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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 | 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 | } |