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
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.
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.
21 #define JPEG_INTERNALS
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.
34 jinit_compress_master(j_compress_ptr cinfo
)
36 /* Initialize master control (includes parameter checking/processing) */
37 jinit_c_master_control(cinfo
, FALSE
/* full compression */);
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 */);
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
);
52 ERREXIT(cinfo
, JERR_ARITH_NOTIMPL
);
55 if (cinfo
->progressive_mode
) {
56 #ifdef C_PROGRESSIVE_SUPPORTED
57 jinit_phuff_encoder(cinfo
);
59 ERREXIT(cinfo
, JERR_NOT_COMPILED
);
62 jinit_huff_encoder(cinfo
);
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 */);
70 jinit_marker_writer(cinfo
);
72 /* We can now tell the memory manager to allocate virtual arrays. */
73 (*cinfo
->mem
->realize_virt_arrays
) ((j_common_ptr
)cinfo
);
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.
79 (*cinfo
->marker
->write_file_header
) (cinfo
);