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iso-2022-cn.c

/* Conversion module for ISO-2022-CN.
   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 <dlfcn.h>
#include <gconv.h>
#include <stdint.h>
#include <string.h>
#include "gb2312.h"
#include "cns11643l1.h"
#include "cns11643l2.h"

#include <assert.h>

/* This makes obvious what everybody knows: 0x1b is the Esc character.  */
#define ESC 0x1b

/* We have single-byte shift-in and shift-out sequences, and the single
   shift sequence SS2 which replaces the SS2 designation for the next
   two bytes.  */
#define SI  0x0f
#define SO  0x0e
#define SS2_0     ESC
#define SS2_1     0x4e

/* Definitions used in the body of the `gconv' function.  */
#define CHARSET_NAME          "ISO-2022-CN//"
#define DEFINE_INIT           1
#define DEFINE_FINI           1
#define FROM_LOOP       from_iso2022cn_loop
#define TO_LOOP               to_iso2022cn_loop
#define FROM_LOOP_MIN_NEEDED_FROM   1
#define FROM_LOOP_MAX_NEEDED_FROM   4
#define FROM_LOOP_MIN_NEEDED_TO           4
#define FROM_LOOP_MAX_NEEDED_TO           4
#define TO_LOOP_MIN_NEEDED_FROM           4
#define TO_LOOP_MAX_NEEDED_FROM           4
#define TO_LOOP_MIN_NEEDED_TO       1
#define TO_LOOP_MAX_NEEDED_TO       6
#define PREPARE_LOOP \
  int save_set;                                                   \
  int *setp = &data->__statep->__count;
#define EXTRA_LOOP_ARGS       , setp


/* The COUNT element of the state keeps track of the currently selected
   character set.  The possible values are:  */
enum
{
  ASCII_set = 0,
  GB2312_set = 8,
  CNS11643_1_set = 16,
  CNS11643_2_set = 24,
  CURRENT_SEL_MASK = 24,
  GB2312_ann = 32,
  CNS11643_1_ann = 64,
  CNS11643_2_ann = 128,
  CURRENT_ANN_MASK = 224
};


/* Since this is a stateful encoding we have to provide code which resets
   the output state to the initial state.  This has to be done during the
   flushing.  */
#define EMIT_SHIFT_TO_INIT \
  if (data->__statep->__count != ASCII_set)                             \
    {                                                       \
      if (FROM_DIRECTION)                                         \
      /* It's easy, we don't have to emit anything, we just reset the         \
         state for the input.  */                                 \
      data->__statep->__count = ASCII_set;                              \
      else                                                  \
      {                                                     \
        /* We are not in the initial state.  To switch back we have           \
           to emit `SI'.  */                                      \
        if (__builtin_expect (outbuf == outend, 0))                     \
          /* We don't have enough room in the output buffer.  */        \
          status = __GCONV_FULL_OUTPUT;                           \
        else                                                      \
          {                                                 \
            /* Write out the shift sequence.  */                        \
            *outbuf++ = SI;                                       \
            data->__statep->__count = ASCII_set;                        \
          }                                                 \
      }                                                     \
    }


/* Since we might have to reset input pointer we must be able to save
   and retore the state.  */
#define SAVE_RESET_STATE(Save) \
  if (Save)                                                 \
    save_set = *setp;                                             \
  else                                                            \
    *setp = save_set


/* First define the conversion function from ISO-2022-CN to UCS4.  */
#define MIN_NEEDED_INPUT      FROM_LOOP_MIN_NEEDED_FROM
#define MAX_NEEDED_INPUT      FROM_LOOP_MAX_NEEDED_FROM
#define MIN_NEEDED_OUTPUT     FROM_LOOP_MIN_NEEDED_TO
#define MAX_NEEDED_OUTPUT     FROM_LOOP_MAX_NEEDED_TO
#define LOOPFCT               FROM_LOOP
#define BODY \
  {                                                         \
    uint32_t ch = *inptr;                                         \
                                                            \
    /* This is a 7bit character set, disallow all 8bit characters.  */        \
    if (__builtin_expect (ch >= 0x7f, 0))                         \
      STANDARD_FROM_LOOP_ERR_HANDLER (1);                         \
                                                            \
    /* Recognize escape sequences.  */                                  \
    if (__builtin_expect (ch, 0) == ESC)                          \
      {                                                           \
      /* There are two kinds of escape sequences we have to handle:           \
         - those announcing the use of GB and CNS characters on the           \
           line; we can simply ignore them                              \
         - the initial byte of the SS2 sequence.                        \
      */                                                    \
      if (__builtin_expect (inptr + 2 > inend, 0)                       \
          || (inptr[1] == '$'                                     \
            && (__builtin_expect (inptr + 3 > inend, 0)                 \
                || (inptr[2] == ')'                               \
                  && __builtin_expect (inptr + 4 > inend, 0))           \
                || (inptr[2] == '*'                               \
                  && __builtin_expect (inptr + 4 > inend, 0))))         \
          || (inptr[1] == SS2_1                                   \
            && __builtin_expect (inptr + 4 > inend, 0)))                \
        {                                                   \
          result = __GCONV_INCOMPLETE_INPUT;                            \
          break;                                            \
        }                                                   \
      if (inptr[1] == '$'                                         \
          && ((inptr[2] == ')' && (inptr[3] == 'A' || inptr[3] == 'G'))     \
            || (inptr[2] == '*' && inptr[3] == 'H')))             \
        {                                                   \
          /* OK, we accept those character sets.  */                    \
          if (inptr[3] == 'A')                                    \
            ann = GB2312_ann;                                     \
          else if (inptr[3] == 'G')                               \
            ann = CNS11643_1_ann;                                 \
          inptr += 4;                                             \
          continue;                                               \
        }                                                   \
      }                                                           \
    else if (__builtin_expect (ch, 0) == SO)                            \
      {                                                           \
      /* Switch to use GB2312 or CNS 11643 plane 1, depending on which      \
         S0 designation came last.  The only problem is what to do with     \
         faulty input files where no designator came.                   \
         XXX For now I'll default to use GB2312.  If this is not the          \
         best behaviour (e.g., we should flag an error) let me know.  */    \
      ++inptr;                                              \
      set = ann == CNS11643_1_ann ? CNS11643_1_set : GB2312_set;        \
      continue;                                             \
      }                                                           \
    else if (__builtin_expect (ch, 0) == SI)                            \
      {                                                           \
      /* Switch to use ASCII.  */                                 \
      ++inptr;                                              \
      set = ASCII_set;                                      \
      continue;                                             \
      }                                                           \
                                                            \
    if (__builtin_expect (ch, 0) == ESC && inptr[1] == SS2_1)                 \
      {                                                           \
      /* This is a character from CNS 11643 plane 2.                    \
         XXX We could test here whether the use of this character       \
         set was announced.  */                                   \
      inptr += 2;                                           \
      ch = cns11643l2_to_ucs4 (&inptr, 2, 0);                           \
      if (__builtin_expect (ch, 0) == __UNKNOWN_10646_CHAR)             \
        {                                                   \
          inptr -= 2;                                             \
          STANDARD_FROM_LOOP_ERR_HANDLER (2);                           \
        }                                                   \
      }                                                           \
    else if (set == ASCII_set)                                          \
      {                                                           \
      /* Almost done, just advance the input pointer.  */               \
      ++inptr;                                              \
      }                                                           \
    else                                                    \
      {                                                           \
      /* That's pretty easy, we have a dedicated functions for this.  */    \
      if (set == GB2312_set)                                      \
        ch = gb2312_to_ucs4 (&inptr, inend - inptr, 0);                 \
      else                                                  \
        {                                                   \
          assert (set == CNS11643_1_set);                         \
          ch = cns11643l1_to_ucs4 (&inptr, inend - inptr, 0);                 \
        }                                                   \
                                                            \
      if (__builtin_expect (ch, 1) == 0)                          \
        {                                                   \
          result = __GCONV_INCOMPLETE_INPUT;                            \
          break;                                            \
        }                                                   \
      else if (__builtin_expect (ch, 1) == __UNKNOWN_10646_CHAR)        \
        {                                                   \
          STANDARD_FROM_LOOP_ERR_HANDLER (1);                           \
        }                                                   \
      }                                                           \
                                                            \
    put32 (outptr, ch);                                           \
    outptr += 4;                                            \
  }
#define LOOP_NEED_FLAGS
#define EXTRA_LOOP_DECLS      , int *setp
#define INIT_PARAMS           int set = *setp & CURRENT_SEL_MASK; \
                        int ann = *setp & CURRENT_ANN_MASK
#define UPDATE_PARAMS         *setp = set | ann
#include <iconv/loop.c>


/* Next, define the other direction.  */
#define MIN_NEEDED_INPUT      TO_LOOP_MIN_NEEDED_FROM
#define MAX_NEEDED_INPUT      TO_LOOP_MAX_NEEDED_FROM
#define MIN_NEEDED_OUTPUT     TO_LOOP_MIN_NEEDED_TO
#define MAX_NEEDED_OUTPUT     TO_LOOP_MAX_NEEDED_TO
#define LOOPFCT               TO_LOOP
#define BODY \
  {                                                         \
    uint32_t ch = get32 (inptr);                                  \
                                                            \
    /* First see whether we can write the character using the currently       \
       selected character set.  */                                \
    if (ch < 0x80)                                                \
      {                                                           \
      if (set != ASCII_set)                                       \
        {                                                   \
          *outptr++ = SI;                                         \
          set = ASCII_set;                                        \
          if (__builtin_expect (outptr == outend, 0))                   \
            {                                                     \
            result = __GCONV_FULL_OUTPUT;                         \
            break;                                                \
            }                                                     \
        }                                                   \
                                                            \
      *outptr++ = ch;                                             \
                                                            \
      /* At the end of the line we have to clear the `ann' flags since      \
         every line must contain this information again.  */                  \
      if (ch == L'\n')                                      \
        ann = 0;                                            \
      }                                                           \
    else                                                    \
      {                                                           \
      char buf[2];                                                \
      int used;                                             \
      size_t written = 0;                                         \
                                                            \
      if (set == GB2312_set || (ann & CNS11643_1_ann) == 0)             \
        {                                                   \
          written = ucs4_to_gb2312 (ch, buf, 2);                        \
          used = GB2312_set;                                      \
        }                                                   \
      else                                                  \
        {                                                   \
          written = ucs4_to_cns11643l1 (ch, buf, 2);                    \
          used = CNS11643_1_set;                                  \
        }                                                   \
                                                            \
      if (written == __UNKNOWN_10646_CHAR)                              \
        {                                                   \
          /* Cannot convert it using the currently selected SO set.           \
             Next try the SS2 set.  */                            \
          written = ucs4_to_cns11643l2 (ch, buf, 2);                    \
          if (written != __UNKNOWN_10646_CHAR)                    \
            /* Yep, that worked.  */                                    \
            used = CNS11643_2_set;                                \
          else                                              \
            {                                                     \
            /* Well, see whether we have to change the SO set.  */            \
            if (used == GB2312_set)                               \
              written = ucs4_to_cns11643l1 (ch, buf, 2);                \
            else                                            \
              written = ucs4_to_gb2312 (ch, buf, 2);              \
                                                            \
            if (__builtin_expect (written, 0) != __UNKNOWN_10646_CHAR)    \
              /* Oh well, then switch SO.  */                     \
              used = GB2312_set + CNS11643_1_set - used;                \
            else                                            \
              {                                             \
                UNICODE_TAG_HANDLER (ch, 4);                      \
                                                            \
                /* Even this does not work.  Error.  */                 \
                STANDARD_TO_LOOP_ERR_HANDLER (4);                       \
              }                                             \
            }                                                     \
        }                                                   \
      assert (written == 2);                                      \
                                                            \
      /* See whether we have to emit an escape sequence.  */                  \
      if (set != used)                                      \
        {                                                   \
          /* First see whether we announced that we use this                  \
             character set.  */                                   \
          if ((ann & (16 << (used >> 3))) == 0)                   \
            {                                                     \
            const char *escseq;                                   \
                                                            \
            if (__builtin_expect (outptr + 4 > outend, 0))              \
              {                                             \
                result = __GCONV_FULL_OUTPUT;                     \
                break;                                      \
              }                                             \
                                                            \
            assert ((used >> 3) >= 1 && (used >> 3) <= 3);              \
            escseq = ")A)G*H" + ((used >> 3) - 1) * 2;                  \
            *outptr++ = ESC;                                \
            *outptr++ = '$';                                \
            *outptr++ = *escseq++;                                \
            *outptr++ = *escseq++;                                \
                                                            \
            if (used == GB2312_set)                               \
              ann = (ann & CNS11643_2_ann) | GB2312_ann;                \
            else if (used == CNS11643_1_set)                      \
              ann = (ann & CNS11643_2_ann) | CNS11643_1_ann;            \
            else                                            \
              ann |= CNS11643_2_ann;                              \
            }                                                     \
                                                            \
          if (used == CNS11643_2_set)                                   \
            {                                                     \
            if (__builtin_expect (outptr + 2 > outend, 0))              \
              {                                             \
                result = __GCONV_FULL_OUTPUT;                     \
                break;                                      \
              }                                             \
            *outptr++ = SS2_0;                                    \
            *outptr++ = SS2_1;                                    \
            }                                                     \
          else                                              \
            {                                                     \
            /* We only have to emit something is currently ASCII is           \
               selected.  Otherwise we are switching within the         \
               SO charset.  */                                    \
            if (set == ASCII_set)                                 \
              {                                             \
                if (__builtin_expect (outptr + 1 > outend, 0))          \
                  {                                               \
                  result = __GCONV_FULL_OUTPUT;                   \
                  break;                                          \
                  }                                               \
                *outptr++ = SO;                                   \
              }                                             \
            }                                                     \
                                                            \
          /* Always test the length here since we have used up all the      \
             guaranteed output buffer slots.  */                        \
          if (__builtin_expect (outptr + 2 > outend, 0))                \
            {                                                     \
            result = __GCONV_FULL_OUTPUT;                         \
            break;                                                \
            }                                                     \
        }                                                   \
      else if (__builtin_expect (outptr + 2 > outend, 0))               \
        {                                                   \
          result = __GCONV_FULL_OUTPUT;                           \
          break;                                            \
        }                                                   \
                                                            \
      *outptr++ = buf[0];                                         \
      *outptr++ = buf[1];                                         \
      set = used;                                           \
      }                                                           \
                                                            \
    /* Now that we wrote the output increment the input pointer.  */          \
    inptr += 4;                                                   \
  }
#define LOOP_NEED_FLAGS
#define EXTRA_LOOP_DECLS      , int *setp
#define INIT_PARAMS           int set = *setp & CURRENT_SEL_MASK; \
                        int ann = *setp & CURRENT_ANN_MASK
#define UPDATE_PARAMS         *setp = set | ann
#include <iconv/loop.c>


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

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