third_party/libjpeg/jcinit.c

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