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unicode.c

/* Conversion module for Unicode
   Copyright (C) 1999, 2000-2002 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1999.

   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 0xfeff
/* And in the other endian format.  */
#define BOM_OE    0xfffe


/* Definitions used in the body of the `gconv' function.  */
#define FROM_LOOP       from_unicode_loop
#define TO_LOOP               to_unicode_loop
#define DEFINE_INIT           0
#define DEFINE_FINI           0
#define MIN_NEEDED_FROM       2
#define MIN_NEEDED_TO         4
#define FROM_DIRECTION        (dir == from_unicode)
#define PREPARE_LOOP \
  enum direction dir = ((struct unicode_data *) step->__data)->dir;           \
  int swap;                                                 \
  if (FROM_DIRECTION)                                             \
    {                                                       \
      if (data->__invocation_counter == 0)                              \
      {                                                     \
        /* We have to find out which byte order the file is encoded in.  */ \
        if (inptr + 2 > inend)                                    \
          return (inptr == inend                                  \
                ? __GCONV_EMPTY_INPUT : __GCONV_INCOMPLETE_INPUT);            \
                                                            \
        if (get16u (inptr) == BOM)                                \
          /* Simply ignore the BOM character.  */                       \
          *inptrp = inptr += 2;                                   \
        else if (get16u (inptr) == BOM_OE)                              \
          {                                                 \
            ((struct unicode_data *) step->__data)->swap = 1;                 \
            *inptrp = inptr += 2;                                 \
          }                                                 \
      }                                                     \
    }                                                       \
  else if (!data->__internal_use && data->__invocation_counter == 0)          \
    {                                                       \
      /* Emit the Byte Order Mark.  */                                  \
      if (__builtin_expect (outbuf + 2 > outend, 0))                    \
      return __GCONV_FULL_OUTPUT;                                 \
                                                            \
      put16u (outbuf, BOM);                                       \
      outbuf += 2;                                                \
    }                                                       \
  swap = ((struct unicode_data *) step->__data)->swap;
#define EXTRA_LOOP_ARGS       , swap


/* Direction of the transformation.  */
enum direction
{
  illegal_dir,
  to_unicode,
  from_unicode
};

struct unicode_data
{
  enum direction dir;
  int swap;
};


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

  if (strcmp (step->__from_name, "UNICODE//") == 0)
    dir = from_unicode;
  else
    dir = to_unicode;

  new_data = (struct unicode_data *) malloc (sizeof (struct unicode_data));

  result = __GCONV_NOMEM;
  if (new_data != NULL)
    {
      new_data->dir = dir;
      new_data->swap = 0;
      step->__data = new_data;

      if (dir == from_unicode)
      {
        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 UCS2.  */
#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 >= 0x10000, 0))                             \
      {                                                           \
      UNICODE_TAG_HANDLER (c, 4);                                 \
      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, because the UCS-2 output might be          \
         interpreted as UTF-16 by other programs.  If we let                  \
         surrogates pass through, attackers could make a security       \
         hole exploit by synthesizing any desired plane 1-16                  \
         character.  */                                     \
      result = __GCONV_ILLEGAL_INPUT;                                   \
      if (! ignore_errors_p ())                                   \
        break;                                              \
      inptr += 4;                                           \
      ++*irreversible;                                      \
      continue;                                             \
      }                                                           \
    else                                                    \
      {                                                           \
      put16 (outptr, c);                                          \
      outptr += 2;                                                \
      }                                                           \
                                                            \
    inptr += 4;                                                   \
  }
#define LOOP_NEED_FLAGS
#define EXTRA_LOOP_DECLS \
      , int swap
#include <iconv/loop.c>


/* Convert from UCS2 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 \
  {                                                         \
    uint16_t u1 = get16 (inptr);                                  \
                                                            \
    if (swap)                                                     \
      u1 = bswap_16 (u1);                                         \
                                                            \
    if (__builtin_expect (u1 >= 0xd800 && u1 < 0xe000, 0))              \
      {                                                           \
      /* Surrogate characters in UCS-2 input are not valid.  Reject           \
         them.  (Catching this here is not security relevant.)  */            \
      STANDARD_FROM_LOOP_ERR_HANDLER (2);                         \
      }                                                           \
                                                            \
    put32 (outptr, u1);                                           \
                                                            \
    inptr += 2;                                                   \
    outptr += 4;                                            \
  }
#define LOOP_NEED_FLAGS
#define EXTRA_LOOP_DECLS \
      , int swap
#include <iconv/loop.c>


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

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