69 lines
2.3 KiB
C++
69 lines
2.3 KiB
C++
// * jcinit.c
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// *
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// * Copyright (C) 1991-1995, Thomas G. Lane.
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// * This file is part of the Independent JPEG Group's software.
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// * For conditions of distribution and use, see the accompanying README file.
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// *
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// * This file contains initialization logic for the JPEG compressor.
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// * This routine is in charge of selecting the modules to be executed and
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// * making an initialization call to each one.
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// *
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// * Logically, this code belongs in jcmaster.c. It's split out because
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// * linking this routine implies linking the entire compression library.
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// * For a transcoding-only application, we want to be able to use jcmaster.c
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// * without linking in the whole library.
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#define JPEG_INTERNALS
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#include "JINCLUDE.h"
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#include "JPEGLIB.h"
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// * Master selection of compression modules.
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// * This is done once at the start of processing an image. We determine
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// * which modules will be used and give them appropriate initialization calls.
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GLOBAL void
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jinit_compress_master (j_compress_ptr cinfo)
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{
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// Initialize master control (includes parameter checking/processing)
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jinit_c_master_control(cinfo, FALSE /* full compression */);
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// Preprocessing
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if (! cinfo->raw_data_in) {
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jinit_color_converter(cinfo);
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jinit_downsampler(cinfo);
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jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */);
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}
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// Forward DCT
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jinit_forward_dct(cinfo);
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// Entropy encoding: either Huffman or arithmetic coding.
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if (cinfo->arith_code) {
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ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
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} else {
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if (cinfo->progressive_mode) {
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#ifdef C_PROGRESSIVE_SUPPORTED
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jinit_phuff_encoder(cinfo);
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#else
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ERREXIT(cinfo, JERR_NOT_COMPILED);
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#endif
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} else
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jinit_huff_encoder(cinfo);
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}
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// Need a full-image coefficient buffer in any multi-pass mode.
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jinit_c_coef_controller(cinfo,
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(cinfo->num_scans > 1 || cinfo->optimize_coding));
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jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
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jinit_marker_writer(cinfo);
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// We can now tell the memory manager to allocate virtual arrays.
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(*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);
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// Write the datastream header (SOI) immediately.
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// * Frame and scan headers are postponed till later.
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// * This lets application insert special markers after the SOI.
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(*cinfo->marker->write_file_header) (cinfo);
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}
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