/* Copyright (C) 1999-2000 Free Software Foundation, Inc.
   This file is part of the GNU ICONV Library.

   The GNU ICONV Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU ICONV 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
   Library General Public License for more details.

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

/* This file defines the conversion loop via Unicode as a pivot encoding. */

static size_t unicode_loop_convert (iconv_t icd,
                                    const char* * inbuf, size_t *inbytesleft,
                                    char* * outbuf, size_t *outbytesleft)
{
  conv_t cd = (conv_t) icd;
  size_t result = 0;
  const unsigned char* inptr = (const unsigned char*) *inbuf;
  size_t inleft = *inbytesleft;
  unsigned char* outptr = (unsigned char*) *outbuf;
  size_t outleft = *outbytesleft;
  while (inleft > 0) {
    ucs4_t wc;
    int incount;
    int outcount;
    incount = cd->ifuncs.xxx_mbtowc(cd,&wc,inptr,inleft);
    if (incount <= 0) {
      if (incount == 0) {
        /* Case 1: invalid input */
        errno = EILSEQ;
        result = -1;
        break;
      }
      if (incount == -1) {
        /* Case 2: not enough bytes available to detect anything */
        errno = EINVAL;
        result = -1;
        break;
      }
      /* Case 3: k bytes read, but only a shift sequence */
      incount = -1-incount;
    } else {
      /* Case 4: k bytes read, making up a wide character */
      if (outleft == 0) {
        errno = E2BIG;
        result = -1;
        break;
      }
      outcount = cd->ofuncs.xxx_wctomb(cd,outptr,wc,outleft);
      if (outcount != 0)
        goto outcount_ok;
      /* Try transliteration. */
      result++;
      if (cd->transliterate) {
        if (cd->oflags & HAVE_HANGUL_JAMO) {
          /* Decompose Hangul into Jamo. Use double-width Jamo (contained
             in all Korean encodings and ISO-2022-JP-2), not half-width Jamo
             (contained in Unicode only). */
          ucs4_t buf[3];
          int ret = johab_hangul_decompose(cd,buf,wc);
          if (ret != RET_ILSEQ) {
            /* we know 1 <= ret <= 3 */
            state_t backup_state = cd->ostate;
            unsigned char* backup_outptr = outptr;
            size_t backup_outleft = outleft;
            int i, sub_outcount;
            for (i = 0; i < ret; i++) {
              if (outleft == 0) {
                sub_outcount = RET_TOOSMALL;
                goto johab_hangul_failed;
              }
              sub_outcount = cd->ofuncs.xxx_wctomb(cd,outptr,buf[i],outleft);
              if (sub_outcount <= 0)
                goto johab_hangul_failed;
              if (!(sub_outcount <= outleft)) abort();
              outptr += sub_outcount; outleft -= sub_outcount;
            }
            goto char_done;
          johab_hangul_failed:
            cd->ostate = backup_state;
            outptr = backup_outptr;
            outleft = backup_outleft;
            if (sub_outcount < 0) {
              errno = E2BIG;
              result = -1;
              break;
            }
          }
        }
        {
          /* Try to use a variant, but postfix it with
             U+303E IDEOGRAPHIC VARIATION INDICATOR
             (cf. Ken Lunde's "CJKV information processing", p. 188). */
          int indx = -1;
          if (wc == 0x3006)
            indx = 0;
          else if (wc == 0x30f6)
            indx = 1;
          else if (wc >= 0x4e00 && wc < 0xa000)
            indx = cjk_variants_indx[wc-0x4e00];
          if (indx >= 0) {
            for (;; indx++) {
              ucs4_t buf[2];
              unsigned short variant = cjk_variants[indx];
              unsigned short last = variant & 0x8000;
              variant &= 0x7fff;
              variant += 0x3000;
              buf[0] = variant; buf[1] = 0x303e;
              {
                state_t backup_state = cd->ostate;
                unsigned char* backup_outptr = outptr;
                size_t backup_outleft = outleft;
                int i, sub_outcount;
                for (i = 0; i < 2; i++) {
                  if (outleft == 0) {
                    sub_outcount = RET_TOOSMALL;
                    goto variant_failed;
                  }
                  sub_outcount = cd->ofuncs.xxx_wctomb(cd,outptr,buf[i],outleft);
                  if (sub_outcount <= 0)
                    goto variant_failed;
                  if (!(sub_outcount <= outleft)) abort();
                  outptr += sub_outcount; outleft -= sub_outcount;
                }
                goto char_done;
              variant_failed:
                cd->ostate = backup_state;
                outptr = backup_outptr;
                outleft = backup_outleft;
                if (sub_outcount < 0) {
                  errno = E2BIG;
                  result = -1;
                  break;
                }
              }
              if (last)
                break;
            }
          }
        }
        if (wc >= 0x2018 && wc <= 0x201a) {
          /* Special case for quotation marks 0x2018, 0x2019, 0x201a */
          ucs4_t substitute =
            (cd->oflags & HAVE_QUOTATION_MARKS
             ? (wc == 0x201a ? 0x2018 : wc)
             : (cd->oflags & HAVE_ACCENTS
                ? (wc==0x2019 ? 0x00b4 : 0x0060) /* use accents */
                : 0x0027 /* use apostrophe */
            )  );
          outcount = cd->ofuncs.xxx_wctomb(cd,outptr,substitute,outleft);
          if (outcount != 0)
            goto outcount_ok;
        }
        {
          /* Use the transliteration table. */
          int indx = translit_index(wc);
          if (indx >= 0) {
            const unsigned char * cp = &translit_data[indx];
            unsigned int num = *cp++;
            state_t backup_state = cd->ostate;
            unsigned char* backup_outptr = outptr;
            size_t backup_outleft = outleft;
            unsigned int i;
            int sub_outcount;
            for (i = 0; i < num; i++) {
              if (outleft == 0) {
                sub_outcount = RET_TOOSMALL;
                goto translit_failed;
              }
              sub_outcount = cd->ofuncs.xxx_wctomb(cd,outptr,cp[i],outleft);
              if (sub_outcount <= 0)
                goto translit_failed;
              if (!(sub_outcount <= outleft)) abort();
              outptr += sub_outcount; outleft -= sub_outcount;
            }
            goto char_done;
          translit_failed:
            cd->ostate = backup_state;
            outptr = backup_outptr;
            outleft = backup_outleft;
            if (sub_outcount < 0) {
              errno = E2BIG;
              result = -1;
              break;
            }
          }
        }
      }
      outcount = cd->ofuncs.xxx_wctomb(cd,outptr,0xFFFD,outleft);
      if (outcount != 0)
        goto outcount_ok;
      errno = EILSEQ;
      result = -1;
      break;
    outcount_ok:
      if (outcount < 0) {
        errno = E2BIG;
        result = -1;
        break;
      }
      if (!(outcount <= outleft)) abort();
      outptr += outcount; outleft -= outcount;
    char_done:
      ;
    }
    if (!(incount <= inleft)) abort();
    inptr += incount; inleft -= incount;
  }
  *inbuf = (const char*) inptr;
  *inbytesleft = inleft;
  *outbuf = (char*) outptr;
  *outbytesleft = outleft;
  return result;
}

static size_t unicode_loop_reset (iconv_t icd,
                                  char* * outbuf, size_t *outbytesleft)
{
  conv_t cd = (conv_t) icd;
  if (outbuf == NULL || *outbuf == NULL) {
    /* Reset the states. */
    memset(&cd->istate,'\0',sizeof(state_t));
    memset(&cd->ostate,'\0',sizeof(state_t));
    return 0;
  } else {
    if (cd->ofuncs.xxx_reset) {
      int outcount =
        cd->ofuncs.xxx_reset(cd, (unsigned char *) *outbuf, *outbytesleft);
      if (outcount < 0) {
        errno = E2BIG;
        return -1;
      }
      *outbuf += outcount; *outbytesleft -= outcount;
    }
    memset(&cd->istate,'\0',sizeof(state_t));
    memset(&cd->ostate,'\0',sizeof(state_t));
    return 0;
  }
}