prl2offz.c

   1 /*
   2  * (C) Copyright 2019 Leo C. <erbl259-lmu@yahoo.de>
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7
   8 #include <stdlib.h>
   9 #include <stdio.h>
  10 #include <stdint.h>
  11 #include <errno.h>
  12 #include <stdarg.h>
  13 #include <string.h>
  14
  15 char *progname;
  16 FILE *prlfile;
  17 char *prlfilename;
  18 FILE *outfile;
  19 char *outfilename;
  20 uint16_t progsize;
  21
  22 void die(int status, const char *format, ...)
  23 {
  24         va_list arg;
  25
  26         fflush(stdout);
  27         va_start(arg, format);
  28         fprintf(stderr, "%s: ", progname);
  29         vfprintf(stderr, format, arg);
  30         va_end(arg);
  31
  32         exit(status);
  33 }
  34
  35 static
  36 int get_bit(void)
  37 {
  38         static unsigned bitpos;
  39         static int bytebuf;
  40         int retval;
  41
  42         if (bitpos == progsize) {
  43                 return -2;
  44         }
  45         if (bitpos%8 == 0) {
  46                 bytebuf = fgetc(prlfile);
  47                 if (bytebuf == EOF) {
  48                         return -1;
  49                 }
  50         }
  51         retval = (bytebuf & 0x80) !=0;
  52         bytebuf <<= 1;
  53         bitpos++;
  54
  55         return retval;
  56 }
  57
  58 static
  59 int get_nr_of_bits(void)
  60 {
  61         int bits = 0;
  62         int bit;
  63
  64         do {
  65                 bits++;
  66         } while ((bit = get_bit()) == 0);
  67
  68         if (bit >= 0)
  69                 return bits;
  70
  71         if (bit == -2)
  72                 return 0;
  73
  74         return bit;
  75 }
  76
  77 static
  78 void put_bits(int width, unsigned val)
  79 {
  80         static unsigned bytebuf;
  81         static int bitcount = 8;
  82
  83         while (width--) {
  84                 bytebuf <<= 1;
  85                 if (val & (1 << width))
  86                         bytebuf += 1;
  87                 bitcount--;
  88                 if (bitcount == 0) {
  89                         if (fputc(bytebuf, outfile) == EOF)
  90                                 die(1,"Error writing output file %s: %s\n",
  91                                                 outfilename, strerror(errno));
  92                         bitcount = 8;
  93                 }
  94         }
  95 }
  96
  97 static
  98 void fill_sector(void)
  99 {
 100         long curpos;
 101
 102         if ((curpos = ftell(outfile)) == -1)
 103                 die(1,"File error %s: %s\n", outfilename, strerror(errno));
 104
 105         for (int i = 0; i < 128 - curpos % 128; i++)
 106                 if (fputc(0, outfile) == EOF)
 107                         die(1,"Error writing output file %s: %s\n",
 108                                         outfilename, strerror(errno));
 109
 110         return;
 111 }
 112
 113
 114 static
 115 int process_prlfile(void)
 116 {
 117         fgetc(prlfile);
 118         progsize = fgetc(prlfile) + (fgetc(prlfile) << 8);
 119
 120         /* skip header */
 121         fseek(prlfile, 0x100, SEEK_SET);
 122
 123         for (unsigned i = 0; i < progsize; i++) {
 124                 int c = fgetc(prlfile);
 125                 if (c == EOF)
 126                         die(1,"Unexpected end of prl file %s\n", prlfilename);
 127                 if (fputc(c, outfile) == EOF)
 128                         die(1,"Error writing output file %s: %s\n",
 129                                         outfilename, strerror(errno));
 130         }
 131
 132
 133         int bits;
 134         while ((bits = get_nr_of_bits()) >= 2) {
 135                 unsigned off = bits - 2;
 136                 if (off < (1<<2)) {
 137                         put_bits(0 + 2 + 1, off);
 138                 } else if (off < (1<<4) + (1<<2)) {
 139                         off -= (1<<2);
 140                         off += (1<<(4+1));
 141                         put_bits(1 + 4 + 1, off);
 142                 } else if (off < (1<<8) + (1<<4) + (1<<2)) {
 143                         off -= (1<<4) + (1<<2);
 144                         off += (1<<(8+1));
 145                         off += (1<<(8+2));
 146                         put_bits(2 + 8 + 1, off);
 147                 } else {
 148                         off -= (1<<8) + (1<<4) + (1<<2);
 149                         off += (1<<(16+1));
 150                         off += (1<<(16+2));
 151                         off += (1<<(16+3));
 152                         put_bits(3 + 16 + 1, off);
 153                 }
 154         }
 155
 156         if (bits == 1)
 157                         die(1,"Bitmap error");
 158
 159         if (bits < 0)
 160                         die(1,"Error while reading bitmap from prl file %s\n", prlfilename);
 161
 162         /* end mark */
 163         put_bits(4, 0xf);
 164
 165         /* flush output bit buffer */
 166         put_bits(7, 0);
 167
 168         fill_sector();
 169
 170         return 0;
 171 }
 172
 173 static
 174 void usage(void)
 175 {
 176         fprintf(stderr,
 177 "Usage:\n"
 178 "%s prlfile outfile\n", progname);
 179
 180 }
 181
 182 int main(int argc, char **argv)
 183 {
 184         progname = argv[0];
 185
 186         if (argc != 3) {
 187                 usage();
 188                 die(1, "");
 189         }
 190
 191         prlfilename = argv[1];
 192         prlfile=fopen(prlfilename,"rb");
 193         if (prlfile==NULL)
 194                 die(1,"Cannot open prl file %s: %s\n",
 195                                 prlfilename, strerror(errno));
 196
 197         outfilename = argv[2];
 198         outfile=fopen(outfilename,"wb");
 199         if (outfile==NULL)
 200                 die(1,"Cannot open output file %s: %s\n",
 201                                 outfilename, strerror(errno));
 202
 203         process_prlfile();
 204         fclose(prlfile);
 205         fclose(outfile);
 206
 207         return 0;
 208 }