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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 #ifdef C_ARITH_CODING_SUPPORTED
     46     jinit_arith_encoder(cinfo);
     47 #else
     48     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
     49 #endif
     50   } else {
     51     if (cinfo->progressive_mode) {
     52 #ifdef C_PROGRESSIVE_SUPPORTED
     53       jinit_phuff_encoder(cinfo);
     54 #else
     55       ERREXIT(cinfo, JERR_NOT_COMPILED);
     56 #endif
     57     } else
     58       jinit_huff_encoder(cinfo);
     59   }
     60 
     61   /* Need a full-image coefficient buffer in any multi-pass mode. */
     62   jinit_c_coef_controller(cinfo,
     63 		(boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding));
     64   jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
     65 
     66   jinit_marker_writer(cinfo);
     67 
     68   /* We can now tell the memory manager to allocate virtual arrays. */
     69   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
     70 
     71   /* Write the datastream header (SOI) immediately.
     72    * Frame and scan headers are postponed till later.
     73    * This lets application insert special markers after the SOI.
     74    */
     75   (*cinfo->marker->write_file_header) (cinfo);
     76 }
     77