Coverage Report

Created: 2025-03-06 06:58

/src/wget/lib/mbiter.h
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/* Iterating through multibyte strings: macros for multi-byte encodings.
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   Copyright (C) 2001, 2005, 2007, 2009-2025 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 2.1 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.
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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 < buf + buflen; 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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      mbi_iterator_t iter;
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      for (mbi_init (iter, buf, buflen); mbi_avail (iter); mbi_advance (iter))
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        {
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          do_something (mbi_cur_ptr (iter), mb_len (mbi_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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   mbi_iterator_t
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     is a type usable for variable declarations.
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   mbi_init (iter, startptr, length)
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     initializes the iterator, starting at startptr and crossing length bytes.
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   mbi_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, mbi_cur (iter) is
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     initialized to the next multibyte character.
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   mbi_advance (iter)
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     advances the iterator by one multibyte character.
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   mbi_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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   mbi_cur_ptr (iter)
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     return a pointer to the beginning of the current multibyte character.
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   mbi_reloc (iter, ptrdiff)
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     relocates iterator when the string is moved by ptrdiff bytes.
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   mbi_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          mbi_init (mbi_iterator_t iter,
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                                  const char *startptr, size_t length);
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   extern bool          mbi_avail (mbi_iterator_t iter);
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   extern void          mbi_advance (mbi_iterator_t iter);
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   extern mbchar_t      mbi_cur (mbi_iterator_t iter);
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   extern const char *  mbi_cur_ptr (mbi_iterator_t iter);
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   extern void          mbi_reloc (mbi_iterator_t iter, ptrdiff_t ptrdiff);
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   extern void          mbi_copy (mbi_iterator_t *new, const mbi_iterator_t *old);
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 */
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#ifndef _MBITER_H
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#define _MBITER_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 <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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_GL_INLINE_HEADER_BEGIN
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#ifndef MBITER_INLINE
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# define MBITER_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 mbiter_multi
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{
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  const char *limit;    /* pointer to end of string */
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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 mbiter_multi_next invocation.
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                         */
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  bool next_done;       /* true if mbi_avail has already filled the following */
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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 mbi_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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MBITER_INLINE void
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mbiter_multi_next (struct mbiter_multi *iter)
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0
{
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  if (iter->next_done)
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0
    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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                                  iter->limit - iter->cur.ptr, &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 = iter->limit - iter->cur.ptr;
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          iter->cur.wc_valid = false;
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          #if !GNULIB_MBRTOC32_REGULAR
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          /* Cause the next mbi_avail invocation to return false.  */
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          iter->in_shift = false;
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          #endif
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          /* Whether to reset iter->state or not is not important; the
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             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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MBITER_INLINE void
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mbiter_multi_reloc (struct mbiter_multi *iter, ptrdiff_t ptrdiff)
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0
{
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  iter->cur.ptr += ptrdiff;
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  iter->limit += ptrdiff;
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}
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MBITER_INLINE void
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mbiter_multi_copy (struct mbiter_multi *new_iter, const struct mbiter_multi *old_iter)
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0
{
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  new_iter->limit = old_iter->limit;
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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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  mb_copy (&new_iter->cur, &old_iter->cur);
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0
}
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/* Iteration macros.  */
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typedef struct mbiter_multi mbi_iterator_t;
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#if !GNULIB_MBRTOC32_REGULAR
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#define mbi_init(iter, startptr, length) \
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  ((iter).cur.ptr = (startptr), (iter).limit = (iter).cur.ptr + (length), \
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   (iter).in_shift = false, mbszero (&(iter).state), \
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   (iter).next_done = false)
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#else
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/* Optimized: no in_shift.  */
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#define mbi_init(iter, startptr, length) \
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  ((iter).cur.ptr = (startptr), (iter).limit = (iter).cur.ptr + (length), \
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   mbszero (&(iter).state), \
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   (iter).next_done = false)
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#endif
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#if !GNULIB_MBRTOC32_REGULAR
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#define mbi_avail(iter) \
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  (((iter).cur.ptr < (iter).limit || (iter).in_shift) \
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   && (mbiter_multi_next (&(iter)), true))
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#else
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/* Optimized: no in_shift.  */
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#define mbi_avail(iter) \
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  ((iter).cur.ptr < (iter).limit \
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   && (mbiter_multi_next (&(iter)), true))
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#endif
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#define mbi_advance(iter) \
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0
  ((iter).cur.ptr += (iter).cur.bytes, (iter).next_done = false)
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/* Access to the current character.  */
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0
#define mbi_cur(iter) (iter).cur
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#define mbi_cur_ptr(iter) (iter).cur.ptr
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/* Relocation.  */
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#define mbi_reloc(iter, ptrdiff) mbiter_multi_reloc (&iter, ptrdiff)
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/* Copying an iterator.  */
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#define mbi_copy mbiter_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 /* _MBITER_H */