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Diffstat (limited to 'src/tiff_parser.cc')
| -rwxr-xr-x | src/tiff_parser.cc | 755 |
1 files changed, 755 insertions, 0 deletions
diff --git a/src/tiff_parser.cc b/src/tiff_parser.cc new file mode 100755 index 0000000..3ceaa75 --- /dev/null +++ b/src/tiff_parser.cc @@ -0,0 +1,755 @@ +// Copyright 2015 Google Inc. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +//////////////////////////////////////////////////////////////////////////////// + +#include "src/tiff_parser.h" + +#include <cstring> +#include <limits> +#include <numeric> + +#include "src/tiff_directory/tiff_directory.h" + +namespace piex { +namespace { + +using tiff_directory::Endian; +using tiff_directory::Rational; +using tiff_directory::SizeOfType; +using tiff_directory::TIFF_TYPE_LONG; +using tiff_directory::TIFF_TYPE_UNDEFINED; +using tiff_directory::TiffDirectory; +using tiff_directory::kBigEndian; +using tiff_directory::kLittleEndian; + +// Specifies all tags that might be of interest to parse JPEG data. +const std::uint32_t kStartOfFrame = 0xFFC0; +const std::uint32_t kStartOfImage = 0xFFD8; +const std::uint32_t kStartOfScan = 0xFFDA; + +bool GetFullDimension16(const TiffDirectory& tiff_directory, + std::uint16_t* width, std::uint16_t* height) { + std::uint32_t tmp_width = 0; + std::uint32_t tmp_height = 0; + if (!GetFullDimension32(tiff_directory, &tmp_width, &tmp_height) || + tmp_width > std::numeric_limits<std::uint16_t>::max() || + tmp_height > std::numeric_limits<std::uint16_t>::max()) { + return false; + } + *width = static_cast<std::uint16_t>(tmp_width); + *height = static_cast<std::uint16_t>(tmp_height); + return true; +} + +void FillGpsPreviewImageData(const TiffDirectory& gps_directory, + PreviewImageData* preview_image_data) { + if (gps_directory.Has(kGpsTagLatitudeRef) && + gps_directory.Has(kGpsTagLatitude) && + gps_directory.Has(kGpsTagLongitudeRef) && + gps_directory.Has(kGpsTagLongitude) && + gps_directory.Has(kGpsTagTimeStamp) && + gps_directory.Has(kGpsTagDateStamp)) { + preview_image_data->gps.is_valid = false; + std::string value; + if (!gps_directory.Get(kGpsTagLatitudeRef, &value) || value.empty() || + (value[0] != 'N' && value[0] != 'S') || + !GetRational(kGpsTagLatitude, gps_directory, 3 /* data size */, + preview_image_data->gps.latitude)) { + return; + } + preview_image_data->gps.latitude_ref = value[0]; + + if (!gps_directory.Get(kGpsTagLongitudeRef, &value) || value.empty() || + (value[0] != 'E' && value[0] != 'W') || + !GetRational(kGpsTagLongitude, gps_directory, 3 /* data size */, + preview_image_data->gps.longitude)) { + return; + } + preview_image_data->gps.longitude_ref = value[0]; + + if (!GetRational(kGpsTagTimeStamp, gps_directory, 3 /* data size */, + preview_image_data->gps.time_stamp)) { + return; + } + + const size_t kGpsDateStampSize = 11; + if (!gps_directory.Get(kGpsTagDateStamp, + &preview_image_data->gps.date_stamp)) { + return; + } + if (preview_image_data->gps.date_stamp.size() == kGpsDateStampSize) { + // Resize the date_stamp to remove the "NULL" at the end of string. + preview_image_data->gps.date_stamp.resize(kGpsDateStampSize - 1); + } else { + return; + } + + if (gps_directory.Has(kGpsTagAltitudeRef) && + gps_directory.Has(kGpsTagAltitude)) { + std::vector<std::uint8_t> bytes; + if (!gps_directory.Get(kGpsTagAltitudeRef, &bytes) || bytes.empty() || + !GetRational(kGpsTagAltitude, gps_directory, 1, + &preview_image_data->gps.altitude)) { + return; + } + preview_image_data->gps.altitude_ref = bytes[0] != 0; + } + preview_image_data->gps.is_valid = true; + } +} + +void GetImageSize(const TiffDirectory& tiff_directory, StreamInterface* stream, + Image* image) { + switch (image->format) { + case Image::kUncompressedRgb: { + GetFullDimension16(tiff_directory, &image->width, &image->height); + break; + } + case Image::kJpegCompressed: { + GetJpegDimensions(image->offset, stream, &image->width, &image->height); + break; + } + default: { return; } + } +} + +bool FillPreviewImageData(const TiffDirectory& tiff_directory, + StreamInterface* stream, + PreviewImageData* preview_image_data) { + bool success = true; + // Get preview or thumbnail. The code assumes that only thumbnails can be + // uncompressed. Preview images are always JPEG compressed. + Image image; + if (GetImageData(tiff_directory, stream, &image)) { + if (IsThumbnail(image)) { + preview_image_data->thumbnail = image; + } else if (image.format == Image::kJpegCompressed) { + preview_image_data->preview = image; + } + } + + // Get exif_orientation if it was not set already. + if (tiff_directory.Has(kTiffTagOrientation) && + preview_image_data->exif_orientation == 1) { + success &= tiff_directory.Get(kTiffTagOrientation, + &preview_image_data->exif_orientation); + } + + // Get color_space + if (tiff_directory.Has(kExifTagColorSpace)) { + std::uint32_t color_space; + if (tiff_directory.Get(kExifTagColorSpace, &color_space)) { + if (color_space == 1) { + preview_image_data->color_space = PreviewImageData::kSrgb; + } else if (color_space == 65535 || color_space == 2) { + preview_image_data->color_space = PreviewImageData::kAdobeRgb; + } + } else { + success = false; + } + } + + success &= GetFullDimension32(tiff_directory, &preview_image_data->full_width, + &preview_image_data->full_height); + + if (tiff_directory.Has(kTiffTagMake)) { + success &= tiff_directory.Get(kTiffTagMake, &preview_image_data->maker); + } + + if (tiff_directory.Has(kTiffTagModel)) { + success &= tiff_directory.Get(kTiffTagModel, &preview_image_data->model); + } + + if (tiff_directory.Has(kTiffTagCfaPatternDim)) { + std::vector<std::uint32_t> cfa_pattern_dim; + if (tiff_directory.Get(kTiffTagCfaPatternDim, &cfa_pattern_dim) && + cfa_pattern_dim.size() == 2) { + preview_image_data->cfa_pattern_dim[0] = cfa_pattern_dim[0]; + preview_image_data->cfa_pattern_dim[1] = cfa_pattern_dim[1]; + } + } + + if (tiff_directory.Has(kExifTagDateTimeOriginal)) { + success &= tiff_directory.Get(kExifTagDateTimeOriginal, + &preview_image_data->date_time); + } + + if (tiff_directory.Has(kExifTagIsoSpeed)) { + success &= tiff_directory.Get(kExifTagIsoSpeed, &preview_image_data->iso); + } else if (tiff_directory.Has(kPanaTagIso)) { + success &= tiff_directory.Get(kPanaTagIso, &preview_image_data->iso); + } + + if (tiff_directory.Has(kExifTagExposureTime)) { + success &= GetRational(kExifTagExposureTime, tiff_directory, 1, + &preview_image_data->exposure_time); + } + + if (tiff_directory.Has(kExifTagFnumber)) { + success &= GetRational(kExifTagFnumber, tiff_directory, 1, + &preview_image_data->fnumber); + } + + if (tiff_directory.Has(kExifTagFocalLength)) { + success &= GetRational(kExifTagFocalLength, tiff_directory, 1, + &preview_image_data->focal_length); + } + + return success; +} + +const TiffDirectory* FindFirstTagInIfds(const TiffDirectory::Tag& tag, + const IfdVector& tiff_directory) { + for (std::uint32_t i = 0; i < tiff_directory.size(); ++i) { + if (tiff_directory[i].Has(tag)) { + return &tiff_directory[i]; + } + + // Recursively search sub directories. + const TiffDirectory* sub_directory = + FindFirstTagInIfds(tag, tiff_directory[i].GetSubDirectories()); + if (sub_directory != NULL) { + return sub_directory; + } + } + return NULL; +} + +// Return true if all data blocks are ordered one after the other without gaps. +bool OffsetsAreConsecutive( + const std::vector<std::uint32_t>& strip_offsets, + const std::vector<std::uint32_t>& strip_byte_counts) { + if (strip_offsets.size() != strip_byte_counts.size() || + strip_offsets.empty()) { + return false; + } + + for (size_t i = 0; i < strip_offsets.size() - 1; ++i) { + if (strip_offsets[i] + strip_byte_counts[i] != strip_offsets[i + 1]) { + return false; + } + } + return true; +} + +// Gets the SubIfd content. +bool ParseSubIfds(const std::uint32_t tiff_offset, const TagSet& desired_tags, + const std::uint32_t max_number_ifds, const Endian endian, + StreamInterface* stream, TiffDirectory* tiff_ifd) { + if (tiff_ifd->Has(kTiffTagSubIfd)) { + std::uint32_t offset = 0; + std::uint32_t length = 0; + tiff_ifd->GetOffsetAndLength(kTiffTagSubIfd, TIFF_TYPE_LONG, &offset, + &length); + length /= 4; // length in bytes divided by 4 gives number of IFDs. + for (std::uint32_t j = 0; j < length && j < max_number_ifds; ++j) { + std::uint32_t sub_offset; + if (!Get32u(stream, offset + 4 * j, endian, &sub_offset)) { + return false; + } + + std::uint32_t next_ifd_offset; + TiffDirectory sub_ifd(static_cast<Endian>(endian)); + if (!ParseDirectory(tiff_offset, sub_offset, endian, desired_tags, stream, + &sub_ifd, &next_ifd_offset)) { + return false; + } + + tiff_ifd->AddSubDirectory(sub_ifd); + } + } + return true; +} + +} // namespace + +bool Get16u(StreamInterface* stream, const std::uint32_t offset, + const Endian& endian, std::uint16_t* value) { + std::uint8_t data[2]; + if (stream->GetData(offset, 2, data) == kOk) { + if (endian == kBigEndian) { + *value = (data[0] * 0x100) | data[1]; + } else { + *value = (data[1] * 0x100) | data[0]; + } + return true; + } else { + return false; + } +} + +bool Get32u(StreamInterface* stream, const std::uint32_t offset, + const Endian& endian, std::uint32_t* value) { + std::uint8_t data[4]; + if (stream->GetData(offset, 4, data) == kOk) { + if (endian == kBigEndian) { + *value = (data[0] * 0x1000000u) | (data[1] * 0x10000u) | + (data[2] * 0x100u) | data[3]; + } else { + *value = (data[3] * 0x1000000u) | (data[2] * 0x10000u) | + (data[1] * 0x100u) | data[0]; + } + return true; + } else { + return false; + } +} + +std::vector<std::uint8_t> GetData(const size_t offset, const size_t length, + StreamInterface* stream, Error* error) { + // Read in chunks with a maximum size of 1 MiB. + const size_t kChunkSize = 1048576; + + std::vector<std::uint8_t> data; + size_t processed_data = 0; + while (*error == kOk && processed_data < length) { + size_t chunk_length = kChunkSize; + if (length - data.size() < kChunkSize) { + chunk_length = length - data.size(); + } + + data.resize(processed_data + chunk_length); + *error = stream->GetData(offset + processed_data, chunk_length, + &data[processed_data]); + + processed_data += chunk_length; + } + return data; +} + +bool GetEndianness(const std::uint32_t tiff_offset, StreamInterface* stream, + Endian* endian) { + const std::uint8_t kTiffBigEndianMagic[] = {'M', 'M'}; + const std::uint8_t kTiffLittleEndianMagic[] = {'I', 'I'}; + std::uint8_t tiff_endian[sizeof(kTiffBigEndianMagic)]; + if (stream->GetData(tiff_offset, sizeof(tiff_endian), &tiff_endian[0]) != + kOk) { + return false; + } + + if (!memcmp(tiff_endian, kTiffLittleEndianMagic, sizeof(tiff_endian))) { + *endian = kLittleEndian; + return true; + } else if (!memcmp(tiff_endian, kTiffBigEndianMagic, sizeof(tiff_endian))) { + *endian = kBigEndian; + return true; + } else { + return false; + } +} + +bool GetImageData(const TiffDirectory& tiff_directory, StreamInterface* stream, + Image* image) { + std::uint32_t length = 0; + std::uint32_t offset = 0; + + if (tiff_directory.Has(kTiffTagJpegOffset) && + tiff_directory.Has(kTiffTagJpegByteCount)) { + if (!tiff_directory.Get(kTiffTagJpegOffset, &offset) || + !tiff_directory.Get(kTiffTagJpegByteCount, &length)) { + return false; + } + image->format = Image::kJpegCompressed; + } else if (tiff_directory.Has(kTiffTagStripOffsets) && + tiff_directory.Has(kTiffTagStripByteCounts)) { + std::vector<std::uint32_t> strip_offsets; + std::vector<std::uint32_t> strip_byte_counts; + if (!tiff_directory.Get(kTiffTagStripOffsets, &strip_offsets) || + !tiff_directory.Get(kTiffTagStripByteCounts, &strip_byte_counts)) { + return false; + } + + std::uint32_t compression = 0; + if (!OffsetsAreConsecutive(strip_offsets, strip_byte_counts) || + !tiff_directory.Get(kTiffTagCompression, &compression)) { + return false; + } + + std::uint32_t photometric_interpretation = 0; + if (tiff_directory.Get(kTiffTagPhotometric, &photometric_interpretation) && + photometric_interpretation != 2 /* RGB */ && + photometric_interpretation != 6 /* YCbCr */) { + return false; + } + + switch (compression) { + case 1: /*uncompressed*/ + image->format = Image::kUncompressedRgb; + break; + case 6: /* JPEG(old) */ + case 7: /* JPEG */ + image->format = Image::kJpegCompressed; + break; + default: + return false; + } + length = static_cast<std::uint32_t>(std::accumulate( + strip_byte_counts.begin(), strip_byte_counts.end(), 0U)); + offset = strip_offsets[0]; + } else if (tiff_directory.Has(kPanaTagJpegImage)) { + if (!tiff_directory.GetOffsetAndLength( + kPanaTagJpegImage, TIFF_TYPE_UNDEFINED, &offset, &length)) { + return false; + } + image->format = Image::kJpegCompressed; + } else { + return false; + } + + image->length = length; + image->offset = offset; + GetImageSize(tiff_directory, stream, image); + return true; +} + +bool GetJpegDimensions(const std::uint32_t jpeg_offset, StreamInterface* stream, + std::uint16_t* width, std::uint16_t* height) { + const Endian endian = kBigEndian; + std::uint32_t offset = jpeg_offset; + std::uint16_t segment; + + // Parse the JPEG header until we find Frame0 which contains the image width + // and height or the actual image data starts (StartOfScan) + do { + if (!Get16u(stream, offset, endian, &segment)) { + return false; + } + offset += 2; + + switch (segment) { + case kStartOfImage: + break; + case kStartOfFrame: + return Get16u(stream, offset + 3, endian, height) && + Get16u(stream, offset + 5, endian, width); + default: { + std::uint16_t length; + if (!Get16u(stream, offset, endian, &length)) { + return false; + } + offset += length; + } + } + } while (segment != kStartOfScan); + + // No width and hight information found. + return false; +} + +bool GetRational(const TiffDirectory::Tag& tag, const TiffDirectory& directory, + const int data_size, PreviewImageData::Rational* data) { + std::vector<Rational> value; + if (directory.Get(tag, &value) && + value.size() == static_cast<size_t>(data_size)) { + for (size_t i = 0; i < value.size(); ++i) { + data[i].numerator = value[i].numerator; + data[i].denominator = value[i].denominator; + } + return true; + } + return false; +} + +bool IsThumbnail(const Image& image, const int max_dimension) { + return image.width <= max_dimension && image.height <= max_dimension; +} + +bool ParseDirectory(const std::uint32_t tiff_offset, + const std::uint32_t ifd_offset, const Endian endian, + const TagSet& desired_tags, StreamInterface* stream, + TiffDirectory* tiff_directory, + std::uint32_t* next_ifd_offset) { + std::uint16_t number_of_entries; + if (!Get16u(stream, ifd_offset, endian, &number_of_entries)) { + return false; + } + + for (std::uint32_t i = 0; + i < static_cast<std::uint32_t>(number_of_entries) * 12; i += 12) { + std::uint16_t tag; + std::uint16_t type; + std::uint32_t number_of_elements; + if (Get16u(stream, ifd_offset + 2 + i, endian, &tag) && + Get16u(stream, ifd_offset + 4 + i, endian, &type) && + Get32u(stream, ifd_offset + 6 + i, endian, &number_of_elements)) { + // Check if the current tag should be handled. + if (desired_tags.count(static_cast<TiffDirectory::Tag>(tag)) != 1) { + continue; + } + } else { + return false; + } + + const size_t type_size = SizeOfType(type, nullptr /* no error */); + + // Check that type_size * number_of_elements does not exceed UINT32_MAX. + if (type_size != 0 && number_of_elements > UINT32_MAX / type_size) { + return false; + } + const size_t byte_count = + type_size * static_cast<size_t>(number_of_elements); + + std::uint32_t value_offset; + if (byte_count > 4 && + Get32u(stream, ifd_offset + 10 + i, endian, &value_offset)) { + value_offset += tiff_offset; + } else if (byte_count != 0) { + value_offset = ifd_offset + 10 + i; + } else { + // Ignore entries with an invalid byte count. + continue; + } + + Error error = kOk; + const std::vector<std::uint8_t> data = + GetData(value_offset, byte_count, stream, &error); + if (error != kOk) { + return false; + } + tiff_directory->AddEntry(tag, type, number_of_elements, value_offset, data); + } + + return Get32u(stream, ifd_offset + 2u + number_of_entries * 12u, endian, + next_ifd_offset); +} + +bool GetExifOrientation(StreamInterface* stream, const std::uint32_t offset, + std::uint32_t* orientation) { + const TagSet kOrientationTagSet = {kTiffTagOrientation}; + const std::uint32_t kNumberOfIfds = 1; + + TiffContent tiff_content; + if (!TiffParser(stream, offset) + .Parse(kOrientationTagSet, kNumberOfIfds, &tiff_content)) { + return false; + } + + for (const auto& tiff_directory : tiff_content.tiff_directory) { + if (tiff_directory.Has(kTiffTagOrientation) && + tiff_directory.Get(kTiffTagOrientation, orientation)) { + return true; + } + } + + return false; +} + +bool GetFullDimension32(const TiffDirectory& tiff_directory, + std::uint32_t* width, std::uint32_t* height) { + // The sub file type needs to be 0 (main image) to contain a valid full + // dimensions. This is important in particular for DNG. + if (tiff_directory.Has(kTiffTagSubFileType)) { + std::uint32_t sub_file_type; + if (!tiff_directory.Get(kTiffTagSubFileType, &sub_file_type) || + sub_file_type != 0) { + return false; + } + } + + if (tiff_directory.Has(kExifTagDefaultCropSize)) { + if (!GetFullCropDimension(tiff_directory, width, height)) { + return false; + } + } else if (tiff_directory.Has(kExifTagWidth) && + tiff_directory.Has(kExifTagHeight)) { + if (!tiff_directory.Get(kExifTagWidth, width) || + !tiff_directory.Get(kExifTagHeight, height)) { + return false; + } + } else if (tiff_directory.Has(kTiffTagImageWidth) && + tiff_directory.Has(kTiffTagImageLength)) { + if (!tiff_directory.Get(kTiffTagImageWidth, width) || + !tiff_directory.Get(kTiffTagImageLength, height)) { + return false; + } + } else if (tiff_directory.Has(kPanaTagTopBorder) && + tiff_directory.Has(kPanaTagLeftBorder) && + tiff_directory.Has(kPanaTagBottomBorder) && + tiff_directory.Has(kPanaTagRightBorder)) { + std::uint32_t left; + std::uint32_t right; + std::uint32_t top; + std::uint32_t bottom; + if (tiff_directory.Get(kPanaTagLeftBorder, &left) && + tiff_directory.Get(kPanaTagRightBorder, &right) && + tiff_directory.Get(kPanaTagTopBorder, &top) && + tiff_directory.Get(kPanaTagBottomBorder, &bottom) && bottom > top && + right > left) { + *height = bottom - top; + *width = right - left; + } else { + return false; + } + } + return true; +} + +bool GetFullCropDimension(const tiff_directory::TiffDirectory& tiff_directory, + std::uint32_t* width, std::uint32_t* height) { + if (!tiff_directory.Has(kExifTagDefaultCropSize)) { + // This doesn't look right to return true here, as we have not written + // anything to *width and *height. However, changing the return value here + // causes a whole bunch of tests to fail. + // TODO(timurrrr): Return false and fix the tests. + // In fact, this whole if() seems to be not needed, + // as tiff_directory(kExifTagDefaultCropSize) will return false below. + return true; + } + + std::vector<std::uint32_t> crop(2); + if (tiff_directory.Get(kExifTagDefaultCropSize, &crop)) { + if (crop.size() == 2 && crop[0] > 0 && crop[1] > 0) { + *width = crop[0]; + *height = crop[1]; + return true; + } else { + return false; + } + } + + std::vector<Rational> crop_rational(2); + if (tiff_directory.Get(kExifTagDefaultCropSize, &crop_rational)) { + if (crop_rational.size() == 2 && crop_rational[0].numerator > 0 && + crop_rational[0].denominator > 0 && crop_rational[1].numerator > 0 && + crop_rational[1].denominator > 0) { + *width = crop_rational[0].numerator / crop_rational[0].denominator; + *height = crop_rational[1].numerator / crop_rational[1].denominator; + return true; + } else { + return false; + } + } + + return false; +} + +TiffParser::TiffParser(StreamInterface* stream) : stream_(stream) {} + +TiffParser::TiffParser(StreamInterface* stream, const std::uint32_t offset) + : stream_(stream), tiff_offset_(offset) {} + +bool TiffParser::GetPreviewImageData(const TiffContent& tiff_content, + PreviewImageData* preview_image_data) { + bool success = true; + for (const auto& tiff_directory : tiff_content.tiff_directory) { + success = FillPreviewImageData(tiff_directory, stream_, preview_image_data); + if (success && tiff_directory.Has(kTiffTagExifIfd) && + tiff_content.exif_directory) { + success = FillPreviewImageData(*tiff_content.exif_directory, stream_, + preview_image_data); + } + if (success && tiff_directory.Has(kExifTagGps) && + tiff_content.gps_directory) { + FillGpsPreviewImageData(*tiff_content.gps_directory, preview_image_data); + } + for (const auto& sub_directory : tiff_directory.GetSubDirectories()) { + if (success) { + success = + FillPreviewImageData(sub_directory, stream_, preview_image_data); + } + } + } + return success; +} + +bool TiffParser::Parse(const TagSet& desired_tags, + const std::uint16_t max_number_ifds, + TiffContent* tiff_content) { + if (!tiff_content->tiff_directory.empty()) { + return false; // You shall call Parse() only once. + } + + const std::uint32_t kTiffIdentifierSize = 4; + std::uint32_t offset_to_ifd = 0; + if (!GetEndianness(tiff_offset_, stream_, &endian_) || + !Get32u(stream_, tiff_offset_ + kTiffIdentifierSize, endian_, + &offset_to_ifd)) { + return false; + } + + if (!ParseIfd(tiff_offset_ + offset_to_ifd, desired_tags, max_number_ifds, + &tiff_content->tiff_directory)) { + return false; + } + + // Get the Exif data. + if (FindFirstTagInIfds(kTiffTagExifIfd, tiff_content->tiff_directory) != + nullptr) { + const TiffDirectory* tiff_ifd = + FindFirstTagInIfds(kTiffTagExifIfd, tiff_content->tiff_directory); + std::uint32_t offset; + if (tiff_ifd->Get(kTiffTagExifIfd, &offset)) { + tiff_content->exif_directory.reset(new TiffDirectory(endian_)); + std::uint32_t next_ifd_offset; + if (!ParseDirectory( + tiff_offset_, tiff_offset_ + offset, endian_, desired_tags, + stream_, tiff_content->exif_directory.get(), &next_ifd_offset)) { + return false; + } + + return ParseGpsData(tiff_ifd, tiff_content); + } + } + + // Get the GPS data from the tiff ifd. + if (FindFirstTagInIfds(kExifTagGps, tiff_content->tiff_directory) != + nullptr) { + const TiffDirectory* tiff_ifd = + FindFirstTagInIfds(kExifTagGps, tiff_content->tiff_directory); + return ParseGpsData(tiff_ifd, tiff_content); + } + + return true; +} + +bool TiffParser::ParseIfd(const std::uint32_t ifd_offset, + const TagSet& desired_tags, + const std::uint16_t max_number_ifds, + IfdVector* tiff_directory) { + std::uint32_t next_ifd_offset; + TiffDirectory tiff_ifd(static_cast<Endian>(endian_)); + if (!ParseDirectory(tiff_offset_, ifd_offset, endian_, desired_tags, stream_, + &tiff_ifd, &next_ifd_offset) || + !ParseSubIfds(tiff_offset_, desired_tags, max_number_ifds, endian_, + stream_, &tiff_ifd)) { + return false; + } + + tiff_directory->push_back(tiff_ifd); + if (next_ifd_offset != 0 && tiff_directory->size() < max_number_ifds) { + return ParseIfd(tiff_offset_ + next_ifd_offset, desired_tags, + max_number_ifds, tiff_directory); + } + return true; +} + +bool TiffParser::ParseGpsData(const TiffDirectory* tiff_ifd, + TiffContent* tiff_content) { + std::uint32_t offset; + if (tiff_ifd->Get(kExifTagGps, &offset)) { + tiff_content->gps_directory.reset(new TiffDirectory(endian_)); + const TagSet gps_tags = {kGpsTagLatitudeRef, kGpsTagLatitude, + kGpsTagLongitudeRef, kGpsTagLongitude, + kGpsTagAltitudeRef, kGpsTagAltitude, + kGpsTagTimeStamp, kGpsTagDateStamp}; + std::uint32_t next_ifd_offset; + return ParseDirectory(tiff_offset_, tiff_offset_ + offset, endian_, + gps_tags, stream_, tiff_content->gps_directory.get(), + &next_ifd_offset); + } + return true; +} + +} // namespace piex |