QRDecoder.cpp Example File
appdemos/qtws/QZXing/zxing/zxing/qrcode/decoder/QRDecoder.cpp
#include <zxing/qrcode/decoder/Decoder.h>
#include <zxing/qrcode/decoder/BitMatrixParser.h>
#include <zxing/qrcode/ErrorCorrectionLevel.h>
#include <zxing/qrcode/Version.h>
#include <zxing/qrcode/decoder/DataBlock.h>
#include <zxing/qrcode/decoder/DecodedBitStreamParser.h>
#include <zxing/ReaderException.h>
#include <zxing/ChecksumException.h>
#include <zxing/common/reedsolomon/ReedSolomonException.h>
using zxing::DecoderResult;
using zxing::Ref;
using zxing::ArrayRef;
using zxing::BitMatrix;
namespace zxing {
namespace qrcode {
Decoder::Decoder() :
rsDecoder_(GenericGF::QR_CODE_FIELD_256) {
}
void Decoder::correctErrors(ArrayRef<byte> codewordBytes, int numDataCodewords) {
int numCodewords = codewordBytes->size();
ArrayRef<int> codewordInts(numCodewords);
for (int i = 0; i < numCodewords; i++) {
codewordInts[i] = codewordBytes[i] & 0xff;
}
int numECCodewords = numCodewords - numDataCodewords;
try {
rsDecoder_.decode(codewordInts, numECCodewords);
} catch (ReedSolomonException const& ignored) {
(void)ignored;
throw ChecksumException();
}
for (int i = 0; i < numDataCodewords; i++) {
codewordBytes[i] = (byte)codewordInts[i];
}
}
Ref<DecoderResult> Decoder::decode(Ref<BitMatrix> bits) {
BitMatrixParser parser(bits);
Version *version = parser.readVersion();
ErrorCorrectionLevel &ecLevel = parser.readFormatInformation()->getErrorCorrectionLevel();
ArrayRef<byte> codewords(parser.readCodewords());
std::vector<Ref<DataBlock> > dataBlocks(DataBlock::getDataBlocks(codewords, version, ecLevel));
int totalBytes = 0;
for (size_t i = 0; i < dataBlocks.size(); i++) {
totalBytes += dataBlocks[i]->getNumDataCodewords();
}
ArrayRef<byte> resultBytes(totalBytes);
int resultOffset = 0;
for (size_t j = 0; j < dataBlocks.size(); j++) {
Ref<DataBlock> dataBlock(dataBlocks[j]);
ArrayRef<byte> codewordBytes = dataBlock->getCodewords();
int numDataCodewords = dataBlock->getNumDataCodewords();
correctErrors(codewordBytes, numDataCodewords);
for (int i = 0; i < numDataCodewords; i++) {
resultBytes[resultOffset++] = (byte)codewordBytes[i];
}
}
return DecodedBitStreamParser::decode(resultBytes,
version,
ecLevel,
DecodedBitStreamParser::Hashtable());
}
}
}