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utf-16.c

/* Conversion module for UTF-16.
   Copyright (C) 1999, 2000-2002, 2003 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 byte order.  */
#define BOM_OE    0xfffe


/* Definitions used in the body of the `gconv' function.  */
#define FROM_LOOP       from_utf16_loop
#define TO_LOOP               to_utf16_loop
#define DEFINE_INIT           0
#define DEFINE_FINI           0
#define MIN_NEEDED_FROM       2
#define MAX_NEEDED_FROM       4
#define MIN_NEEDED_TO         4
#define FROM_DIRECTION        (dir == from_utf16)
#define PREPARE_LOOP \
  enum direction dir = ((struct utf16_data *) step->__data)->dir;       \
  enum variant var = ((struct utf16_data *) step->__data)->var;               \
  int swap;                                                 \
  if (FROM_DIRECTION && var == UTF_16)                                  \
    {                                                       \
      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 utf16_data *) step->__data)->swap = 1;             \
            *inptrp = inptr += 2;                                 \
          }                                                 \
      }                                                     \
    }                                                       \
  else if (!FROM_DIRECTION && var == UTF_16 && !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 utf16_data *) step->__data)->swap;
#define EXTRA_LOOP_ARGS       , var, swap


/* Direction of the transformation.  */
enum direction
{
  illegal_dir,
  to_utf16,
  from_utf16
};

enum variant
{
  illegal_var,
  UTF_16,
  UTF_16LE,
  UTF_16BE
};

struct utf16_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 utf16_data *new_data;
  enum direction dir = illegal_dir;
  enum variant var = illegal_var;
  int result;

  if (__strcasecmp (step->__from_name, "UTF-16//") == 0)
    {
      dir = from_utf16;
      var = UTF_16;
    }
  else if (__strcasecmp (step->__to_name, "UTF-16//") == 0)
    {
      dir = to_utf16;
      var = UTF_16;
    }
  else if (__strcasecmp (step->__from_name, "UTF-16BE//") == 0)
    {
      dir = from_utf16;
      var = UTF_16BE;
    }
  else if (__strcasecmp (step->__to_name, "UTF-16BE//") == 0)
    {
      dir = to_utf16;
      var = UTF_16BE;
    }
  else if (__strcasecmp (step->__from_name, "UTF-16LE//") == 0)
    {
      dir = from_utf16;
      var = UTF_16LE;
    }
  else if (__strcasecmp (step->__to_name, "UTF-16LE//") == 0)
    {
      dir = to_utf16;
      var = UTF_16LE;
    }

  result = __GCONV_NOCONV;
  if (__builtin_expect (dir, to_utf16) != illegal_dir)
    {
      new_data = (struct utf16_data *) malloc (sizeof (struct utf16_data));

      result = __GCONV_NOMEM;
      if (new_data != NULL)
      {
        new_data->dir = dir;
        new_data->var = var;
        new_data->swap = ((var == UTF_16LE && BYTE_ORDER == BIG_ENDIAN)
                      || (var == UTF_16BE
                        && BYTE_ORDER == LITTLE_ENDIAN));
        step->__data = new_data;

        if (dir == from_utf16)
          {
            step->__min_needed_from = MIN_NEEDED_FROM;
            step->__max_needed_from = MAX_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 = MAX_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-16.  */
#define MIN_NEEDED_INPUT      MIN_NEEDED_TO
#define MIN_NEEDED_OUTPUT     MIN_NEEDED_FROM
#define MAX_NEEDED_OUTPUT     MAX_NEEDED_FROM
#define LOOPFCT               TO_LOOP
#define BODY \
  {                                                         \
    uint32_t c = get32 (inptr);                                         \
                                                            \
    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                \
         synthesizing any desired plane 1-16 character.  */             \
      result = __GCONV_ILLEGAL_INPUT;                                   \
      if (! ignore_errors_p ())                                   \
        break;                                              \
      inptr += 4;                                           \
      ++*irreversible;                                      \
      continue;                                             \
      }                                                           \
                                                            \
    if (swap)                                                     \
      {                                                           \
      if (__builtin_expect (c >= 0x10000, 0))                           \
        {                                                   \
          if (__builtin_expect (c >= 0x110000, 0))                      \
            {                                                     \
            STANDARD_TO_LOOP_ERR_HANDLER (4);                     \
            }                                                     \
                                                            \
          /* Generate a surrogate character.  */                        \
          if (__builtin_expect (outptr + 4 > outend, 0))                \
            {                                                     \
            /* Overflow in the output buffer.  */                       \
            result = __GCONV_FULL_OUTPUT;                         \
            break;                                                \
            }                                                     \
                                                            \
          put16 (outptr, bswap_16 (0xd7c0 + (c >> 10)));                \
          outptr += 2;                                      \
          put16 (outptr, bswap_16 (0xdc00 + (c & 0x3ff)));              \
        }                                                   \
      else                                                  \
        put16 (outptr, bswap_16 (c));                                   \
      }                                                           \
    else                                                    \
      {                                                           \
      if (__builtin_expect (c >= 0x10000, 0))                           \
        {                                                   \
          if (__builtin_expect (c >= 0x110000, 0))                      \
            {                                                     \
            STANDARD_TO_LOOP_ERR_HANDLER (4);                     \
            }                                                     \
                                                            \
          /* Generate a surrogate character.  */                        \
          if (__builtin_expect (outptr + 4 > outend, 0))                \
            {                                                     \
            /* Overflow in the output buffer.  */                       \
            result = __GCONV_FULL_OUTPUT;                         \
            break;                                                \
            }                                                     \
                                                            \
          put16 (outptr, 0xd7c0 + (c >> 10));                           \
          outptr += 2;                                      \
          put16 (outptr, 0xdc00 + (c & 0x3ff));                   \
        }                                                   \
      else                                                  \
        put16 (outptr, c);                                        \
      }                                                           \
    outptr += 2;                                            \
    inptr += 4;                                                   \
  }
#define LOOP_NEED_FLAGS
#define EXTRA_LOOP_DECLS \
      , enum variant var, int swap
#include <iconv/loop.c>


/* Convert from UTF-16 to the internal (UCS4-like) format.  */
#define MIN_NEEDED_INPUT      MIN_NEEDED_FROM
#define MAX_NEEDED_INPUT      MAX_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, 1) || u1 > 0xdfff)             \
        {                                                   \
          /* No surrogate.  */                                    \
          put32 (outptr, u1);                                     \
          inptr += 2;                                             \
        }                                                   \
      else                                                  \
        {                                                   \
          uint16_t u2;                                      \
                                                            \
          /* It's a surrogate character.  At least the first word says      \
             it is.  */                                     \
          if (__builtin_expect (inptr + 4 > inend, 0))                  \
            {                                                     \
            /* We don't have enough input for another complete input      \
               character.  */                               \
            result = __GCONV_INCOMPLETE_INPUT;                    \
            break;                                                \
            }                                                     \
                                                            \
          inptr += 2;                                             \
          u2 = bswap_16 (get16 (inptr));                          \
          if (__builtin_expect (u2 < 0xdc00, 0)                   \
            || __builtin_expect (u2 > 0xdfff, 0))                       \
            {                                                     \
            /* This is no valid second word for a surrogate.  */        \
            inptr -= 2;                                     \
            STANDARD_FROM_LOOP_ERR_HANDLER (2);                   \
            }                                                     \
                                                            \
          put32 (outptr, ((u1 - 0xd7c0) << 10) + (u2 - 0xdc00));        \
          inptr += 2;                                             \
        }                                                   \
      }                                                           \
    else                                                    \
      {                                                           \
      if (__builtin_expect (u1 < 0xd800, 1) || u1 > 0xdfff)             \
        {                                                   \
          /* No surrogate.  */                                    \
          put32 (outptr, u1);                                     \
          inptr += 2;                                             \
        }                                                   \
      else                                                  \
        {                                                   \
          uint16_t u2;                                      \
                                                            \
          /* It's a surrogate character.  At least the first word says      \
             it is.  */                                     \
          if (__builtin_expect (inptr + 4 > inend, 0))                  \
            {                                                     \
            /* We don't have enough input for another complete input      \
               character.  */                               \
            result = __GCONV_INCOMPLETE_INPUT;                    \
            break;                                                \
            }                                                     \
                                                            \
          inptr += 2;                                             \
          u2 = get16 (inptr);                                     \
          if (__builtin_expect (u2 < 0xdc00, 0)                   \
            || __builtin_expect (u2 > 0xdfff, 0))                       \
            {                                                     \
            /* This is no valid second word for a surrogate.  */        \
            inptr -= 2;                                     \
            STANDARD_FROM_LOOP_ERR_HANDLER (2);                   \
            }                                                     \
                                                            \
          put32 (outptr, ((u1 - 0xd7c0) << 10) + (u2 - 0xdc00));        \
          inptr += 2;                                             \
        }                                                   \
      }                                                           \
    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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