pmt: initial 3.0.2 update
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277
include/libgnulib/mbuiter.h
Executable file
277
include/libgnulib/mbuiter.h
Executable file
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/* Iterating through multibyte strings: macros for multi-byte encodings.
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Copyright (C) 2001, 2005, 2007, 2009-2024 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation, either version 3 of the
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License, or (at your option) any later version.
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This file 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
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Bruno Haible <bruno@clisp.org>. */
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/* The macros in this file implement forward iteration through a
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multi-byte string, without knowing its length a-priori.
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With these macros, an iteration loop that looks like
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char *iter;
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for (iter = buf; *iter != '\0'; iter++)
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{
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do_something (*iter);
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}
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becomes
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mbui_iterator_t iter;
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for (mbui_init (iter, buf); mbui_avail (iter); mbui_advance (iter))
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{
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do_something (mbui_cur_ptr (iter), mb_len (mbui_cur (iter)));
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}
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The benefit of these macros over plain use of mbrtowc is:
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- Handling of invalid multibyte sequences is possible without
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making the code more complicated, while still preserving the
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invalid multibyte sequences.
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Compared to mbiter.h, the macros here don't need to know the string's
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length a-priori. The downside is that at each step, the look-ahead
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that guards against overrunning the terminating '\0' is more expensive.
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The mbui_* macros are therefore suitable when there is a high probability
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that only the first few multibyte characters need to be inspected.
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Whereas the mbi_* macros are better if usually the iteration runs
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through the entire string.
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mbui_iterator_t
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is a type usable for variable declarations.
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mbui_init (iter, startptr)
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initializes the iterator, starting at startptr.
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mbui_avail (iter)
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returns true if there are more multibyte characters available before
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the end of string is reached. In this case, mbui_cur (iter) is
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initialized to the next multibyte character.
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mbui_advance (iter)
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advances the iterator by one multibyte character.
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mbui_cur (iter)
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returns the current multibyte character, of type mbchar_t. All the
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macros defined in mbchar.h can be used on it.
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mbui_cur_ptr (iter)
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return a pointer to the beginning of the current multibyte character.
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mbui_reloc (iter, ptrdiff)
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relocates iterator when the string is moved by ptrdiff bytes.
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mbui_copy (&destiter, &srciter)
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copies srciter to destiter.
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Here are the function prototypes of the macros.
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extern void mbui_init (mbui_iterator_t iter, const char *startptr);
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extern bool mbui_avail (mbui_iterator_t iter);
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extern void mbui_advance (mbui_iterator_t iter);
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extern mbchar_t mbui_cur (mbui_iterator_t iter);
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extern const char * mbui_cur_ptr (mbui_iterator_t iter);
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extern void mbui_reloc (mbui_iterator_t iter, ptrdiff_t ptrdiff);
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extern void mbui_copy (mbui_iterator_t *new, const mbui_iterator_t *old);
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*/
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#ifndef _MBUITER_H
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#define _MBUITER_H 1
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/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE,
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_GL_ATTRIBUTE_ALWAYS_INLINE. */
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#if !_GL_CONFIG_H_INCLUDED
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#error "Please include config.h first."
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#endif
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#include <assert.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <uchar.h>
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#include <wchar.h>
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#include "mbchar.h"
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#include "strnlen1.h"
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_GL_INLINE_HEADER_BEGIN
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#ifndef MBUITER_INLINE
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# define MBUITER_INLINE _GL_INLINE _GL_ATTRIBUTE_ALWAYS_INLINE
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct mbuiter_multi
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{
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#if !GNULIB_MBRTOC32_REGULAR
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bool in_shift; /* true if next byte may not be interpreted as ASCII */
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/* If GNULIB_MBRTOC32_REGULAR, it is always false,
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so optimize it away. */
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#endif
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mbstate_t state; /* if in_shift: current shift state */
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/* If GNULIB_MBRTOC32_REGULAR, it is in an initial state
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before and after every mbuiter_multi_next invocation.
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*/
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bool next_done; /* true if mbui_avail has already filled the following */
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unsigned int cur_max; /* A cache of MB_CUR_MAX. */
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struct mbchar cur; /* the current character:
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const char *cur.ptr pointer to current character
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The following are only valid after mbui_avail.
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size_t cur.bytes number of bytes of current character
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bool cur.wc_valid true if wc is a valid 32-bit wide character
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char32_t cur.wc if wc_valid: the current character
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*/
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};
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MBUITER_INLINE void
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mbuiter_multi_next (struct mbuiter_multi *iter)
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{
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if (iter->next_done)
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return;
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#if !GNULIB_MBRTOC32_REGULAR
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if (iter->in_shift)
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goto with_shift;
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#endif
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/* Handle most ASCII characters quickly, without calling mbrtowc(). */
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if (is_basic (*iter->cur.ptr))
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{
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/* These characters are part of the POSIX portable character set.
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For most of them, namely those in the ISO C basic character set,
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ISO C 99 guarantees that their wide character code is identical to
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their char code. For the few other ones, this is the case as well,
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in all locale encodings that are in use. The 32-bit wide character
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code is the same as well. */
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iter->cur.bytes = 1;
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iter->cur.wc = *iter->cur.ptr;
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iter->cur.wc_valid = true;
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}
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else
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{
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assert (mbsinit (&iter->state));
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#if !GNULIB_MBRTOC32_REGULAR
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iter->in_shift = true;
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with_shift:
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#endif
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iter->cur.bytes = mbrtoc32 (&iter->cur.wc, iter->cur.ptr,
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strnlen1 (iter->cur.ptr, iter->cur_max),
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&iter->state);
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if (iter->cur.bytes == (size_t) -1)
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{
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/* An invalid multibyte sequence was encountered. */
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iter->cur.bytes = 1;
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iter->cur.wc_valid = false;
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/* Allow the next invocation to continue from a sane state. */
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#if !GNULIB_MBRTOC32_REGULAR
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iter->in_shift = false;
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#endif
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mbszero (&iter->state);
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}
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else if (iter->cur.bytes == (size_t) -2)
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{
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/* An incomplete multibyte character at the end. */
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iter->cur.bytes = strlen (iter->cur.ptr);
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iter->cur.wc_valid = false;
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/* Whether to set iter->in_shift = false and reset iter->state
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or not is not important; the string end is reached anyway. */
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}
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else
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{
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if (iter->cur.bytes == 0)
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{
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/* A null wide character was encountered. */
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iter->cur.bytes = 1;
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assert (*iter->cur.ptr == '\0');
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assert (iter->cur.wc == 0);
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}
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#if !GNULIB_MBRTOC32_REGULAR
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else if (iter->cur.bytes == (size_t) -3)
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/* The previous multibyte sequence produced an additional 32-bit
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wide character. */
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iter->cur.bytes = 0;
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#endif
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iter->cur.wc_valid = true;
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/* When in an initial state, we can go back treating ASCII
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characters more quickly. */
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#if !GNULIB_MBRTOC32_REGULAR
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if (mbsinit (&iter->state))
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iter->in_shift = false;
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#endif
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}
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}
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iter->next_done = true;
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}
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MBUITER_INLINE void
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mbuiter_multi_reloc (struct mbuiter_multi *iter, ptrdiff_t ptrdiff)
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{
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iter->cur.ptr += ptrdiff;
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}
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MBUITER_INLINE void
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mbuiter_multi_copy (struct mbuiter_multi *new_iter, const struct mbuiter_multi *old_iter)
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{
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#if !GNULIB_MBRTOC32_REGULAR
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if ((new_iter->in_shift = old_iter->in_shift))
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memcpy (&new_iter->state, &old_iter->state, sizeof (mbstate_t));
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else
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#endif
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mbszero (&new_iter->state);
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new_iter->next_done = old_iter->next_done;
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new_iter->cur_max = old_iter->cur_max;
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mb_copy (&new_iter->cur, &old_iter->cur);
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}
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/* Iteration macros. */
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typedef struct mbuiter_multi mbui_iterator_t;
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#if !GNULIB_MBRTOC32_REGULAR
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#define mbui_init(iter, startptr) \
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((iter).cur.ptr = (startptr), \
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(iter).in_shift = false, mbszero (&(iter).state), \
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(iter).next_done = false, \
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(iter).cur_max = MB_CUR_MAX)
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#else
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/* Optimized: no in_shift. */
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#define mbui_init(iter, startptr) \
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((iter).cur.ptr = (startptr), \
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mbszero (&(iter).state), \
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(iter).next_done = false, \
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(iter).cur_max = MB_CUR_MAX)
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#endif
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#define mbui_avail(iter) \
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(mbuiter_multi_next (&(iter)), !mb_isnul ((iter).cur))
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#define mbui_advance(iter) \
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((iter).cur.ptr += (iter).cur.bytes, (iter).next_done = false)
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/* Access to the current character. */
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#define mbui_cur(iter) (iter).cur
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#define mbui_cur_ptr(iter) (iter).cur.ptr
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/* Relocation. */
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#define mbui_reloc(iter, ptrdiff) mbuiter_multi_reloc (&iter, ptrdiff)
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/* Copying an iterator. */
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#define mbui_copy mbuiter_multi_copy
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#ifdef __cplusplus
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}
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#endif
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_GL_INLINE_HEADER_END
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#endif /* _MBUITER_H */
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