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/* Internal header for proving correct grouping in strings of numbers.
Copyright (C) 1995-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <limits.h>
#include <stddef.h>
#include <string.h>
#ifndef MAX
#define MAX(a,b) ({ typeof(a) _a = (a); typeof(b) _b = (b); \
_a > _b ? _a : _b; })
#endif
#ifdef USE_WIDE_CHAR
# include <wctype.h>
# define L_(Ch) L##Ch
# define UCHAR_TYPE wint_t
# define STRING_TYPE wchar_t
#else
# define L_(Ch) Ch
# define UCHAR_TYPE unsigned char
# define STRING_TYPE char
#endif
#include "grouping.h"
/* Find the maximum prefix of the string between BEGIN and END which
satisfies the grouping rules. It is assumed that at least one digit
follows BEGIN directly. */
const STRING_TYPE *
#ifdef USE_WIDE_CHAR
__correctly_grouped_prefixwc (const STRING_TYPE *begin, const STRING_TYPE *end,
wchar_t thousands,
#else
__correctly_grouped_prefixmb (const STRING_TYPE *begin, const STRING_TYPE *end,
const char *thousands,
#endif
const char *grouping)
{
if (grouping == NULL)
return end;
#ifdef USE_WIDE_CHAR
size_t thousands_len = 1;
#else
size_t thousands_len = strlen (thousands);
#endif
while (end - begin >= thousands_len)
{
const STRING_TYPE *cp = end - thousands_len;
const char *gp = grouping;
/* Check first group. */
while (cp >= begin)
{
#ifdef USE_WIDE_CHAR
if (*cp == thousands)
break;
#else
if (memcmp (cp, thousands, thousands_len) == 0)
break;
#endif
--cp;
}
/* We allow the representation to contain no grouping at all even if
the locale specifies we can have grouping. */
if (cp < begin)
return end;
if (end - cp == (int) *gp + thousands_len)
{
/* This group matches the specification. */
const STRING_TYPE *new_end;
if (cp < begin)
/* There is just one complete group. We are done. */
return end;
/* CP points to a thousands separator character. The preceding
remainder of the string from BEGIN to NEW_END is the part we
will consider if there is a grouping error in this trailing
portion from CP to END. */
new_end = cp;
/* Loop while the grouping is correct. */
while (1)
{
/* Get the next grouping rule. */
++gp;
if (*gp == 0)
/* If end is reached use last rule. */
--gp;
/* Skip the thousands separator. */
--cp;
if (*gp == CHAR_MAX
#if CHAR_MIN < 0
|| *gp < 0
#endif
)
{
/* No more thousands separators are allowed to follow. */
while (cp >= begin)
{
#ifdef USE_WIDE_CHAR
if (*cp == thousands)
break;
#else
if (memcmp (cp, thousands, thousands_len) == 0)
break;
#endif
--cp;
}
if (cp < begin)
/* OK, only digits followed. */
return end;
}
else
{
/* Check the next group. */
const STRING_TYPE *group_end = cp;
while (cp >= begin)
{
#ifdef USE_WIDE_CHAR
if (*cp == thousands)
break;
#else
if (memcmp (cp, thousands, thousands_len) == 0)
break;
#endif
--cp;
}
if (cp < begin && group_end - cp <= (int) *gp + thousands_len - 1)
/* Final group is correct. */
return end;
if (cp < begin || group_end - cp != (int) *gp + thousands_len - 1)
/* Incorrect group. Punt. */
break;
}
}
/* The trailing portion of the string starting at NEW_END
contains a grouping error. So we will look for a correctly
grouped number in the preceding portion instead. */
end = new_end;
}
else
{
/* Even the first group was wrong; determine maximum shift. */
if (end - cp > (int) *gp + thousands_len)
end = cp + (int) *gp + thousands_len;
else if (cp < begin)
/* This number does not fill the first group, but is correct. */
return end;
else
/* CP points to a thousands separator character. */
end = cp;
}
}
return MAX (begin, end);
}
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