aboutsummaryrefslogtreecommitdiff
path: root/stdlib/grouping.h
diff options
context:
space:
mode:
Diffstat (limited to 'stdlib/grouping.h')
-rw-r--r--stdlib/grouping.h123
1 files changed, 123 insertions, 0 deletions
diff --git a/stdlib/grouping.h b/stdlib/grouping.h
new file mode 100644
index 0000000..566f6a6
--- /dev/null
+++ b/stdlib/grouping.h
@@ -0,0 +1,123 @@
+/* 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);
+}