jpeg_src.c

   1 /************************************************************************************
   2 Partially based on TerraLib, from https://svn.dpi.inpe.br/terralib
   3
   4 TerraLib - a library for developing GIS applications.
   5 Copyright © 2001-2007 INPE and Tecgraf/PUC-Rio.
   6
   7 This code is part of the TerraLib library.
   8 This library is free software; you can redistribute it and/or
   9 modify it under the terms of the GNU Lesser General Public
  10 License as published by the Free Software Foundation; either
  11 version 2.1 of the License, or (at your option) any later version.
  12
  13 You should have received a copy of the GNU Lesser General Public
  14 License along with this library.
  15
  16 The authors reassure the license terms regarding the warranties.
  17 They specifically disclaim any warranties, including, but not limited to,
  18 the implied warranties of merchantability and fitness for a particular purpose.
  19 The library provided hereunder is on an "as is" basis, and the authors have no
  20 obligation to provide maintenance, support, updates, enhancements, or modifications.
  21 In no event shall INPE and Tecgraf / PUC-Rio be held liable to any party for direct,
  22 indirect, special, incidental, or consequential damages arising out of the use
  23 of this library and its documentation.
  24 *************************************************************************************/
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include "jpeglib.h"
  28 #include "gstsparrow.h"
  29 #include "sparrow.h"
  30
  31 // Expanded data source object for memory buffer input
  32 typedef struct
  33 {
  34   struct jpeg_source_mgr pub;
  35   unsigned char* buffer;
  36   unsigned int   bufsize;
  37 } sparrow_src_mgr;
  38
  39 #define COLOURSPACE JCS_EXT_XBGR
  40
  41
  42 /*
  43  Initialize source --- Nothing to do
  44  */
  45 static void
  46 init_source (j_decompress_ptr cinfo)
  47 {}
  48
  49 /*
  50  Fill the input buffer --- called whenever buffer is emptied.
  51  */
  52 static gboolean
  53 fill_input_buffer (j_decompress_ptr cinfo)
  54 {
  55   sparrow_src_mgr *src = (sparrow_src_mgr *) cinfo->src;
  56   src->pub.next_input_byte = src->buffer;
  57   src->pub.bytes_in_buffer = src->bufsize;
  58
  59   return TRUE;
  60 }
  61
  62 /*
  63  Skip data --- used to skip over a potentially large amount of
  64  uninteresting data.
  65  */
  66 static void
  67 skip_input_data (j_decompress_ptr cinfo, long num_bytes)
  68 {
  69   sparrow_src_mgr * src = (sparrow_src_mgr *) cinfo->src;
  70
  71   /* just move the ptr */
  72   src->pub.next_input_byte += num_bytes;
  73   src->pub.bytes_in_buffer -= num_bytes;
  74 }
  75
  76 /*
  77   Terminate source --- called by jpeg_finish_decompress
  78  */
  79 static void
  80 term_source (j_decompress_ptr cinfo)
  81 {}
  82
  83 /*
  84  Prepare for input from a memory buffer.
  85  */
  86 void
  87 jpeg_mem_src (j_decompress_ptr cinfo, unsigned char* buffer, unsigned int bufsize)
  88 {
  89   sparrow_src_mgr *src;
  90
  91   if (cinfo->src == NULL) {
  92     cinfo->src = (struct jpeg_source_mgr *)
  93       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, sizeof(sparrow_src_mgr));
  94   }
  95
  96   src = (sparrow_src_mgr *) cinfo->src;
  97   src->pub.init_source = init_source;
  98   src->pub.fill_input_buffer = fill_input_buffer;
  99   src->pub.skip_input_data = skip_input_data;
 100   src->pub.resync_to_restart = jpeg_resync_to_restart;
 101   src->pub.term_source = term_source;
 102   src->pub.bytes_in_buffer = 0;
 103   src->pub.next_input_byte = NULL;
 104
 105   src->buffer = buffer;
 106   src->bufsize = bufsize;
 107 }
 108
 109 #define ROWS_PER_CYCLE 1 /*I think this needs to be 1 in anycase*/
 110
 111 void
 112 decompress_buffer(struct jpeg_decompress_struct *cinfo, guint8* src, int size, guint8* dest,
 113     int *width, int *height)
 114 {
 115   jpeg_create_decompress(cinfo);
 116   jpeg_mem_src(cinfo, src, size);
 117
 118   jpeg_read_header(cinfo, TRUE);
 119   jpeg_start_decompress(cinfo);
 120   cinfo->out_color_space = COLOURSPACE;
 121
 122   *width = cinfo->output_width;
 123   *height = cinfo->output_height;
 124
 125   /*use 4 here, not cinfo->num_channels, because libjpeg_turbo is doing the
 126     RGBx colour space conversion */
 127   int stride = 4 * cinfo->output_width;
 128   guint8* row = dest;
 129   while (cinfo->output_scanline < cinfo->output_height){
 130     int read = jpeg_read_scanlines(cinfo, &row, ROWS_PER_CYCLE);
 131     row += stride * read;
 132   }
 133   jpeg_finish_decompress(cinfo);
 134 }
 135
 136 void
 137 init_jpeg_src(GstSparrow *sparrow){
 138   sparrow->cinfo = zalloc_or_die(sizeof(struct jpeg_decompress_struct));
 139   struct jpeg_error_mgr *jerr = zalloc_or_die(sizeof(struct jpeg_error_mgr));
 140   sparrow->cinfo->err = jpeg_std_error(jerr);
 141   sparrow->cinfo->out_color_space = COLOURSPACE;
 142 }
 143
 144 void
 145 finalise_jpeg_src(GstSparrow *sparrow){
 146   jpeg_destroy_decompress(sparrow->cinfo);
 147   free(sparrow->cinfo->err);
 148   free(sparrow->cinfo);
 149 }