/* Copyright (C) 2000-2002, 2004-2005 Free Software Foundation, Inc.
   This file is part of the GNU LIBICONV Library.

   The GNU LIBICONV 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 LIBICONV 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 LIBICONV Library; see the file COPYING.LIB.
   If not, see <https://www.gnu.org/licenses/>.  */

/* Create a table from CHARSET to Unicode. */

#include "config.h"

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iconv.h>
#include <errno.h>

#include "binary-io.h"

/* If nonzero, ignore conversions outside Unicode plane 0. */
static int bmp_only;

static const char* hexbuf (unsigned char buf[], unsigned int buflen)
{
  static char msg[50];
  switch (buflen) {
    case 1: sprintf(msg,"0x%02X",buf[0]); break;
    case 2: sprintf(msg,"0x%02X%02X",buf[0],buf[1]); break;
    case 3: sprintf(msg,"0x%02X%02X%02X",buf[0],buf[1],buf[2]); break;
    case 4: sprintf(msg,"0x%02X%02X%02X%02X",buf[0],buf[1],buf[2],buf[3]); break;
    default: abort();
  }
  return msg;
}

static int try (iconv_t cd, unsigned char buf[], unsigned int buflen, unsigned int* out)
{
  const char* inbuf = (const char*) buf;
  size_t inbytesleft = buflen;
  char* outbuf = (char*) out;
  size_t outbytesleft = 3*sizeof(unsigned int);
  size_t result;
  iconv(cd,NULL,NULL,NULL,NULL);
  result = iconv(cd,(ICONV_CONST char**)&inbuf,&inbytesleft,&outbuf,&outbytesleft);
  if (result != (size_t)(-1))
    result = iconv(cd,NULL,NULL,&outbuf,&outbytesleft);
  if (result == (size_t)(-1)) {
    if (errno == EILSEQ) {
      return -1;
    } else if (errno == EINVAL) {
      return 0;
    } else {
      int saved_errno = errno;
      fprintf(stderr,"%s: iconv error: ",hexbuf(buf,buflen));
      errno = saved_errno;
      perror("");
      exit(1);
    }
  } else if (result > 0) /* ignore conversions with transliteration */ {
    return -1;
  } else {
    if (inbytesleft != 0) {
      fprintf(stderr,"%s: inbytes = %ld, outbytes = %ld\n",hexbuf(buf,buflen),(long)(buflen-inbytesleft),(long)(3*sizeof(unsigned int)-outbytesleft));
      exit(1);
    }
    return (3*sizeof(unsigned int)-outbytesleft)/sizeof(unsigned int);
  }
}

/* Returns the out[] buffer as a Unicode value, formatted as 0x%04X. */
static const char* ucs4_decode (const unsigned int* out, unsigned int outlen)
{
  static char hexbuf[21];
  char* p = hexbuf;
  while (outlen > 0) {
    if (p > hexbuf)
      *p++ = ' ';
    sprintf (p, "0x%04X", out[0]);
    out += 1; outlen -= 1;
    if (bmp_only && strlen(p) > 6)
      return NULL;
    p += strlen(p);
  }
  return hexbuf;
}

int main (int argc, char* argv[])
{
  const char* charset;
  iconv_t cd;
  int search_depth;

  if (argc != 2) {
    fprintf(stderr,"Usage: table-from charset\n");
    exit(1);
  }
  charset = argv[1];

#if O_BINARY
  SET_BINARY(fileno(stdout));
#endif

  cd = iconv_open("UCS-4-INTERNAL",charset);
  if (cd == (iconv_t)(-1)) {
    perror("iconv_open");
    exit(1);
  }

  /* When testing UTF-8, stop at 0x10000, otherwise the output file gets too
     big. */
  bmp_only = (strcmp(charset,"UTF-8") == 0);
  search_depth = (strcmp(charset,"UTF-8") == 0 ? 3 : 4);

  {
    unsigned int out[3];
    unsigned char buf[4];
    unsigned int i0, i1, i2, i3;
    int result;
    for (i0 = 0; i0 < 0x100; i0++) {
      buf[0] = i0;
      result = try(cd,buf,1,out);
      if (result < 0) {
      } else if (result > 0) {
        const char* unicode = ucs4_decode(out,result);
        if (unicode != NULL)
          printf("0x%02X\t%s\n",i0,unicode);
      } else {
        for (i1 = 0; i1 < 0x100; i1++) {
          buf[1] = i1;
          result = try(cd,buf,2,out);
          if (result < 0) {
          } else if (result > 0) {
            const char* unicode = ucs4_decode(out,result);
            if (unicode != NULL)
              printf("0x%02X%02X\t%s\n",i0,i1,unicode);
          } else {
            for (i2 = 0; i2 < 0x100; i2++) {
              buf[2] = i2;
              result = try(cd,buf,3,out);
              if (result < 0) {
              } else if (result > 0) {
                const char* unicode = ucs4_decode(out,result);
                if (unicode != NULL)
                  printf("0x%02X%02X%02X\t%s\n",i0,i1,i2,unicode);
              } else if (search_depth > 3) {
                for (i3 = 0; i3 < 0x100; i3++) {
                  buf[3] = i3;
                  result = try(cd,buf,4,out);
                  if (result < 0) {
                  } else if (result > 0) {
                    const char* unicode = ucs4_decode(out,result);
                    if (unicode != NULL)
                      printf("0x%02X%02X%02X%02X\t%s\n",i0,i1,i2,i3,unicode);
                  } else {
                    fprintf(stderr,"%s: incomplete byte sequence\n",hexbuf(buf,4));
                    exit(1);
                  }
                }
              }
            }
          }
        }
      }
    }
  }

  if (iconv_close(cd) < 0) {
    perror("iconv_close");
    exit(1);
  }

  if (ferror(stdin) || ferror(stdout) || fclose(stdout)) {
    fprintf(stderr,"I/O error\n");
    exit(1);
  }

  exit(0);
}