workbench/libs/jpeg/jcinit.c

   1 /*
   2  * jcinit.c
   3  *
   4  * Copyright (C) 1991-1997, Thomas G. Lane.
   5  * Modified 2003-2013 by Guido Vollbeding.
   6  * This file is part of the Independent JPEG Group's software.
   7  * For conditions of distribution and use, see the accompanying README file.
   8  *
   9  * This file contains initialization logic for the JPEG compressor.
  10  * This routine is in charge of selecting the modules to be executed and
  11  * making an initialization call to each one.
  12  *
  13  * Logically, this code belongs in jcmaster.c.  It's split out because
  14  * linking this routine implies linking the entire compression library.
  15  * For a transcoding-only application, we want to be able to use jcmaster.c
  16  * without linking in the whole library.
  17  */
  18
  19 #define JPEG_INTERNALS
  20 #include "jinclude.h"
  21 #include "jpeglib.h"
  22
  23
  24 /*
  25  * Master selection of compression modules.
  26  * This is done once at the start of processing an image.  We determine
  27  * which modules will be used and give them appropriate initialization calls.
  28  */
  29
  30 GLOBAL(void)
  31 jinit_compress_master (j_compress_ptr cinfo)
  32 {
  33   long samplesperrow;
  34   JDIMENSION jd_samplesperrow;
  35
  36   /* For now, precision must match compiled-in value... */
  37   if (cinfo->data_precision != BITS_IN_JSAMPLE)
  38     ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);
  39
  40   /* Sanity check on image dimensions */
  41   if (cinfo->image_height <= 0 || cinfo->image_width <= 0 ||
  42       cinfo->input_components <= 0)
  43     ERREXIT(cinfo, JERR_EMPTY_IMAGE);
  44
  45   /* Width of an input scanline must be representable as JDIMENSION. */
  46   samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components;
  47   jd_samplesperrow = (JDIMENSION) samplesperrow;
  48   if ((long) jd_samplesperrow != samplesperrow)
  49     ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);
  50
  51   /* Initialize master control (includes parameter checking/processing) */
  52   jinit_c_master_control(cinfo, FALSE /* full compression */);
  53
  54   /* Preprocessing */
  55   if (! cinfo->raw_data_in) {
  56     jinit_color_converter(cinfo);
  57     jinit_downsampler(cinfo);
  58     jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
  59   }
  60   /* Forward DCT */
  61   jinit_forward_dct(cinfo);
  62   /* Entropy encoding: either Huffman or arithmetic coding. */
  63   if (cinfo->arith_code)
  64     jinit_arith_encoder(cinfo);
  65   else {
  66     jinit_huff_encoder(cinfo);
  67   }
  68
  69   /* Need a full-image coefficient buffer in any multi-pass mode. */
  70   jinit_c_coef_controller(cinfo,
  71                 (boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));
  72   jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
  73
  74   jinit_marker_writer(cinfo);
  75
  76   /* We can now tell the memory manager to allocate virtual arrays. */
  77   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
  78
  79   /* Write the datastream header (SOI) immediately.
  80    * Frame and scan headers are postponed till later.
  81    * This lets application insert special markers after the SOI.
  82    */
  83   (*cinfo->marker->write_file_header) (cinfo);
  84 }