Re: [Groff] Re: man page encoding

[Werner LEMBERG]

> BTW, attached is the file gpreconv [...]

Since it possible that some mailers don't accept attachments, I resend
it here, directly embedded in the email.


    Werner


======================================================================


#define I18N

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>

#ifdef I18N
#include <locale.h>
#include <langinfo.h>
#include <iconv.h>
#endif /* I18N */

#define MAX_VAR_LEN 100

char *check_encoding_tag(char *);
char *check_encoding_tag_parse_tag(char *, char **, char **);
char *read_file (FILE *);
char *emacs2mime(char *);
char *mime2locale(char *);
void conversion_latin1 (char *, char *);
void conversion_utf8 (char *, char *);
void conversion_cp1047 (char *, char *);
void conversion_iconv (char *, char *);
void help (char *);

typedef struct {
  char * from;
  char * to;
} encname_t;

encname_t emacs_to_mime[] = {
  {"alternativnyj",                   ""},
  {"big5",                            "Big5"},
  {"chinese-big5",                    "Big5"},
  {"chinese-euc",                     "EUC-CN"},
  {"chinese-hz",                      "HZ-GB-2312"},
  {"chinese-iso-7bit",                ""},
  {"chinese-iso-8bit",                ""},
  {"chinese-iso-8bit-with-esc",       ""},
  {"cn-big5",                         "Big5"},
  {"cn-gb-2312",                      "GB2312"},
  {"compound-text",                   ""},
  {"ctext",                           ""},
  {"cyrillic-alternativnyj",          ""},
  {"cyrillic-iso-8bit",               "ISO-8859-5"},
  {"cyrillic-iso-8bit-with-esc",      ""},
  {"cyrillic-koi8",                   "KOI8-R"},
  {"dos",                             ""},
  {"emacs-mule",                      ""},
  {"euc-china",                       "EUC-CN"},
  {"euc-cn",                          "EUC-CN"},
  {"euc-japan",                       "EUC-JP"},
  {"euc-jisx0213",                    "EUC-JP"},
  {"euc-jisx0213-with-esc",           "EUC-JP"},
  {"euc-jp",                          "EUC-JP"},
  {"euc-korea",                       "EUC-KR"},
  {"euc-kr",                          "EUC-KR"},
  {"gb2312",                          "GB2312"},
  {"greek-iso-8bit",                  "ISO-8859-7"},
  {"greek-iso-8bit-with-esc",         "ISO-8859-7"},
  {"hebrew-iso-8bit",                 "ISO-8859-8"},
  {"hebrew-iso-8bit-with-esc",        "ISO-8859-8"},
  {"hz",                              "HZ-GB-2312"},
  {"hz-gb-2312",                      "HZ-GB-2312"},
  {"in-is13194-devanagari",           ""},
  {"in-is13194-devanagari-with-esc",  ""},
  {"iso-2022-7",                      ""},
  {"iso-2022-7bit",                   ""},
  {"iso-2022-7bit-lock",              ""},
  {"iso-2022-7bit-lock-ss2",          ""},
  {"iso-2022-7bit-ss2",               ""},
  {"iso-2022-8",                      ""},
  {"iso-2022-8bit",                   ""},
  {"iso-2022-8bit-lock"    ,          ""},
  {"iso-2022-8bit-lock-ss2",          ""},
  {"iso-2022-8bit-ss2",               ""},
  {"iso-2022-cjk",                    ""},
  {"iso-2022-cn",                     "ISO-2022-CN"},
  {"iso-2022-cn-ext",                 "ISO-2022-CN-EXT"},
  {"iso-2022-int-1",                  ""},
  {"iso-2022-jp",                     "ISO-2022-JP"},
  {"iso-2022-jp-1978-irv",            "ISO-2022-JP"},
  {"iso-2022-jp-2",                   "ISO-2022-JP-2"},
  {"iso-2022-jp-3",                   ""},
  {"iso-2022-jp-3-compatible",        ""},
  {"iso-2022-jp-3-strict",            ""},
  {"iso-2022-kr",                     "ISO-2022-KR"},
  {"iso-2022-lock",                   ""},
  {"iso-8859-1",                      "ISO-8859-1"},
  {"iso-8859-2",                      "ISO-8859-2"},
  {"iso-8859-3",                      "ISO-8859-3"},
  {"iso-8859-4",                      "ISO-8859-4"},
  {"iso-8859-5",                      "ISO-8859-5"},
  {"iso-8859-6",                      "ISO-8859-6"},
  {"iso-8859-7",                      "ISO-8859-7"},
  {"iso-8859-8",                      "ISO-8859-8"},
  {"iso-8859-9",                      "ISO-8859-9"},
  {"iso-latin-1",                     "ISO-8859-1"},
  {"iso-latin-2",                     "ISO-8859-2"},
  {"iso-latin-3",                     "ISO-8859-3"},
  {"iso-latin-4",                     "ISO-8859-4"},
  {"iso-latin-5",                     "ISO-8859-9"},
  {"iso-safe",                        ""},
  {"japanese-iso-7bit-1978-irv",      "ISO-2022-JP"},
  {"japanese-iso-8bit",               ""},
  {"japanese-iso-8bit-with-esc",      ""},
  {"japanese-euc",                    "EUC-JP"},
  {"japanese-shift-jis",              "Shift_JIS"},
  {"japanese-shift-jisx0213",         ""},
  {"junet",                           "ISO-2022-JP"},
  {"koi8",                            "KOI8-R"},
  {"koi8-r",                          "KOI8-R"},
  {"korean-euc",                      "EUC-KR"},
  {"korean-iso-7bit-lock",            "ISO-2022-KR"},
  {"korean-iso-8bit",                 ""},
  {"korean-iso-8bit-with-esc",        ""},
  {"lao",                             ""},
  {"lao-with-esc",                    ""},
  {"latin-1",                         "ISO-8859-1"},
  {"latin-2",                         "ISO-8859-2"},
  {"latin-3",                         "ISO-8859-3"},
  {"latin-4",                         "ISO-8859-4"},
  {"latin-5",                         "ISO-8859-9"},
  {"mac",                             ""},
  {"old-jis",                         "ISO-2022-JP"},
  {"raw-text",                        ""},
  {"shift_jis",                       "Shift_JIS"},
  {"shift_jisx0213",                  "Shift_JIS"},
  {"sjis",                            "Shift_JIS"},
  {"th-tis620",                       "TIS-620"},
  {"thai-tis620",                     "TIS-620"},
  {"tibetan",                         ""},
  {"tis-620",                         "TIS-620"},
  {"tis620",                          "TIS-620"},
  {"us-ascii",                        "US-ASCII"},
  {"utf-16-be",                       "UTF-16BE"},
  {"utf-16-be-no-signature",          "UTF-16BE"},
  {"utf-16-le",                       "UTF-16LE"},
  {"utf-16-le-no-signature",          "UTF-16LE"},
  {"utf-7",                           "UTF-7"},
  {"utf-7-safe",                      "UTF-7"},
  {"utf-8",                           "UTF-8"},
  {"utf-8-ws",                        "UTF-8"},
  {"vietnamese-viqr",                 "VIQR"},
  {"vietnamese-viscii",               "VISCII"},
  {"vietnamese-vscii",                "VISCII"},
  {"viqr",                            "VIQR"},
  {"viscii",                          "VISCII"},
  {"vscii",                           "VSCII"},
  {"x-ctext",                         ""},
  {NULL,                              NULL}
};

encname_t mime_to_locale[] = {
  {NULL,                              NULL}
};

main(int argc, char **argv)
{
  char *encoding=NULL, *default_encoding, *inbuf, *locale;
  FILE *fp;

  /* determine the default encoding.  This part has to be located
   * before getopt() since the help message shows the default
   * encoding.
   */ 
#ifdef I18N
  setlocale(LC_ALL, "");
  locale = setlocale(LC_CTYPE, NULL);
  if (!locale || !strcmp(locale, "C") || !strcmp(locale, "POSIX")) {
    default_encoding = "latin1";
  } else {
    default_encoding = nl_langinfo(CODESET);
    if (!default_encoding) default_encoding = "latin1";
  }
#else
  default_encoding = "latin1";
#endif

  /* parse the command option */
  while(1){
    int opt;
    opt = getopt(argc, argv, "e:h");
    if (opt == -1) break;
    switch(opt){
    case 'e':
      encoding = (char *)strdup(optarg); break;
    case 'h':
      help(default_encoding); exit(0);
    default:
      exit(1);
    }
  }

  /* read a source */
  if (optind < argc) {
    fp = fopen(argv[optind], "r");
    if (!fp) {
      printf("Cannot open %s\n", argv[optind]);
      exit(1);
    }
    inbuf = read_file(fp);
    fclose(fp);
  } else {
    inbuf = read_file(stdin);
  }

  /* finally determine the encoding */
  if (encoding == NULL) {
    encoding = check_encoding_tag(inbuf);
    if (encoding == NULL) {
      encoding = default_encoding;
    }
  }

  /* translate from MIME & Emacs encoding names to locale encoding names */
  encoding = emacs2mime(encoding);
  encoding = mime2locale(encoding);

  /* call converter (converters write to stdout) */
  if (!strcasecmp(encoding, "latin1")) {
    conversion_latin1(inbuf, encoding);
  } else if (!strcasecmp(encoding, "utf8")) {
    conversion_utf8(inbuf, encoding);
  } else if (!strcasecmp(encoding, "cp1047")) {
    conversion_cp1047(inbuf, encoding);
  } else {
#ifdef I18N
    conversion_iconv(inbuf, encoding);
#else
    printf("Conversion from %s to UTF-8 is not supported.\n", encoding);
    exit(1);
#endif
  }
}

/*  ---------------------------------------------------------
 *  print help message
 *  ---------------------------------------------------------
 */
void help(char *default_encoding)
{
  printf(
         "Preprocessor for Groff system (%s)\n"
         "Usage: gpreconv [option] [input file]\n"
         "  -e encoding     specify encoding\n"
         "  -h              this message\n"
         "The default encoding is \"%s\".\n",
#ifdef I18N
         "internationalized version",
#else
         "non-internationalized version",
#endif
         default_encoding);
}

/*  ---------------------------------------------------------
 *  read input file
 *  The file has to be inputed as a whole before conversion
 *  since the encoding may be stateful like ISO-2022 series.
 *  ---------------------------------------------------------
 */
char *read_file (FILE *fp)
{
#define READBUF_SIZE 32768
  char *buf = NULL;
  size_t bufsize = 0;
  size_t readsize = 0;
  size_t n;
  while(1) {
    if (readsize == bufsize) {
      bufsize += READBUF_SIZE;
      buf = (char *)realloc(buf, bufsize + 1);
      if (!buf) {
        printf("Unable to allocate memory.\n"); exit(1);
      }
    }
    n = fread (buf+readsize, 1, bufsize-readsize, fp);
    readsize += n;
    if (feof(fp)) break;
    if (ferror(fp)) {
      printf("Read error.\n"); exit(1);
    }
  }
  buf[readsize] = 0;
  return buf;
}

/*  ---------------------------------------------------------
 *  check encoding tag in the read buffer (not implemented yet)
 *  ---------------------------------------------------------
 */
char *check_encoding_tag(char *inbuf)
{
  char *p, *lineend, *d1, *d2, *variable, *value;
  for (p=inbuf ; !strncmp(p, ".\\\"", 3) ; p = lineend + 1) {
    if ((lineend = strchr(p, '\n')) == NULL) break;
    *lineend = 0;
    d1 = strstr(p, "-*-"); if (d1) d2 = strstr(d1+3, "-*-");
    *lineend = '\n';
    if (!d1 || !d2) continue;
    *d2 = 0; d1+=3;
    while(*d1) {
      d1 = check_encoding_tag_parse_tag(d1, &variable, &value);
      if (!strcasecmp(variable, "coding")) {
        *d2 = '-';
        return value;
      }
    }
    *d2 = '-';
  }
  return NULL;
}

char *check_encoding_tag_parse_tag(char *d1, char **variable, char **value)
{
  static char var[MAX_VAR_LEN], val[MAX_VAR_LEN];
  int l;

  *variable = var; *value = val;

  while (*d1 == ' ' || *d1 == '\t') d1++;
  l = 0;
  while (l<MAX_VAR_LEN-1 && *d1 && !strchr(";: \t", *d1)) {
    var[l++] = *(d1++);
  }
  var[l] = 0;
  while (*d1 && *d1!=':' && *d1!=';') d1++;
  val[0] = 0;
  if (!*d1) return d1;
  if (*d1 == ';') return d1+1;
  d1++;
  while (*d1 == ' ' || *d1 == '\t') d1++;  
  l = 0;
  while (l<MAX_VAR_LEN-1 && *d1 && !strchr("; \t", *d1)) {
    val[l++] = *(d1++);
  }
  val[l] = 0;
  while (*d1 && *d1!=';') d1++;
  if (!*d1) return d1;
  if (*d1 == ';') return d1+1;
}

/*  ---------------------------------------------------------
 *  convert encoding name from emacs to mime
 *  ---------------------------------------------------------
 */
char *emacs2mime(char *emacs_encoding)
{
  static char emacs_enc[MAX_VAR_LEN];
  int emacs_enc_len;
  encname_t *table;

  strncpy(emacs_enc, emacs_encoding, MAX_VAR_LEN-1);
  emacs_enc[MAX_VAR_LEN-1] = 0;
  emacs_enc_len = strlen(emacs_enc);
  if (!strcasecmp(emacs_enc + emacs_enc_len - 4, "-dos"))
    emacs_enc[emacs_enc_len - 4] = 0;
  if (!strcasecmp(emacs_enc + emacs_enc_len - 4, "-mac"))
    emacs_enc[emacs_enc_len - 4] = 0;
  if (!strcasecmp(emacs_enc + emacs_enc_len - 5, "-unix"))
    emacs_enc[emacs_enc_len - 5] = 0;
  for (table = emacs_to_mime; table->from; table++) {
    if (!strcasecmp(emacs_enc, table->from)) return table->to;
  }
  return emacs_enc;
}

/*  ---------------------------------------------------------
 *  convert encoding name from mime to locale
 *  ---------------------------------------------------------
 */
char *mime2locale(char *mime_encoding)
{
  encname_t *table;

  for (table = mime_to_locale; table->from; table++) {
    if (!strcasecmp(mime_encoding, table->from)) return table->to;
  }
  return mime_encoding;
}

/*  ---------------------------------------------------------
 *  conversion functions
 *  ---------------------------------------------------------
 */

/* conversion from ISO-8859-1 (aka Latin-1) to UTF-8 */
void conversion_latin1 (char *inbuf, char *encoding)
{
  unsigned char *p;
  for(p=inbuf; *p; p++) {
    if (*p < 0x80) putchar(*p);
    else {putchar(0xc0 + (*p >> 6)); putchar(0x80 + (*p & 0x3f));}
  }
  return;
}

/* conversion from UTF-8 to UTF-8, i.e., do nothing */
void conversion_utf8 (char *inbuf, char *encoding)
{
  fwrite(inbuf, 1, strlen(inbuf), stdout);
  return;
}

/* conversion from CP1047 (EBCDIC) to UTF-8 */
/* the table is made from /font/devcp1047/R.proto in groff 1.16 */
void conversion_cp1047 (char *inbuf, char *encoding)
{
  static unsigned char cp1047[] = {
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 0x00-0x07 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 0x08-0x0f */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 0x10-0x17 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 0x18-0x1f */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 0x20-0x27 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 0x28-0x2f */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 0x30-0x37 */
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,  /* 0x38-0x3f */
    0x00, 0x00, 0xe2, 0xe4, 0xe0, 0xe1, 0xe3, 0xe5,  /* 0x40-0x47 */
    0xe7, 0xf1, 0xa2, '.' , '<' , '(' , '+' , '|' ,  /* 0x48-0x4f */
    '&' , 0xe8, 0xea, 0xeb, 0xe8, 0xed, 0xee, 0xef,  /* 0x50-0x57 */
    0xec, 0xdf, '!' , '$' , '*' , ')' , ';' , '^' ,  /* 0x58-0x5f */
    '-' , '/' , 0xc2, 0xc4, 0xc0, 0xc1, 0xc3, 0xc5,  /* 0x60-0x67 */
    0xc7, 0xd1, 0xa6, ',' , '%' , '_' , '>' , '?' ,  /* 0x68-0x6f */
    0xf8, 0xc9, 0xca, 0xcb, 0xc8, 0xcd, 0xce, 0xcf,  /* 0x70-0x77 */
    0xcc, '`' , ':' , '#' , '@' , '\'', '=' , '\"',  /* 0x78-0x7f */
    0xd8, 'a' , 'b' , 'c' , 'd' , 'e' , 'f' , 'g' ,  /* 0x80-0x87 */
    'h' , 'i' , 0xab, 0xbb, 0xf0, 0xfd, 0xfe, 0xb1,  /* 0x88-0x8f */
    0xb0, 'j' , 'k' , 'l' , 'm' , 'n' , 'o' , 'p' ,  /* 0x90-0x97 */
    'q' , 'r' , 0xaa, 0xba, 0xe6, 0xb8, 0xc6, 0xa4,  /* 0x98-0x9f */
    0xb5, '~' , 's' , 't' , 'u' , 'v' , 'w' , 'x' ,  /* 0xa0-0xa7 */
    'y' , 'z' , 0xa1, 0xbf, 0xd0, '[' , 0xde, 0xae,  /* 0xa8-0xaf */
    0xac, 0xa3, 0xa5, 0xb7, 0xa9, 0xa7, 0xb6, 0xbc,  /* 0xb0-0xb7 */
    0xbd, 0xbe, 0xdd, 0xa8, 0xaf, ']' , 0xb4, 0xd7,  /* 0xb8-0xbf */
    '{' , 'A' , 'B' , 'C' , 'D' , 'E' , 'F' , 'G' ,  /* 0xc0-0xc7 */
    'H' , 'I' , 0xad, 0xf4, 0xf6, 0xf2, 0xf3, 0xf5,  /* 0xc8-0xcf */
    '}' , 'J' , 'K' , 'L' , 'M' , 'N' , 'O' , 'P' ,  /* 0xd0-0xd7 */
    'Q' , 'R' , 0xb9, 0xfb, 0xfc, 0xf9, 0xfa, 0xff,  /* 0xd8-0xdf */
    '\\', 0xf7, 'S' , 'T' , 'U' , 'V' , 'W' , 'X' ,  /* 0xe0-0xe7 */
    'Y' , 'Z' , 0xb2, 0xd4, 0xd6, 0xd2, 0xd3, 0xd5,  /* 0xe8-0xef */
    '0' , '1' , '2' , '3' , '4' , '5' , '6' , '7' ,  /* 0xf0-0xf7 */
    '8' , '9' , 0xb3, 0xdb, 0xdc, 0xd9, 0xda, 0x00   /* 0xf8-0xff */
  };
  unsigned char *p, c;
  for(p=inbuf; *p; p++) {
    c = cp1047[*p];
    if (c == 0) c = *p; /* fail safe */
    if (c < 0x80) putchar(c);
    else {
      putchar(0xc0 + (c >> 6));
      putchar(0x80 + (c & 0x3f));
    }
  }
  return;
}

/* locale-sensible conversion */
#ifdef I18N
void conversion_iconv (char *inbuf, char *encoding)
{
#define OUTBUF_SIZE 32768
#define OUTBUF_LIMIT 10
  char *outbuf = NULL, *outbuf_top = NULL;
  size_t bufsize = 0;
  size_t inbytesleft, outbytesleft, status;
  iconv_t handle;

  handle = iconv_open("UTF-8", encoding);
  if (handle == (iconv_t)-1) {
    if (errno == EINVAL) {
      printf("Conversion from %s to UTF-8 is not supported.\n", encoding);
      exit(1);
    }
    printf("iconv_open failed!\n"); exit(1);
  }

  inbytesleft = strlen(inbuf) + 1;
  outbytesleft = 0;
  while (inbytesleft > 0) {
    if (outbytesleft < OUTBUF_LIMIT) {
      size_t outsize = outbuf - outbuf_top;
      outbuf_top = (char *)realloc(outbuf_top, bufsize+=OUTBUF_SIZE);
      if (!outbuf_top) {
        printf("Unable to allocate memory.\n"); exit(1);
      }
      outbuf = outbuf_top + outsize;
      outbytesleft += OUTBUF_SIZE;
    }
    status = iconv(handle, &inbuf, &inbytesleft, &outbuf, &outbytesleft);
    if (status == -1) {
      if (errno == EINVAL || errno == EILSEQ) {
        printf("Invalid character.\n"); exit(1);
      }
    }
  }
  fwrite(outbuf_top, 1, strlen(outbuf_top), stdout);
  return;
}
#endif