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exiv2/src/gifimage.cpp

91 lines
2.6 KiB
C++

// SPDX-License-Identifier: GPL-2.0-or-later
// included header files
#include "gifimage.hpp"
#include "config.h"
#include "error.hpp"
#include "futils.hpp"
#include <iostream>
// *****************************************************************************
// class member definitions
namespace Exiv2 {
GifImage::GifImage(BasicIo::UniquePtr io) : Image(ImageType::gif, mdNone, std::move(io)) {
}
std::string GifImage::mimeType() const {
return "image/gif";
}
void GifImage::setExifData(const ExifData& /*exifData*/) {
// Todo: implement me!
throw(Error(ErrorCode::kerInvalidSettingForImage, "Exif metadata", "GIF"));
}
void GifImage::setIptcData(const IptcData& /*iptcData*/) {
// Todo: implement me!
throw(Error(ErrorCode::kerInvalidSettingForImage, "IPTC metadata", "GIF"));
}
void GifImage::setComment(const std::string&) {
// not supported
throw(Error(ErrorCode::kerInvalidSettingForImage, "Image comment", "GIF"));
}
void GifImage::readMetadata() {
#ifdef EXIV2_DEBUG_MESSAGES
std::cerr << "Exiv2::GifImage::readMetadata: Reading GIF file " << io_->path() << "\n";
#endif
if (io_->open() != 0) {
throw Error(ErrorCode::kerDataSourceOpenFailed, io_->path(), strError());
}
IoCloser closer(*io_);
// Ensure that this is the correct image type
if (!isGifType(*io_, true)) {
if (io_->error() || io_->eof())
throw Error(ErrorCode::kerFailedToReadImageData);
throw Error(ErrorCode::kerNotAnImage, "GIF");
}
clearMetadata();
byte buf[4];
if (io_->read(buf, sizeof(buf)) == sizeof(buf)) {
pixelWidth_ = getShort(buf, littleEndian);
pixelHeight_ = getShort(buf + 2, littleEndian);
}
} // GifImage::readMetadata
void GifImage::writeMetadata() {
// Todo: implement me!
throw(Error(ErrorCode::kerWritingImageFormatUnsupported, "GIF"));
} // GifImage::writeMetadata
// *************************************************************************
// free functions
Image::UniquePtr newGifInstance(BasicIo::UniquePtr io, bool /*create*/) {
auto image = std::make_unique<GifImage>(std::move(io));
if (!image->good()) {
return nullptr;
}
return image;
}
bool isGifType(BasicIo& iIo, bool advance) {
const int32_t len = 6;
const unsigned char Gif87aId[8] = {'G', 'I', 'F', '8', '7', 'a'};
const unsigned char Gif89aId[8] = {'G', 'I', 'F', '8', '9', 'a'};
byte buf[len];
iIo.read(buf, len);
if (iIo.error() || iIo.eof()) {
return false;
}
bool matched = (memcmp(buf, Gif87aId, len) == 0) || (memcmp(buf, Gif89aId, len) == 0);
if (!advance || !matched) {
iIo.seek(-len, BasicIo::cur);
}
return matched;
}
} // namespace Exiv2