/* jbig2topdf: Assemble a bunch of JBIG2 files into a PDF file.
Syntax: jbig2topdf hresolution vresolution symbols file-names
A bunch of JBIG2 files is taken as input together with a symbol file
and a PDF-1.4 file is printed to the standard output.
Compile with cc jbig2topdf.c -o jbig2topdf
For gcc you might need to use an addtional option -std=c99.
Written and copyrighted by Dmitri Pavlov in 2010.
Distributed under the terms of GNU General Public License version 3.
Feedback welcome via SMTP: host math.berkeley.edu, user pavlov. */

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>

int offset = 0;

void print( const char *format, ... ) {
  va_list ap;
  va_start(ap, format);
  int n = vprintf(format, ap);
  if (n < 0) {
    perror("vprintf");
    exit(1);
  }
  offset += n;
  va_end(ap);
}

int get_size( FILE *stream ) {
  if (fseek(stream, 0, SEEK_END) != 0) {
    perror("fseek");
    exit(1);
  }
  int size = ftell(stream);
  if (size == -1) {
    perror("ftell");
    exit(1);
  }
  if (fseek(stream, 0, SEEK_SET) != 0) {
    perror("fseek");
    exit(1);
  }
  return size;
}

void dump( FILE *stream, int size ) {
  int c;
  while ((c = fgetc(stream)) != EOF) {
    if (putchar(c) == EOF) {
      perror("putchar");
      exit(1);
    }
    offset++;
    if (size == 0) {
      fprintf(stderr, "File size mismatch\n");
      exit(1);
    }
    size--;
  }
  if (ferror(stream) != 0) {
    perror("fgetc");
    exit(1);
  }
  if (size != 0) {
    fprintf(stderr, "File size mismatch\n");
    exit(1);
  }
  if (fclose(stream) != 0) {
    perror("fclose");
    exit(1);
  }
  print("\nendstream endobj\n");
}

int get_int( FILE *stream ) {
  int n = 0, c;
  for (int l = 0; l < 4; l++)
    if ((c = fgetc(stream)) == EOF) {
      fprintf(stderr, "Error reading 4-byte integer\n");
      exit(1);
    }
    else
      n = (n << 8) + c;
  return n;
}

int main( int argc, char *argv[] ) {
  int hres, vres;
  if (argc < 4 || sscanf(argv[1], "%d", &hres) != 1 || sscanf(argv[2], "%d", &vres) != 1) {
    fprintf(stderr, "Usage: jbig2topdf hresolution vresolution symbols file-names\n");
    exit(1);
  }
  int *obj = malloc(sizeof(int) * 3 * argc - 8);
  if (obj == 0) {
    perror("malloc");
    exit(1);
  }
  print("%%PDF-1.4\n%%\200\200\200\200\n");
  obj[1] = offset;
  print("1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj\n");
  obj[2] = offset;
  print("2 0 obj << /Type /Pages /Count %d /Kids [", argc - 4);
  for (int k = 4; k < argc; k++)
    print(" %d 0 R", 3 * k - 8);
  print(" ] >> endobj\n");
  FILE *stream = fopen(argv[3], "rb");
  if (stream == 0) {
    perror("fopen");
    exit(1);
  }
  int size = get_size(stream);
  obj[3] = offset;
  print("3 0 obj << /Length %d >> stream\n", size);
  dump(stream, size);
  for (int k = 4; k < argc; k++) {
    FILE *stream = fopen(argv[k], "rb");
    if (stream == 0) {
      perror("fopen");
      exit(1);
    }
    if (fseek(stream, 11, SEEK_SET) != 0) {
      perror("fseek");
      exit(1);
    }
    int w = get_int(stream), h = get_int(stream);
    double ww = 72.0 * w / hres, hh = 72.0 * h / vres;
    int size = get_size(stream);
    obj[3 * k - 8] = offset;
    print("%d 0 obj << /Type /Page /Parent 2 0 R /Resources << /ProcSet [ /PDF /ImageB ] "
          "/XObject << /image %d 0 R >> >> /MediaBox [ 0 0 %.2f %.2f ] "
          "/Contents [ %d 0 R ] >> endobj\n",
          3 * k - 8, 3 * k - 6, ww, hh, 3 * k - 7);
    obj[3 * k - 7] = offset;
    char s[64];
    sprintf(s, "%.2f 0 0 %.2f 0 0 cm /image Do", ww, hh);
    print("%d 0 obj << /Length %d >> stream\n%s\nendstream endobj\n", 3 * k - 7, strlen(s), s);
    obj[3 * k - 6] = offset;
    print("%d 0 obj << /Length %d /Filter /JBIG2Decode /DecodeParms << /JBIG2Globals 3 0 R >>"
          " /Subtype /Image /Width %d /Height %d "
          "/ColorSpace /DeviceGray /BitsPerComponent 1 >> stream\n",
          3 * k - 6, size, w, h);
    dump(stream, size);
  }
  int xref = offset;
  print("xref\n0 %d\n0000000000 65535 f \n", 3 * argc - 8);
  for (int k = 1; k < 3 * argc - 8; k++)
    print("%010d 00000 n \n", obj[k]);
  print("trailer << /Size %d /Root 1 0 R >>\nstartxref\n%d\n%%%%EOF\n", 3 * argc - 8, xref);
  return 0;
}