b5a9ef64ea
In libjpeg-turbo 2.1.x and prior, the WITH_12BIT CMake variable was used to enable 12-bit JPEG support at compile time, because the libjpeg API library could not handle multiple JPEG data precisions at run time. The initial approach to handling multiple JPEG data precisions at run time (7fec5074f9) created a whole new API, library, and applications for 12-bit data precision, so it made sense to repurpose WITH_12BIT to allow 12-bit data precision to be disabled.e8b40f3c2bmade it so that the libjpeg API library can handle multiple JPEG data precisions at run time via a handful of straightforward API extensions. Referring to6c2bc901e2, it hasn't been possible to build libjpeg-turbo with both forward and backward libjpeg API/ABI compatibility since libjpeg-turbo 1.4.x. Thus, whereas we retain full backward API/ABI compatibility with libjpeg v6b-v8, forward libjpeg API/ABI compatibility ceased being realistic years ago, so it no longer makes sense to provide compile-time options that give a false sense of forward API/ABI compatibility by allowing some (but not all) of our libjpeg API extensions to be disabled. Such options are difficult to maintain and clutter the code with #ifdefs.
97 lines
3.1 KiB
C
97 lines
3.1 KiB
C
/*
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* jcinit.c
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*
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* This file was part of the Independent JPEG Group's software:
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* Copyright (C) 1991-1997, Thomas G. Lane.
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* libjpeg-turbo Modifications:
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* Copyright (C) 2020, 2022, D. R. Commander.
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* For conditions of distribution and use, see the accompanying README.ijg
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* 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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*/
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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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#include "jpegapicomp.h"
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/*
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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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*/
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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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if (cinfo->data_precision == 12) {
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j12init_color_converter(cinfo);
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j12init_downsampler(cinfo);
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j12init_c_prep_controller(cinfo,
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FALSE /* never need full buffer here */);
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} else {
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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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}
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/* Forward DCT */
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if (cinfo->data_precision == 12)
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j12init_forward_dct(cinfo);
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else
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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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#ifdef C_ARITH_CODING_SUPPORTED
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jinit_arith_encoder(cinfo);
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#else
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ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
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#endif
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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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if (cinfo->data_precision == 12) {
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j12init_c_coef_controller(cinfo, (boolean)(cinfo->num_scans > 1 ||
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cinfo->optimize_coding));
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j12init_c_main_controller(cinfo, FALSE /* never need full buffer here */);
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} else {
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jinit_c_coef_controller(cinfo, (boolean)(cinfo->num_scans > 1 ||
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cinfo->optimize_coding));
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jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */);
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}
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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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*/
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(*cinfo->marker->write_file_header) (cinfo);
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}
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