/*--------------------------------------------------------------------------
NETREK II -- Paradise

Permission to use, copy, modify, and distribute this software and its
documentation, or any derivative works thereof, for any NON-COMMERCIAL
purpose and without fee is hereby granted, provided that this copyright
notice appear in all copies.  No representations are made about the
suitability of this software for any purpose.  This software is provided
"as is" without express or implied warranty.

    Xtrek Copyright 1986                            Chris Guthrie
    Netrek (Xtrek II) Copyright 1989                Kevin P. Smith
                                                    Scott Silvey
    Paradise II (Netrek II) Copyright 1993          Larry Denys
                                                    Kurt Olsen
                                                    Brandon Gillespie
--------------------------------------------------------------------------*/

#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define pm_error(str) {\
fprintf(stderr, "Error in ParseXbmFile(): %s\n", str);\
if(*dataP) { free(*dataP); *dataP = 0; }\
return -1; }

/*
 * most of the following function came from xbmtopbm.c in the PBMPLUS library
 */

#define MAX_LINE 500

int
ParseXbmFile(stream, widthP, heightP, dataP)
  FILE *stream;
  int *widthP;
  int *heightP;
  char **dataP;
{
  char line[MAX_LINE], name_and_type[MAX_LINE];
  char *ptr;
  char *t;
  int raster_length, v;
  register int bytes, bytes_per_line;
  register int c1, c2, value1, value2;
  int hex_table[256];

  *widthP = *heightP = -1;
  *dataP = 0;

  for (;;)
  {
    if (fgets(line, MAX_LINE, stream) == NULL)
      pm_error("EOF / read error");
    if (strlen(line) == MAX_LINE - 1)
      pm_error("line too long");

    if (sscanf(line, "#define %s %d", name_and_type, &v) == 2)
    {
      if ((t = strrchr(name_and_type, '_')) == NULL)
	t = name_and_type;
      else
	++t;
      if (!strcmp("width", t))
	*widthP = v;
      else if (!strcmp("height", t))
	*heightP = v;
      continue;
    }

    if (sscanf(line, "static char %s = {", name_and_type) == 1 ||
	sscanf(line, "static unsigned char %s = {", name_and_type) == 1)
      break;
  }

  if (*widthP == -1)
    pm_error("invalid width");
  if (*heightP == -1)
    pm_error("invalid height");

  bytes_per_line = (*widthP + 7) / 8;

  raster_length = bytes_per_line * *heightP;
  *dataP = (char *) malloc(raster_length);
  if (*dataP == (char *) 0)
    pm_error("out of memory");

  /* Initialize hex_table. */
  for (c1 = 0; c1 < 256; ++c1)
    hex_table[c1] = 256;

  hex_table['0'] = 0;
  hex_table['1'] = 1;
  hex_table['2'] = 2;
  hex_table['3'] = 3;
  hex_table['4'] = 4;
  hex_table['5'] = 5;
  hex_table['6'] = 6;
  hex_table['7'] = 7;
  hex_table['8'] = 8;
  hex_table['9'] = 9;
  hex_table['A'] = 10;
  hex_table['B'] = 11;
  hex_table['C'] = 12;
  hex_table['D'] = 13;
  hex_table['E'] = 14;
  hex_table['F'] = 15;
  hex_table['a'] = 10;
  hex_table['b'] = 11;
  hex_table['c'] = 12;
  hex_table['d'] = 13;
  hex_table['e'] = 14;
  hex_table['f'] = 15;

  for (bytes = 0, ptr = *dataP; bytes < raster_length; ++bytes)
  {
    /*
     * Skip until digit is found.
     */
    for (;;)
    {
      c1 = getc(stream);
      if (c1 == EOF)
	pm_error("EOF / read error");
      value1 = hex_table[c1];
      if (value1 != 256)
	break;
    }
    /*
     * Loop on digits.
     */
    for (;;)
    {
      c2 = getc(stream);
      if (c2 == EOF)
	pm_error("EOF / read error");
      value2 = hex_table[c2];
      if (value2 != 256)
      {
	value1 = (value1 << 4) | value2;
	if (value1 >= 256)
	  pm_error("syntax error");
      }
      else if (c2 == 'x' || c2 == 'X')
      {
	if (value1 == 0)
	  continue;
	else
	  pm_error("syntax error");
      }
      else
	break;
    }
    *ptr++ = (char) (value1 ^ 0xFF);
  }
  return (raster_length);
}