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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 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     jinit_arith_encoder(cinfo);
     46   else {
     47     jinit_huff_encoder(cinfo);
     48   }
     49 
     50   /* Need a full-image coefficient buffer in any multi-pass mode. */
     51   jinit_c_coef_controller(cinfo,
     52                 (boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));
     53   jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
     54 
     55   jinit_marker_writer(cinfo);
     56 
     57   /* We can now tell the memory manager to allocate virtual arrays. */
     58   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
     59 
     60   /* Write the datastream header (SOI) immediately.
     61    * Frame and scan headers are postponed till later.
     62    * This lets application insert special markers after the SOI.
     63    */
     64   (*cinfo->marker->write_file_header) (cinfo);
     65 }
     66