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127 lines
4.0 KiB
C++
127 lines
4.0 KiB
C++
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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File: bmpimage.cpp
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Author(s): Marco Piovanelli, Ovolab (marco)
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History: 05-Mar-2007, marco: created
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*/
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#include "basicio.hpp"
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#include "bmpimage.hpp"
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#include "error.hpp"
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#include "futils.hpp"
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#include "image.hpp"
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// + standard includes
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#include <cstring>
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#include <string>
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#include <iostream>
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// *****************************************************************************
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// class member definitions
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namespace Exiv2
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{
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BmpImage::BmpImage(BasicIo::UniquePtr io) : Image(ImageType::bmp, mdNone, std::move(io))
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{
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}
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std::string BmpImage::mimeType() const
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{
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// "image/bmp" is a Generic Bitmap
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return "image/x-ms-bmp"; // Microsoft Bitmap
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}
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void BmpImage::setExifData(const ExifData& /*exifData*/)
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{
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throw(Error(ErrorCode::kerInvalidSettingForImage, "Exif metadata", "BMP"));
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}
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void BmpImage::setIptcData(const IptcData& /*iptcData*/)
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{
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throw(Error(ErrorCode::kerInvalidSettingForImage, "IPTC metadata", "BMP"));
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}
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void BmpImage::setComment(std::string_view /*comment*/)
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{
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throw(Error(ErrorCode::kerInvalidSettingForImage, "Image comment", "BMP"));
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}
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void BmpImage::readMetadata()
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{
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#ifdef EXIV2_DEBUG_MESSAGES
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std::cerr << "Exiv2::BmpImage::readMetadata: Reading Windows bitmap file " << io_->path() << "\n";
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#endif
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if (io_->open() != 0) {
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throw Error(ErrorCode::kerDataSourceOpenFailed, io_->path(), strError());
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}
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IoCloser closer(*io_);
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// Ensure that this is the correct image type
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if (!isBmpType(*io_, false)) {
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if (io_->error() || io_->eof())
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throw Error(ErrorCode::kerFailedToReadImageData);
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throw Error(ErrorCode::kerNotAnImage, "BMP");
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}
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clearMetadata();
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/*
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The Windows bitmap header goes as follows -- all numbers are in little-endian byte order:
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offset length name description
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====== ======= ===================== =======
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0 2 bytes signature always 'BM'
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2 4 bytes bitmap size
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6 4 bytes reserved
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10 4 bytes bitmap offset
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14 4 bytes header size
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18 4 bytes bitmap width
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22 4 bytes bitmap height
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26 2 bytes plane count
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28 2 bytes depth
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30 4 bytes compression 0 = none; 1 = RLE, 8 bits/pixel; 2 = RLE, 4 bits/pixel; 3 = bitfield; 4 = JPEG; 5 = PNG
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34 4 bytes image size size of the raw bitmap data, in bytes
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38 4 bytes horizontal resolution (in pixels per meter)
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42 4 bytes vertical resolution (in pixels per meter)
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46 4 bytes color count
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50 4 bytes important colors number of "important" colors
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*/
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byte buf[26];
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if (io_->read(buf, sizeof(buf)) == sizeof(buf)) {
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pixelWidth_ = getLong(buf + 18, littleEndian);
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pixelHeight_ = getLong(buf + 22, littleEndian);
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}
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}
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void BmpImage::writeMetadata()
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{
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/// \todo implement me!
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throw(Error(ErrorCode::kerWritingImageFormatUnsupported, "BMP"));
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}
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// *************************************************************************
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// free functions
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Image::UniquePtr newBmpInstance(BasicIo::UniquePtr io, bool /*create*/)
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{
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auto image = std::make_unique<BmpImage>(std::move(io));
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if (!image->good()) {
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image.reset();
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}
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return image;
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}
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bool isBmpType(BasicIo& iIo, bool advance)
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{
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const int32_t len = 2;
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const unsigned char BmpImageId[2] = {'B', 'M'};
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byte buf[len];
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iIo.read(buf, len);
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if (iIo.error() || iIo.eof()) {
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return false;
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}
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bool matched = (memcmp(buf, BmpImageId, len) == 0);
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if (!advance || !matched) {
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iIo.seek(-len, BasicIo::cur);
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}
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return matched;
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}
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} // namespace Exiv2
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