//
// "$Id: Fl_JPEG_Image.cxx 9980 2013-09-21 16:41:23Z greg.ercolano $"
//
// Fl_JPEG_Image routines.
//
// Copyright 1997-2011 by Easy Software Products.
// Image support by Matthias Melcher, Copyright 2000-2009.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     http://www.fltk.org/COPYING.php
//
// Please report all bugs and problems on the following page:
//
//     http://www.fltk.org/str.php
//
// Contents:
//
//   Fl_JPEG_Image::Fl_JPEG_Image() - Load a JPEG image file.
//

//
// Include necessary header files...
//

#include <FL/Fl_JPEG_Image.H>
#include <FL/Fl_Shared_Image.H>
#include <FL/fl_utf8.h>
#include <FL/Fl.H>
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <setjmp.h>


// Some releases of the Cygwin JPEG libraries don't have a correctly
// updated header file for the INT32 data type; the following define
// from Shane Hill seems to be a usable workaround...

#if defined(WIN32) && defined(__CYGWIN__)
#  define XMD_H
#endif // WIN32 && __CYGWIN__


extern "C"
{
#ifdef HAVE_LIBJPEG
#  include <jpeglib.h>
#endif // HAVE_LIBJPEG
}


//
// Custom JPEG error handling structure...
//

#ifdef HAVE_LIBJPEG
struct fl_jpeg_error_mgr {
  jpeg_error_mgr	pub_;		// Destination manager...
  jmp_buf		errhand_;	// Error handler
};
#endif // HAVE_LIBJPEG


//
// Error handler for JPEG files...
//

#ifdef HAVE_LIBJPEG
extern "C" {
  static void
  fl_jpeg_error_handler(j_common_ptr dinfo) {	// I - Decompressor info
    longjmp(((fl_jpeg_error_mgr *)(dinfo->err))->errhand_, 1);
  }

  static void
  fl_jpeg_output_handler(j_common_ptr) {	// I - Decompressor info (not used)
  }
}
#endif // HAVE_LIBJPEG


/**
 \brief The constructor loads the JPEG image from the given jpeg filename.
 
 The inherited destructor frees all memory and server resources that are used 
 by the image.
 
 There is no error function in this class. If the image has loaded correctly, 
 w(), h(), and d() should return values greater zero.
 
 \param[in] filename a full path and name pointing to a valid jpeg file.
 */
Fl_JPEG_Image::Fl_JPEG_Image(const char *filename)	// I - File to load
: Fl_RGB_Image(0,0,0) {
#ifdef HAVE_LIBJPEG
  FILE				*fp;	// File pointer
  jpeg_decompress_struct	dinfo;	// Decompressor info
  fl_jpeg_error_mgr		jerr;	// Error handler info
  JSAMPROW			row;	// Sample row pointer
  
  // the following variables are pointers allocating some private space that
  // is not reset by 'setjmp()'
  char* max_finish_decompress_err;      // count errors and give up afer a while
  char* max_destroy_decompress_err;     // to avoid recusion and deadlock
  
  // Clear data...
  alloc_array = 0;
  array = (uchar *)0;
  
  // Open the image file...
  if ((fp = fl_fopen(filename, "rb")) == NULL) return;
  
  // Setup the decompressor info and read the header...
  dinfo.err                = jpeg_std_error((jpeg_error_mgr *)&jerr);
  jerr.pub_.error_exit     = fl_jpeg_error_handler;
  jerr.pub_.output_message = fl_jpeg_output_handler;
  
  // Setup error loop variables
  max_finish_decompress_err = (char*)malloc(1);   // allocate space on the frame for error counters
  max_destroy_decompress_err = (char*)malloc(1);  // otherwise, the variables are reset on the longjmp
  *max_finish_decompress_err=10;
  *max_destroy_decompress_err=10;
  
  if (setjmp(jerr.errhand_))
  {
    // JPEG error handling...
    Fl::warning("JPEG file \"%s\" is too large or contains errors!\n", filename);
    // if any of the cleanup routines hits another error, we would end up 
    // in a loop. So instead, we decrement max_err for some upper cleanup limit.
    if ( ((*max_finish_decompress_err)-- > 0) && array)
      jpeg_finish_decompress(&dinfo);
    if ( (*max_destroy_decompress_err)-- > 0)
      jpeg_destroy_decompress(&dinfo);
    
    fclose(fp);
    
    w(0);
    h(0);
    d(0);
    
    if (array) {
      delete[] (uchar *)array;
      array = 0;
      alloc_array = 0;
    }
    
    free(max_destroy_decompress_err);
    free(max_finish_decompress_err);
    
    return;
  }
  
  jpeg_create_decompress(&dinfo);
  jpeg_stdio_src(&dinfo, fp);
  jpeg_read_header(&dinfo, 1);
  
  dinfo.quantize_colors      = (boolean)FALSE;
  dinfo.out_color_space      = JCS_RGB;
  dinfo.out_color_components = 3;
  dinfo.output_components    = 3;
  
  jpeg_calc_output_dimensions(&dinfo);
  
  w(dinfo.output_width); 
  h(dinfo.output_height);
  d(dinfo.output_components);
  
  if (((size_t)w()) * h() * d() > max_size() ) longjmp(jerr.errhand_, 1);
  array = new uchar[w() * h() * d()];
  alloc_array = 1;
  
  jpeg_start_decompress(&dinfo);
  
  while (dinfo.output_scanline < dinfo.output_height) {
    row = (JSAMPROW)(array +
                     dinfo.output_scanline * dinfo.output_width *
                     dinfo.output_components);
    jpeg_read_scanlines(&dinfo, &row, (JDIMENSION)1);
  }
  
  jpeg_finish_decompress(&dinfo);
  jpeg_destroy_decompress(&dinfo);
  
  free(max_destroy_decompress_err);
  free(max_finish_decompress_err);
  
  fclose(fp);
#endif // HAVE_LIBJPEG
}


// data source manager for reading jpegs from memory
// init_source (j_decompress_ptr cinfo)
// fill_input_buffer (j_decompress_ptr cinfo)
// skip_input_data (j_decompress_ptr cinfo, long num_bytes)
// resync_to_restart (j_decompress_ptr cinfo, int desired)
// term_source (j_decompress_ptr cinfo)
//         JOCTET * next_output_byte;  /* => next byte to write in buffer */
//         size_t free_in_buffer;      /* # of byte spaces remaining in buffer */

#ifdef HAVE_LIBJPEG
typedef struct {
  struct jpeg_source_mgr pub;
  const unsigned char *data, *s;
  // JOCTET * buffer;              /* start of buffer */
  // boolean start_of_file;        /* have we gotten any data yet? */
} my_source_mgr;

typedef my_source_mgr *my_src_ptr;


extern "C" {

  static void init_source(j_decompress_ptr cinfo) {
    my_src_ptr src = (my_src_ptr)cinfo->src;
    src->s = src->data;
  }

  static boolean fill_input_buffer(j_decompress_ptr cinfo) {
    my_src_ptr src = (my_src_ptr)cinfo->src;
    size_t nbytes = 4096;
    src->pub.next_input_byte = src->s;
    src->pub.bytes_in_buffer = nbytes;
    src->s += nbytes;
    return TRUE;
  }

  static void term_source(j_decompress_ptr cinfo)
  {
  }

  static void skip_input_data(j_decompress_ptr cinfo, long num_bytes) {
    my_src_ptr src = (my_src_ptr)cinfo->src;
    if (num_bytes > 0) {
      while (num_bytes > (long)src->pub.bytes_in_buffer) {
        num_bytes -= (long)src->pub.bytes_in_buffer;
        fill_input_buffer(cinfo);
      }
      src->pub.next_input_byte += (size_t) num_bytes;
      src->pub.bytes_in_buffer -= (size_t) num_bytes;
    }
  }

} // extern "C"

static void jpeg_mem_src(j_decompress_ptr cinfo, const unsigned char *data)
{
  my_src_ptr src;
  cinfo->src = (struct jpeg_source_mgr *)malloc(sizeof(my_source_mgr));
  src = (my_src_ptr)cinfo->src;
  src->pub.init_source = init_source;
  src->pub.fill_input_buffer = fill_input_buffer;
  src->pub.skip_input_data = skip_input_data;
  src->pub.resync_to_restart = jpeg_resync_to_restart;
  src->pub.term_source = term_source;
  src->pub.bytes_in_buffer = 0; /* forces fill_input_buffer on first read */
  src->pub.next_input_byte = NULL; /* until buffer loaded */
  src->data = data;
  src->s = data;
}
#endif // HAVE_LIBJPEG


/**
 \brief The constructor loads the JPEG image from memory.

 Construct an image from a block of memory inside the application. Fluid offers
 "binary Data" chunks as a great way to add image data into the C++ source code.
 name_png can be NULL. If a name is given, the image is added to the list of 
 shared images (see: Fl_Shared_Image) and will be available by that name.

 The inherited destructor frees all memory and server resources that are used 
 by the image.

 There is no error function in this class. If the image has loaded correctly, 
 w(), h(), and d() should return values greater zero.

 \param name A unique name or NULL
 \param data A pointer to the memory location of the JPEG image
 */
Fl_JPEG_Image::Fl_JPEG_Image(const char *name, const unsigned char *data)
: Fl_RGB_Image(0,0,0) {
#ifdef HAVE_LIBJPEG
  jpeg_decompress_struct	dinfo;	// Decompressor info
  fl_jpeg_error_mgr		jerr;	// Error handler info
  JSAMPROW			row;	// Sample row pointer
  
  // the following variables are pointers allocating some private space that
  // is not reset by 'setjmp()'
  char* max_finish_decompress_err;      // count errors and give up afer a while
  char* max_destroy_decompress_err;     // to avoid recusion and deadlock
  
  // Clear data...
  alloc_array = 0;
  array = (uchar *)0;
  
  // Setup the decompressor info and read the header...
  dinfo.err                = jpeg_std_error((jpeg_error_mgr *)&jerr);
  jerr.pub_.error_exit     = fl_jpeg_error_handler;
  jerr.pub_.output_message = fl_jpeg_output_handler;
  
  // Setup error loop variables
  max_finish_decompress_err = (char*)malloc(1);   // allocate space on the frame for error counters
  max_destroy_decompress_err = (char*)malloc(1);  // otherwise, the variables are reset on the longjmp
  *max_finish_decompress_err=10;
  *max_destroy_decompress_err=10;
  
  if (setjmp(jerr.errhand_))
  {
    // JPEG error handling...
    Fl::warning("JPEG data is too large or contains errors!\n");
    // if any of the cleanup routines hits another error, we would end up 
    // in a loop. So instead, we decrement max_err for some upper cleanup limit.
    if ( ((*max_finish_decompress_err)-- > 0) && array)
      jpeg_finish_decompress(&dinfo);
    if ( (*max_destroy_decompress_err)-- > 0)
      jpeg_destroy_decompress(&dinfo);
    
    w(0);
    h(0);
    d(0);
    
    if (array) {
      delete[] (uchar *)array;
      array = 0;
      alloc_array = 0;
    }
    
    free(max_destroy_decompress_err);
    free(max_finish_decompress_err);
    
    return;
  }
  
  jpeg_create_decompress(&dinfo);
  jpeg_mem_src(&dinfo, data);
  jpeg_read_header(&dinfo, 1);
  
  dinfo.quantize_colors      = (boolean)FALSE;
  dinfo.out_color_space      = JCS_RGB;
  dinfo.out_color_components = 3;
  dinfo.output_components    = 3;
  
  jpeg_calc_output_dimensions(&dinfo);
  
  w(dinfo.output_width); 
  h(dinfo.output_height);
  d(dinfo.output_components);
  
  if (((size_t)w()) * h() * d() > max_size() ) longjmp(jerr.errhand_, 1);
  array = new uchar[w() * h() * d()];
  alloc_array = 1;
  
  jpeg_start_decompress(&dinfo);
  
  while (dinfo.output_scanline < dinfo.output_height) {
    row = (JSAMPROW)(array +
                     dinfo.output_scanline * dinfo.output_width *
                     dinfo.output_components);
    jpeg_read_scanlines(&dinfo, &row, (JDIMENSION)1);
  }
  
  jpeg_finish_decompress(&dinfo);
  jpeg_destroy_decompress(&dinfo);
  
  free(max_destroy_decompress_err);
  free(max_finish_decompress_err);

  if (w() && h() && name) {
    Fl_Shared_Image *si = new Fl_Shared_Image(name, this);
    si->add();
  }
#endif // HAVE_LIBJPEG
}

//
// End of "$Id: Fl_JPEG_Image.cxx 9980 2013-09-21 16:41:23Z greg.ercolano $".
//
