142 lines
4.0 KiB
C
142 lines
4.0 KiB
C
/* Internal header for proving correct grouping in strings of numbers.
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Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
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Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <limits.h>
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#ifndef MAX
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#define MAX(a,b) ({ typeof(a) _a = (a); typeof(b) _b = (b); \
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_a > _b ? _a : _b; })
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#endif
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/* Find the maximum prefix of the string between BEGIN and END which
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satisfies the grouping rules. It is assumed that at least one digit
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follows BEGIN directly. */
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static inline const STRING_TYPE *
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correctly_grouped_prefix (const STRING_TYPE *begin, const STRING_TYPE *end,
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wchar_t thousands, const char *grouping)
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{
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if (grouping == NULL)
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return end;
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if (*grouping == '\0')
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{
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/* No grouping allowed. Accept all characters up to the first
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thousands separator. */
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while (begin < end && *begin != thousands)
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++begin;
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return begin;
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}
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while (end > begin)
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{
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const STRING_TYPE *cp = end - 1;
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const char *gp = grouping;
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/* Check first group. */
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while (cp >= begin && (wchar_t) *cp != thousands)
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--cp;
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/* We allow the representation to contain no grouping at all even if
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the locale specifies we can have grouping. */
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if (cp < begin)
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return end;
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if (end - cp == (int) *gp + 1)
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{
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/* This group matches the specification. */
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const STRING_TYPE *new_end;
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if (cp < begin)
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/* There is just one complete group. We are done. */
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return end;
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/* CP points to a thousands separator character. The preceding
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remainder of the string from BEGIN to NEW_END is the part we
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will consider if there is a grouping error in this trailing
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portion from CP to END. */
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new_end = cp - 1;
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/* Loop while the grouping is correct. */
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while (1)
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{
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/* Get the next grouping rule. */
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++gp;
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if (*gp == 0)
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/* If end is reached use last rule. */
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--gp;
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/* Skip the thousands separator. */
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--cp;
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if (*gp == CHAR_MAX
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#if CHAR_MIN < 0
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|| *gp < 0
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#endif
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)
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{
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/* No more thousands separators are allowed to follow. */
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while (cp >= begin && (wchar_t) *cp != thousands)
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--cp;
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if (cp < begin)
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/* OK, only digits followed. */
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return end;
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}
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else
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{
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/* Check the next group. */
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const STRING_TYPE *group_end = cp;
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while (cp >= begin && (wchar_t) *cp != thousands)
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--cp;
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if (cp < begin && group_end - cp <= (int) *gp)
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/* Final group is correct. */
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return end;
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if (cp < begin || group_end - cp != (int) *gp)
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/* Incorrect group. Punt. */
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break;
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}
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}
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/* The trailing portion of the string starting at NEW_END
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contains a grouping error. So we will look for a correctly
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grouped number in the preceding portion instead. */
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end = new_end;
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}
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else
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{
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/* Even the first group was wrong; determine maximum shift. */
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if (end - cp > (int) *gp + 1)
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end = cp + (int) *gp + 1;
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else if (cp < begin)
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/* This number does not fill the first group, but is correct. */
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return end;
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else
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/* CP points to a thousands separator character. */
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end = cp;
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}
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}
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return MAX (begin, end);
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}
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