MicroQRCodeDecoder.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#pragma once
 
#include "ocean/cv/detector/qrcodes/QRCodes.h"
 
#include "ocean/cv/detector/qrcodes/MicroQRCode.h"
 
namespace Ocean
{
 
namespace CV
{
 
namespace Detector
{
 
namespace QRCodes
{
 
/**
 * Definition of a QR code decoder
 * @ingroup cvdetectorqrcodes
 */
class OCEAN_CV_DETECTOR_QRCODES_EXPORT MicroQRCodeDecoder
{
    public:
 
        /*
         * Definition of a bit stream
         */
        class BitStream
        {
            public:
 
                /**
                 * Constructor for bit streams
                 * @param buffer The buffer holding the bit stream, must be valid
                 * @param numberOfBits The number of bits in the bit stream, range: [0, 8 * buffer.size()]
                 */
                BitStream(std::vector<uint8_t>&& buffer, const unsigned int numberOfBits);
 
                /**
                 * Returns the number of bits remaining in the bit stream
                 */
                inline unsigned int bitsRemaining() const;
 
                /**
                 * Consumes a number of bits from the bit stream
                 * @param numberOfBits The number of bits to consume, range: [0, max(32, bitsRemaining())]
                 * @return The consumed bits
                 */
                uint32_t consumeBits(const unsigned int numberOfBits);
 
                /**
                 * Peeks at a number of bits from the bit stream, checking if any are non-zero
                 * @param numberOfBits The number of bits to peek, range: [0, bitsRemaining()]
                 * @return True if any of the bits are non-zero, otherwise false
                 */
                bool peekNonzeroBits(const unsigned int numberOfBits) const;
 
            protected:
 
                /**
                 * Consumes a single bit from the bit stream
                 * @return True if the bit is non-zero, otherwise false
                 */
                bool consumeBit();
 
                /// The buffer holding the bit stream
                std::vector<uint8_t> buffer_;
 
                /// The portion of the current byte that have already been consumed
                unsigned int bitsConsumed_ = 0u;
 
                /// The number of bytes that have already been consumed
                unsigned int bytesConsumed_ = 0u;
 
                /// The number of bits remaining in the bit stream
                unsigned int bitsRemaining_;
        };
 
        /**
         * Decodes the modules of a Micro QR code
         * @param modules The modules of a Micro QR code, e.g., as sampled after a detection, must be valid
         * @param code The resulting QR code instance that will hold the decoded data
         * @return True if the modules are successfully decoded, otherwise false
         */
        static bool decodeMicroQRCode(const std::vector<uint8_t>& modules, MicroQRCode& code);
};
 
inline unsigned int MicroQRCodeDecoder::BitStream::bitsRemaining() const
{
    return bitsRemaining_;
}
 
} // namespace QRCodes
 
} // namespace Detector
 
} // namespace CV
 
} // namespace Ocean