--- /dev/null
+/* Iterating through multibyte strings: macros for multi-byte encodings.
+ Copyright (C) 2001, 2005 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software Foundation,
+ Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/* Written by Bruno Haible <bruno@clisp.org>. */
+
+/* The macros in this file implement forward iteration through a
+ multi-byte string, without knowing its length a-priori.
+
+ With these macros, an iteration loop that looks like
+
+ char *iter;
+ for (iter = buf; *iter != '\0'; iter++)
+ {
+ do_something (*iter);
+ }
+
+ becomes
+
+ mbui_iterator_t iter;
+ for (mbui_init (iter, buf); mbui_avail (iter); mbui_advance (iter))
+ {
+ do_something (mbui_cur_ptr (iter), mb_len (mbui_cur (iter)));
+ }
+
+ The benefit of these macros over plain use of mbrtowc is:
+ - Handling of invalid multibyte sequences is possible without
+ making the code more complicated, while still preserving the
+ invalid multibyte sequences.
+
+ Compared to mbiter.h, the macros here don't need to know the string's
+ length a-priori. The downside is that at each step, the look-ahead
+ that guards against overrunning the terminating '\0' is more expensive.
+ The mbui_* macros are therefore suitable when there is a high probability
+ that only the first few multibyte characters need to be inspected.
+ Whereas the mbi_* macros are better if usually the iteration runs
+ through the entire string.
+
+ mbui_iterator_t
+ is a type usable for variable declarations.
+
+ mbui_init (iter, startptr)
+ initializes the iterator, starting at startptr.
+
+ mbui_avail (iter)
+ returns true if there are more multibyte chracters available before
+ the end of string is reached. In this case, mbui_cur (iter) is
+ initialized to the next multibyte chracter.
+
+ mbui_advance (iter)
+ advances the iterator by one multibyte character.
+
+ mbui_cur (iter)
+ returns the current multibyte character, of type mbchar_t. All the
+ macros defined in mbchar.h can be used on it.
+
+ mbui_cur_ptr (iter)
+ return a pointer to the beginning of the current multibyte character.
+
+ mbui_reloc (iter, ptrdiff)
+ relocates iterator when the string is moved by ptrdiff bytes.
+
+ Here are the function prototypes of the macros.
+
+ extern void mbui_init (mbui_iterator_t iter, const char *startptr);
+ extern bool mbui_avail (mbui_iterator_t iter);
+ extern void mbui_advance (mbui_iterator_t iter);
+ extern mbchar_t mbui_cur (mbui_iterator_t iter);
+ extern const char * mbui_cur_ptr (mbui_iterator_t iter);
+ extern void mbui_reloc (mbui_iterator_t iter, ptrdiff_t ptrdiff);
+ */
+
+#ifndef _MBUITER_H
+#define _MBUITER_H 1
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+/* Tru64 with Desktop Toolkit C has a bug: <stdio.h> must be included before
+ <wchar.h>.
+ BSD/OS 4.1 has a bug: <stdio.h> and <time.h> must be included before
+ <wchar.h>. */
+#include <stdio.h>
+#include <time.h>
+#include <wchar.h>
+
+#include "mbchar.h"
+#include "strnlen1.h"
+
+struct mbuiter_multi
+{
+ bool in_shift; /* true if next byte may not be interpreted as ASCII */
+ mbstate_t state; /* if in_shift: current shift state */
+ bool next_done; /* true if mbui_avail has already filled the following */
+ struct mbchar cur; /* the current character:
+ const char *cur.ptr pointer to current character
+ The following are only valid after mbui_avail.
+ size_t cur.bytes number of bytes of current character
+ bool cur.wc_valid true if wc is a valid wide character
+ wchar_t cur.wc if wc_valid: the current character
+ */
+};
+
+static inline void
+mbuiter_multi_next (struct mbuiter_multi *iter)
+{
+ if (iter->next_done)
+ return;
+ if (iter->in_shift)
+ goto with_shift;
+ /* Handle most ASCII characters quickly, without calling mbrtowc(). */
+ if (is_basic (*iter->cur.ptr))
+ {
+ /* These characters are part of the basic character set. ISO C 99
+ guarantees that their wide character code is identical to their
+ char code. */
+ iter->cur.bytes = 1;
+ iter->cur.wc = *iter->cur.ptr;
+ iter->cur.wc_valid = true;
+ }
+ else
+ {
+ assert (mbsinit (&iter->state));
+ iter->in_shift = true;
+ with_shift:
+ iter->cur.bytes = mbrtowc (&iter->cur.wc, iter->cur.ptr,
+ strnlen1 (iter->cur.ptr, MB_CUR_MAX),
+ &iter->state);
+ if (iter->cur.bytes == (size_t) -1)
+ {
+ /* An invalid multibyte sequence was encountered. */
+ iter->cur.bytes = 1;
+ iter->cur.wc_valid = false;
+ /* Whether to set iter->in_shift = false and reset iter->state
+ or not is not very important; the string is bogus anyway. */
+ }
+ else if (iter->cur.bytes == (size_t) -2)
+ {
+ /* An incomplete multibyte character at the end. */
+ iter->cur.bytes = strlen (iter->cur.ptr);
+ iter->cur.wc_valid = false;
+ /* Whether to set iter->in_shift = false and reset iter->state
+ or not is not important; the string end is reached anyway. */
+ }
+ else
+ {
+ if (iter->cur.bytes == 0)
+ {
+ /* A null wide character was encountered. */
+ iter->cur.bytes = 1;
+ assert (*iter->cur.ptr == '\0');
+ assert (iter->cur.wc == 0);
+ }
+ iter->cur.wc_valid = true;
+
+ /* When in the initial state, we can go back treating ASCII
+ characters more quickly. */
+ if (mbsinit (&iter->state))
+ iter->in_shift = false;
+ }
+ }
+ iter->next_done = true;
+}
+
+static inline void
+mbuiter_multi_reloc (struct mbuiter_multi *iter, ptrdiff_t ptrdiff)
+{
+ iter->cur.ptr += ptrdiff;
+}
+
+/* Iteration macros. */
+typedef struct mbuiter_multi mbui_iterator_t;
+#define mbui_init(iter, startptr) \
+ ((iter).cur.ptr = (startptr), \
+ (iter).in_shift = false, memset (&(iter).state, '\0', sizeof (mbstate_t)), \
+ (iter).next_done = false)
+#define mbui_avail(iter) \
+ (mbuiter_multi_next (&(iter)), !mb_isnul ((iter).cur))
+#define mbui_advance(iter) \
+ ((iter).cur.ptr += (iter).cur.bytes, (iter).next_done = false)
+
+/* Access to the current character. */
+#define mbui_cur(iter) (iter).cur
+#define mbui_cur_ptr(iter) (iter).cur.ptr
+
+/* Relocation. */
+#define mbui_reloc(iter, ptrdiff) mbuiter_multi_reloc (&iter, ptrdiff)
+
+#endif /* _MBUITER_H */
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