/* The MIT License

   Copyright (C) 2011 by Attractive Chaos <attractor@live.co.uk>
   Copyright (C) 2013-2014, 2016, 2018-2020, 2022, 2024 Genome Research Ltd.

   Permission is hereby granted, free of charge, to any person obtaining
   a copy of this software and associated documentation files (the
   "Software"), to deal in the Software without restriction, including
   without limitation the rights to use, copy, modify, merge, publish,
   distribute, sublicense, and/or sell copies of the Software, and to
   permit persons to whom the Software is furnished to do so, subject to
   the following conditions:

   The above copyright notice and this permission notice shall be
   included in all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE.
*/

#ifndef KSTRING_H
#define KSTRING_H

#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <limits.h>
#include <errno.h>
#include <sys/types.h>

#include "hts_defs.h"
#include "kroundup.h"

#if defined __GNUC__ && (__GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 4))
#ifdef __MINGW_PRINTF_FORMAT
#define KS_ATTR_PRINTF(fmt, arg) __attribute__((__format__ (__MINGW_PRINTF_FORMAT, fmt, arg)))
#else
#define KS_ATTR_PRINTF(fmt, arg) __attribute__((__format__ (__printf__, fmt, arg)))
#endif // __MINGW_PRINTF_FORMAT
#else
#define KS_ATTR_PRINTF(fmt, arg)
#endif

#ifndef HAVE___BUILTIN_CLZ
#if defined __GNUC__ && (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
#define HAVE___BUILTIN_CLZ 1
#endif
#endif

// Ensure ssize_t exists within this header. All #includes must precede this,
// and ssize_t must be undefined again at the end of this header.
#if defined _MSC_VER && defined _INTPTR_T_DEFINED && !defined _SSIZE_T_DEFINED && !defined ssize_t
#define HTSLIB_SSIZE_T
#define ssize_t intptr_t
#endif

/* kstring_t is a simple non-opaque type whose fields are likely to be
 * used directly by user code (but see also ks_str() and ks_len() below).
 * A kstring_t object is initialised by either of
 *       kstring_t str = KS_INITIALIZE;
 *       kstring_t str; ...; ks_initialize(&str);
 * and either ownership of the underlying buffer should be given away before
 * the object disappears (see ks_release() below) or the kstring_t should be
 * destroyed with  ks_free(&str) or free(str.s) */
#ifndef KSTRING_T
#define KSTRING_T kstring_t
typedef struct kstring_t {
	size_t l, m;
	char *s;
} kstring_t;
#endif

typedef struct ks_tokaux_t {
	uint64_t tab[4];
	int sep, finished;
	const char *p; // end of the current token
} ks_tokaux_t;

#ifdef __cplusplus
extern "C" {
#endif

    HTSLIB_EXPORT
	int kvsprintf(kstring_t *s, const char *fmt, va_list ap) KS_ATTR_PRINTF(2,0);

    HTSLIB_EXPORT
	int ksprintf(kstring_t *s, const char *fmt, ...) KS_ATTR_PRINTF(2,3);

    HTSLIB_EXPORT
    int kputd(double d, kstring_t *s); // custom %g only handler

    HTSLIB_EXPORT
	int ksplit_core(char *s, int delimiter, int *_max, int **_offsets);

    HTSLIB_EXPORT
	char *kstrstr(const char *str, const char *pat, int **_prep);

    HTSLIB_EXPORT
	char *kstrnstr(const char *str, const char *pat, int n, int **_prep);

    HTSLIB_EXPORT
	void *kmemmem(const void *_str, int n, const void *_pat, int m, int **_prep);

	/* kstrtok() is similar to strtok_r() except that str is not
	 * modified and both str and sep can be NULL. For efficiency, it is
	 * actually recommended to set both to NULL in the subsequent calls
	 * if sep is not changed. */
    HTSLIB_EXPORT
	char *kstrtok(const char *str, const char *sep, ks_tokaux_t *aux);

    /* kgetline() uses the supplied fgets()-like function to read a "\n"-
     * or "\r\n"-terminated line from fp.  The line read is appended to the
     * kstring without its terminator and 0 is returned; EOF is returned at
     * EOF or on error (determined by querying fp, as per fgets()). */
    typedef char *kgets_func(char *, int, void *);
    HTSLIB_EXPORT
    int kgetline(kstring_t *s, kgets_func *fgets_fn, void *fp);

    /* kgetline2() uses the supplied hgetln()-like function to read a "\n"-
     * or "\r\n"-terminated line from fp.  The line read is appended to the
     * ksring without its terminator and 0 is returned; EOF is returned at
     * EOF or on error (determined by querying fp, as per fgets()). */
    typedef ssize_t kgets_func2(char *, size_t, void *);
    HTSLIB_EXPORT
    int kgetline2(kstring_t *s, kgets_func2 *fgets_fn, void *fp);

#ifdef __cplusplus
}
#endif

/// kstring initializer for structure assignment
#define KS_INITIALIZE { 0, 0, NULL }

/// kstring initializer for pointers
/**
   @note Not to be used if the buffer has been allocated.  Use ks_release()
   or ks_clear() instead.
*/

static inline void ks_initialize(kstring_t *s)
{
    s->l = s->m = 0;
    s->s = NULL;
}

/// Resize a kstring to a given capacity
static inline int ks_resize(kstring_t *s, size_t size)
{
	if (s->m < size) {
	    char *tmp;
	    size = (size > (SIZE_MAX>>2)) ? size : size + (size >> 1);
	    tmp = (char*)realloc(s->s, size);
	    if (!tmp)
	        return -1;
	    s->s = tmp;
	    s->m = size;
	}
	return 0;
}

/// Increase kstring capacity by a given number of bytes
static inline int ks_expand(kstring_t *s, size_t expansion)
{
    size_t new_size = s->l + expansion;

    if (new_size < s->l) // Overflow check
        return -1;
    return ks_resize(s, new_size);
}

/// Returns the kstring buffer
static inline char *ks_str(kstring_t *s)
{
	return s->s;
}

/// Returns the kstring buffer, or an empty string if l == 0
/**
 * Unlike ks_str(), this function will never return NULL.  If the kstring is
 * empty it will return a read-only empty string.  As the returned value
 * may be read-only, the caller should not attempt to modify it.
 */
static inline const char *ks_c_str(kstring_t *s)
{
    return s->l && s->s ? s->s : "";
}

static inline size_t ks_len(kstring_t *s)
{
	return s->l;
}

/// Reset kstring length to zero
/**
   @return The kstring itself

   Example use: kputsn(string, len, ks_clear(s))
*/
static inline kstring_t *ks_clear(kstring_t *s)
{
    s->l = 0;
    return s;
}

// Give ownership of the underlying buffer away to something else (making
// that something else responsible for freeing it), leaving the kstring_t
// empty and ready to be used again, or ready to go out of scope without
// needing  free(str.s)  to prevent a memory leak.
static inline char *ks_release(kstring_t *s)
{
	char *ss = s->s;
	s->l = s->m = 0;
	s->s = NULL;
	return ss;
}

/// Safely free the underlying buffer in a kstring.
static inline void ks_free(kstring_t *s)
{
    if (s) {
        free(s->s);
        ks_initialize(s);
    }
}

static inline int kputsn(const char *p, size_t l, kstring_t *s)
{
	size_t new_sz = s->l + l + 2;
	if (new_sz <= s->l || ks_resize(s, new_sz) < 0)
		return EOF;
	memcpy(s->s + s->l, p, l);
	s->l += l;
	s->s[s->l] = 0;
	return l;
}

static inline int kputs(const char *p, kstring_t *s)
{
	if (!p) { errno = EFAULT; return -1; }
	return kputsn(p, strlen(p), s);
}

static inline int kputc(int c, kstring_t *s)
{
	if (ks_resize(s, s->l + 2) < 0)
		return EOF;
	s->s[s->l++] = c;
	s->s[s->l] = 0;
	return (unsigned char)c;
}

static inline int kputc_(int c, kstring_t *s)
{
	if (ks_resize(s, s->l + 1) < 0)
		return EOF;
	s->s[s->l++] = c;
	return 1;
}

static inline int kputsn_(const void *p, size_t l, kstring_t *s)
{
	size_t new_sz = s->l + l;
	if (new_sz < s->l || ks_resize(s, new_sz ? new_sz : 1) < 0)
		return EOF;
	memcpy(s->s + s->l, p, l);
	s->l += l;
	return l;
}

static inline int kputuw(unsigned x, kstring_t *s)
{
#if HAVE___BUILTIN_CLZ && UINT_MAX == 4294967295U
    static const unsigned int kputuw_num_digits[32] = {
        10, 10, 10,  9,  9,  9,  8,  8,
        8,   7,  7,  7,  7,  6,  6,  6,
        5,   5,  5,  4,  4,  4,  4,  3,
        3,   3,  2,  2,  2,  1,  1,  1
    };
    static const unsigned int kputuw_thresholds[32] = {
        0,        0, 1000000000U, 0,       0, 100000000U,   0,      0,
        10000000, 0,          0,  0, 1000000,         0,    0, 100000,
        0,        0,      10000,  0,       0,         0, 1000,      0,
        0,      100,          0,  0,      10,         0,    0,      0
    };
#else
    uint64_t m;
#endif
    static const char kputuw_dig2r[] =
        "00010203040506070809"
        "10111213141516171819"
        "20212223242526272829"
        "30313233343536373839"
        "40414243444546474849"
        "50515253545556575859"
        "60616263646566676869"
        "70717273747576777879"
        "80818283848586878889"
        "90919293949596979899";
    unsigned int l, j;
    char *cp;

    // Trivial case - also prevents __builtin_clz(0), which is undefined
    if (x < 10) {
        if (ks_resize(s, s->l + 2) < 0)
            return EOF;
        s->s[s->l++] = '0'+x;
        s->s[s->l] = 0;
        return 0;
    }

    // Find out how many digits are to be printed.
#if HAVE___BUILTIN_CLZ && UINT_MAX == 4294967295U
    /*
     * Table method - should be quick if clz can be done in hardware.
     * Find the most significant bit of the value to print and look
     * up in a table to find out how many decimal digits are needed.
     * This number needs to be adjusted by 1 for cases where the decimal
     * length could vary for a given number of bits (for example,
     * a four bit number could be between 8 and 15).
     */

    l = __builtin_clz(x);
    l = kputuw_num_digits[l] - (x < kputuw_thresholds[l]);
#else
    // Fallback for when clz is not available
    m = 1;
    l = 0;
    do {
        l++;
        m *= 10;
    } while (x >= m);
#endif

    if (ks_resize(s, s->l + l + 2) < 0)
        return EOF;

    // Add digits two at a time
    j = l;
    cp = s->s + s->l;
    while (x >= 10) {
        const char *d = &kputuw_dig2r[2*(x%100)];
        x /= 100;
        memcpy(&cp[j-=2], d, 2);
    }

    // Last one (if necessary).  We know that x < 10 by now.
    if (j == 1)
        cp[0] = x + '0';

    s->l += l;
    s->s[s->l] = 0;
    return 0;
}

static inline int kputw(int c, kstring_t *s)
{
    unsigned int x = c;
    if (c < 0) {
        x = -x;
        if (ks_resize(s, s->l + 3) < 0)
            return EOF;
        s->s[s->l++] = '-';
    }

    return kputuw(x, s);
}

static inline int kputll(long long c, kstring_t *s)
{
    // Worst case expansion.  One check reduces function size
    // and aids inlining chance.  Memory overhead is minimal.
    if (ks_resize(s, s->l + 23) < 0)
	return EOF;

    unsigned long long x = c;
    if (c < 0) {
	x = -x;
        s->s[s->l++] = '-';
    }

    if (x <= UINT32_MAX)
	return kputuw(x, s);

    static const char kputull_dig2r[] =
        "00010203040506070809"
        "10111213141516171819"
        "20212223242526272829"
        "30313233343536373839"
        "40414243444546474849"
        "50515253545556575859"
        "60616263646566676869"
        "70717273747576777879"
        "80818283848586878889"
        "90919293949596979899";
    unsigned int l, j;
    char *cp;

    // Find out how long the number is (could consider clzll)
    uint64_t m = 1;
    l = 0;
    if (sizeof(long long)==sizeof(uint64_t) && x >= 10000000000000000000ULL) {
	// avoids overflow below
	l = 20;
    } else {
	do {
	    l++;
	    m *= 10;
	} while (x >= m);
    }

    // Add digits two at a time
    j = l;
    cp = s->s + s->l;
    while (x >= 10) {
        const char *d = &kputull_dig2r[2*(x%100)];
        x /= 100;
        memcpy(&cp[j-=2], d, 2);
    }

    // Last one (if necessary).  We know that x < 10 by now.
    if (j == 1)
        cp[0] = x + '0';

    s->l += l;
    s->s[s->l] = 0;
    return 0;
}

static inline int kputl(long c, kstring_t *s) {
    return kputll(c, s);
}

/*
 * Returns 's' split by delimiter, with *n being the number of components;
 *         NULL on failure.
 */
static inline int *ksplit(kstring_t *s, int delimiter, int *n)
{
	int max = 0, *offsets = 0;
	*n = ksplit_core(s->s, delimiter, &max, &offsets);
	return offsets;
}

#ifdef HTSLIB_SSIZE_T
#undef HTSLIB_SSIZE_T
#undef ssize_t
#endif

#endif
