/* jbig2topdf: Assemble a bunch of JBIG2 files into a PDF file.
Syntax: jbig2topdf [-t title] [-a author] hresolution vresolution symbols files
A bunch of JBIG2 files together with a symbol file is taken as input
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>
#include <locale.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);
}

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

void put_char(int c) {
  if (putchar(c) == EOF) {
    perror("putchar");
    exit(1);
  }
  offset++;
}

void dump(FILE *stream, long size) {
  int c;
  while ((c = fgetc(stream)) != EOF) {
    put_char(c);
    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 objn, obj_size;
int *obj;

void pobj(void) {
  objn++;
  if (objn == obj_size) {
    fprintf(stderr, "Increase obj_size\n");
    exit(1);
  }
  obj[objn] = offset;
  print("%d 0 obj ", objn);
}

void put_16(wchar_t c) {
  put_char(c >> 8);
  put_char(c & 0xFF);
}

void put_string(const char *s) {
  put_char(254);
  put_char(255);
  mbtowc(NULL, NULL, 0);
  while (*s != 0) {
    wchar_t c;
    int n = mbtowc(&c, s, MB_CUR_MAX);
    if (n <= 0) {
      fprintf(stderr, "mbtowc error\n");
      exit(1);
    }
    s += n;
    if (c < 0xD800)
      put_16(c);
    else if (c >= 0x10000 && c < 0x110000) {
      c -= 0x10000;
      put_16(0xD800 + (c >> 10));
      put_16(0xDC00 + (c & 0x3FF));
    } else {
      fprintf(stderr, "Invalid character\n");
      exit(1);
    }
  }
}

int main(int argc, char *argv[]) {
  const char *title = NULL, *author = NULL;
  int cur;
  for (cur = 1; cur + 1 < argc; cur += 2)
    if (strcmp(argv[cur], "-t") == 0)
      title = argv[cur + 1];
    else if (strcmp(argv[cur], "-a") == 0)
      author = argv[cur + 1];
    else
      break;
  int hres, vres;
  if (cur + 3 > argc || sscanf(argv[cur], "%d", &hres) != 1 || sscanf(argv[cur + 1], "%d", &vres) != 1) {
    fprintf(stderr, "Usage: jbig2topdf [-t title] [-a author] hresolution vresolution symbols files\n");
    exit(1);
  }
  cur += 2;
  obj_size = 3 * (argc - cur) + 2;
  obj = malloc(sizeof(int) * obj_size);
  if (obj == NULL) {
    perror("malloc");
    exit(1);
  }
  objn = 0;
  print("%%PDF-1.4\n%%\200\200\200\200\n");
  pobj();
  print("<< /Type /Catalog /Pages 2 0 R >> endobj\n");
  pobj();
  print("<< /Type /Pages /Count %d /Kids [", argc - cur - 1);
  for (int k = 0; k < argc - cur - 1; k++)
    print(" %d 0 R", 3 * k + 4);
  print(" ] >> endobj\n");
  FILE *stream = fopen(argv[cur], "rb");
  if (stream == 0) {
    perror("fopen");
    exit(1);
  }
  long size = get_size(stream);
  pobj();
  print("<< /Length %d >> stream\n", size);
  dump(stream, size);
  cur++;
  for (; cur < argc; cur++) {
    FILE *stream = fopen(argv[cur], "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;
    long size = get_size(stream);
    pobj();
    print("<< /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",
          objn + 2, ww, hh, objn + 1);
    pobj();
    char s[64];
    sprintf(s, "%.2f 0 0 %.2f 0 0 cm /image Do", ww, hh);
    print("<< /Length %d >> stream\n%s\nendstream endobj\n", strlen(s), s);
    pobj();
    print("<< /Length %d /Filter /JBIG2Decode /DecodeParms << /JBIG2Globals 3 0 R >>"
          " /Subtype /Image /Width %d /Height %d "
          "/ColorSpace /DeviceGray /BitsPerComponent 1 >> stream\n",
          size, w, h);
    dump(stream, size);
  }
  if (title != NULL || author != NULL) {
    setlocale(LC_CTYPE, "");
    pobj();
    print("<< ");
    if (title != NULL) {
      print("/Title (");
      put_string(title);
      print(") ");
    }
    if (author != NULL) {
      print("/Author (");
      put_string(author);
      print(") ");
    }
    print(">> endobj\n");
  }
  int xref = offset;
  print("xref\n0 %d\n0000000000 65535 f \n", objn + 1);
  for (int k = 1; k <= objn; k++)
    print("%010d 00000 n \n", obj[k]);
  print("trailer << /Size %d /Root 1 0 R ", objn + 1);
  if (title != NULL || author != NULL)
    print("/Info %d 0 R ", objn);
  print(">>\nstartxref\n%d\n%%%%EOF\n", xref);
  return 0;
}