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