mirror of https://github.com/status-im/qzxing.git
187 lines
5.7 KiB
C++
187 lines
5.7 KiB
C++
/*
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* BitMatrixParser.cpp
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* zxing
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*
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* Created by Christian Brunschen on 20/05/2008.
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* Copyright 2008 ZXing authors All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <zxing/qrcode/decoder/BitMatrixParser.h>
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#include <zxing/qrcode/decoder/DataMask.h>
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namespace zxing {
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namespace qrcode {
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int BitMatrixParser::copyBit(size_t x, size_t y, int versionBits) {
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return bitMatrix_->get(x, y) ? (versionBits << 1) | 0x1 : versionBits << 1;
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}
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BitMatrixParser::BitMatrixParser(Ref<BitMatrix> bitMatrix) :
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bitMatrix_(bitMatrix), parsedVersion_(0), parsedFormatInfo_() {
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size_t dimension = bitMatrix->getDimension();
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if ((dimension < 21) || (dimension & 0x03) != 1) {
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throw ReaderException("Dimension must be 1 mod 4 and >= 21");
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}
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}
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Ref<FormatInformation> BitMatrixParser::readFormatInformation() {
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if (parsedFormatInfo_ != 0) {
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return parsedFormatInfo_;
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}
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// Read top-left format info bits
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int formatInfoBits1 = 0;
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for (int i = 0; i < 6; i++) {
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formatInfoBits1 = copyBit(i, 8, formatInfoBits1);
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}
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// .. and skip a bit in the timing pattern ...
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formatInfoBits1 = copyBit(7, 8, formatInfoBits1);
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formatInfoBits1 = copyBit(8, 8, formatInfoBits1);
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formatInfoBits1 = copyBit(8, 7, formatInfoBits1);
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// .. and skip a bit in the timing pattern ...
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for (int j = 5; j >= 0; j--) {
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formatInfoBits1 = copyBit(8, j, formatInfoBits1);
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}
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// Read the top-right/bottom-left pattern
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int dimension = bitMatrix_->getDimension();
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int formatInfoBits2 = 0;
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int jMin = dimension - 7;
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for (int j = dimension - 1; j >= jMin; j--) {
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formatInfoBits2 = copyBit(8, j, formatInfoBits2);
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}
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for (int i = dimension - 8; i < dimension; i++) {
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formatInfoBits2 = copyBit(i, 8, formatInfoBits2);
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}
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parsedFormatInfo_ = FormatInformation::decodeFormatInformation(formatInfoBits1,formatInfoBits2);
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if (parsedFormatInfo_ != 0) {
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return parsedFormatInfo_;
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}
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throw ReaderException("Could not decode format information");
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}
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Version *BitMatrixParser::readVersion() {
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if (parsedVersion_ != 0) {
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return parsedVersion_;
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}
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int dimension = bitMatrix_->getDimension();
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int provisionalVersion = (dimension - 17) >> 2;
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if (provisionalVersion <= 6) {
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return Version::getVersionForNumber(provisionalVersion);
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}
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// Read top-right version info: 3 wide by 6 tall
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int versionBits = 0;
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for (int y = 5; y >= 0; y--) {
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int xMin = dimension - 11;
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for (int x = dimension - 9; x >= xMin; x--) {
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versionBits = copyBit(x, y, versionBits);
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}
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}
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parsedVersion_ = Version::decodeVersionInformation(versionBits);
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if (parsedVersion_ != 0 && parsedVersion_->getDimensionForVersion() == dimension) {
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return parsedVersion_;
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}
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// Hmm, failed. Try bottom left: 6 wide by 3 tall
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versionBits = 0;
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for (int x = 5; x >= 0; x--) {
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int yMin = dimension - 11;
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for (int y = dimension - 9; y >= yMin; y--) {
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versionBits = copyBit(x, y, versionBits);
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}
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}
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parsedVersion_ = Version::decodeVersionInformation(versionBits);
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if (parsedVersion_ != 0 && parsedVersion_->getDimensionForVersion() == dimension) {
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return parsedVersion_;
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}
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throw ReaderException("Could not decode version");
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}
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ArrayRef<unsigned char> BitMatrixParser::readCodewords() {
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Ref<FormatInformation> formatInfo = readFormatInformation();
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Version *version = readVersion();
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// cerr << *bitMatrix_ << endl;
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// cerr << bitMatrix_->getDimension() << endl;
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// Get the data mask for the format used in this QR Code. This will exclude
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// some bits from reading as we wind through the bit matrix.
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DataMask &dataMask = DataMask::forReference((int)formatInfo->getDataMask());
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// cout << (int)formatInfo->getDataMask() << endl;
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int dimension = bitMatrix_->getDimension();
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dataMask.unmaskBitMatrix(*bitMatrix_, dimension);
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// cerr << *bitMatrix_ << endl;
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// cerr << version->getTotalCodewords() << endl;
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Ref<BitMatrix> functionPattern = version->buildFunctionPattern();
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// cout << *functionPattern << endl;
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bool readingUp = true;
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ArrayRef<unsigned char> result(version->getTotalCodewords());
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int resultOffset = 0;
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int currentByte = 0;
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int bitsRead = 0;
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// Read columns in pairs, from right to left
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for (int x = dimension - 1; x > 0; x -= 2) {
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if (x == 6) {
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// Skip whole column with vertical alignment pattern;
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// saves time and makes the other code proceed more cleanly
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x--;
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}
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// Read alternatingly from bottom to top then top to bottom
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for (int counter = 0; counter < dimension; counter++) {
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int y = readingUp ? dimension - 1 - counter : counter;
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for (int col = 0; col < 2; col++) {
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// Ignore bits covered by the function pattern
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if (!functionPattern->get(x - col, y)) {
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// Read a bit
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bitsRead++;
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currentByte <<= 1;
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if (bitMatrix_->get(x - col, y)) {
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currentByte |= 1;
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}
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// If we've made a whole byte, save it off
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if (bitsRead == 8) {
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result[resultOffset++] = (unsigned char)currentByte;
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bitsRead = 0;
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currentByte = 0;
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}
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}
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}
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}
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readingUp = !readingUp; // switch directions
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}
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if (resultOffset != version->getTotalCodewords()) {
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throw ReaderException("Did not read all codewords");
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}
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return result;
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}
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}
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}
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