/* ---------------------------------------------------------
                        gen_cptable.c

   Erzeugt eine CPxxx -> UTF-8 Lookup-Tabelle
   mittels iconv.

   Beispiel:

      ./gen_cptable CP437 > cp437.lookup
      ./gen_cptable CP850 > cp850.lookup

   06.07.2026 R. Seelig
   --------------------------------------------------------- */

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <iconv.h>

/* -------------------------------------------------------------------------
                                      main
   ------------------------------------------------------------------------- */
int main(int argc, char *argv[])
{
  iconv_t cd;
  int i;

  if (argc != 2)
  {
    fprintf(stderr,
        "Verwendung: %s <Codepage>\n"
        "Beispiel:\n\r"
        "   %s cp437 > outputfile\n\r"
        "   %s cp850 > outputfile\n\r"
        "   %s cp1252 > outputfile\n\r",
        argv[0], argv[0], argv[0], argv[0]);
    return 1;
  }

  cd = iconv_open("UTF-8", argv[1]);

  if (cd == (iconv_t)-1)
  {
    perror("iconv_open");
    return 1;
  }

  printf("const uint8_t UTF_chars[384] =\n");
  printf("{\n");

  for (i = 128; i < 256; i++)
  {
    uint8_t in;
    uint8_t out[10];       // sicherheitshalber 10, theoretisch muessten 3 reichen

    char *pin;
    char *pout;

    size_t inleft;
    size_t outleft;

    memset(out, 0, sizeof(out));

    in = (uint8_t)i;

    pin = (char *)&in;
    pout = (char *)out;

    inleft = 1;
    outleft = sizeof(out);

    if (iconv(cd, &pin, &inleft, &pout, &outleft) == (size_t)-1)
    {
      out[0] = '?';
      out[1] = 0;
      out[2] = 0;
    }

    printf("  0x%02X,0x%02X,0x%02X,   // ASCII-%d\n", out[0], out[1], out[2], i);
  }

  printf("};\n");

  iconv_close(cd);

  return 0;
}