91 lines
3.1 KiB
C++
91 lines
3.1 KiB
C++
// Copyright (c) the JPEG XL Project Authors. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "lib/jpegli/decode.h"
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#include "lib/jpegli/error.h"
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#include "lib/jpegli/memory_manager.h"
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namespace jpegli {
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void init_mem_source(j_decompress_ptr cinfo) {}
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void init_stdio_source(j_decompress_ptr cinfo) {}
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void skip_input_data(j_decompress_ptr cinfo, long num_bytes /* NOLINT */) {
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if (num_bytes <= 0) return;
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while (num_bytes >
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static_cast<long>(cinfo->src->bytes_in_buffer)) { // NOLINT
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num_bytes -= cinfo->src->bytes_in_buffer;
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(*cinfo->src->fill_input_buffer)(cinfo);
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}
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cinfo->src->next_input_byte += num_bytes;
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cinfo->src->bytes_in_buffer -= num_bytes;
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}
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void term_source(j_decompress_ptr cinfo) {}
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boolean EmitFakeEoiMarker(j_decompress_ptr cinfo) {
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static constexpr uint8_t kFakeEoiMarker[2] = {0xff, 0xd9};
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cinfo->src->next_input_byte = kFakeEoiMarker;
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cinfo->src->bytes_in_buffer = 2;
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return TRUE;
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}
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constexpr size_t kStdioBufferSize = 64 << 10;
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struct StdioSourceManager {
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jpeg_source_mgr pub;
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FILE* f;
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uint8_t* buffer;
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static boolean fill_input_buffer(j_decompress_ptr cinfo) {
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auto* src = reinterpret_cast<StdioSourceManager*>(cinfo->src);
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size_t num_bytes_read = fread(src->buffer, 1, kStdioBufferSize, src->f);
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if (num_bytes_read == 0) {
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return EmitFakeEoiMarker(cinfo);
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}
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src->pub.next_input_byte = src->buffer;
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src->pub.bytes_in_buffer = num_bytes_read;
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return TRUE;
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}
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};
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} // namespace jpegli
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void jpegli_mem_src(j_decompress_ptr cinfo, const unsigned char* inbuffer,
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unsigned long insize /* NOLINT */) {
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if (cinfo->src && cinfo->src->init_source != jpegli::init_mem_source) {
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JPEGLI_ERROR("jpegli_mem_src: a different source manager was already set");
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}
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if (!cinfo->src) {
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cinfo->src = jpegli::Allocate<jpeg_source_mgr>(cinfo, 1);
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}
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cinfo->src->next_input_byte = inbuffer;
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cinfo->src->bytes_in_buffer = insize;
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cinfo->src->init_source = jpegli::init_mem_source;
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cinfo->src->fill_input_buffer = jpegli::EmitFakeEoiMarker;
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cinfo->src->skip_input_data = jpegli::skip_input_data;
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cinfo->src->resync_to_restart = jpegli_resync_to_restart;
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cinfo->src->term_source = jpegli::term_source;
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}
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void jpegli_stdio_src(j_decompress_ptr cinfo, FILE* infile) {
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if (cinfo->src && cinfo->src->init_source != jpegli::init_stdio_source) {
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JPEGLI_ERROR("jpeg_stdio_src: a different source manager was already set");
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}
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if (!cinfo->src) {
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cinfo->src = reinterpret_cast<jpeg_source_mgr*>(
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jpegli::Allocate<jpegli::StdioSourceManager>(cinfo, 1));
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}
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auto* src = reinterpret_cast<jpegli::StdioSourceManager*>(cinfo->src);
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src->f = infile;
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src->buffer = jpegli::Allocate<uint8_t>(cinfo, jpegli::kStdioBufferSize);
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src->pub.next_input_byte = src->buffer;
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src->pub.bytes_in_buffer = 0;
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src->pub.init_source = jpegli::init_stdio_source;
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src->pub.fill_input_buffer = jpegli::StdioSourceManager::fill_input_buffer;
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src->pub.skip_input_data = jpegli::skip_input_data;
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src->pub.resync_to_restart = jpegli_resync_to_restart;
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src->pub.term_source = jpegli::term_source;
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}
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