include/mysql-8.0/m_string.h

// Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License, version 2.0, as
// published by the Free Software Foundation.
//
// This program is also distributed with certain software (including
// but not limited to OpenSSL) that is licensed under separate terms,
// as designated in a particular file or component or in included license
// documentation. The authors of MySQL hereby grant you an
// additional permission to link the program and your derivative works
// with the separately licensed software that they have included with
// MySQL.
//
// Without limiting anything contained in the foregoing, this file,
// which is part of MySQL Server, is also subject to the
// Universal FOSS Exception, version 1.0, a copy of which can be found at
// http://oss.oracle.com/licenses/universal-foss-exception.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License, version 2.0, for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

#ifndef _m_string_h
#define _m_string_h

/**
  @file include/m_string.h
*/

#include <float.h>
#include <stdbool.h>  // IWYU pragma: keep
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "lex_string.h"
#include "my_config.h"
#include "my_inttypes.h"
#include "my_macros.h"

/**
  Definition of the null string (a null pointer of type char *),
  used in some of our string handling code. New code should use
  nullptr instead.
*/
#define NullS (char *)0

/*
  my_str_malloc(), my_str_realloc() and my_str_free() are assigned to
  implementations in strings/alloc.c, but can be overridden in
  the calling program.
 */
extern void *(*my_str_malloc)(size_t);
extern void *(*my_str_realloc)(void *, size_t);
extern void (*my_str_free)(void *);

/* Declared in int2str() */
extern char _dig_vec_upper[];
extern char _dig_vec_lower[];

/* Prototypes for string functions */

extern char *strmake(char *dst, const char *src, size_t length);
extern char *strcont(const char *src, const char *set);
extern char *strxmov(char *dst, const char *src, ...);
extern char *strxnmov(char *dst, size_t len, const char *src, ...);

/*
  bchange(dst, old_length, src, new_length, tot_length)
  replaces old_length characters at dst to new_length characters from
  src in a buffer with tot_length bytes.
*/
static inline void bchange(uchar *dst, size_t old_length, const uchar *src,
                           size_t new_length, size_t tot_length) {
  memmove(dst + new_length, dst + old_length, tot_length - old_length);
  memcpy(dst, src, new_length);
}

/*
  strend(s) returns a character pointer to the NUL which ends s.  That
  is,  strend(s)-s  ==  strlen(s). This is useful for adding things at
  the end of strings.  It is redundant, because  strchr(s,'\0')  could
  be used instead, but this is clearer and faster.
*/
static inline char *strend(const char *s) {
  while (*s++)
    ;
  return (char *)(s - 1);
}

/*
  strcend(s, c) returns a pointer to the  first  place  in  s where  c
  occurs,  or a pointer to the end-null of s if c does not occur in s.
*/
static inline char *strcend(const char *s, char c) {
  for (;;) {
    if (*s == (char)c) return (char *)s;
    if (!*s++) return (char *)s - 1;
  }
}

/*
  strfill(dest, len, fill) makes a string of fill-characters. The result
  string is of length == len. The des+len character is allways set to NULL.
  strfill() returns pointer to dest+len;
*/
static inline char *strfill(char *s, size_t len, char fill) {
  while (len--) *s++ = fill;
  *(s) = '\0';
  return (s);
}

/*
  my_stpmov(dst, src) moves all the  characters  of  src  (including  the
  closing NUL) to dst, and returns a pointer to the new closing NUL in
  dst.	 The similar UNIX routine strcpy returns the old value of dst,
  which I have never found useful.  my_stpmov(my_stpmov(dst,a),b) moves a//b
  into dst, which seems useful.
*/
static inline char *my_stpmov(char *dst, const char *src) {
  while ((*dst++ = *src++))
    ;
  return dst - 1;
}

/*
  my_stpnmov(dst,src,length) moves length characters, or until end, of src to
  dst and appends a closing NUL to dst if src is shorter than length.
  The result is a pointer to the first NUL in dst, or is dst+n if dst was
  truncated.
*/
static inline char *my_stpnmov(char *dst, const char *src, size_t n) {
  while (n-- != 0) {
    if (!(*dst++ = *src++)) return (char *)dst - 1;
  }
  return dst;
}

/**
   Copy a string from src to dst until (and including) terminating null byte.

   @param dst   Destination
   @param src   Source

   @note src and dst cannot overlap.
         Use my_stpmov() if src and dst overlaps.

   @note Unsafe, consider using my_stpnpy() instead.

   @return pointer to terminating null byte.
*/
static inline char *my_stpcpy(char *dst, const char *src) {
#if defined(HAVE_BUILTIN_STPCPY)
  return __builtin_stpcpy(dst, src);
#elif defined(HAVE_STPCPY)
  return stpcpy(dst, src);
#else
  /* Fallback to implementation supporting overlap. */
  return my_stpmov(dst, src);
#endif
}

/**
   Copy fixed-size string from src to dst.

   @param dst   Destination
   @param src   Source
   @param n     Maximum number of characters to copy.

   @note src and dst cannot overlap
         Use my_stpnmov() if src and dst overlaps.

   @return pointer to terminating null byte.
*/
static inline char *my_stpncpy(char *dst, const char *src, size_t n) {
#if defined(HAVE_STPNCPY)
  return stpncpy(dst, src, n);
#else
  /* Fallback to implementation supporting overlap. */
  return my_stpnmov(dst, src, n);
#endif
}

static inline longlong my_strtoll(const char *nptr, char **endptr, int base) {
#if defined _WIN32
  return _strtoi64(nptr, endptr, base);
#else
  return strtoll(nptr, endptr, base);
#endif
}

static inline ulonglong my_strtoull(const char *nptr, char **endptr, int base) {
#if defined _WIN32
  return _strtoui64(nptr, endptr, base);
#else
  return strtoull(nptr, endptr, base);
#endif
}

static inline char *my_strtok_r(char *str, const char *delim, char **saveptr) {
#if defined _WIN32
  return strtok_s(str, delim, saveptr);
#else
  return strtok_r(str, delim, saveptr);
#endif
}

/* native_ rather than my_ since my_strcasecmp already exists */
static inline int native_strcasecmp(const char *s1, const char *s2) {
#if defined _WIN32
  return _stricmp(s1, s2);
#else
  return strcasecmp(s1, s2);
#endif
}

/* native_ rather than my_ for consistency with native_strcasecmp */
static inline int native_strncasecmp(const char *s1, const char *s2, size_t n) {
#if defined _WIN32
  return _strnicmp(s1, s2, n);
#else
  return strncasecmp(s1, s2, n);
#endif
}

/*
  is_prefix(s, t) returns 1 if s starts with t.
  A empty t is always a prefix.
*/
static inline int is_prefix(const char *s, const char *t) {
  while (*t)
    if (*s++ != *t++) return 0;
  return 1; /* WRONG */
}

/* Conversion routines */
typedef enum { MY_GCVT_ARG_FLOAT, MY_GCVT_ARG_DOUBLE } my_gcvt_arg_type;

double my_strtod(const char *str, char **end, int *error);
double my_atof(const char *nptr);
size_t my_fcvt(double x, int precision, char *to, bool *error);
size_t my_gcvt(double x, my_gcvt_arg_type type, int width, char *to,
               bool *error);

#define NOT_FIXED_DEC 31

/*
  The longest string my_fcvt can return is 311 + "precision" bytes.
  Here we assume that we never cal my_fcvt() with precision >= NOT_FIXED_DEC
  (+ 1 byte for the terminating '\0').
*/
#define FLOATING_POINT_BUFFER (311 + NOT_FIXED_DEC)

/*
  We want to use the 'e' format in some cases even if we have enough space
  for the 'f' one just to mimic sprintf("%.15g") behavior for large integers,
  and to improve it for numbers < 10^(-4).
  That is, for |x| < 1 we require |x| >= 10^(-15), and for |x| > 1 we require
  it to be integer and be <= 10^DBL_DIG for the 'f' format to be used.
  We don't lose precision, but make cases like "1e200" or "0.00001" look nicer.
*/
#define MAX_DECPT_FOR_F_FORMAT DBL_DIG

/*
  The maximum possible field width for my_gcvt() conversion.
  (DBL_DIG + 2) significant digits + sign + "." + ("e-NNN" or
  MAX_DECPT_FOR_F_FORMAT zeros for cases when |x|<1 and the 'f' format is used).
*/
#define MY_GCVT_MAX_FIELD_WIDTH \
  (DBL_DIG + 4 + MY_MAX(5, MAX_DECPT_FOR_F_FORMAT))

extern char *int2str(long val, char *dst, int radix, int upcase);
C_MODE_START
extern char *int10_to_str(long val, char *dst, int radix);
C_MODE_END
extern char *str2int(const char *src, int radix, long lower, long upper,
                     long *val);
longlong my_strtoll10(const char *nptr, char **endptr, int *error);
#if SIZEOF_LONG == SIZEOF_LONG_LONG
#define ll2str(A, B, C, D) int2str((A), (B), (C), (D))
#define longlong10_to_str(A, B, C) int10_to_str((A), (B), (C))
#undef strtoll
#define strtoll(A, B, C) strtol((A), (B), (C))
#define strtoull(A, B, C) strtoul((A), (B), (C))
#else
extern char *ll2str(longlong val, char *dst, int radix, int upcase);
extern char *longlong10_to_str(longlong val, char *dst, int radix);
#endif
#define longlong2str(A, B, C) ll2str((A), (B), (C), 1)

/*
  This function saves a longlong value in a buffer and returns the pointer to
  the buffer.
*/
static inline char *llstr(longlong value, char *buff) {
  longlong10_to_str(value, buff, -10);
  return buff;
}

static inline char *ullstr(longlong value, char *buff) {
  longlong10_to_str(value, buff, 10);
  return buff;
}

#define STRING_WITH_LEN(X) (X), ((sizeof(X) - 1))
#define USTRING_WITH_LEN(X) ((uchar *)X), ((sizeof(X) - 1))
#define C_STRING_WITH_LEN(X) ((char *)(X)), ((sizeof(X) - 1))

/**
  Skip trailing space (ASCII spaces only).

  @return New end of the string.
*/
static inline const uchar *skip_trailing_space(const uchar *ptr, size_t len) {
  const uchar *end = ptr + len;
  while (end - ptr >= 8) {
    uint64_t chunk;
    memcpy(&chunk, end - 8, sizeof(chunk));
    if (chunk != 0x2020202020202020ULL) break;
    end -= 8;
  }
  while (end > ptr && end[-1] == 0x20) end--;
  return (end);
}

static inline void lex_string_set(LEX_STRING *lex_str, const char *c_str) {
  lex_str->str = (char *)c_str;
  lex_str->length = strlen(c_str);
}

static inline void lex_cstring_set(LEX_CSTRING *lex_str, const char *c_str) {
  lex_str->str = c_str;
  lex_str->length = strlen(c_str);
}

#endif