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 | |
33 | GLOBAL(void) |
34 | jinit_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 | |