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)
jinit_compress_master(j_compress_ptr cinfo)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 }
73