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utf-32.c

/* Conversion module for UTF-32.
   Copyright (C) 1999, 2000-2002 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <byteswap.h>
#include <dlfcn.h>
#include <gconv.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

/* This is the Byte Order Mark character (BOM).  */
#define BOM 0x0000feffu
/* And in the other byte order.  */
#define BOM_OE    0xfffe0000u


/* Definitions used in the body of the `gconv' function.  */
#define FROM_LOOP       from_utf32_loop
#define TO_LOOP               to_utf32_loop
#define DEFINE_INIT           0
#define DEFINE_FINI           0
#define MIN_NEEDED_FROM       4
#define MIN_NEEDED_TO         4
#define FROM_DIRECTION        (dir == from_utf32)
#define PREPARE_LOOP \
  enum direction dir = ((struct utf32_data *) step->__data)->dir;       \
  enum variant var = ((struct utf32_data *) step->__data)->var;               \
  int swap;                                                 \
  if (FROM_DIRECTION && var == UTF_32)                                  \
    {                                                       \
      if (data->__invocation_counter == 0)                              \
      {                                                     \
        /* We have to find out which byte order the file is encoded in.  */ \
        if (inptr + 4 > inend)                                    \
          return (inptr == inend                                  \
                ? __GCONV_EMPTY_INPUT : __GCONV_INCOMPLETE_INPUT);            \
                                                            \
        if (get32u (inptr) == BOM)                                \
          /* Simply ignore the BOM character.  */                       \
          *inptrp = inptr += 4;                                   \
        else if (get32u (inptr) == BOM_OE)                              \
          {                                                 \
            ((struct utf32_data *) step->__data)->swap = 1;             \
            *inptrp = inptr += 4;                                 \
          }                                                 \
      }                                                     \
    }                                                       \
  else if (!FROM_DIRECTION && var == UTF_32 && !data->__internal_use          \
         && data->__invocation_counter == 0)                            \
    {                                                       \
      /* Emit the Byte Order Mark.  */                                  \
      if (__builtin_expect (outbuf + 4 > outend, 0))                    \
      return __GCONV_FULL_OUTPUT;                                 \
                                                            \
      put32u (outbuf, BOM);                                       \
      outbuf += 4;                                                \
    }                                                       \
  swap = ((struct utf32_data *) step->__data)->swap;
#define EXTRA_LOOP_ARGS       , var, swap


/* Direction of the transformation.  */
enum direction
{
  illegal_dir,
  to_utf32,
  from_utf32
};

enum variant
{
  illegal_var,
  UTF_32,
  UTF_32LE,
  UTF_32BE
};

struct utf32_data
{
  enum direction dir;
  enum variant var;
  int swap;
};


extern int gconv_init (struct __gconv_step *step);
int
gconv_init (struct __gconv_step *step)
{
  /* Determine which direction.  */
  struct utf32_data *new_data;
  enum direction dir = illegal_dir;
  enum variant var = illegal_var;
  int result;

  if (__strcasecmp (step->__from_name, "UTF-32//") == 0)
    {
      dir = from_utf32;
      var = UTF_32;
    }
  else if (__strcasecmp (step->__to_name, "UTF-32//") == 0)
    {
      dir = to_utf32;
      var = UTF_32;
    }
  else if (__strcasecmp (step->__from_name, "UTF-32BE//") == 0)
    {
      dir = from_utf32;
      var = UTF_32BE;
    }
  else if (__strcasecmp (step->__to_name, "UTF-32BE//") == 0)
    {
      dir = to_utf32;
      var = UTF_32BE;
    }
  else if (__strcasecmp (step->__from_name, "UTF-32LE//") == 0)
    {
      dir = from_utf32;
      var = UTF_32LE;
    }
  else if (__strcasecmp (step->__to_name, "UTF-32LE//") == 0)
    {
      dir = to_utf32;
      var = UTF_32LE;
    }

  result = __GCONV_NOCONV;
  if (__builtin_expect (dir, to_utf32) != illegal_dir)
    {
      new_data = (struct utf32_data *) malloc (sizeof (struct utf32_data));

      result = __GCONV_NOMEM;
      if (new_data != NULL)
      {
        new_data->dir = dir;
        new_data->var = var;
        new_data->swap = ((var == UTF_32LE && BYTE_ORDER == BIG_ENDIAN)
                      || (var == UTF_32BE
                        && BYTE_ORDER == LITTLE_ENDIAN));
        step->__data = new_data;

        if (dir == from_utf32)
          {
            step->__min_needed_from = MIN_NEEDED_FROM;
            step->__max_needed_from = MIN_NEEDED_FROM;
            step->__min_needed_to = MIN_NEEDED_TO;
            step->__max_needed_to = MIN_NEEDED_TO;
          }
        else
          {
            step->__min_needed_from = MIN_NEEDED_TO;
            step->__max_needed_from = MIN_NEEDED_TO;
            step->__min_needed_to = MIN_NEEDED_FROM;
            step->__max_needed_to = MIN_NEEDED_FROM;
          }

        step->__stateful = 0;

        result = __GCONV_OK;
      }
    }

  return result;
}


extern void gconv_end (struct __gconv_step *data);
void
gconv_end (struct __gconv_step *data)
{
  free (data->__data);
}


/* Convert from the internal (UCS4-like) format to UTF-32.  */
#define MIN_NEEDED_INPUT      MIN_NEEDED_TO
#define MIN_NEEDED_OUTPUT     MIN_NEEDED_FROM
#define LOOPFCT               TO_LOOP
#define BODY \
  {                                                         \
    uint32_t c = get32 (inptr);                                         \
                                                            \
    if (__builtin_expect (c >= 0x110000, 0))                            \
      {                                                           \
      STANDARD_TO_LOOP_ERR_HANDLER (4);                           \
      }                                                           \
    else if (__builtin_expect (c >= 0xd800 && c < 0xe000, 0))                 \
      {                                                           \
      /* Surrogate characters in UCS-4 input are not valid.             \
         We must catch this.  If we let surrogates pass through,        \
         attackers could make a security hole exploit by                \
         generating "irregular UTF-32" sequences.  */                   \
      result = __GCONV_ILLEGAL_INPUT;                                   \
      if (! ignore_errors_p ())                                   \
        break;                                              \
      inptr += 4;                                           \
      ++*irreversible;                                      \
      continue;                                             \
      }                                                           \
                                                            \
    if (swap)                                                     \
      put32 (outptr, bswap_32 (c));                               \
    else                                                    \
      put32 (outptr, c);                                          \
                                                            \
    outptr += 4;                                            \
    inptr += 4;                                                   \
  }
#define LOOP_NEED_FLAGS
#define EXTRA_LOOP_DECLS \
      , enum variant var, int swap
#include <iconv/loop.c>


/* Convert from UTF-32 to the internal (UCS4-like) format.  */
#define MIN_NEEDED_INPUT      MIN_NEEDED_FROM
#define MIN_NEEDED_OUTPUT     MIN_NEEDED_TO
#define LOOPFCT               FROM_LOOP
#define BODY \
  {                                                         \
    uint32_t u1 = get32 (inptr);                                  \
                                                            \
    if (swap)                                                     \
      u1 = bswap_32 (u1);                                         \
                                                            \
    if (__builtin_expect (u1 >= 0x110000, 0))                           \
      {                                                           \
      /* This is illegal.  */                                     \
      STANDARD_FROM_LOOP_ERR_HANDLER (4);                         \
      }                                                           \
                                                            \
    put32 (outptr, u1);                                           \
    inptr += 4;                                                   \
    outptr += 4;                                            \
  }
#define LOOP_NEED_FLAGS
#define EXTRA_LOOP_DECLS \
      , enum variant var, int swap
#include <iconv/loop.c>


/* Now define the toplevel functions.  */
#include <iconv/skeleton.c>

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