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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)
jinit_compress_master(j_compress_ptr cinfo)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, (boolean)(cinfo->num_scans > 1 ||
64                                            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