compiler/libjpeg/main/jclossy.c

   1 /*
   2  ,   $Id$
   3 */
   4
   5 /*
   6  * jclossy.c
   7  *
   8  * Copyright (C) 1998, Thomas G. Lane.
   9  * This file is part of the Independent JPEG Group's software.
  10  * For conditions of distribution and use, see the accompanying README file.
  11  *
  12  * This file contains the control logic for the lossy JPEG compressor.
  13  */
  14
  15 #define JPEG_INTERNALS
  16 #include "jinclude.h"
  17 #include "jpeglib.h"
  18 #include "jlossy.h"
  19
  20
  21 /*
  22  * Initialize for a processing pass.
  23  */
  24
  25 METHODDEF(void)
  26 start_pass (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
  27 {
  28   j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
  29
  30   (*lossyc->fdct_start_pass) (cinfo);
  31   (*lossyc->coef_start_pass) (cinfo, pass_mode);
  32 }
  33
  34
  35 /*
  36  * Initialize the lossy compression codec.
  37  * This is called only once, during master selection.
  38  */
  39
  40 JGLOBAL(void)
  41 jinit_lossy_c_codec (j_compress_ptr cinfo)
  42 {
  43   j_lossy_c_ptr lossyc;
  44
  45   /* Create subobject in permanent pool */
  46   lossyc = (j_lossy_c_ptr)
  47     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
  48                                 SIZEOF(jpeg_lossy_c_codec));
  49   cinfo->codec = (struct jpeg_c_codec *) lossyc;
  50
  51   /* Initialize sub-modules */
  52
  53   /* Forward DCT */
  54   jinit_forward_dct(cinfo);
  55   /* Entropy encoding: either Huffman or arithmetic coding. */
  56   if (cinfo->arith_code) {
  57     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
  58   } else {
  59     if (cinfo->process == JPROC_PROGRESSIVE) {
  60 #ifdef C_PROGRESSIVE_SUPPORTED
  61       jinit_phuff_encoder(cinfo);
  62 #else
  63       ERREXIT(cinfo, JERR_NOT_COMPILED);
  64 #endif
  65     } else
  66       jinit_shuff_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 ||
  72                                      cinfo->optimize_coding));
  73
  74   /* Initialize method pointers.
  75    *
  76    * Note: entropy_start_pass and entropy_finish_pass are assigned in
  77    * jcshuff.c or jcphuff.c and compress_data is assigned in jccoefct.c.
  78    */
  79   lossyc->pub.start_pass = start_pass;
  80 }