xref: /plan9/sys/src/cmd/gs/jpeg/jcinit.c (revision 7dd7cddf99dd7472612f1413b4da293630e6b1bc)
1*7dd7cddfSDavid du Colombier /*
2*7dd7cddfSDavid du Colombier  * jcinit.c
3*7dd7cddfSDavid du Colombier  *
4*7dd7cddfSDavid du Colombier  * Copyright (C) 1991-1996, Thomas G. Lane.
5*7dd7cddfSDavid du Colombier  * This file is part of the Independent JPEG Group's software.
6*7dd7cddfSDavid du Colombier  * For conditions of distribution and use, see the accompanying README file.
7*7dd7cddfSDavid du Colombier  *
8*7dd7cddfSDavid du Colombier  * This file contains initialization logic for the JPEG compressor.
9*7dd7cddfSDavid du Colombier  * This routine is in charge of selecting the modules to be executed and
10*7dd7cddfSDavid du Colombier  * making an initialization call to each one.
11*7dd7cddfSDavid du Colombier  *
12*7dd7cddfSDavid du Colombier  * Logically, this code belongs in jcmaster.c.  It's split out because
13*7dd7cddfSDavid du Colombier  * linking this routine implies linking the entire compression library.
14*7dd7cddfSDavid du Colombier  * For a transcoding-only application, we want to be able to use jcmaster.c
15*7dd7cddfSDavid du Colombier  * without linking in the whole library.
16*7dd7cddfSDavid du Colombier  */
17*7dd7cddfSDavid du Colombier 
18*7dd7cddfSDavid du Colombier #define JPEG_INTERNALS
19*7dd7cddfSDavid du Colombier #include "jinclude.h"
20*7dd7cddfSDavid du Colombier #include "jpeglib.h"
21*7dd7cddfSDavid du Colombier 
22*7dd7cddfSDavid du Colombier 
23*7dd7cddfSDavid du Colombier /*
24*7dd7cddfSDavid du Colombier  * Master selection of compression modules.
25*7dd7cddfSDavid du Colombier  * This is done once at the start of processing an image.  We determine
26*7dd7cddfSDavid du Colombier  * which modules will be used and give them appropriate initialization calls.
27*7dd7cddfSDavid du Colombier  */
28*7dd7cddfSDavid du Colombier 
29*7dd7cddfSDavid du Colombier GLOBAL(void)
30*7dd7cddfSDavid du Colombier jinit_compress_master (j_compress_ptr cinfo)
31*7dd7cddfSDavid du Colombier {
32*7dd7cddfSDavid du Colombier   /* Initialize master control (includes parameter checking/processing) */
33*7dd7cddfSDavid du Colombier   jinit_c_master_control(cinfo, FALSE /* full compression */);
34*7dd7cddfSDavid du Colombier 
35*7dd7cddfSDavid du Colombier   /* Preprocessing */
36*7dd7cddfSDavid du Colombier   if (! cinfo->raw_data_in) {
37*7dd7cddfSDavid du Colombier     jinit_color_converter(cinfo);
38*7dd7cddfSDavid du Colombier     jinit_downsampler(cinfo);
39*7dd7cddfSDavid du Colombier     jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
40*7dd7cddfSDavid du Colombier   }
41*7dd7cddfSDavid du Colombier   /* Forward DCT */
42*7dd7cddfSDavid du Colombier   jinit_forward_dct(cinfo);
43*7dd7cddfSDavid du Colombier   /* Entropy encoding: either Huffman or arithmetic coding. */
44*7dd7cddfSDavid du Colombier   if (cinfo->arith_code) {
45*7dd7cddfSDavid du Colombier     ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
46*7dd7cddfSDavid du Colombier   } else {
47*7dd7cddfSDavid du Colombier     if (cinfo->progressive_mode) {
48*7dd7cddfSDavid du Colombier #ifdef C_PROGRESSIVE_SUPPORTED
49*7dd7cddfSDavid du Colombier       jinit_phuff_encoder(cinfo);
50*7dd7cddfSDavid du Colombier #else
51*7dd7cddfSDavid du Colombier       ERREXIT(cinfo, JERR_NOT_COMPILED);
52*7dd7cddfSDavid du Colombier #endif
53*7dd7cddfSDavid du Colombier     } else
54*7dd7cddfSDavid du Colombier       jinit_huff_encoder(cinfo);
55*7dd7cddfSDavid du Colombier   }
56*7dd7cddfSDavid du Colombier 
57*7dd7cddfSDavid du Colombier   /* Need a full-image coefficient buffer in any multi-pass mode. */
58*7dd7cddfSDavid du Colombier   jinit_c_coef_controller(cinfo,
59*7dd7cddfSDavid du Colombier 			  (cinfo->num_scans > 1 || cinfo->optimize_coding));
60*7dd7cddfSDavid du Colombier   jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
61*7dd7cddfSDavid du Colombier 
62*7dd7cddfSDavid du Colombier   jinit_marker_writer(cinfo);
63*7dd7cddfSDavid du Colombier 
64*7dd7cddfSDavid du Colombier   /* We can now tell the memory manager to allocate virtual arrays. */
65*7dd7cddfSDavid du Colombier   (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
66*7dd7cddfSDavid du Colombier 
67*7dd7cddfSDavid du Colombier   /* Write the datastream header (SOI) immediately.
68*7dd7cddfSDavid du Colombier    * Frame and scan headers are postponed till later.
69*7dd7cddfSDavid du Colombier    * This lets application insert special markers after the SOI.
70*7dd7cddfSDavid du Colombier    */
71*7dd7cddfSDavid du Colombier   (*cinfo->marker->write_file_header) (cinfo);
72*7dd7cddfSDavid du Colombier }
73