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      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.ijg
      7  * 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   /* Initialize master control (includes parameter checking/processing) */
     34   jinit_c_master_control(cinfo, FALSE /* full compression */);
     35 
     36   /* Preprocessing */
     37   if (! cinfo->raw_data_in) {
     38     jinit_color_converter(cinfo);
     39     jinit_downsampler(cinfo);
     40     jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
     41   }
     42   /* Forward DCT */
     43   jinit_forward_dct(cinfo);
     44   /* Entropy encoding: either Huffman or arithmetic coding. */
     45   if (cinfo->arith_code) {
     46 #ifdef C_ARITH_CODING_SUPPORTED
     47     jinit_arith_encoder(cinfo);
     48 #else
     49     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
     50 #endif
     51   } else {
     52     if (cinfo->progressive_mode) {
     53 #ifdef C_PROGRESSIVE_SUPPORTED
     54       jinit_phuff_encoder(cinfo);
     55 #else
     56       ERREXIT(cinfo, JERR_NOT_COMPILED);
     57 #endif
     58     } else
     59       jinit_huff_encoder(cinfo);
     60   }
     61 
     62   /* Need a full-image coefficient buffer in any multi-pass mode. */
     63   jinit_c_coef_controller(cinfo,
     64                 (boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));
     65   jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
     66 
     67   jinit_marker_writer(cinfo);
     68 
     69   /* We can now tell the memory manager to allocate virtual arrays. */
     70   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
     71 
     72   /* Write the datastream header (SOI) immediately.
     73    * Frame and scan headers are postponed till later.
     74    * This lets application insert special markers after the SOI.
     75    */
     76   (*cinfo->marker->write_file_header) (cinfo);
     77 }
     78