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.WriterException;
20 import com.google.zxing.common.ByteArray;
21 import com.google.zxing.common.ByteMatrix;
22 import com.google.zxing.common.reedsolomon.GF256;
23 import com.google.zxing.common.reedsolomon.ReedSolomonEncoder;
24 import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
25 import com.google.zxing.qrcode.decoder.Mode;
26 import com.google.zxing.qrcode.decoder.Version;
28 import java.util.Vector;
31 * @author satorux@google.com (Satoru Takabayashi) - creator
32 * @author dswitkin@google.com (Daniel Switkin) - ported from C++
34 public final class Encoder {
36 // The original table is defined in the table 5 of JISX0510:2004 (p.19).
37 private static final int[] ALPHANUMERIC_TABLE = {
38 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0x00-0x0f
39 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0x10-0x1f
40 36, -1, -1, -1, 37, 38, -1, -1, -1, -1, 39, 40, -1, 41, 42, 43, // 0x20-0x2f
41 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 44, -1, -1, -1, -1, -1, // 0x30-0x3f
42 -1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 0x40-0x4f
43 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1, // 0x50-0x5f
46 private static final class RSBlockInfo {
49 final int[][] blockInfo;
51 public RSBlockInfo(int numBytes, int[][] blockInfo) {
52 this.numBytes = numBytes;
53 this.blockInfo = blockInfo;
58 // The table is from table 12 of JISX0510:2004 (p. 30). The "blockInfo" parts are ordered by
59 // L, M, Q, H. Within each blockInfo, the 0th element is getNumECBytes, and the 1st element is
60 // getNumRSBlocks. The table was doublechecked by komatsu.
61 private static final RSBlockInfo[] RS_BLOCK_TABLE = {
62 new RSBlockInfo( 26, new int[][]{ { 7, 1}, { 10, 1}, { 13, 1}, { 17, 1}}), // Version 1
63 new RSBlockInfo( 44, new int[][]{ { 10, 1}, { 16, 1}, { 22, 1}, { 28, 1}}), // Version 2
64 new RSBlockInfo( 70, new int[][]{ { 15, 1}, { 26, 1}, { 36, 2}, { 44, 2}}), // Version 3
65 new RSBlockInfo( 100, new int[][]{ { 20, 1}, { 36, 2}, { 52, 2}, { 64, 4}}), // Version 4
66 new RSBlockInfo( 134, new int[][]{ { 26, 1}, { 48, 2}, { 72, 4}, { 88, 4}}), // Version 5
67 new RSBlockInfo( 172, new int[][]{ { 36, 2}, { 64, 4}, { 96, 4}, { 112, 4}}), // Version 6
68 new RSBlockInfo( 196, new int[][]{ { 40, 2}, { 72, 4}, { 108, 6}, { 130, 5}}), // Version 7
69 new RSBlockInfo( 242, new int[][]{ { 48, 2}, { 88, 4}, { 132, 6}, { 156, 6}}), // Version 8
70 new RSBlockInfo( 292, new int[][]{ { 60, 2}, { 110, 5}, { 160, 8}, { 192, 8}}), // Version 9
71 new RSBlockInfo( 346, new int[][]{ { 72, 4}, { 130, 5}, { 192, 8}, { 224, 8}}), // Version 10
72 new RSBlockInfo( 404, new int[][]{ { 80, 4}, { 150, 5}, { 224, 8}, { 264, 11}}), // Version 11
73 new RSBlockInfo( 466, new int[][]{ { 96, 4}, { 176, 8}, { 260, 10}, { 308, 11}}), // Version 12
74 new RSBlockInfo( 532, new int[][]{ {104, 4}, { 198, 9}, { 288, 12}, { 352, 16}}), // Version 13
75 new RSBlockInfo( 581, new int[][]{ {120, 4}, { 216, 9}, { 320, 16}, { 384, 16}}), // Version 14
76 new RSBlockInfo( 655, new int[][]{ {132, 6}, { 240, 10}, { 360, 12}, { 432, 18}}), // Version 15
77 new RSBlockInfo( 733, new int[][]{ {144, 6}, { 280, 10}, { 408, 17}, { 480, 16}}), // Version 16
78 new RSBlockInfo( 815, new int[][]{ {168, 6}, { 308, 11}, { 448, 16}, { 532, 19}}), // Version 17
79 new RSBlockInfo( 901, new int[][]{ {180, 6}, { 338, 13}, { 504, 18}, { 588, 21}}), // Version 18
80 new RSBlockInfo( 991, new int[][]{ {196, 7}, { 364, 14}, { 546, 21}, { 650, 25}}), // Version 19
81 new RSBlockInfo(1085, new int[][]{ {224, 8}, { 416, 16}, { 600, 20}, { 700, 25}}), // Version 20
82 new RSBlockInfo(1156, new int[][]{ {224, 8}, { 442, 17}, { 644, 23}, { 750, 25}}), // Version 21
83 new RSBlockInfo(1258, new int[][]{ {252, 9}, { 476, 17}, { 690, 23}, { 816, 34}}), // Version 22
84 new RSBlockInfo(1364, new int[][]{ {270, 9}, { 504, 18}, { 750, 25}, { 900, 30}}), // Version 23
85 new RSBlockInfo(1474, new int[][]{ {300, 10}, { 560, 20}, { 810, 27}, { 960, 32}}), // Version 24
86 new RSBlockInfo(1588, new int[][]{ {312, 12}, { 588, 21}, { 870, 29}, {1050, 35}}), // Version 25
87 new RSBlockInfo(1706, new int[][]{ {336, 12}, { 644, 23}, { 952, 34}, {1110, 37}}), // Version 26
88 new RSBlockInfo(1828, new int[][]{ {360, 12}, { 700, 25}, {1020, 34}, {1200, 40}}), // Version 27
89 new RSBlockInfo(1921, new int[][]{ {390, 13}, { 728, 26}, {1050, 35}, {1260, 42}}), // Version 28
90 new RSBlockInfo(2051, new int[][]{ {420, 14}, { 784, 28}, {1140, 38}, {1350, 45}}), // Version 29
91 new RSBlockInfo(2185, new int[][]{ {450, 15}, { 812, 29}, {1200, 40}, {1440, 48}}), // Version 30
92 new RSBlockInfo(2323, new int[][]{ {480, 16}, { 868, 31}, {1290, 43}, {1530, 51}}), // Version 31
93 new RSBlockInfo(2465, new int[][]{ {510, 17}, { 924, 33}, {1350, 45}, {1620, 54}}), // Version 32
94 new RSBlockInfo(2611, new int[][]{ {540, 18}, { 980, 35}, {1440, 48}, {1710, 57}}), // Version 33
95 new RSBlockInfo(2761, new int[][]{ {570, 19}, {1036, 37}, {1530, 51}, {1800, 60}}), // Version 34
96 new RSBlockInfo(2876, new int[][]{ {570, 19}, {1064, 38}, {1590, 53}, {1890, 63}}), // Version 35
97 new RSBlockInfo(3034, new int[][]{ {600, 20}, {1120, 40}, {1680, 56}, {1980, 66}}), // Version 36
98 new RSBlockInfo(3196, new int[][]{ {630, 21}, {1204, 43}, {1770, 59}, {2100, 70}}), // Version 37
99 new RSBlockInfo(3362, new int[][]{ {660, 22}, {1260, 45}, {1860, 62}, {2220, 74}}), // Version 38
100 new RSBlockInfo(3532, new int[][]{ {720, 24}, {1316, 47}, {1950, 65}, {2310, 77}}), // Version 39
101 new RSBlockInfo(3706, new int[][]{ {750, 25}, {1372, 49}, {2040, 68}, {2430, 81}}), // Version 40
104 private static final class BlockPair {
106 private final ByteArray dataBytes;
107 private final ByteArray errorCorrectionBytes;
109 public BlockPair(ByteArray data, ByteArray errorCorrection) {
111 errorCorrectionBytes = errorCorrection;
114 public ByteArray getDataBytes() {
118 public ByteArray getErrorCorrectionBytes() {
119 return errorCorrectionBytes;
124 // Encode "bytes" with the error correction level "getECLevel". The encoding mode will be chosen
125 // internally by chooseMode(). On success, store the result in "qrCode" and return true.
126 // We recommend you to use QRCode.EC_LEVEL_L (the lowest level) for
127 // "getECLevel" since our primary use is to show QR code on desktop screens. We don't need very
128 // strong error correction for this purpose.
130 // Note that there is no way to encode bytes in MODE_KANJI. We might want to add EncodeWithMode()
131 // with which clients can specify the encoding mode. For now, we don't need the functionality.
132 public static void encode(final ByteArray bytes, ErrorCorrectionLevel ecLevel, QRCode qrCode)
133 throws WriterException {
134 // Step 1: Choose the mode (encoding).
135 final Mode mode = chooseMode(bytes);
137 // Step 2: Append "bytes" into "dataBits" in appropriate encoding.
138 BitVector dataBits = new BitVector();
139 appendBytes(bytes, mode, dataBits);
140 // Step 3: Initialize QR code that can contain "dataBits".
141 final int numInputBytes = dataBits.sizeInBytes();
142 initQRCode(numInputBytes, ecLevel, mode, qrCode);
144 // Step 4: Build another bit vector that contains header and data.
145 BitVector headerAndDataBits = new BitVector();
146 appendModeInfo(qrCode.getMode(), headerAndDataBits);
147 appendLengthInfo(bytes.size(), qrCode.getVersion(), qrCode.getMode(), headerAndDataBits);
148 headerAndDataBits.appendBitVector(dataBits);
150 // Step 5: Terminate the bits properly.
151 terminateBits(qrCode.getNumDataBytes(), headerAndDataBits);
153 // Step 6: Interleave data bits with error correction code.
154 BitVector finalBits = new BitVector();
155 interleaveWithECBytes(headerAndDataBits, qrCode.getNumTotalBytes(), qrCode.getNumDataBytes(),
156 qrCode.getNumRSBlocks(), finalBits);
158 // Step 7: Choose the mask pattern and set to "qrCode".
159 ByteMatrix matrix = new ByteMatrix(qrCode.getMatrixWidth(), qrCode.getMatrixWidth());
160 qrCode.setMaskPattern(chooseMaskPattern(finalBits, qrCode.getECLevel(), qrCode.getVersion(),
163 // Step 8. Build the matrix and set it to "qrCode".
164 MatrixUtil.buildMatrix(finalBits, qrCode.getECLevel(), qrCode.getVersion(),
165 qrCode.getMaskPattern(), matrix);
166 qrCode.setMatrix(matrix);
167 // Step 9. Make sure we have a valid QR Code.
168 if (!qrCode.isValid()) {
169 throw new WriterException("Invalid QR code: " + qrCode.toString());
173 // Return the code point of the table used in alphanumeric mode. Return -1 if there is no
174 // corresponding code in the table.
175 static int getAlphanumericCode(int code) {
176 if (code < ALPHANUMERIC_TABLE.length) {
177 return ALPHANUMERIC_TABLE[code];
182 // Choose the best mode by examining the content of "bytes". The function is guaranteed to return
185 // Note that this function does not return MODE_KANJI, as we cannot distinguish Shift_JIS from
186 // other encodings such as ISO-8859-1, from data bytes alone. For example "\xE0\xE0" can be
187 // interpreted as one character in Shift_JIS, but also two characters in ISO-8859-1.
189 // JAVAPORT: This MODE_KANJI limitation sounds like a problem for us.
190 public static Mode chooseMode(final ByteArray bytes) throws WriterException {
191 boolean hasNumeric = false;
192 boolean hasAlphanumeric = false;
193 boolean hasOther = false;
194 for (int i = 0; i < bytes.size(); ++i) {
195 final int oneByte = bytes.at(i);
196 if (oneByte >= '0' && oneByte <= '9') {
198 } else if (getAlphanumericCode(oneByte) != -1) {
199 hasAlphanumeric = true;
206 } else if (hasAlphanumeric) {
207 return Mode.ALPHANUMERIC;
208 } else if (hasNumeric) {
211 // "bytes" must be empty to reach here.
212 if (!bytes.empty()) {
213 throw new WriterException("Bytes left over");
218 private static int chooseMaskPattern(final BitVector bits, ErrorCorrectionLevel ecLevel, int version,
219 ByteMatrix matrix) throws WriterException {
220 if (!QRCode.isValidMatrixWidth(matrix.width())) {
221 throw new WriterException("Invalid matrix width: " + matrix.width());
224 int minPenalty = Integer.MAX_VALUE; // Lower penalty is better.
225 int bestMaskPattern = -1;
226 // We try all mask patterns to choose the best one.
227 for (int maskPattern = 0; maskPattern < QRCode.NUM_MASK_PATTERNS; maskPattern++) {
228 MatrixUtil.buildMatrix(bits, ecLevel, version, maskPattern, matrix);
229 final int penalty = MaskUtil.calculateMaskPenalty(matrix);
230 if (penalty < minPenalty) {
231 minPenalty = penalty;
232 bestMaskPattern = maskPattern;
235 return bestMaskPattern;
238 // Initialize "qrCode" according to "numInputBytes", "ecLevel", and "mode". On success, modify
239 // "qrCode" and return true.
240 private static void initQRCode(int numInputBytes, ErrorCorrectionLevel ecLevel, Mode mode, QRCode qrCode)
241 throws WriterException {
242 qrCode.setECLevel(ecLevel);
243 qrCode.setMode(mode);
245 // In the following comments, we use numbers of Version 7-H.
246 for (int i = 0; i < RS_BLOCK_TABLE.length; ++i) {
247 final RSBlockInfo row = RS_BLOCK_TABLE[i];
249 final int numBytes = row.numBytes;
250 // getNumECBytes = 130
251 final int numEcBytes = row.blockInfo[ecLevel.ordinal()][0];
252 // getNumRSBlocks = 5
253 final int numRSBlocks = row.blockInfo[ecLevel.ordinal()][1];
254 // getNumDataBytes = 196 - 130 = 66
255 final int numDataBytes = numBytes - numEcBytes;
256 // We want to choose the smallest version which can contain data of "numInputBytes" + some
257 // extra bits for the header (mode info and length info). The header can be three bytes
258 // (precisely 4 + 16 bits) at most. Hence we do +3 here.
259 if (numDataBytes >= numInputBytes + 3) {
260 // Yay, we found the proper rs block info!
261 qrCode.setVersion(i + 1);
262 qrCode.setNumTotalBytes(numBytes);
263 qrCode.setNumDataBytes(numDataBytes);
264 qrCode.setNumRSBlocks(numRSBlocks);
265 // getNumECBytes = 196 - 66 = 130
266 qrCode.setNumECBytes(numBytes - numDataBytes);
267 // matrix width = 21 + 6 * 4 = 45
268 qrCode.setMatrixWidth(21 + i * 4);
272 throw new WriterException("Cannot find proper rs block info (input data too big?)");
275 // Terminate bits as described in 8.4.8 and 8.4.9 of JISX0510:2004 (p.24).
276 static void terminateBits(int numDataBytes, BitVector bits) throws WriterException {
277 final int capacity = numDataBytes * 8;
278 if (bits.size() > capacity) {
279 throw new WriterException("data bits cannot fit in the QR Code" + bits.size() + " > " + capacity);
281 // Append termination bits. See 8.4.8 of JISX0510:2004 (p.24) for details.
282 for (int i = 0; i < 4 && bits.size() < capacity; ++i) {
285 final int numBitsInLastByte = bits.size() % 8;
286 // If the last byte isn't 8-bit aligned, we'll add padding bits.
287 if (numBitsInLastByte > 0) {
288 final int numPaddingBits = 8 - numBitsInLastByte;
289 for (int i = 0; i < numPaddingBits; ++i) {
293 // Should be 8-bit aligned here.
294 if (bits.size() % 8 != 0) {
295 throw new WriterException("Number of bits is not a multiple of 8");
297 // If we have more space, we'll fill the space with padding patterns defined in 8.4.9 (p.24).
298 final int numPaddingBytes = numDataBytes - bits.sizeInBytes();
299 for (int i = 0; i < numPaddingBytes; ++i) {
301 bits.appendBits(0xec, 8);
303 bits.appendBits(0x11, 8);
306 if (bits.size() != capacity) {
307 throw new WriterException("Bits size does not equal capacity");
311 // Get number of data bytes and number of error correction bytes for block id "blockID". Store
312 // the result in "numDataBytesInBlock", and "numECBytesInBlock". See table 12 in 8.5.1 of
313 // JISX0510:2004 (p.30)
314 static void getNumDataBytesAndNumECBytesForBlockID(int numTotalBytes, int numDataBytes,
315 int numRSBlocks, int blockID, int[] numDataBytesInBlock,
316 int[] numECBytesInBlock) throws WriterException {
317 if (blockID >= numRSBlocks) {
318 throw new WriterException("Block ID too large");
320 // numRsBlocksInGroup2 = 196 % 5 = 1
321 final int numRsBlocksInGroup2 = numTotalBytes % numRSBlocks;
322 // numRsBlocksInGroup1 = 5 - 1 = 4
323 final int numRsBlocksInGroup1 = numRSBlocks - numRsBlocksInGroup2;
324 // numTotalBytesInGroup1 = 196 / 5 = 39
325 final int numTotalBytesInGroup1 = numTotalBytes / numRSBlocks;
326 // numTotalBytesInGroup2 = 39 + 1 = 40
327 final int numTotalBytesInGroup2 = numTotalBytesInGroup1 + 1;
328 // numDataBytesInGroup1 = 66 / 5 = 13
329 final int numDataBytesInGroup1 = numDataBytes / numRSBlocks;
330 // numDataBytesInGroup2 = 13 + 1 = 14
331 final int numDataBytesInGroup2 = numDataBytesInGroup1 + 1;
332 // numEcBytesInGroup1 = 39 - 13 = 26
333 final int numEcBytesInGroup1 = numTotalBytesInGroup1 - numDataBytesInGroup1;
334 // numEcBytesInGroup2 = 40 - 14 = 26
335 final int numEcBytesInGroup2 = numTotalBytesInGroup2 - numDataBytesInGroup2;
338 if (numEcBytesInGroup1 != numEcBytesInGroup2) {
339 throw new WriterException("EC bytes mismatch");
342 if (numRSBlocks != numRsBlocksInGroup1 + numRsBlocksInGroup2) {
343 throw new WriterException("RS blocks mismatch");
345 // 196 = (13 + 26) * 4 + (14 + 26) * 1
347 ((numDataBytesInGroup1 + numEcBytesInGroup1) *
348 numRsBlocksInGroup1) +
349 ((numDataBytesInGroup2 + numEcBytesInGroup2) *
350 numRsBlocksInGroup2)) {
351 throw new WriterException("Total bytes mismatch");
354 if (blockID < numRsBlocksInGroup1) {
355 numDataBytesInBlock[0] = numDataBytesInGroup1;
356 numECBytesInBlock[0] = numEcBytesInGroup1;
358 numDataBytesInBlock[0] = numDataBytesInGroup2;
359 numECBytesInBlock[0] = numEcBytesInGroup2;
363 // Interleave "bits" with corresponding error correction bytes. On success, store the result in
364 // "result" and return true. The interleave rule is complicated. See 8.6
365 // of JISX0510:2004 (p.37) for details.
366 static void interleaveWithECBytes(final BitVector bits, int numTotalBytes,
367 int numDataBytes, int numRSBlocks, BitVector result) throws WriterException {
369 // "bits" must have "getNumDataBytes" bytes of data.
370 if (bits.sizeInBytes() != numDataBytes) {
371 throw new WriterException("Number of bits and data bytes does not match");
374 // Step 1. Divide data bytes into blocks and generate error correction bytes for them. We'll
375 // store the divided data bytes blocks and error correction bytes blocks into "blocks".
376 int dataBytesOffset = 0;
377 int maxNumDataBytes = 0;
378 int maxNumEcBytes = 0;
380 // Since, we know the number of reedsolmon blocks, we can initialize the vector with the number.
381 Vector blocks = new Vector(numRSBlocks);
383 for (int i = 0; i < numRSBlocks; ++i) {
384 int[] numDataBytesInBlock = new int[1];
385 int[] numEcBytesInBlock = new int[1];
386 getNumDataBytesAndNumECBytesForBlockID(
387 numTotalBytes, numDataBytes, numRSBlocks, i,
388 numDataBytesInBlock, numEcBytesInBlock);
390 ByteArray dataBytes = new ByteArray();
391 dataBytes.set(bits.getArray(), dataBytesOffset, numDataBytesInBlock[0]);
392 ByteArray ecBytes = generateECBytes(dataBytes, numEcBytesInBlock[0]);
393 blocks.addElement(new BlockPair(dataBytes, ecBytes));
395 maxNumDataBytes = Math.max(maxNumDataBytes, dataBytes.size());
396 maxNumEcBytes = Math.max(maxNumEcBytes, ecBytes.size());
397 dataBytesOffset += numDataBytesInBlock[0];
399 if (numDataBytes != dataBytesOffset) {
400 throw new WriterException("Data bytes does not match offset");
403 // First, place data blocks.
404 for (int i = 0; i < maxNumDataBytes; ++i) {
405 for (int j = 0; j < blocks.size(); ++j) {
406 final ByteArray dataBytes = ((BlockPair) blocks.elementAt(j)).getDataBytes();
407 if (i < dataBytes.size()) {
408 result.appendBits(dataBytes.at(i), 8);
412 // Then, place error correction blocks.
413 for (int i = 0; i < maxNumEcBytes; ++i) {
414 for (int j = 0; j < blocks.size(); ++j) {
415 final ByteArray ecBytes = ((BlockPair) blocks.elementAt(j)).getErrorCorrectionBytes();
416 if (i < ecBytes.size()) {
417 result.appendBits(ecBytes.at(i), 8);
421 if (numTotalBytes != result.sizeInBytes()) { // Should be same.
422 throw new WriterException("Interleaving error: " + numTotalBytes + " and " + result.sizeInBytes() +
427 static ByteArray generateECBytes(ByteArray dataBytes, int numEcBytesInBlock) {
428 int numDataBytes = dataBytes.size();
429 int[] toEncode = new int[numDataBytes + numEcBytesInBlock];
430 for (int i = 0; i < numDataBytes; i++) {
431 toEncode[i] = dataBytes.at(i);
433 new ReedSolomonEncoder(GF256.QR_CODE_FIELD).encode(toEncode, numEcBytesInBlock);
435 ByteArray ecBytes = new ByteArray(numEcBytesInBlock);
436 for (int i = 0; i < numEcBytesInBlock; i++) {
437 ecBytes.set(i, toEncode[numDataBytes + i]);
442 // Append mode info. On success, store the result in "bits" and return true. On error, return
444 static void appendModeInfo(Mode mode, BitVector bits) {
445 bits.appendBits(mode.getBits(), 4);
449 // Append length info. On success, store the result in "bits" and return true. On error, return
451 static void appendLengthInfo(int numBytes, int version, Mode mode, BitVector bits) throws WriterException {
452 int numLetters = numBytes;
453 // In Kanji mode, a letter is represented in two bytes.
454 if (mode.equals(Mode.KANJI)) {
455 if (numLetters % 2 != 0) {
456 throw new WriterException("Number of letters must be even");
461 final int numBits = mode.getCharacterCountBits(Version.getVersionForNumber(version));
463 if (numLetters > ((1 << numBits) - 1)) {
464 throw new WriterException(numLetters + "is bigger than" + ((1 << numBits) - 1));
466 bits.appendBits(numLetters, numBits);
469 // Append "bytes" in "mode" mode (encoding) into "bits". On success, store the result in "bits"
471 static void appendBytes(final ByteArray bytes, Mode mode, BitVector bits) throws WriterException {
472 if (mode.equals(Mode.NUMERIC)) {
473 appendNumericBytes(bytes, bits);
474 } else if (mode.equals(Mode.ALPHANUMERIC)) {
475 appendAlphanumericBytes(bytes, bits);
476 } else if (mode.equals(Mode.BYTE)) {
477 append8BitBytes(bytes, bits);
478 } else if (mode.equals(Mode.KANJI)) {
479 appendKanjiBytes(bytes, bits);
481 throw new WriterException("Invalid mode: " + mode);
485 // Append "bytes" to "bits" using QRCode.MODE_NUMERIC mode. On success, store the result in "bits"
487 static void appendNumericBytes(final ByteArray bytes, BitVector bits) throws WriterException {
488 // Validate all the bytes first.
489 for (int i = 0; i < bytes.size(); ++i) {
490 int oneByte = bytes.at(i);
491 if (oneByte < '0' || oneByte > '9') {
492 throw new WriterException("Non-digit found");
495 for (int i = 0; i < bytes.size();) {
496 final int num1 = bytes.at(i) - '0';
497 if (i + 2 < bytes.size()) {
498 // Encode three numeric letters in ten bits.
499 final int num2 = bytes.at(i + 1) - '0';
500 final int num3 = bytes.at(i + 2) - '0';
501 bits.appendBits(num1 * 100 + num2 * 10 + num3, 10);
503 } else if (i + 1 < bytes.size()) {
504 // Encode two numeric letters in seven bits.
505 final int num2 = bytes.at(i + 1) - '0';
506 bits.appendBits(num1 * 10 + num2, 7);
509 // Encode one numeric letter in four bits.
510 bits.appendBits(num1, 4);
516 // Append "bytes" to "bits" using QRCode.MODE_ALPHANUMERIC mode. On success, store the result in
517 // "bits" and return true.
518 static void appendAlphanumericBytes(final ByteArray bytes, BitVector bits) throws WriterException {
519 for (int i = 0; i < bytes.size();) {
520 final int code1 = getAlphanumericCode(bytes.at(i));
522 throw new WriterException();
524 if (i + 1 < bytes.size()) {
525 final int code2 = getAlphanumericCode(bytes.at(i + 1));
527 throw new WriterException();
529 // Encode two alphanumeric letters in 11 bits.
530 bits.appendBits(code1 * 45 + code2, 11);
533 // Encode one alphanumeric letter in six bits.
534 bits.appendBits(code1, 6);
540 // Append "bytes" to "bits" using QRCode.MODE_8BIT_BYTE mode. On success, store the result in
541 // "bits" and return true.
542 static void append8BitBytes(final ByteArray bytes, BitVector bits) {
543 for (int i = 0; i < bytes.size(); ++i) {
544 bits.appendBits(bytes.at(i), 8);
548 // Append "bytes" to "bits" using QRCode.MODE_KANJI mode. On success, store the result in "bits"
549 // and return true. See 8.4.5 of JISX0510:2004 (p.21) for how to encode
551 static void appendKanjiBytes(final ByteArray bytes, BitVector bits) throws WriterException {
552 if (bytes.size() % 2 != 0) {
553 throw new WriterException("Number of bytes must be even");
555 for (int i = 0; i < bytes.size(); i += 2) {
556 if (!isValidKanji(bytes.at(i), bytes.at(i + 1))) {
557 throw new WriterException("Invalid Kanji at " + i);
559 final int code = (bytes.at(i) << 8) | bytes.at(i + 1);
561 if (code >= 0x8140 && code <= 0x9ffc) {
562 subtracted = code - 0x8140;
563 } else if (code >= 0xe040 && code <= 0xebbf) {
564 subtracted = code - 0xc140;
566 if (subtracted == -1) {
567 throw new WriterException("Invalid byte sequence: " + bytes);
569 final int encoded = ((subtracted >> 8) * 0xc0) + (subtracted & 0xff);
570 bits.appendBits(encoded, 13);
574 // Check if "byte1" and "byte2" can compose a valid Kanji letter (2-byte Shift_JIS letter). The
575 // numbers are from http://ja.wikipedia.org/wiki/Shift_JIS.
576 static boolean isValidKanji(final int byte1, final int byte2) {
577 return (byte2 != 0x7f &&
578 ((byte1 >= 0x81 && byte1 <= 0x9f &&
579 byte2 >= 0x40 && byte2 <= 0xfc) ||
580 ((byte1 >= 0xe0 && byte1 <= 0xfc &&
581 byte2 >= 0x40 && byte2 <= 0xfc))));
584 // Check if "bytes" is a valid Kanji sequence. Used by the unit tests.
585 static boolean isValidKanjiSequence(final ByteArray bytes) {
586 if (bytes.size() % 2 != 0) {
590 for (; i < bytes.size(); i += 2) {
591 if (!isValidKanji(bytes.at(i), bytes.at(i + 1))) {
595 return i == bytes.size(); // Consumed all bytes?