1/*
2 * jcinit.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1997, Thomas G. Lane.
6 * libjpeg-turbo Modifications:
7 * Copyright (C) 2020, D. R. Commander.
8 * For conditions of distribution and use, see the accompanying README.ijg
9 * file.
10 *
11 * This file contains initialization logic for the JPEG compressor.
12 * This routine is in charge of selecting the modules to be executed and
13 * making an initialization call to each one.
14 *
15 * Logically, this code belongs in jcmaster.c. It's split out because
16 * linking this routine implies linking the entire compression library.
17 * For a transcoding-only application, we want to be able to use jcmaster.c
18 * without linking in the whole library.
19 */
20
21#define JPEG_INTERNALS
22#include "jinclude.h"
23#include "jpeglib.h"
24#include "jpegcomp.h"
25
26
27/*
28 * Master selection of compression modules.
29 * This is done once at the start of processing an image. We determine
30 * which modules will be used and give them appropriate initialization calls.
31 */
32
33GLOBAL(void)
34jinit_compress_master(j_compress_ptr cinfo)
35{
36 /* Initialize master control (includes parameter checking/processing) */
37 jinit_c_master_control(cinfo, FALSE /* full compression */);
38
39 /* Preprocessing */
40 if (!cinfo->raw_data_in) {
41 jinit_color_converter(cinfo);
42 jinit_downsampler(cinfo);
43 jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
44 }
45 /* Forward DCT */
46 jinit_forward_dct(cinfo);
47 /* Entropy encoding: either Huffman or arithmetic coding. */
48 if (cinfo->arith_code) {
49#ifdef C_ARITH_CODING_SUPPORTED
50 jinit_arith_encoder(cinfo);
51#else
52 ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
53#endif
54 } else {
55 if (cinfo->progressive_mode) {
56#ifdef C_PROGRESSIVE_SUPPORTED
57 jinit_phuff_encoder(cinfo);
58#else
59 ERREXIT(cinfo, JERR_NOT_COMPILED);
60#endif
61 } else
62 jinit_huff_encoder(cinfo);
63 }
64
65 /* Need a full-image coefficient buffer in any multi-pass mode. */
66 jinit_c_coef_controller(cinfo, (boolean)(cinfo->num_scans > 1 ||
67 cinfo->optimize_coding));
68 jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
69
70 jinit_marker_writer(cinfo);
71
72 /* We can now tell the memory manager to allocate virtual arrays. */
73 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr)cinfo);
74
75 /* Write the datastream header (SOI) immediately.
76 * Frame and scan headers are postponed till later.
77 * This lets application insert special markers after the SOI.
78 */
79 (*cinfo->marker->write_file_header) (cinfo);
80}
81