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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This C++ example decodes a JPEG XL image progressively (input bytes are
// passed in chunks). The example outputs the intermediate steps to PAM files.
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <jxl/decode.h>
#include <jxl/decode_cxx.h>
#include <jxl/resizable_parallel_runner.h>
#include <jxl/resizable_parallel_runner_cxx.h>
#include <limits.h>
#include <cinttypes> // PRIu64
#include <cstdint>
#include <cstdio>
#include <cstring>
#include <vector>
bool WritePAM(const char* filename, const uint8_t* buffer, size_t w, size_t h) {
FILE* fp = fopen(filename, "wb");
if (!fp) {
fprintf(stderr, "Could not open %s for writing", filename);
return false;
}
fprintf(fp,
"P7\nWIDTH %d\nHEIGHT %d\nDEPTH 4\nMAXVAL 255\nTUPLTYPE "
"RGB_ALPHA\nENDHDR\n",
static_cast<int>(w), static_cast<int>(h));
size_t num_bytes = w * h * 4;
if (fwrite(buffer, 1, num_bytes, fp) != num_bytes) {
fclose(fp);
return false;
};
if (fclose(fp) != 0) {
return false;
}
return true;
}
/** Decodes JPEG XL image to 8-bit integer RGBA pixels and an ICC Profile, in a
* progressive way, saving the intermediate steps.
*/
bool DecodeJpegXlProgressive(const uint8_t* jxl, size_t size,
const char* filename, size_t chunksize) {
std::vector<uint8_t> pixels;
std::vector<uint8_t> icc_profile;
size_t xsize = 0;
size_t ysize = 0;
// Multi-threaded parallel runner.
auto runner = JxlResizableParallelRunnerMake(nullptr);
auto dec = JxlDecoderMake(nullptr);
if (JXL_DEC_SUCCESS !=
JxlDecoderSubscribeEvents(dec.get(), JXL_DEC_BASIC_INFO |
JXL_DEC_COLOR_ENCODING |
JXL_DEC_FULL_IMAGE)) {
fprintf(stderr, "JxlDecoderSubscribeEvents failed\n");
return false;
}
if (JXL_DEC_SUCCESS != JxlDecoderSetParallelRunner(dec.get(),
JxlResizableParallelRunner,
runner.get())) {
fprintf(stderr, "JxlDecoderSetParallelRunner failed\n");
return false;
}
JxlBasicInfo info;
JxlPixelFormat format = {4, JXL_TYPE_UINT8, JXL_NATIVE_ENDIAN, 0};
size_t seen = 0;
JxlDecoderSetInput(dec.get(), jxl, chunksize);
size_t remaining = chunksize;
for (;;) {
JxlDecoderStatus status = JxlDecoderProcessInput(dec.get());
if (status == JXL_DEC_ERROR) {
fprintf(stderr, "Decoder error\n");
return false;
} else if (status == JXL_DEC_NEED_MORE_INPUT || status == JXL_DEC_SUCCESS ||
status == JXL_DEC_FULL_IMAGE) {
seen += remaining - JxlDecoderReleaseInput(dec.get());
printf("Flushing after %" PRIu64 " bytes\n", static_cast<uint64_t>(seen));
if (status == JXL_DEC_NEED_MORE_INPUT &&
JXL_DEC_SUCCESS != JxlDecoderFlushImage(dec.get())) {
printf("flush error (no preview yet)\n");
} else {
char fname[1024];
if (snprintf(fname, 1024, "%s-%" PRIu64 ".pam", filename,
static_cast<uint64_t>(seen)) >= 1024) {
fprintf(stderr, "Filename too long\n");
return false;
};
if (!WritePAM(fname, pixels.data(), xsize, ysize)) {
fprintf(stderr, "Error writing progressive output\n");
}
}
remaining = size - seen;
if (remaining > chunksize) remaining = chunksize;
if (remaining == 0) {
if (status == JXL_DEC_NEED_MORE_INPUT) {
fprintf(stderr, "Error, already provided all input\n");
return false;
} else {
return true;
}
}
JxlDecoderSetInput(dec.get(), jxl + seen, remaining);
} else if (status == JXL_DEC_BASIC_INFO) {
if (JXL_DEC_SUCCESS != JxlDecoderGetBasicInfo(dec.get(), &info)) {
fprintf(stderr, "JxlDecoderGetBasicInfo failed\n");
return false;
}
xsize = info.xsize;
ysize = info.ysize;
JxlResizableParallelRunnerSetThreads(
runner.get(),
JxlResizableParallelRunnerSuggestThreads(info.xsize, info.ysize));
} else if (status == JXL_DEC_COLOR_ENCODING) {
// Get the ICC color profile of the pixel data
size_t icc_size;
if (JXL_DEC_SUCCESS !=
JxlDecoderGetICCProfileSize(
dec.get(), JXL_COLOR_PROFILE_TARGET_ORIGINAL, &icc_size)) {
fprintf(stderr, "JxlDecoderGetICCProfileSize failed\n");
return false;
}
icc_profile.resize(icc_size);
if (JXL_DEC_SUCCESS != JxlDecoderGetColorAsICCProfile(
dec.get(), JXL_COLOR_PROFILE_TARGET_ORIGINAL,
icc_profile.data(), icc_profile.size())) {
fprintf(stderr, "JxlDecoderGetColorAsICCProfile failed\n");
return false;
}
} else if (status == JXL_DEC_NEED_IMAGE_OUT_BUFFER) {
size_t buffer_size;
if (JXL_DEC_SUCCESS !=
JxlDecoderImageOutBufferSize(dec.get(), &format, &buffer_size)) {
fprintf(stderr, "JxlDecoderImageOutBufferSize failed\n");
return false;
}
if (buffer_size != xsize * ysize * 4) {
fprintf(stderr, "Invalid out buffer size %" PRIu64 " != %" PRIu64 "\n",
static_cast<uint64_t>(buffer_size),
static_cast<uint64_t>(xsize * ysize * 4));
return false;
}
pixels.resize(xsize * ysize * 4);
if (JXL_DEC_SUCCESS != JxlDecoderSetImageOutBuffer(dec.get(), &format,
pixels.data(),
pixels.size())) {
fprintf(stderr, "JxlDecoderSetImageOutBuffer failed\n");
return false;
}
} else {
fprintf(stderr, "Unknown decoder status\n");
return false;
}
}
}
bool LoadFile(const char* filename, std::vector<uint8_t>* out) {
FILE* file = fopen(filename, "rb");
if (!file) {
return false;
}
if (fseek(file, 0, SEEK_END) != 0) {
fclose(file);
return false;
}
long size = ftell(file); // NOLINT
// Avoid invalid file or directory.
if (size >= LONG_MAX || size < 0) {
fclose(file);
return false;
}
if (fseek(file, 0, SEEK_SET) != 0) {
fclose(file);
return false;
}
out->resize(size);
size_t readsize = fread(out->data(), 1, size, file);
if (fclose(file) != 0) {
return false;
}
return readsize == static_cast<size_t>(size);
}
int main(int argc, char* argv[]) {
if (argc < 3) {
fprintf(
stderr,
"Usage: %s <jxl> <basename> [chunksize]\n"
"Where:\n"
" jxl = input JPEG XL image filename\n"
" basename = prefix of output filenames\n"
" chunksize = loads chunksize bytes at a time and writes\n"
" intermediate results to basename-[bytes loaded].pam\n"
"Output files will be overwritten.\n",
argv[0]);
return 1;
}
const char* jxl_filename = argv[1];
const char* png_filename = argv[2];
std::vector<uint8_t> jxl;
if (!LoadFile(jxl_filename, &jxl)) {
fprintf(stderr, "couldn't load %s\n", jxl_filename);
return 1;
}
size_t chunksize = jxl.size();
if (argc > 3) {
long cs = atol(argv[3]); // NOLINT
if (cs < 100) {
fprintf(stderr, "Chunk size is too low, try at least 100 bytes\n");
return 1;
}
chunksize = cs;
}
if (!DecodeJpegXlProgressive(jxl.data(), jxl.size(), png_filename,
chunksize)) {
fprintf(stderr, "Error while decoding the jxl file\n");
return 1;
}
return 0;
}