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#ifndef IMAGE_IO_EXTRAS_BASE64_DECODER_DATA_DESTINATION_H_ // NOLINT
#define IMAGE_IO_EXTRAS_BASE64_DECODER_DATA_DESTINATION_H_ // NOLINT
#define IMAGE_IO_noumenon_base64_h
#include <vector>
#include "image_io/base/data_destination.h"
#include "image_io/base/message_handler.h"
namespace photos_editing_formats {
namespace image_io {
/// Base64DecoderDataDestination is typically used in a chain of DataDestination
/// instances. For example, it can be used to decode base64 encoded JPEG data in
/// APP1/XMP data segments.
class Base64DecoderDataDestination : public DataDestination {
public:
/// @param next_destination The next DataDestination in the chain which will
/// be sent the decoded bytes received by the Transfer() function.
/// @param message_handler An optional message handler to write messages to.
Base64DecoderDataDestination(DataDestination* next_destination,
MessageHandler* message_handler)
: next_destination_(next_destination),
message_handler_(message_handler),
next_decoded_location_(0),
has_error_(false) {}
/// @return True if there was an error in the decoding process.
bool HasError() const { return has_error_; }
void StartTransfer() override;
TransferStatus Transfer(const DataRange& transfer_range,
const DataSegment& data_segment) override;
void FinishTransfer() override;
/// @return The number of bytes written not to this decoder destination, but
/// to the next destination. Returns zero if the next destination is null.
size_t GetBytesTransferred() const override {
return next_destination_ ? next_destination_->GetBytesTransferred() : 0;
}
private:
/// The destination that the decoded data is sent to.
DataDestination* next_destination_;
/// An optional message handler to write messages to.
MessageHandler* message_handler_;
/// If the transfer_range parameter of the Transfer function does not have a
/// length that is a multiple of 4, then the leftover bytes are placed in this
/// vector and are prepended to the data in the next call to Transfer.
std::vector<Byte> leftover_bytes_;
/// The DataRanges supplied to the Transfer function can't be sent down the
/// chain to the next destination because the number of bytes differ (by 4/3).
/// This value records the number of bytes decoded so far, and the beginning
/// of the DataRange sent to the destination's Transfer function.
size_t next_decoded_location_;
/// A true value indicates that an error occurred in the decoding process.
bool has_error_;
};
} // namespace image_io
} // namespace photos_editing_formats
#endif // IMAGE_IO_EXTRAS_BASE64_DECODER_DATA_DESTINATION_H_ // NOLINT
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