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/* Internal header for proving correct grouping in strings of numbers.
Copyright (C) 1995 Free Software Foundation, Inc.
Contributed by Ulrich Drepper.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <limits.h>
#ifndef MAX
#define MAX(a,b) ({ typeof(a) _a = (a); typeof(b) _b = (b); \
_a > _b ? _a : _b; })
#endif
/* 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. */
static inline const char *
correctly_grouped_prefix (const char *begin, const char *end,
wchar_t thousands, const char *grouping)
{
if (! grouping)
return end;
while (end > begin)
{
const char *cp = end - 1;
const char *gp = grouping;
/* Check first group. */
while (cp >= begin && (wchar_t) *cp != thousands)
--cp;
if (end - cp == (int) *gp + 1)
{
/* This group matches the specification. */
const char *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 || *gp < 0)
{
/* No more thousands separators are allowed to follow. */
while (cp >= begin && (wchar_t) *cp != thousands)
--cp;
if (cp < begin)
/* OK, only digits followed. */
return end;
}
else
{
/* Check the next group. */
const char *group_end = cp;
while (cp >= begin && (wchar_t) *cp != thousands)
--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
gouped 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 seperator character. */
end = cp;
}
}
return MAX (begin, end);
}
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