mariadb/include/m_string.h

/*
   Copyright (c) 2000, 2012, Oracle and/or its affiliates.
   Copyright (c) 2019, 2021, MariaDB Corporation.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   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 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 02110-1335  USA */

/* There may be problems included in all of these. Try to test in
   configure which ones are needed? */

/*  This is needed for the definitions of strchr... on solaris */

#ifndef _m_string_h
#define _m_string_h

#include "my_decimal_limits.h"

#ifndef __USE_GNU
#define __USE_GNU				/* We want to use stpcpy */
#endif
#if defined(HAVE_STRINGS_H)
#include <strings.h>
#endif
#if defined(HAVE_STRING_H)
#include <string.h>
#endif

/*  This is needed for the definitions of memcpy... on solaris */
#if defined(HAVE_MEMORY_H) && !defined(__cplusplus)
#include <memory.h>
#endif

#if !defined(HAVE_MEMCPY) && !defined(HAVE_MEMMOVE)
# define memcpy(d, s, n)	bcopy ((s), (d), (n))
# define memset(A,C,B)		bfill((A),(B),(C))
# define memmove(d, s, n)	bmove ((d), (s), (n))
#elif defined(HAVE_MEMMOVE)
# define bmove(d, s, n)		memmove((d), (s), (n))
#endif

/* Unixware 7 */
#if !defined(HAVE_BFILL)
# define bfill(A,B,C)           memset((A),(C),(B))
#endif

# define bmove_align(A,B,C)     memcpy((A),(B),(C))

# define bcmp(A,B,C)		memcmp((A),(B),(C))

#if !defined(bzero)
# define bzero(A,B)             memset((A),0,(B))
#endif

#if defined(__cplusplus)
extern "C" {
#endif

#ifdef DBUG_OFF
#if defined(HAVE_STPCPY) && defined(__GNUC__) && !defined(__INTEL_COMPILER)
#define strmov(A,B) __builtin_stpcpy((A),(B))
#elif defined(HAVE_STPCPY)
#define strmov(A,B) stpcpy((A),(B))
#endif
#endif

/* Declared in int2str() */
extern const char _dig_vec_base62[];
extern const char _dig_vec_upper[];
extern const char _dig_vec_lower[];

extern char *strmov_overlapp(char *dest, const char *src);

#if defined(_lint) || defined(FORCE_INIT_OF_VARS)
#define LINT_INIT_STRUCT(var) bzero(&var, sizeof(var)) /* No uninitialize-warning */
#else
#define LINT_INIT_STRUCT(var)
#endif

/* Prototypes for string functions */

extern	void bmove_upp(uchar *dst,const uchar *src,size_t len);
extern	void bchange(uchar *dst,size_t old_len,const uchar *src,
		     size_t new_len,size_t tot_len);
extern	void strappend(char *s,size_t len,pchar fill);
extern	char *strend(const char *s);
extern  char *strcend(const char *, pchar);
extern	char *strfill(char * s,size_t len,pchar fill);
extern	char *strmake(char *dst,const char *src,size_t length);

#if !defined(__GNUC__) || (__GNUC__ < 4)
#define strmake_buf(D,S)        strmake(D, S, sizeof(D) - 1)
#else
#define strmake_buf(D,S) ({                             \
  __typeof__ (D) __x __attribute__((unused)) = { 2 };   \
  strmake(D, S, sizeof(D) - 1);                         \
  })
#endif

#ifndef strmov
extern	char *strmov(char *dst,const char *src);
#endif
extern	char *strnmov(char *dst, const char *src, size_t n);
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, ...);

/* Prototypes of normal stringfunctions (with may ours) */
#ifndef HAVE_STRNLEN
extern size_t strnlen(const char *s, size_t n);
#endif

extern int is_prefix(const char *, const char *);

/* 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, my_bool *error);
size_t my_gcvt(double x, my_gcvt_arg_type type, int width, char *to,
               my_bool *error);

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

/*
  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 *llstr(longlong value,char *buff);
extern char *ullstr(longlong value,char *buff);
#ifndef HAVE_STRTOUL
extern long strtol(const char *str, char **ptr, int base);
extern ulong strtoul(const char *str, char **ptr, int base);
#endif

extern char *int2str(long val, char *dst, int radix, int upcase);
extern char *int10_to_str(long val,char *dst,int radix);
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))
#ifndef HAVE_STRTOULL
#define HAVE_STRTOULL
#endif
#ifndef HAVE_STRTOLL
#define HAVE_STRTOLL
#endif
#else
#ifdef HAVE_LONG_LONG
extern char *ll2str(longlong val,char *dst,int radix, int upcase);
extern char *longlong10_to_str(longlong val,char *dst,int radix);
#if (!defined(HAVE_STRTOULL) || defined(NO_STRTOLL_PROTO))
extern longlong strtoll(const char *str, char **ptr, int base);
extern ulonglong strtoull(const char *str, char **ptr, int base);
#endif
#endif
#endif
#define longlong2str(A,B,C) ll2str((A),(B),(C),1)

#if defined(__cplusplus)
}
#endif

#include <mysql/plugin.h>

#ifdef __cplusplus
#include <type_traits>
template<typename T> inline constexpr const char *_swl_check(T s)
{
  static_assert(std::is_same<T, const char (&)[sizeof(T)]>::value
             || std::is_same<T, const char [sizeof(T)]>::value,
             "Wrong argument for STRING_WITH_LEN()");
  return s;
}
#define STRING_WITH_LEN(X) _swl_check<decltype(X)>(X), ((size_t) (sizeof(X) - 1))
#else
#define STRING_WITH_LEN(X) (X ""), ((size_t) (sizeof(X) - 1))
#endif

#define USTRING_WITH_LEN(X) (uchar*) STRING_WITH_LEN(X)
#define C_STRING_WITH_LEN(X) (char *) STRING_WITH_LEN(X)
#define LEX_STRING_WITH_LEN(X) (X).str, (X).length

typedef struct st_mysql_const_lex_string LEX_CSTRING;

#ifdef  __cplusplus
static inline constexpr
LEX_CSTRING operator""_LEX_CSTRING(const char *str, size_t length)
{
  return LEX_CSTRING{str, length};
}
#endif /* __cplusplus */


/* A variant with const and unsigned */
struct st_mysql_const_unsigned_lex_string
{
  const uchar *str;
  size_t length;
};
typedef struct st_mysql_const_unsigned_lex_string LEX_CUSTRING;

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

/**
  Copies a string.

  @param dst        destination buffer, will be NUL padded.
  @param dst_size   size of dst buffer, must be > 0
  @param src        NUL terminated source string
*/
static inline void safe_strcpy(char *dst, size_t dst_size, const char *src)
{
  DBUG_ASSERT(dst_size > 0);

  /* 1) IF there is a 0 byte in the first dst_size bytes of src, strncpy will
   *    0-terminate dst, and pad dst with additional 0 bytes out to dst_size.
   *
   * 2) IF there is no 0 byte in the first dst_size bytes of src, strncpy will
   *    copy dst_size bytes, and the final byte won't be 0.
   *
   * In GCC 8+, the `-Wstringop-truncation` warning may object to strncpy()
   * being used in this way, so we need to disable this warning for this
   * single statement.
   */

#if defined __GNUC__ && __GNUC__ >= 8
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstringop-truncation"
#endif
  strncpy(dst, src, dst_size);
#if defined __GNUC__ && __GNUC__ >= 8
#pragma GCC diagnostic pop
#endif
  dst[dst_size - 1]= 0;
}

/**
  Copies a string, checking for truncation.

  @param dst        destination buffer, will be NUL padded.
  @param dst_size   size of dst buffer, must be > 0
  @param src        NUL terminated source string

  @retval 1 if the src string was truncated due to too small size of dst.
  @retval 0 if src completely fit within dst,
*/
static inline int safe_strcpy_truncated(char *dst, size_t dst_size,
                                        const char *src)
{

  DBUG_ASSERT(dst_size > 0);
  if (dst_size == 0)
    return 1;
  /*
    We do not want to use strncpy() as we do not want to rely on
    strncpy() filling the unused dst with 0.
    We cannot use strmake() here as it in debug mode fills the buffers
    with 'Z'.
  */
  if (strnmov(dst, src, dst_size) == dst+dst_size)
  {
    dst[dst_size-1]= 0;
    return 1;
  }
  return 0;
}

/**
  Appends src to dst and ensures dst is a NUL terminated C string.

  @retval 1 if the src string was truncated due to too small size of dst.
  @retval 0 if src completely fit within the remaining dst space,
  including NUL termination.
*/
static inline int safe_strcat(char *dst, size_t dst_size, const char *src)
{
  size_t init_len= strlen(dst);
  if (init_len >= dst_size)
    return 1;
  return safe_strcpy_truncated(dst + init_len, dst_size - init_len, src);
}

#ifdef __cplusplus
static inline char *safe_str(char *str)
{ return str ? str : const_cast<char*>(""); }
#endif

static inline const char *safe_str(const char *str)
{ return str ? str : ""; }

static inline size_t safe_strlen(const char *str)
{ return str ? strlen(str) : 0; }

#endif