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// 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::SRational;
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;
}
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;
}
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;
success &= 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;
}
}
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(), 0));
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 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 offset_to_ifd,
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_, offset_to_ifd, 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