/* * Copyright 2008 ZXing authors * * 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. */ package com.google.zxing.qrcode.encoder; import com.google.zxing.EncodeHintType; import com.google.zxing.WriterException; import com.google.zxing.common.BitArray; import com.google.zxing.common.CharacterSetECI; import com.google.zxing.common.reedsolomon.GenericGF; import com.google.zxing.common.reedsolomon.ReedSolomonEncoder; import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel; import com.google.zxing.qrcode.decoder.Mode; import com.google.zxing.qrcode.decoder.Version; import java.io.UnsupportedEncodingException; import java.util.ArrayList; import java.util.Collection; import java.util.Map; /** * @author [email protected] (Satoru Takabayashi) - creator * @author [email protected] (Daniel Switkin) - ported from C++ */ public final class Encoder { // The original table is defined in the table 5 of JISX0510:2004 (p.19). private static final int[] ALPHANUMERIC_TABLE = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0x00-0x0f -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0x10-0x1f 36, -1, -1, -1, 37, 38, -1, -1, -1, -1, 39, 40, -1, 41, 42, 43, // 0x20-0x2f 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 44, -1, -1, -1, -1, -1, // 0x30-0x3f -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 0x40-0x4f 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1, // 0x50-0x5f }; static final String DEFAULT_BYTE_MODE_ENCODING = "ISO-8859-1"; private Encoder() { } // The mask penalty calculation is complicated. See Table 21 of JISX0510:2004 (p.45) for details. // Basically it applies four rules and summate all penalties. private static int calculateMaskPenalty(ByteMatrix matrix) { return MaskUtil.applyMaskPenaltyRule1(matrix) + MaskUtil.applyMaskPenaltyRule2(matrix) + MaskUtil.applyMaskPenaltyRule3(matrix) + MaskUtil.applyMaskPenaltyRule4(matrix); } /** * @param content text to encode * @param ecLevel error correction level to use * @return {@link QRCode} representing the encoded QR code * @throws WriterException if encoding can't succeed, because of for example invalid content * or configuration */ public static QRCode encode(String content, ErrorCorrectionLevel ecLevel) throws WriterException { return encode(content, ecLevel, null); } public static QRCode encode(String content, ErrorCorrectionLevel ecLevel, Map<EncodeHintType,?> hints) throws WriterException { // Determine what character encoding has been specified by the caller, if any String encoding = DEFAULT_BYTE_MODE_ENCODING; boolean hasEncodingHint = hints != null && hints.containsKey(EncodeHintType.CHARACTER_SET); if (hasEncodingHint) { encoding = hints.get(EncodeHintType.CHARACTER_SET).toString(); } // Pick an encoding mode appropriate for the content. Note that this will not attempt to use // multiple modes / segments even if that were more efficient. Twould be nice. Mode mode = chooseMode(content, encoding); // This will store the header information, like mode and // length, as well as "header" segments like an ECI segment. BitArray headerBits = new BitArray(); // Append ECI segment if applicable if (mode == Mode.BYTE && (hasEncodingHint || !DEFAULT_BYTE_MODE_ENCODING.equals(encoding))) { CharacterSetECI eci = CharacterSetECI.getCharacterSetECIByName(encoding); if (eci != null) { appendECI(eci, headerBits); } } // (With ECI in place,) Write the mode marker appendModeInfo(mode, headerBits); // Collect data within the main segment, separately, to count its size if needed. Don't add it to // main payload yet. BitArray dataBits = new BitArray(); appendBytes(content, mode, dataBits, encoding); Version version; if (hints != null && hints.containsKey(EncodeHintType.QR_VERSION)) { int versionNumber = Integer.parseInt(hints.get(EncodeHintType.QR_VERSION).toString()); version = Version.getVersionForNumber(versionNumber); int bitsNeeded = calculateBitsNeeded(mode, headerBits, dataBits, version); if (!willFit(bitsNeeded, version, ecLevel)) { throw new WriterException("Data too big for requested version"); } } else { version = recommendVersion(ecLevel, mode, headerBits, dataBits); } BitArray headerAndDataBits = new BitArray(); headerAndDataBits.appendBitArray(headerBits); // Find "length" of main segment and write it int numLetters = mode == Mode.BYTE ? dataBits.getSizeInBytes() : content.length(); appendLengthInfo(numLetters, version, mode, headerAndDataBits); // Put data together into the overall payload headerAndDataBits.appendBitArray(dataBits); Version.ECBlocks ecBlocks = version.getECBlocksForLevel(ecLevel); int numDataBytes = version.getTotalCodewords() - ecBlocks.getTotalECCodewords(); // Terminate the bits properly. terminateBits(numDataBytes, headerAndDataBits); // Interleave data bits with error correction code. BitArray finalBits = interleaveWithECBytes(headerAndDataBits, version.getTotalCodewords(), numDataBytes, ecBlocks.getNumBlocks()); QRCode qrCode = new QRCode(); qrCode.setECLevel(ecLevel); qrCode.setMode(mode); qrCode.setVersion(version); // Choose the mask pattern and set to "qrCode". int dimension = version.getDimensionForVersion(); ByteMatrix matrix = new ByteMatrix(dimension, dimension); int maskPattern = chooseMaskPattern(finalBits, ecLevel, version, matrix); qrCode.setMaskPattern(maskPattern); // Build the matrix and set it to "qrCode". MatrixUtil.buildMatrix(finalBits, ecLevel, version, maskPattern, matrix); qrCode.setMatrix(matrix); return qrCode; } /** * Decides the smallest version of QR code that will contain all of the provided data. * * @throws WriterException if the data cannot fit in any version */ private static Version recommendVersion(ErrorCorrectionLevel ecLevel, Mode mode, BitArray headerBits, BitArray dataBits) throws WriterException { // Hard part: need to know version to know how many bits length takes. But need to know how many // bits it takes to know version. First we take a guess at version by assuming version will be // the minimum, 1: int provisionalBitsNeeded = calculateBitsNeeded(mode, headerBits, dataBits, Version.getVersionForNumber(1)); Version provisionalVersion = chooseVersion(provisionalBitsNeeded, ecLevel); // Use that guess to calculate the right version. I am still not sure this works in 100% of cases. int bitsNeeded = calculateBitsNeeded(mode, headerBits, dataBits, provisionalVersion); return chooseVersion(bitsNeeded, ecLevel); } private static int calculateBitsNeeded(Mode mode, BitArray headerBits, BitArray dataBits, Version version) { return headerBits.getSize() + mode.getCharacterCountBits(version) + dataBits.getSize(); } /** * @return the code point of the table used in alphanumeric mode or * -1 if there is no corresponding code in the table. */ static int getAlphanumericCode(int code) { if (code < ALPHANUMERIC_TABLE.length) { return ALPHANUMERIC_TABLE[code]; } return -1; } public static Mode chooseMode(String content) { return chooseMode(content, null); } /** * Choose the best mode by examining the content. Note that 'encoding' is used as a hint; * if it is Shift_JIS, and the input is only double-byte Kanji, then we return {@link Mode#KANJI}. */ private static Mode chooseMode(String content, String encoding) { if ("Shift_JIS".equals(encoding) && isOnlyDoubleByteKanji(content)) { // Choose Kanji mode if all input are double-byte characters return Mode.KANJI; } boolean hasNumeric = false; boolean hasAlphanumeric = false; for (int i = 0; i < content.length(); ++i) { char c = content.charAt(i); if (c >= '0' && c <= '9') { hasNumeric = true; } else if (getAlphanumericCode(c) != -1) { hasAlphanumeric = true; } else { return Mode.BYTE; } } if (hasAlphanumeric) { return Mode.ALPHANUMERIC; } if (hasNumeric) { return Mode.NUMERIC; } return Mode.BYTE; } private static boolean isOnlyDoubleByteKanji(String content) { byte[] bytes; try { bytes = content.getBytes("Shift_JIS"); } catch (UnsupportedEncodingException ignored) { return false; } int length = bytes.length; if (length % 2 != 0) { return false; } for (int i = 0; i < length; i += 2) { int byte1 = bytes[i] & 0xFF; if ((byte1 < 0x81 || byte1 > 0x9F) && (byte1 < 0xE0 || byte1 > 0xEB)) { return false; } } return true; } private static int chooseMaskPattern(BitArray bits, ErrorCorrectionLevel ecLevel, Version version, ByteMatrix matrix) throws WriterException { int minPenalty = Integer.MAX_VALUE; // Lower penalty is better. int bestMaskPattern = -1; // We try all mask patterns to choose the best one. for (int maskPattern = 0; maskPattern < QRCode.NUM_MASK_PATTERNS; maskPattern++) { MatrixUtil.buildMatrix(bits, ecLevel, version, maskPattern, matrix); int penalty = calculateMaskPenalty(matrix); if (penalty < minPenalty) { minPenalty = penalty; bestMaskPattern = maskPattern; } } return bestMaskPattern; } private static Version chooseVersion(int numInputBits, ErrorCorrectionLevel ecLevel) throws WriterException { for (int versionNum = 1; versionNum <= 40; versionNum++) { Version version = Version.getVersionForNumber(versionNum); if (willFit(numInputBits, version, ecLevel)) { return version; } } throw new WriterException("Data too big"); } /** * @return true if the number of input bits will fit in a code with the specified version and * error correction level. */ private static boolean willFit(int numInputBits, Version version, ErrorCorrectionLevel ecLevel) { // In the following comments, we use numbers of Version 7-H. // numBytes = 196 int numBytes = version.getTotalCodewords(); // getNumECBytes = 130 Version.ECBlocks ecBlocks = version.getECBlocksForLevel(ecLevel); int numEcBytes = ecBlocks.getTotalECCodewords(); // getNumDataBytes = 196 - 130 = 66 int numDataBytes = numBytes - numEcBytes; int totalInputBytes = (numInputBits + 7) / 8; return numDataBytes >= totalInputBytes; } /** * Terminate bits as described in 8.4.8 and 8.4.9 of JISX0510:2004 (p.24). */ static void terminateBits(int numDataBytes, BitArray bits) throws WriterException { int capacity = numDataBytes * 8; if (bits.getSize() > capacity) { throw new WriterException("data bits cannot fit in the QR Code" + bits.getSize() + " > " + capacity); } for (int i = 0; i < 4 && bits.getSize() < capacity; ++i) { bits.appendBit(false); } // Append termination bits. See 8.4.8 of JISX0510:2004 (p.24) for details. // If the last byte isn't 8-bit aligned, we'll add padding bits. int numBitsInLastByte = bits.getSize() & 0x07; if (numBitsInLastByte > 0) { for (int i = numBitsInLastByte; i < 8; i++) { bits.appendBit(false); } } // If we have more space, we'll fill the space with padding patterns defined in 8.4.9 (p.24). int numPaddingBytes = numDataBytes - bits.getSizeInBytes(); for (int i = 0; i < numPaddingBytes; ++i) { bits.appendBits((i & 0x01) == 0 ? 0xEC : 0x11, 8); } if (bits.getSize() != capacity) { throw new WriterException("Bits size does not equal capacity"); } } /** * Get number of data bytes and number of error correction bytes for block id "blockID". Store * the result in "numDataBytesInBlock", and "numECBytesInBlock". See table 12 in 8.5.1 of * JISX0510:2004 (p.30) */ static void getNumDataBytesAndNumECBytesForBlockID(int numTotalBytes, int numDataBytes, int numRSBlocks, int blockID, int[] numDataBytesInBlock, int[] numECBytesInBlock) throws WriterException { if (blockID >= numRSBlocks) { throw new WriterException("Block ID too large"); } // numRsBlocksInGroup2 = 196 % 5 = 1 int numRsBlocksInGroup2 = numTotalBytes % numRSBlocks; // numRsBlocksInGroup1 = 5 - 1 = 4 int numRsBlocksInGroup1 = numRSBlocks - numRsBlocksInGroup2; // numTotalBytesInGroup1 = 196 / 5 = 39 int numTotalBytesInGroup1 = numTotalBytes / numRSBlocks; // numTotalBytesInGroup2 = 39 + 1 = 40 int numTotalBytesInGroup2 = numTotalBytesInGroup1 + 1; // numDataBytesInGroup1 = 66 / 5 = 13 int numDataBytesInGroup1 = numDataBytes / numRSBlocks; // numDataBytesInGroup2 = 13 + 1 = 14 int numDataBytesInGroup2 = numDataBytesInGroup1 + 1; // numEcBytesInGroup1 = 39 - 13 = 26 int numEcBytesInGroup1 = numTotalBytesInGroup1 - numDataBytesInGroup1; // numEcBytesInGroup2 = 40 - 14 = 26 int numEcBytesInGroup2 = numTotalBytesInGroup2 - numDataBytesInGroup2; // Sanity checks. // 26 = 26 if (numEcBytesInGroup1 != numEcBytesInGroup2) { throw new WriterException("EC bytes mismatch"); } // 5 = 4 + 1. if (numRSBlocks != numRsBlocksInGroup1 + numRsBlocksInGroup2) { throw new WriterException("RS blocks mismatch"); } // 196 = (13 + 26) * 4 + (14 + 26) * 1 if (numTotalBytes != ((numDataBytesInGroup1 + numEcBytesInGroup1) * numRsBlocksInGroup1) + ((numDataBytesInGroup2 + numEcBytesInGroup2) * numRsBlocksInGroup2)) { throw new WriterException("Total bytes mismatch"); } if (blockID < numRsBlocksInGroup1) { numDataBytesInBlock[0] = numDataBytesInGroup1; numECBytesInBlock[0] = numEcBytesInGroup1; } else { numDataBytesInBlock[0] = numDataBytesInGroup2; numECBytesInBlock[0] = numEcBytesInGroup2; } } /** * Interleave "bits" with corresponding error correction bytes. On success, store the result in * "result". The interleave rule is complicated. See 8.6 of JISX0510:2004 (p.37) for details. */ static BitArray interleaveWithECBytes(BitArray bits, int numTotalBytes, int numDataBytes, int numRSBlocks) throws WriterException { // "bits" must have "getNumDataBytes" bytes of data. if (bits.getSizeInBytes() != numDataBytes) { throw new WriterException("Number of bits and data bytes does not match"); } // Step 1. Divide data bytes into blocks and generate error correction bytes for them. We'll // store the divided data bytes blocks and error correction bytes blocks into "blocks". int dataBytesOffset = 0; int maxNumDataBytes = 0; int maxNumEcBytes = 0; // Since, we know the number of reedsolmon blocks, we can initialize the vector with the number. Collection<BlockPair> blocks = new ArrayList<>(numRSBlocks); for (int i = 0; i < numRSBlocks; ++i) { int[] numDataBytesInBlock = new int[1]; int[] numEcBytesInBlock = new int[1]; getNumDataBytesAndNumECBytesForBlockID( numTotalBytes, numDataBytes, numRSBlocks, i, numDataBytesInBlock, numEcBytesInBlock); int size = numDataBytesInBlock[0]; byte[] dataBytes = new byte[size]; bits.toBytes(8 * dataBytesOffset, dataBytes, 0, size); byte[] ecBytes = generateECBytes(dataBytes, numEcBytesInBlock[0]); blocks.add(new BlockPair(dataBytes, ecBytes)); maxNumDataBytes = Math.max(maxNumDataBytes, size); maxNumEcBytes = Math.max(maxNumEcBytes, ecBytes.length); dataBytesOffset += numDataBytesInBlock[0]; } if (numDataBytes != dataBytesOffset) { throw new WriterException("Data bytes does not match offset"); } BitArray result = new BitArray(); // First, place data blocks. for (int i = 0; i < maxNumDataBytes; ++i) { for (BlockPair block : blocks) { byte[] dataBytes = block.getDataBytes(); if (i < dataBytes.length) { result.appendBits(dataBytes[i], 8); } } } // Then, place error correction blocks. for (int i = 0; i < maxNumEcBytes; ++i) { for (BlockPair block : blocks) { byte[] ecBytes = block.getErrorCorrectionBytes(); if (i < ecBytes.length) { result.appendBits(ecBytes[i], 8); } } } if (numTotalBytes != result.getSizeInBytes()) { // Should be same. throw new WriterException("Interleaving error: " + numTotalBytes + " and " + result.getSizeInBytes() + " differ."); } return result; } static byte[] generateECBytes(byte[] dataBytes, int numEcBytesInBlock) { int numDataBytes = dataBytes.length; int[] toEncode = new int[numDataBytes + numEcBytesInBlock]; for (int i = 0; i < numDataBytes; i++) { toEncode[i] = dataBytes[i] & 0xFF; } new ReedSolomonEncoder(GenericGF.QR_CODE_FIELD_256).encode(toEncode, numEcBytesInBlock); byte[] ecBytes = new byte[numEcBytesInBlock]; for (int i = 0; i < numEcBytesInBlock; i++) { ecBytes[i] = (byte) toEncode[numDataBytes + i]; } return ecBytes; } /** * Append mode info. On success, store the result in "bits". */ static void appendModeInfo(Mode mode, BitArray bits) { bits.appendBits(mode.getBits(), 4); } /** * Append length info. On success, store the result in "bits". */ static void appendLengthInfo(int numLetters, Version version, Mode mode, BitArray bits) throws WriterException { int numBits = mode.getCharacterCountBits(version); if (numLetters >= (1 << numBits)) { throw new WriterException(numLetters + " is bigger than " + ((1 << numBits) - 1)); } bits.appendBits(numLetters, numBits); } /** * Append "bytes" in "mode" mode (encoding) into "bits". On success, store the result in "bits". */ static void appendBytes(String content, Mode mode, BitArray bits, String encoding) throws WriterException { switch (mode) { case NUMERIC: appendNumericBytes(content, bits); break; case ALPHANUMERIC: appendAlphanumericBytes(content, bits); break; case BYTE: append8BitBytes(content, bits, encoding); break; case KANJI: appendKanjiBytes(content, bits); break; default: throw new WriterException("Invalid mode: " + mode); } } static void appendNumericBytes(CharSequence content, BitArray bits) { int length = content.length(); int i = 0; while (i < length) { int num1 = content.charAt(i) - '0'; if (i + 2 < length) { // Encode three numeric letters in ten bits. int num2 = content.charAt(i + 1) - '0'; int num3 = content.charAt(i + 2) - '0'; bits.appendBits(num1 * 100 + num2 * 10 + num3, 10); i += 3; } else if (i + 1 < length) { // Encode two numeric letters in seven bits. int num2 = content.charAt(i + 1) - '0'; bits.appendBits(num1 * 10 + num2, 7); i += 2; } else { // Encode one numeric letter in four bits. bits.appendBits(num1, 4); i++; } } } static void appendAlphanumericBytes(CharSequence content, BitArray bits) throws WriterException { int length = content.length(); int i = 0; while (i < length) { int code1 = getAlphanumericCode(content.charAt(i)); if (code1 == -1) { throw new WriterException(); } if (i + 1 < length) { int code2 = getAlphanumericCode(content.charAt(i + 1)); if (code2 == -1) { throw new WriterException(); } // Encode two alphanumeric letters in 11 bits. bits.appendBits(code1 * 45 + code2, 11); i += 2; } else { // Encode one alphanumeric letter in six bits. bits.appendBits(code1, 6); i++; } } } static void append8BitBytes(String content, BitArray bits, String encoding) throws WriterException { byte[] bytes; try { bytes = content.getBytes(encoding); } catch (UnsupportedEncodingException uee) { throw new WriterException(uee); } for (byte b : bytes) { bits.appendBits(b, 8); } } static void appendKanjiBytes(String content, BitArray bits) throws WriterException { byte[] bytes; try { bytes = content.getBytes("Shift_JIS"); } catch (UnsupportedEncodingException uee) { throw new WriterException(uee); } int length = bytes.length; for (int i = 0; i < length; i += 2) { int byte1 = bytes[i] & 0xFF; int byte2 = bytes[i + 1] & 0xFF; int code = (byte1 << 8) | byte2; int subtracted = -1; if (code >= 0x8140 && code <= 0x9ffc) { subtracted = code - 0x8140; } else if (code >= 0xe040 && code <= 0xebbf) { subtracted = code - 0xc140; } if (subtracted == -1) { throw new WriterException("Invalid byte sequence"); } int encoded = ((subtracted >> 8) * 0xc0) + (subtracted & 0xff); bits.appendBits(encoded, 13); } } private static void appendECI(CharacterSetECI eci, BitArray bits) { bits.appendBits(Mode.ECI.getBits(), 4); // This is correct for values up to 127, which is all we need now. bits.appendBits(eci.getValue(), 8); } }