2 * Copyright 2008 ZXing authors
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package com.google.zxing.qrcode.encoder;
19 import com.google.zxing.common.ByteMatrix;
20 import com.google.zxing.common.ByteArray;
21 import com.google.zxing.common.reedsolomon.GF256;
22 import com.google.zxing.common.reedsolomon.ReedSolomonEncoder;
23 import com.google.zxing.WriterException;
24 import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
26 import java.util.Vector;
29 * @author satorux@google.com (Satoru Takabayashi) - creator
30 * @author dswitkin@google.com (Daniel Switkin) - ported from C++
32 public final class Encoder {
34 // The original table is defined in the table 5 of JISX0510:2004 (p.19).
35 private static final int[] ALPHANUMERIC_TABLE = {
36 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0x00-0x0f
37 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0x10-0x1f
38 36, -1, -1, -1, 37, 38, -1, -1, -1, -1, 39, 40, -1, 41, 42, 43, // 0x20-0x2f
39 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 44, -1, -1, -1, -1, -1, // 0x30-0x3f
40 -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 0x40-0x4f
41 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1, // 0x50-0x5f
44 private static final class RSBlockInfo {
47 final int[][] blockInfo;
49 public RSBlockInfo(int numBytes, int[][] blockInfo) {
50 this.numBytes = numBytes;
51 this.blockInfo = blockInfo;
56 // The table is from table 12 of JISX0510:2004 (p. 30). The "blockInfo" parts are ordered by
57 // L, M, Q, H. Within each blockInfo, the 0th element is getNumECBytes, and the 1st element is
58 // getNumRSBlocks. The table was doublechecked by komatsu.
59 private static final RSBlockInfo[] RS_BLOCK_TABLE = {
60 new RSBlockInfo( 26, new int[][]{ { 7, 1}, { 10, 1}, { 13, 1}, { 17, 1}}), // Version 1
61 new RSBlockInfo( 44, new int[][]{ { 10, 1}, { 16, 1}, { 22, 1}, { 28, 1}}), // Version 2
62 new RSBlockInfo( 70, new int[][]{ { 15, 1}, { 26, 1}, { 36, 2}, { 44, 2}}), // Version 3
63 new RSBlockInfo( 100, new int[][]{ { 20, 1}, { 36, 2}, { 52, 2}, { 64, 4}}), // Version 4
64 new RSBlockInfo( 134, new int[][]{ { 26, 1}, { 48, 2}, { 72, 4}, { 88, 4}}), // Version 5
65 new RSBlockInfo( 172, new int[][]{ { 36, 2}, { 64, 4}, { 96, 4}, { 112, 4}}), // Version 6
66 new RSBlockInfo( 196, new int[][]{ { 40, 2}, { 72, 4}, { 108, 6}, { 130, 5}}), // Version 7
67 new RSBlockInfo( 242, new int[][]{ { 48, 2}, { 88, 4}, { 132, 6}, { 156, 6}}), // Version 8
68 new RSBlockInfo( 292, new int[][]{ { 60, 2}, { 110, 5}, { 160, 8}, { 192, 8}}), // Version 9
69 new RSBlockInfo( 346, new int[][]{ { 72, 4}, { 130, 5}, { 192, 8}, { 224, 8}}), // Version 10
70 new RSBlockInfo( 404, new int[][]{ { 80, 4}, { 150, 5}, { 224, 8}, { 264, 11}}), // Version 11
71 new RSBlockInfo( 466, new int[][]{ { 96, 4}, { 176, 8}, { 260, 10}, { 308, 11}}), // Version 12
72 new RSBlockInfo( 532, new int[][]{ {104, 4}, { 198, 9}, { 288, 12}, { 352, 16}}), // Version 13
73 new RSBlockInfo( 581, new int[][]{ {120, 4}, { 216, 9}, { 320, 16}, { 384, 16}}), // Version 14
74 new RSBlockInfo( 655, new int[][]{ {132, 6}, { 240, 10}, { 360, 12}, { 432, 18}}), // Version 15
75 new RSBlockInfo( 733, new int[][]{ {144, 6}, { 280, 10}, { 408, 17}, { 480, 16}}), // Version 16
76 new RSBlockInfo( 815, new int[][]{ {168, 6}, { 308, 11}, { 448, 16}, { 532, 19}}), // Version 17
77 new RSBlockInfo( 901, new int[][]{ {180, 6}, { 338, 13}, { 504, 18}, { 588, 21}}), // Version 18
78 new RSBlockInfo( 991, new int[][]{ {196, 7}, { 364, 14}, { 546, 21}, { 650, 25}}), // Version 19
79 new RSBlockInfo(1085, new int[][]{ {224, 8}, { 416, 16}, { 600, 20}, { 700, 25}}), // Version 20
80 new RSBlockInfo(1156, new int[][]{ {224, 8}, { 442, 17}, { 644, 23}, { 750, 25}}), // Version 21
81 new RSBlockInfo(1258, new int[][]{ {252, 9}, { 476, 17}, { 690, 23}, { 816, 34}}), // Version 22
82 new RSBlockInfo(1364, new int[][]{ {270, 9}, { 504, 18}, { 750, 25}, { 900, 30}}), // Version 23
83 new RSBlockInfo(1474, new int[][]{ {300, 10}, { 560, 20}, { 810, 27}, { 960, 32}}), // Version 24
84 new RSBlockInfo(1588, new int[][]{ {312, 12}, { 588, 21}, { 870, 29}, {1050, 35}}), // Version 25
85 new RSBlockInfo(1706, new int[][]{ {336, 12}, { 644, 23}, { 952, 34}, {1110, 37}}), // Version 26
86 new RSBlockInfo(1828, new int[][]{ {360, 12}, { 700, 25}, {1020, 34}, {1200, 40}}), // Version 27
87 new RSBlockInfo(1921, new int[][]{ {390, 13}, { 728, 26}, {1050, 35}, {1260, 42}}), // Version 28
88 new RSBlockInfo(2051, new int[][]{ {420, 14}, { 784, 28}, {1140, 38}, {1350, 45}}), // Version 29
89 new RSBlockInfo(2185, new int[][]{ {450, 15}, { 812, 29}, {1200, 40}, {1440, 48}}), // Version 30
90 new RSBlockInfo(2323, new int[][]{ {480, 16}, { 868, 31}, {1290, 43}, {1530, 51}}), // Version 31
91 new RSBlockInfo(2465, new int[][]{ {510, 17}, { 924, 33}, {1350, 45}, {1620, 54}}), // Version 32
92 new RSBlockInfo(2611, new int[][]{ {540, 18}, { 980, 35}, {1440, 48}, {1710, 57}}), // Version 33
93 new RSBlockInfo(2761, new int[][]{ {570, 19}, {1036, 37}, {1530, 51}, {1800, 60}}), // Version 34
94 new RSBlockInfo(2876, new int[][]{ {570, 19}, {1064, 38}, {1590, 53}, {1890, 63}}), // Version 35
95 new RSBlockInfo(3034, new int[][]{ {600, 20}, {1120, 40}, {1680, 56}, {1980, 66}}), // Version 36
96 new RSBlockInfo(3196, new int[][]{ {630, 21}, {1204, 43}, {1770, 59}, {2100, 70}}), // Version 37
97 new RSBlockInfo(3362, new int[][]{ {660, 22}, {1260, 45}, {1860, 62}, {2220, 74}}), // Version 38
98 new RSBlockInfo(3532, new int[][]{ {720, 24}, {1316, 47}, {1950, 65}, {2310, 77}}), // Version 39
99 new RSBlockInfo(3706, new int[][]{ {750, 25}, {1372, 49}, {2040, 68}, {2430, 81}}), // Version 40
102 private static final class BlockPair {
104 private final ByteArray dataBytes;
105 private final ByteArray errorCorrectionBytes;
107 public BlockPair(ByteArray data, ByteArray errorCorrection) {
109 errorCorrectionBytes = errorCorrection;
112 public ByteArray getDataBytes() {
116 public ByteArray getErrorCorrectionBytes() {
117 return errorCorrectionBytes;
122 // Encode "bytes" with the error correction level "getECLevel". The encoding mode will be chosen
123 // internally by chooseMode(). On success, store the result in "qrCode" and return true.
124 // We recommend you to use QRCode.EC_LEVEL_L (the lowest level) for
125 // "getECLevel" since our primary use is to show QR code on desktop screens. We don't need very
126 // strong error correction for this purpose.
128 // Note that there is no way to encode bytes in MODE_KANJI. We might want to add EncodeWithMode()
129 // with which clients can specify the encoding mode. For now, we don't need the functionality.
130 public static void encode(final ByteArray bytes, ErrorCorrectionLevel ecLevel, QRCode qrCode)
131 throws WriterException {
132 // Step 1: Choose the mode (encoding).
133 final int mode = chooseMode(bytes);
135 // Step 2: Append "bytes" into "dataBits" in appropriate encoding.
136 BitVector dataBits = new BitVector();
137 appendBytes(bytes, mode, dataBits);
138 // Step 3: Initialize QR code that can contain "dataBits".
139 final int numInputBytes = dataBits.sizeInBytes();
140 initQRCode(numInputBytes, ecLevel, mode, qrCode);
142 // Step 4: Build another bit vector that contains header and data.
143 BitVector headerAndDataBits = new BitVector();
144 appendModeInfo(qrCode.getMode(), headerAndDataBits);
145 appendLengthInfo(bytes.size(), qrCode.getVersion(), qrCode.getMode(), headerAndDataBits);
146 headerAndDataBits.appendBitVector(dataBits);
148 // Step 5: Terminate the bits properly.
149 terminateBits(qrCode.getNumDataBytes(), headerAndDataBits);
151 // Step 6: Interleave data bits with error correction code.
152 BitVector finalBits = new BitVector();
153 interleaveWithECBytes(headerAndDataBits, qrCode.getNumTotalBytes(), qrCode.getNumDataBytes(),
154 qrCode.getNumRSBlocks(), finalBits);
156 // Step 7: Choose the mask pattern and set to "qrCode".
157 ByteMatrix matrix = new ByteMatrix(qrCode.getMatrixWidth(), qrCode.getMatrixWidth());
158 qrCode.setMaskPattern(chooseMaskPattern(finalBits, qrCode.getECLevel(), qrCode.getVersion(),
161 // Step 8. Build the matrix and set it to "qrCode".
162 MatrixUtil.buildMatrix(finalBits, qrCode.getECLevel(), qrCode.getVersion(),
163 qrCode.getMaskPattern(), matrix);
164 qrCode.setMatrix(matrix);
165 // Step 9. Make sure we have a valid QR Code.
166 if (!qrCode.isValid()) {
167 throw new WriterException("Invalid QR code: " + qrCode.toString());
171 // Return the code point of the table used in alphanumeric mode. Return -1 if there is no
172 // corresponding code in the table.
173 static int getAlphanumericCode(int code) {
174 if (code < ALPHANUMERIC_TABLE.length) {
175 return ALPHANUMERIC_TABLE[code];
180 // Choose the best mode by examining the content of "bytes". The function is guaranteed to return
183 // Note that this function does not return MODE_KANJI, as we cannot distinguish Shift_JIS from
184 // other encodings such as ISO-8859-1, from data bytes alone. For example "\xE0\xE0" can be
185 // interpreted as one character in Shift_JIS, but also two characters in ISO-8859-1.
187 // JAVAPORT: This MODE_KANJI limitation sounds like a problem for us.
188 public static int chooseMode(final ByteArray bytes) throws WriterException {
189 boolean hasNumeric = false;
190 boolean hasAlphanumeric = false;
191 boolean hasOther = false;
192 for (int i = 0; i < bytes.size(); ++i) {
193 final int oneByte = bytes.at(i);
194 if (oneByte >= '0' && oneByte <= '9') {
196 } else if (getAlphanumericCode(oneByte) != -1) {
197 hasAlphanumeric = true;
203 return QRCode.MODE_8BIT_BYTE;
204 } else if (hasAlphanumeric) {
205 return QRCode.MODE_ALPHANUMERIC;
206 } else if (hasNumeric) {
207 return QRCode.MODE_NUMERIC;
209 // "bytes" must be empty to reach here.
210 if (!bytes.empty()) {
211 throw new WriterException("Bytes left over");
213 return QRCode.MODE_8BIT_BYTE;
216 private static int chooseMaskPattern(final BitVector bits, ErrorCorrectionLevel ecLevel, int version,
217 ByteMatrix matrix) throws WriterException {
218 if (!QRCode.isValidMatrixWidth(matrix.width())) {
219 throw new WriterException("Invalid matrix width: " + matrix.width());
222 int minPenalty = Integer.MAX_VALUE; // Lower penalty is better.
223 int bestMaskPattern = -1;
224 // We try all mask patterns to choose the best one.
225 for (int maskPattern = 0; maskPattern < QRCode.NUM_MASK_PATTERNS; maskPattern++) {
226 MatrixUtil.buildMatrix(bits, ecLevel, version, maskPattern, matrix);
227 final int penalty = MaskUtil.calculateMaskPenalty(matrix);
228 if (penalty < minPenalty) {
229 minPenalty = penalty;
230 bestMaskPattern = maskPattern;
233 return bestMaskPattern;
236 // Initialize "qrCode" according to "numInputBytes", "ecLevel", and "mode". On success, modify
237 // "qrCode" and return true.
238 private static void initQRCode(int numInputBytes, ErrorCorrectionLevel ecLevel, int mode, QRCode qrCode)
239 throws WriterException {
240 qrCode.setECLevel(ecLevel);
241 qrCode.setMode(mode);
243 // In the following comments, we use numbers of Version 7-H.
244 for (int i = 0; i < RS_BLOCK_TABLE.length; ++i) {
245 final RSBlockInfo row = RS_BLOCK_TABLE[i];
247 final int numBytes = row.numBytes;
248 // getNumECBytes = 130
249 final int numEcBytes = row.blockInfo[ecLevel.ordinal()][0];
250 // getNumRSBlocks = 5
251 final int numRSBlocks = row.blockInfo[ecLevel.ordinal()][1];
252 // getNumDataBytes = 196 - 130 = 66
253 final int numDataBytes = numBytes - numEcBytes;
254 // We want to choose the smallest version which can contain data of "numInputBytes" + some
255 // extra bits for the header (mode info and length info). The header can be three bytes
256 // (precisely 4 + 16 bits) at most. Hence we do +3 here.
257 if (numDataBytes >= numInputBytes + 3) {
258 // Yay, we found the proper rs block info!
259 qrCode.setVersion(i + 1);
260 qrCode.setNumTotalBytes(numBytes);
261 qrCode.setNumDataBytes(numDataBytes);
262 qrCode.setNumRSBlocks(numRSBlocks);
263 // getNumECBytes = 196 - 66 = 130
264 qrCode.setNumECBytes(numBytes - numDataBytes);
265 // matrix width = 21 + 6 * 4 = 45
266 qrCode.setMatrixWidth(21 + i * 4);
270 throw new WriterException("Cannot find proper rs block info (input data too big?)");
273 // Terminate bits as described in 8.4.8 and 8.4.9 of JISX0510:2004 (p.24).
274 static void terminateBits(int numDataBytes, BitVector bits) throws WriterException {
275 final int capacity = numDataBytes * 8;
276 if (bits.size() > capacity) {
277 throw new WriterException("data bits cannot fit in the QR Code" + bits.size() + " > " + capacity);
279 // Append termination bits. See 8.4.8 of JISX0510:2004 (p.24) for details.
280 for (int i = 0; i < 4 && bits.size() < capacity; ++i) {
283 final int numBitsInLastByte = bits.size() % 8;
284 // If the last byte isn't 8-bit aligned, we'll add padding bits.
285 if (numBitsInLastByte > 0) {
286 final int numPaddingBits = 8 - numBitsInLastByte;
287 for (int i = 0; i < numPaddingBits; ++i) {
291 // Should be 8-bit aligned here.
292 if (bits.size() % 8 != 0) {
293 throw new WriterException("Number of bits is not a multiple of 8");
295 // If we have more space, we'll fill the space with padding patterns defined in 8.4.9 (p.24).
296 final int numPaddingBytes = numDataBytes - bits.sizeInBytes();
297 for (int i = 0; i < numPaddingBytes; ++i) {
299 bits.appendBits(0xec, 8);
301 bits.appendBits(0x11, 8);
304 if (bits.size() != capacity) {
305 throw new WriterException("Bits size does not equal capacity");
309 // Get number of data bytes and number of error correction bytes for block id "blockID". Store
310 // the result in "numDataBytesInBlock", and "numECBytesInBlock". See table 12 in 8.5.1 of
311 // JISX0510:2004 (p.30)
312 static void getNumDataBytesAndNumECBytesForBlockID(int numTotalBytes, int numDataBytes,
313 int numRSBlocks, int blockID, int[] numDataBytesInBlock,
314 int[] numECBytesInBlock) throws WriterException {
315 if (blockID >= numRSBlocks) {
316 throw new WriterException("Block ID too large");
318 // numRsBlocksInGroup2 = 196 % 5 = 1
319 final int numRsBlocksInGroup2 = numTotalBytes % numRSBlocks;
320 // numRsBlocksInGroup1 = 5 - 1 = 4
321 final int numRsBlocksInGroup1 = numRSBlocks - numRsBlocksInGroup2;
322 // numTotalBytesInGroup1 = 196 / 5 = 39
323 final int numTotalBytesInGroup1 = numTotalBytes / numRSBlocks;
324 // numTotalBytesInGroup2 = 39 + 1 = 40
325 final int numTotalBytesInGroup2 = numTotalBytesInGroup1 + 1;
326 // numDataBytesInGroup1 = 66 / 5 = 13
327 final int numDataBytesInGroup1 = numDataBytes / numRSBlocks;
328 // numDataBytesInGroup2 = 13 + 1 = 14
329 final int numDataBytesInGroup2 = numDataBytesInGroup1 + 1;
330 // numEcBytesInGroup1 = 39 - 13 = 26
331 final int numEcBytesInGroup1 = numTotalBytesInGroup1 - numDataBytesInGroup1;
332 // numEcBytesInGroup2 = 40 - 14 = 26
333 final int numEcBytesInGroup2 = numTotalBytesInGroup2 - numDataBytesInGroup2;
336 if (numEcBytesInGroup1 != numEcBytesInGroup2) {
337 throw new WriterException("EC bytes mismatch");
340 if (numRSBlocks != numRsBlocksInGroup1 + numRsBlocksInGroup2) {
341 throw new WriterException("RS blocks mismatch");
343 // 196 = (13 + 26) * 4 + (14 + 26) * 1
345 ((numDataBytesInGroup1 + numEcBytesInGroup1) *
346 numRsBlocksInGroup1) +
347 ((numDataBytesInGroup2 + numEcBytesInGroup2) *
348 numRsBlocksInGroup2)) {
349 throw new WriterException("Total bytes mismatch");
352 if (blockID < numRsBlocksInGroup1) {
353 numDataBytesInBlock[0] = numDataBytesInGroup1;
354 numECBytesInBlock[0] = numEcBytesInGroup1;
356 numDataBytesInBlock[0] = numDataBytesInGroup2;
357 numECBytesInBlock[0] = numEcBytesInGroup2;
361 // Interleave "bits" with corresponding error correction bytes. On success, store the result in
362 // "result" and return true. The interleave rule is complicated. See 8.6
363 // of JISX0510:2004 (p.37) for details.
364 static void interleaveWithECBytes(final BitVector bits, int numTotalBytes,
365 int numDataBytes, int numRSBlocks, BitVector result) throws WriterException {
367 // "bits" must have "getNumDataBytes" bytes of data.
368 if (bits.sizeInBytes() != numDataBytes) {
369 throw new WriterException("Number of bits and data bytes does not match");
372 // Step 1. Divide data bytes into blocks and generate error correction bytes for them. We'll
373 // store the divided data bytes blocks and error correction bytes blocks into "blocks".
374 int dataBytesOffset = 0;
375 int maxNumDataBytes = 0;
376 int maxNumEcBytes = 0;
378 // Since, we know the number of reedsolmon blocks, we can initialize the vector with the number.
379 Vector blocks = new Vector(numRSBlocks);
381 for (int i = 0; i < numRSBlocks; ++i) {
382 int[] numDataBytesInBlock = new int[1];
383 int[] numEcBytesInBlock = new int[1];
384 getNumDataBytesAndNumECBytesForBlockID(
385 numTotalBytes, numDataBytes, numRSBlocks, i,
386 numDataBytesInBlock, numEcBytesInBlock);
388 ByteArray dataBytes = new ByteArray();
389 dataBytes.set(bits.getArray(), dataBytesOffset, numDataBytesInBlock[0]);
390 ByteArray ecBytes = generateECBytes(dataBytes, numEcBytesInBlock[0]);
391 blocks.addElement(new BlockPair(dataBytes, ecBytes));
393 maxNumDataBytes = Math.max(maxNumDataBytes, dataBytes.size());
394 maxNumEcBytes = Math.max(maxNumEcBytes, ecBytes.size());
395 dataBytesOffset += numDataBytesInBlock[0];
397 if (numDataBytes != dataBytesOffset) {
398 throw new WriterException("Data bytes does not match offset");
401 // First, place data blocks.
402 for (int i = 0; i < maxNumDataBytes; ++i) {
403 for (int j = 0; j < blocks.size(); ++j) {
404 final ByteArray dataBytes = ((BlockPair) blocks.elementAt(j)).getDataBytes();
405 if (i < dataBytes.size()) {
406 result.appendBits(dataBytes.at(i), 8);
410 // Then, place error correction blocks.
411 for (int i = 0; i < maxNumEcBytes; ++i) {
412 for (int j = 0; j < blocks.size(); ++j) {
413 final ByteArray ecBytes = ((BlockPair) blocks.elementAt(j)).getErrorCorrectionBytes();
414 if (i < ecBytes.size()) {
415 result.appendBits(ecBytes.at(i), 8);
419 if (numTotalBytes != result.sizeInBytes()) { // Should be same.
420 throw new WriterException("Interleaving error: " + numTotalBytes + " and " + result.sizeInBytes() +
425 static ByteArray generateECBytes(ByteArray dataBytes, int numEcBytesInBlock) {
426 int numDataBytes = dataBytes.size();
427 int[] toEncode = new int[numDataBytes + numEcBytesInBlock];
428 for (int i = 0; i < numDataBytes; i++) {
429 toEncode[i] = dataBytes.at(i);
431 new ReedSolomonEncoder(GF256.QR_CODE_FIELD).encode(toEncode, numEcBytesInBlock);
433 ByteArray ecBytes = new ByteArray(numEcBytesInBlock);
434 for (int i = 0; i < numEcBytesInBlock; i++) {
435 ecBytes.set(i, toEncode[numDataBytes + i]);
440 // Append mode info. On success, store the result in "bits" and return true. On error, return
442 static void appendModeInfo(int mode, BitVector bits) throws WriterException {
443 final int code = QRCode.getModeCode(mode);
444 bits.appendBits(code, 4);
448 // Append length info. On success, store the result in "bits" and return true. On error, return
450 static void appendLengthInfo(int numBytes, int version, int mode, BitVector bits) throws WriterException {
451 int numLetters = numBytes;
452 // In Kanji mode, a letter is represented in two bytes.
453 if (mode == QRCode.MODE_KANJI) {
454 if (numLetters % 2 != 0) {
455 throw new WriterException("Number of letters must be even");
460 final int numBits = QRCode.getNumBitsForLength(version, mode);
461 if (numLetters > ((1 << numBits) - 1)) {
462 throw new WriterException(numLetters + "is bigger than" + ((1 << numBits) - 1));
464 bits.appendBits(numLetters, numBits);
467 // Append "bytes" in "mode" mode (encoding) into "bits". On success, store the result in "bits"
469 static void appendBytes(final ByteArray bytes, int mode, BitVector bits) throws WriterException {
471 case QRCode.MODE_NUMERIC:
472 appendNumericBytes(bytes, bits);
474 case QRCode.MODE_ALPHANUMERIC:
475 appendAlphanumericBytes(bytes, bits);
477 case QRCode.MODE_8BIT_BYTE:
478 append8BitBytes(bytes, bits);
480 case QRCode.MODE_KANJI:
481 appendKanjiBytes(bytes, bits);
484 throw new WriterException("Invalid mode: " + mode);
488 // Append "bytes" to "bits" using QRCode.MODE_NUMERIC mode. On success, store the result in "bits"
490 static void appendNumericBytes(final ByteArray bytes, BitVector bits) throws WriterException {
491 // Validate all the bytes first.
492 for (int i = 0; i < bytes.size(); ++i) {
493 int oneByte = bytes.at(i);
494 if (oneByte < '0' || oneByte > '9') {
495 throw new WriterException("Non-digit found");
498 for (int i = 0; i < bytes.size();) {
499 final int num1 = bytes.at(i) - '0';
500 if (i + 2 < bytes.size()) {
501 // Encode three numeric letters in ten bits.
502 final int num2 = bytes.at(i + 1) - '0';
503 final int num3 = bytes.at(i + 2) - '0';
504 bits.appendBits(num1 * 100 + num2 * 10 + num3, 10);
506 } else if (i + 1 < bytes.size()) {
507 // Encode two numeric letters in seven bits.
508 final int num2 = bytes.at(i + 1) - '0';
509 bits.appendBits(num1 * 10 + num2, 7);
512 // Encode one numeric letter in four bits.
513 bits.appendBits(num1, 4);
519 // Append "bytes" to "bits" using QRCode.MODE_ALPHANUMERIC mode. On success, store the result in
520 // "bits" and return true.
521 static void appendAlphanumericBytes(final ByteArray bytes, BitVector bits) throws WriterException {
522 for (int i = 0; i < bytes.size();) {
523 final int code1 = getAlphanumericCode(bytes.at(i));
525 throw new WriterException();
527 if (i + 1 < bytes.size()) {
528 final int code2 = getAlphanumericCode(bytes.at(i + 1));
530 throw new WriterException();
532 // Encode two alphanumeric letters in 11 bits.
533 bits.appendBits(code1 * 45 + code2, 11);
536 // Encode one alphanumeric letter in six bits.
537 bits.appendBits(code1, 6);
543 // Append "bytes" to "bits" using QRCode.MODE_8BIT_BYTE mode. On success, store the result in
544 // "bits" and return true.
545 static void append8BitBytes(final ByteArray bytes, BitVector bits) {
546 for (int i = 0; i < bytes.size(); ++i) {
547 bits.appendBits(bytes.at(i), 8);
551 // Append "bytes" to "bits" using QRCode.MODE_KANJI mode. On success, store the result in "bits"
552 // and return true. See 8.4.5 of JISX0510:2004 (p.21) for how to encode
554 static void appendKanjiBytes(final ByteArray bytes, BitVector bits) throws WriterException {
555 if (bytes.size() % 2 != 0) {
556 throw new WriterException("Number of bytes must be even");
558 for (int i = 0; i < bytes.size(); i += 2) {
559 if (!isValidKanji(bytes.at(i), bytes.at(i + 1))) {
560 throw new WriterException("Invalid Kanji at " + i);
562 final int code = (bytes.at(i) << 8) | bytes.at(i + 1);
564 if (code >= 0x8140 && code <= 0x9ffc) {
565 subtracted = code - 0x8140;
566 } else if (code >= 0xe040 && code <= 0xebbf) {
567 subtracted = code - 0xc140;
569 if (subtracted == -1) {
570 throw new WriterException("Invalid byte sequence: " + bytes);
572 final int encoded = ((subtracted >> 8) * 0xc0) + (subtracted & 0xff);
573 bits.appendBits(encoded, 13);
577 // Check if "byte1" and "byte2" can compose a valid Kanji letter (2-byte Shift_JIS letter). The
578 // numbers are from http://ja.wikipedia.org/wiki/Shift_JIS.
579 static boolean isValidKanji(final int byte1, final int byte2) {
580 return (byte2 != 0x7f &&
581 ((byte1 >= 0x81 && byte1 <= 0x9f &&
582 byte2 >= 0x40 && byte2 <= 0xfc) ||
583 ((byte1 >= 0xe0 && byte1 <= 0xfc &&
584 byte2 >= 0x40 && byte2 <= 0xfc))));
587 // Check if "bytes" is a valid Kanji sequence. Used by the unit tests.
588 static boolean isValidKanjiSequence(final ByteArray bytes) {
589 if (bytes.size() % 2 != 0) {
593 for (; i < bytes.size(); i += 2) {
594 if (!isValidKanji(bytes.at(i), bytes.at(i + 1))) {
598 return i == bytes.size(); // Consumed all bytes?