/* This is dvipdfmx, an eXtended version of dvipdfm by Mark A. Wicks.

    Copyright (C) 2002-2014 by Jin-Hwan Cho and Matthias Franz,
    the dvipdfmx project team.

    Copyright (C) 1998, 1999 by Mark A. Wicks <mwicks@kettering.edu>

    This program 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.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/

#include "libtexpdf.h"

/*
 * JP2 & JPX baseline support
 *
 * 20150412 Added opacity (transparency) support.
 * TODO: XMP Metadata
 */

#include <math.h>

/* Box types. */
#define JP2_BOX_JP__  0x6a502020  /* Signature */
#define JP2_BOX_FTYP  0x66747970  /* File Type */

#define JP2_BOX_JP2H  0x6a703268  /* JP2 Header */
#define JP2_BOX_IHDR  0x69686472  /* Image Header */
#define JP2_BOX_BPCC  0x62706363  /* Bits Per Component */
#define JP2_BOX_COLR  0x636f6c72  /* Color Specification */
#define JP2_BOX_PCLR  0x70636c72  /* Palette */
#define JP2_BOX_CMAP  0x636d6170  /* Component Mapping */
#define JP2_BOX_CDEF  0x63646566  /* Channel Definition */
#define JP2_BOX_RES_  0x72657320  /* Resolution */
#define JP2_BOX_RESC  0x72657363  /* Capture Resolution */
#define JP2_BOX_RESD  0x72657364  /* Default Display Resolution */

#define JP2_BOX_JP2C  0x6a703263  /* Contiguous Code Stream */

#define JPX_BOX_LBL_  0x6c626c20  /* Label */


static unsigned int
read_box_hdr (FILE *fp, unsigned int *lbox, unsigned int *tbox)
{
  unsigned int bytesread = 0;

  *lbox = get_unsigned_quad(fp);
  *tbox = get_unsigned_quad(fp);
  bytesread += 8;
  if (*lbox == 1) {
    if (get_unsigned_quad(fp) != 0)
      ERROR("JPEG2000: LBox value in JP2 file >32 bits.\nI can't handle this!");
    *lbox = get_unsigned_quad(fp);
    bytesread += 8;
  } else if (*lbox > 1 && *lbox < 8) {
    WARN("JPEG2000: Unknown LBox value %lu in JP2 file!", lbox);
  }

  return bytesread;
}

#define FTYP_BR_JP2_  0x6a703220
#define FTYP_BR_JPX_  0x6a707820
#define FTYP_CL_JPXB  0x6a707862

static int
check_jp___box (FILE *fp)
{
  if (get_unsigned_quad(fp) != 0x0c)
    return 0;
  if (get_unsigned_quad(fp) != JP2_BOX_JP__)
    return 0;
   /* Next 4 bytes shall be 0D 0A 87 0A */
  if (get_unsigned_quad(fp) != 0x0D0A870A)
    return 0;
  return 1;
}

static int
check_ftyp_data (FILE *fp, unsigned int size)
{
  int supported = 0;
  unsigned int BR, CLi;

  BR = get_unsigned_quad(fp);
  size -= 4;
  /* MinV = */ get_unsigned_quad(fp);
  size -= 4;
  switch (BR) {
  case FTYP_BR_JP2_: /* "jp2 " ... supported */
    seek_relative(fp, size);
    size = 0;
    supported = 1;
    break;
  case FTYP_BR_JPX_: /* "jpx " ... baseline subset supported */
    while (size > 0) {
      CLi = get_unsigned_quad(fp);
      if (CLi == FTYP_CL_JPXB)
        supported = 1;
      size -= 4;
    }
    break;
  default:
    WARN("JPEG2000: Unknown JPEG 2000 File Type box Brand field value.");
    seek_relative(fp, size);
    size = 0;
    supported = 0;
  }

  return supported;
}


static void
read_res__data (ximage_info *info, FILE *fp, unsigned int size)
{
  unsigned int  VR_N, VR_D, HR_N, HR_D;
  unsigned char VR_E, HR_E;

  VR_N = get_unsigned_pair(fp);
  VR_D = get_unsigned_pair(fp);
  HR_N = get_unsigned_pair(fp);
  HR_D = get_unsigned_pair(fp);
  VR_E = get_unsigned_byte(fp);
  HR_E = get_unsigned_byte(fp);
  if (compat_mode)
    info->xdensity = info->ydensity = 72.0 / 100.0;
  else {
    info->xdensity = 72.0/(((double) HR_N / HR_D) * pow(10.0, HR_E) * 0.0254);
    info->ydensity = 72.0/(((double) VR_N / VR_D) * pow(10.0, VR_E) * 0.0254);
  }
}

static int
scan_res_ (ximage_info *info, FILE *fp, unsigned int size)
{
  unsigned int len, lbox, tbox;
  int have_resd = 0;

  while (size > 0) {
    len = read_box_hdr(fp, &lbox, &tbox);
    if (lbox == 0) {
      WARN("JPEG2000: Unexpected lbox value 0 in JP2 Resolution box.");
      break;
    }
    switch (tbox) {
    case JP2_BOX_RESC:
      if (!have_resd) {
        read_res__data(info, fp, lbox - len);
      } else {
        seek_relative(fp, lbox - len);
      }
      break;
    case JP2_BOX_RESD:
      read_res__data(info, fp, lbox - len);
      have_resd = 1;
      break;
    default:
      WARN("JPEG2000: Unknown JPEG 2000 box type in Resolution box.");
      seek_relative(fp, lbox - len);
    }
    size -= lbox;
  }

  return size == 0 ? 0 : -1;
}

/* Acrobat seems require Channel Definition box to be defined when image data
 * contains opacity channel. However, OpenJPEG (and maybe most of JPEG 2000 coders?)
 * does not write Channel Definition box so transparency will be ignored.
 */
static int
scan_cdef (ximage_info *info, int *smask, FILE *fp, unsigned int size)
{
  int opacity_channels = 0;
  int have_type0       = 0;
  unsigned int i, Cn, N, Typ, Asoc;

  *smask = 0;

  N = get_unsigned_pair(fp);
  if (size < N * 6 + 2) {
    WARN("JPEG2000: Inconsistent N value in Channel Definition box.");
    return -1;
  }
  for (i = 0; i < N; i++) {
    Cn   = get_unsigned_pair(fp); /* Cn */
    Typ  = get_unsigned_pair(fp);
    Asoc = get_unsigned_pair(fp); /* must be 0 for SMask */
    if (Cn > N)
      WARN("JPEG2000: Invalid Cn value in Channel Definition box.");
    if (Typ == 1) {
      if (Asoc == 0)
        have_type0 = 1;
      opacity_channels++;
    } else if (Typ == 2) {
      opacity_channels++;
    }
  }
 
  if (opacity_channels == 1)
    *smask = have_type0 ? 1 : 0; 
  else if (opacity_channels > 1) {
    WARN("JPEG2000: Unsupported transparency type. (ignored)");
  }

  return 0;
}

static int
scan_jp2h (ximage_info *info, int *smask, FILE *fp, unsigned int size)
{
  int error = 0, have_ihdr = 0;
  unsigned int len, lbox, tbox;

  while (size > 0 && !error) {
    len = read_box_hdr(fp, &lbox, &tbox);
    if (lbox == 0) {
      WARN("JPEG2000: Unexpected lbox value 0 in JP2 Header box...");
      error = -1;
      break;
    }
    switch (tbox) {
    case JP2_BOX_IHDR:
      info->height = get_unsigned_quad(fp);
      info->width  = get_unsigned_quad(fp);
      info->num_components = get_unsigned_pair(fp);
      /* c = */ get_unsigned_byte(fp); /* BPC - 1 */
      /* c = */ get_unsigned_byte(fp); /* C: Compression type */
      /* c = */ get_unsigned_byte(fp); /* UnkC */
      /* c = */ get_unsigned_byte(fp); /* IPR */
      have_ihdr = 1;
      break;
    case JP2_BOX_RES_:
      error = scan_res_(info, fp, lbox - len);
      break;
    case JP2_BOX_CDEF:
      error = scan_cdef(info, smask, fp, lbox - len);
      break;
    case JP2_BOX_BPCC: case JP2_BOX_COLR: case JP2_BOX_PCLR:
    case JP2_BOX_CMAP:
    case JPX_BOX_LBL_:
      seek_relative(fp, lbox - len);
      break;
    default:
      WARN("JPEG2000: Unknown JPEG 2000 box in JP2 Header box.");
      seek_relative(fp, lbox - len);
      error = -1;
    }
    size -= lbox;
  }

  if (!have_ihdr)
    WARN("JPEG2000: Expecting JPEG 2000 Image Header box but could not find.");
  return (!error && have_ihdr && size == 0) ? 0 : -1;
}

static int
scan_file (ximage_info *info, int *smask, FILE *fp)
{
  int  error = 0, have_jp2h = 0;
  int  size;
  unsigned int len, lbox, tbox;


  size = file_size(fp);

  /* Should have already been checked before. */
  /* JPEG 2000 Singature box */
  if (!check_jp___box(fp))
    return -1;
  size -= 12;
  /* File Type box shall immediately follow */
  len = read_box_hdr(fp, &lbox, &tbox);
  if (tbox != JP2_BOX_FTYP)
    return -1;
  if (!check_ftyp_data(fp, lbox - len))
    return -1;
  size -= lbox;

  /* Search for JP2 Header box */
  while (size > 0 && !error) {
    len = read_box_hdr(fp, &lbox, &tbox);
    if (lbox == 0)
      lbox = size;
    switch (tbox) {
    case JP2_BOX_JP2H:
      error = scan_jp2h(info, smask, fp, lbox - len);
      have_jp2h = 1;
      break;
    case JP2_BOX_JP2C:
      /* JP2 requires JP2H appears before JP2C. */
      if (!have_jp2h)
        WARN("JPEG2000: JPEG 2000 Codestream box found before JP2 Header box.");
      seek_relative(fp, lbox - len);
      break;
    default:
      seek_relative(fp, lbox - len);
    }
    size -= lbox;
  }

  /* From ISO/IEC 15444-2 M.9.2.7
   * The JP2 Header box shall be found in the file before the first
   * Contiguous Codestream box, Fragment Table box, Media Data box,
   * Codestream Header box, and Compositing Layer Header box. ...
   */
  if (!have_jp2h && !error) {
    WARN("JPEG2000: No JP2 Header box found. Not a JP2/JPX baseline file?");
    error = -1;
  }
  return error;
}

int
texpdf_check_for_jp2 (FILE *fp)
{
  unsigned int len, lbox, tbox;

  if (!fp)
    return 0;

  rewind(fp);

  /* JPEG 2000 Singature box */
  if (!check_jp___box(fp))
    return 0;

  /* File Type box shall immediately follow */
  len = read_box_hdr(fp, &lbox, &tbox);
  if (tbox != JP2_BOX_FTYP)
    return 0;
  if (!check_ftyp_data(fp, lbox - len))
    return 0;

  return 1;
}

int
jp2_include_image (pdf_ximage *ximage, FILE *fp)
{
  unsigned pdf_version;
  int      smask = 0;
  pdf_obj *stream, *stream_dict;
  ximage_info info;

  pdf_version = texpdf_get_version();
  if (pdf_version < 5) {
    WARN("JPEG 2000 support requires PDF version >= 1.5 (Current setting 1.%d)\n", pdf_version);
    return -1;
  }

  texpdf_ximage_init_image_info(&info);
  stream = stream_dict = NULL;

  rewind(fp);
  if (scan_file(&info, &smask, fp) < 0) {
    WARN("JPEG2000: Reading JPEG 2000 file failed.");
    return -1;
  }

  stream      = texpdf_new_stream(0);
  stream_dict = texpdf_stream_dict(stream);
  texpdf_add_dict(stream_dict,
        texpdf_new_name("Filter"), texpdf_new_name("JPXDecode"));
  if (smask)
    texpdf_add_dict(stream_dict,
                 texpdf_new_name("SMaskInData"), texpdf_new_number(1));
  /* Read whole file */
  {
    size_t nb_read;
    rewind(fp);
    while ((nb_read =
        fread(work_buffer, sizeof(char), WORK_BUFFER_SIZE, fp)) > 0)
      texpdf_add_stream(stream, work_buffer, nb_read);
  }

  texpdf_ximage_set_image(ximage, &info, stream);

  return 0;
}

int
texpdf_jp2_get_bbox (FILE *fp, int *width, int *height,
         double *xdensity, double *ydensity)
{
  int r, smask = 0;
  ximage_info info;

  texpdf_ximage_init_image_info(&info);

  rewind(fp);
  r = scan_file(&info, &smask, fp);

  *width  = info.width;
  *height = info.height;
  *xdensity = info.xdensity;
  *ydensity = info.ydensity;

  return r;
}
