/*
Copyright (c) 1996-2002 Han The Thanh, <thanh@pdftex.org>

This file is part of pdfTeX.

pdfTeX is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

pdfTeX is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with pdfTeX; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

$Id: //depot/Build/source.development/TeX/texk/web2c/pdftexdir/writejpg.c#7 $
*/

#include "ptexlib.h"
#include "image.h"

#define JPG_GRAY  1     /* Gray color space, use /DeviceGray  */
#define JPG_RGB   3     /* RGB color space, use /DeviceRGB    */
#define JPG_CMYK  4     /* CMYK color space, use /DeviceCMYK  */

typedef enum {          /* JPEG marker codes                    */
  M_SOF0  = 0xc0,       /* baseline DCT                         */
  M_SOF1  = 0xc1,       /* extended sequential DCT              */
  M_SOF2  = 0xc2,       /* progressive DCT                      */
  M_SOF3  = 0xc3,       /* lossless (sequential)                */

  M_SOF5  = 0xc5,       /* differential sequential DCT          */
  M_SOF6  = 0xc6,       /* differential progressive DCT         */
  M_SOF7  = 0xc7,       /* differential lossless                */

  M_JPG   = 0xc8,       /* JPEG extensions                      */
  M_SOF9  = 0xc9,       /* extended sequential DCT              */
  M_SOF10 = 0xca,       /* progressive DCT                      */
  M_SOF11 = 0xcb,       /* lossless (sequential)                */

  M_SOF13 = 0xcd,       /* differential sequential DCT          */
  M_SOF14 = 0xce,       /* differential progressive DCT         */
  M_SOF15 = 0xcf,       /* differential lossless                */

  M_DHT   = 0xc4,       /* define Huffman tables                */

  M_DAC   = 0xcc,       /* define arithmetic conditioning table */

  M_RST0  = 0xd0,       /* restart                              */
  M_RST1  = 0xd1,       /* restart                              */
  M_RST2  = 0xd2,       /* restart                              */
  M_RST3  = 0xd3,       /* restart                              */
  M_RST4  = 0xd4,       /* restart                              */
  M_RST5  = 0xd5,       /* restart                              */
  M_RST6  = 0xd6,       /* restart                              */
  M_RST7  = 0xd7,       /* restart                              */

  M_SOI   = 0xd8,       /* start of image                       */
  M_EOI   = 0xd9,       /* end of image                         */
  M_SOS   = 0xda,       /* start of scan                        */
  M_DQT   = 0xdb,       /* define quantization tables           */
  M_DNL   = 0xdc,       /* define number of lines               */
  M_DRI   = 0xdd,       /* define restart interval              */
  M_DHP   = 0xde,       /* define hierarchical progression      */
  M_EXP   = 0xdf,       /* expand reference image(s)            */

  M_APP0  = 0xe0,       /* application marker, used for JFIF    */
  M_APP1  = 0xe1,       /* application marker                   */
  M_APP2  = 0xe2,       /* application marker                   */
  M_APP3  = 0xe3,       /* application marker                   */
  M_APP4  = 0xe4,       /* application marker                   */
  M_APP5  = 0xe5,       /* application marker                   */
  M_APP6  = 0xe6,       /* application marker                   */
  M_APP7  = 0xe7,       /* application marker                   */
  M_APP8  = 0xe8,       /* application marker                   */
  M_APP9  = 0xe9,       /* application marker                   */
  M_APP10 = 0xea,       /* application marker                   */
  M_APP11 = 0xeb,       /* application marker                   */
  M_APP12 = 0xec,       /* application marker                   */
  M_APP13 = 0xed,       /* application marker                   */
  M_APP14 = 0xee,       /* application marker, used by Adobe    */
  M_APP15 = 0xef,       /* application marker                   */

  M_JPG0  = 0xf0,       /* reserved for JPEG extensions         */
  M_JPG13 = 0xfd,       /* reserved for JPEG extensions         */
  M_COM   = 0xfe,       /* comment                              */

  M_TEM   = 0x01,       /* temporary use                        */

  M_ERROR = 0x100       /* dummy marker, internal use only      */
} JPEG_MARKER;

static JPG_UINT16 read2bytes(FILE *f)
{
    int c = xgetc(f);
    return (c << 8) + xgetc(f);
}

void read_jpg_info(integer img)
{
    int i;
    char jpg_id[]="JFIF";
    int units=0;
    img_xres(img)=img_yres(img)=0;
    jpg_ptr(img)->file = xfopen(img_name(img), FOPEN_RBIN_MODE);
    xfseek(jpg_ptr(img)->file,0,SEEK_END,cur_file_name);
    jpg_ptr(img)->length=xftell(jpg_ptr(img)->file,cur_file_name);
    xfseek(jpg_ptr(img)->file,0,SEEK_SET,cur_file_name);
    if(read2bytes(jpg_ptr(img)->file)!=0xFFD8)
        pdftex_fail("reading JPEG image failed");

    if(read2bytes(jpg_ptr(img)->file)==0xFFE0) { /* JFIF APP0 */
      (void)read2bytes(jpg_ptr(img)->file);
      for(i=0;i<5;i++) if(xgetc(jpg_ptr(img)->file)!=jpg_id[i])
        pdftex_fail("reading JPEG image failed");
      (void)read2bytes(jpg_ptr(img)->file);
      units=xgetc(jpg_ptr(img)->file);
      img_xres(img)=read2bytes(jpg_ptr(img)->file);
      img_yres(img)=read2bytes(jpg_ptr(img)->file);
      switch(units) {
          case 1: break; /* pixels per inch */
          case 2: img_xres(img)*=2.54; img_yres(img)*=2.54;
                  break; /* pixels per cm */
          default:img_xres(img)=img_yres(img)=0; break;
      }
    }

    xfseek(jpg_ptr(img)->file,0,SEEK_SET,cur_file_name);
    while(1) {
        if(feof(jpg_ptr(img)->file) || fgetc(jpg_ptr(img)->file)!=0xFF)
            pdftex_fail("reading JPEG image failed");
        switch(xgetc(jpg_ptr(img)->file)) {
        case M_SOF5:
        case M_SOF6:
        case M_SOF7:
        case M_SOF9:
        case M_SOF10:
        case M_SOF11:
        case M_SOF13:
        case M_SOF14:
        case M_SOF15:
            pdftex_fail("unsupported type of compression");
        case M_SOF2:
         if (getintpar(cfgpdfminorversioncode) <= 2)
                 pdftex_fail("cannot use progressive DCT with PDF-1.2");
        case M_SOF0:
        case M_SOF1:
        case M_SOF3:
             (void)read2bytes(jpg_ptr(img)->file);    /* read segment length  */
             jpg_ptr(img)->bits_per_component = xgetc(jpg_ptr(img)->file);
             img_height(img)       = read2bytes(jpg_ptr(img)->file);
             img_width(img)        = read2bytes(jpg_ptr(img)->file);
             jpg_ptr(img)->color_space  = xgetc(jpg_ptr(img)->file);
             xfseek(jpg_ptr(img)->file,0,SEEK_SET,cur_file_name); 
             switch (jpg_ptr(img)->color_space) {
                 case JPG_GRAY:
                     img_color(img) = IMAGE_COLOR_B;
                     break;
                 case JPG_RGB:
                     img_color(img) = IMAGE_COLOR_C;
                     break;
                 case JPG_CMYK:
                     img_color(img) = IMAGE_COLOR_C;
                     break;
                 default:
                     pdftex_fail("Unsupported color space %i", 
                             (int)jpg_ptr(img)->color_space);
             }
             return;
        case M_SOI:             /* ignore markers without parameters */
        case M_EOI:
        case M_TEM:
        case M_RST0:
        case M_RST1:
        case M_RST2:
        case M_RST3:
        case M_RST4:
        case M_RST5:
        case M_RST6:
        case M_RST7:
            break;
        default:                        /* skip variable length markers */
            xfseek(jpg_ptr(img)->file,read2bytes(jpg_ptr(img)->file)-2,SEEK_CUR,cur_file_name);
            break;
        }
    }
}

void write_jpg(integer img)
{
    long unsigned l;
    FILE *f;
    pdf_puts("/Type /XObject\n/Subtype /Image\n");
    pdf_printf("/Width %i\n/Height %i\n/BitsPerComponent %i\n/Length %i\n",
               img_width(img),
               img_height(img),
               (int)jpg_ptr(img)->bits_per_component,
               (int)jpg_ptr(img)->length);
    pdf_puts("/ColorSpace ");
    switch (jpg_ptr(img)->color_space) {
    case JPG_GRAY:
        pdf_puts("/DeviceGray\n");
        break;
    case JPG_RGB:
        pdf_puts("/DeviceRGB\n");
        break;
    case JPG_CMYK:
        pdf_puts("/DeviceCMYK\n/Decode [1 0 1 0 1 0 1 0]\n");
        break;
    default:
        pdftex_fail("Unsupported color space %i", 
             (int)jpg_ptr(img)->color_space);
    }
    pdf_puts("/Filter /DCTDecode\n>>\nstream\n");
    for (l = jpg_ptr(img)->length, f = jpg_ptr(img)->file; l > 0; l--)
        pdfout(xgetc(f));
    pdf_puts("endstream\nendobj\n");
}
