_elem));

  return f.good();
}

//
// handling of PPM images by fields

template <typename T1>
inline bool diskio::load_ppm_binary(field<T1>& x, const std::string& name,
                                    std::string& err_msg) {
  arma_extra_debug_sigprint();

  std::fstream f;
  f.open(name, std::fstream::in | std::fstream::binary);

  bool load_okay = f.is_open();

  if (load_okay) {
    load_okay = diskio::load_ppm_binary(x, f, err_msg);
    f.close();
  }

  return load_okay;
}

template <typename T1>
inline bool diskio::load_ppm_binary(field<T1>& x, std::istream& f, std::string& err_msg) {
  arma_extra_debug_sigprint();

  arma_type_check((is_Mat<T1>::value == false));
  typedef typename T1::elem_type eT;

  bool load_okay = true;

  std::string f_header;

  f >> f_header;

  if (f_header == "P6") {
    uword f_n_rows = 0;
    uword f_n_cols = 0;
    int f_maxval = 0;

    diskio::pnm_skip_comments(f);

    f >> f_n_cols;
    diskio::pnm_skip_comments(f);

    f >> f_n_rows;
    diskio::pnm_skip_comments(f);

    f >> f_maxval;
    f.get();

    if ((f_maxval > 0) && (f_maxval <= 65535)) {
      x.set_size(3);
      Mat<eT>& R = x(0);
      Mat<eT>& G = x(1);
      Mat<eT>& B = x(2);

      try {
        R.set_size(f_n_rows, f_n_cols);
      } catch (...) {
        err_msg = "not enough memory";
        return false;
      }
      try {
        G.set_size(f_n_rows, f_n_cols);
      } catch (...) {
        err_msg = "not enough memory";
        return false;
      }
      try {
        B.set_size(f_n_rows, f_n_cols);
      } catch (...) {
        err_msg = "not enough memory";
        return false;
      }

      if (f_maxval <= 255) {
        const uword n_elem = 3 * f_n_cols * f_n_rows;
        podarray<u8> tmp(n_elem);

        f.read(reinterpret_cast<char*>(tmp.memptr()), std::streamsize(n_elem));

        uword i = 0;

        // cout << "f_n_cols = " << f_n_cols << endl;
        // cout << "f_n_rows = " << f_n_rows << endl;

        for (uword row = 0; row < f_n_rows; ++row) {
          for (uword col = 0; col < f_n_cols; ++col) {
            R.at(row, col) = eT(tmp[i + 0]);
            G.at(row, col) = eT(tmp[i + 1]);
            B.at(row, col) = eT(tmp[i + 2]);
            i += 3;
          }
        }
      } else {
        const uword n_elem = 3 * f_n_cols * f_n_rows;
        podarray<u16> tmp(n_elem);

        f.read(reinterpret_cast<char*>(tmp.memptr()), std::streamsize(2 * n_elem));

        uword i = 0;

        for (uword row = 0; row < f_n_rows; ++row)
          for (uword col = 0; col < f_n_cols; ++col) {
            R.at(row, col) = eT(tmp[i + 0]);
            G.at(row, col) = eT(tmp[i + 1]);
            B.at(row, col) = eT(tmp[i + 2]);
            i += 3;
          }
      }
    } else {
      load_okay = false;
      err_msg = "functionality unimplemented";
    }

    if (f.good() == false) {
      load_okay = false;
    }
  } else {
    load_okay = false;
    err_msg = "unsupported header";
  }

  return load_okay;
}

template <typename T1>
inline bool diskio::save_ppm_binary(const field<T1>& x, const std::string& final_name) {
  arma_extra_debug_sigprint();

  const std::string tmp_name = diskio::gen_tmp_name(final_name);
  std::ofstream f(tmp_name, std::fstream::binary);

  bool save_okay = f.is_open();

  if (save_okay) {
    save_okay = diskio::save_ppm_binary(x, f);

    f.flush();
    f.close();

    if (save_okay) {
      save_okay = diskio::safe_rename(tmp_name, final_name);
    }
  }

  return save_okay;
}

template <typename T1>
inline bool diskio::save_ppm_binary(const field<T1>& x, std::ostream& f) {
  arma_extra_debug_sigprint();

  arma_type_check((is_Mat<T1>::value == false));

  typedef typename T1::elem_type eT;

  arma_debug_check((x.n_elem != 3),
                   "diskio::save_ppm_binary(): given field must have exactly 3 matrices "
                   "of equal size");

  bool same_size = true;
  for (uword i = 1; i < 3; ++i) {
    if ((x(0).n_rows != x(i).n_rows) || (x(0).n_cols != x(i).n_cols)) {
      same_size = false;
      break;
    }
  }

  arma_debug_check((same_size != true),
                   "diskio::save_ppm_binary(): given field must have exactly 3 matrices "
                   "of equal size");

  const Mat<eT>& R = x(0);
  const Mat<eT>& G = x(1);
  const Mat<eT>& B = x(2);

  f << "P6" << '\n';
  f << R.n_cols << '\n';
  f << R.n_rows << '\n';
  f << 255 << '\n';

  const uword n_elem = 3 * R.n_rows * R.n_cols;
  podarray<u8> tmp(n_elem);

  uword i = 0;
  for (uword row = 0; row < R.n_rows; ++row)
    for (uword col = 0; col < R.n_cols; ++col) {
      tmp[i + 0] = u8(access::tmp_real(R.at(row, col)));
      tmp[i + 1] = u8(access::tmp_real(G.at(row, col)));
      tmp[i + 2] = u8(access::tmp_real(B.at(row, col)));

      i += 3;
    }

  f.write(reinterpret_cast<const char*>(tmp.mem), std::streamsize(n_elem));

  return f.good();
}

//! @}
