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glibc/stdlib/grouping.c
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/* Internal header for proving correct grouping in strings of numbers. | |
Copyright (C) 1995-2016 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. | |
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 | |
<http://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) | |
{ | |
#ifndef USE_WIDE_CHAR | |
size_t thousands_len; | |
int cnt; | |
#endif | |
if (grouping == NULL) | |
return end; | |
#ifndef USE_WIDE_CHAR | |
thousands_len = strlen (thousands); | |
#endif | |
while (end > begin) | |
{ | |
const STRING_TYPE *cp = end - 1; | |
const char *gp = grouping; | |
/* Check first group. */ | |
while (cp >= begin) | |
{ | |
#ifdef USE_WIDE_CHAR | |
if (*cp == thousands) | |
break; | |
#else | |
if (cp[thousands_len - 1] == *thousands) | |
{ | |
for (cnt = 1; thousands[cnt] != '\0'; ++cnt) | |
if (thousands[cnt] != cp[thousands_len - 1 - cnt]) | |
break; | |
if (thousands[cnt] == '\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 + 1) | |
{ | |
/* 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 - 1; | |
/* 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 | |
for (cnt = 0; thousands[cnt] != '\0'; ++cnt) | |
if (thousands[cnt] != cp[thousands_len - cnt - 1]) | |
break; | |
if (thousands[cnt] == '\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 | |
for (cnt = 0; thousands[cnt] != '\0'; ++cnt) | |
if (thousands[cnt] != cp[thousands_len - cnt - 1]) | |
break; | |
if (thousands[cnt] == '\0') | |
break; | |
#endif | |
--cp; | |
} | |
if (cp < begin && group_end - cp <= (int) *gp) | |
/* Final group is correct. */ | |
return end; | |
if (cp < begin || group_end - cp != (int) *gp) | |
/* 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 + 1) | |
end = cp + (int) *gp + 1; | |
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); | |
} |