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| /*
| * Copyright 2013 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.
| */
|
| #import "ZXDataMatrixErrorCorrection.h"
| #import "ZXDataMatrixSymbolInfo.h"
|
| /**
| * Lookup table which factors to use for which number of error correction codewords.
| * See FACTORS.
| */
| const int ZX_FACTOR_SETS[] = {5, 7, 10, 11, 12, 14, 18, 20, 24, 28, 36, 42, 48, 56, 62, 68};
|
| /**
| * Precomputed polynomial factors for ECC 200.
| */
| const int ZX_FACTORS[16][68] = {
| {228, 48, 15, 111, 62},
| {23, 68, 144, 134, 240, 92, 254},
| {28, 24, 185, 166, 223, 248, 116, 255, 110, 61},
| {175, 138, 205, 12, 194, 168, 39, 245, 60, 97, 120},
| {41, 153, 158, 91, 61, 42, 142, 213, 97, 178, 100, 242},
| {156, 97, 192, 252, 95, 9, 157, 119, 138, 45, 18, 186, 83, 185},
| {83, 195, 100, 39, 188, 75, 66, 61, 241, 213, 109, 129, 94, 254, 225, 48, 90, 188},
| {15, 195, 244, 9, 233, 71, 168, 2, 188, 160, 153, 145, 253, 79, 108, 82, 27, 174, 186, 172},
| {52, 190, 88, 205, 109, 39, 176, 21, 155, 197, 251, 223, 155, 21, 5, 172,
| 254, 124, 12, 181, 184, 96, 50, 193},
| {211, 231, 43, 97, 71, 96, 103, 174, 37, 151, 170, 53, 75, 34, 249, 121,
| 17, 138, 110, 213, 141, 136, 120, 151, 233, 168, 93, 255},
| {245, 127, 242, 218, 130, 250, 162, 181, 102, 120, 84, 179, 220, 251, 80, 182,
| 229, 18, 2, 4, 68, 33, 101, 137, 95, 119, 115, 44, 175, 184, 59, 25,
| 225, 98, 81, 112},
| {77, 193, 137, 31, 19, 38, 22, 153, 247, 105, 122, 2, 245, 133, 242, 8,
| 175, 95, 100, 9, 167, 105, 214, 111, 57, 121, 21, 1, 253, 57, 54, 101,
| 248, 202, 69, 50, 150, 177, 226, 5, 9, 5},
| {245, 132, 172, 223, 96, 32, 117, 22, 238, 133, 238, 231, 205, 188, 237, 87,
| 191, 106, 16, 147, 118, 23, 37, 90, 170, 205, 131, 88, 120, 100, 66, 138,
| 186, 240, 82, 44, 176, 87, 187, 147, 160, 175, 69, 213, 92, 253, 225, 19},
| {175, 9, 223, 238, 12, 17, 220, 208, 100, 29, 175, 170, 230, 192, 215, 235,
| 150, 159, 36, 223, 38, 200, 132, 54, 228, 146, 218, 234, 117, 203, 29, 232,
| 144, 238, 22, 150, 201, 117, 62, 207, 164, 13, 137, 245, 127, 67, 247, 28,
| 155, 43, 203, 107, 233, 53, 143, 46},
| {242, 93, 169, 50, 144, 210, 39, 118, 202, 188, 201, 189, 143, 108, 196, 37,
| 185, 112, 134, 230, 245, 63, 197, 190, 250, 106, 185, 221, 175, 64, 114, 71,
| 161, 44, 147, 6, 27, 218, 51, 63, 87, 10, 40, 130, 188, 17, 163, 31,
| 176, 170, 4, 107, 232, 7, 94, 166, 224, 124, 86, 47, 11, 204},
| {220, 228, 173, 89, 251, 149, 159, 56, 89, 33, 147, 244, 154, 36, 73, 127,
| 213, 136, 248, 180, 234, 197, 158, 177, 68, 122, 93, 213, 15, 160, 227, 236,
| 66, 139, 153, 185, 202, 167, 179, 25, 220, 232, 96, 210, 231, 136, 223, 239,
| 181, 241, 59, 52, 172, 25, 49, 232, 211, 189, 64, 54, 108, 153, 132, 63,
| 96, 103, 82, 186}};
|
| const int ZX_MODULO_VALUE = 0x12D;
|
| static int ZX_LOG[256], ZX_ALOG[256];
|
| @implementation ZXDataMatrixErrorCorrection
|
| + (void)initialize {
| if ([self class] != [ZXDataMatrixErrorCorrection class]) return;
|
| //Create log and antilog table
| int p = 1;
| for (int i = 0; i < 255; i++) {
| ZX_ALOG[i] = p;
| ZX_LOG[p] = i;
| p *= 2;
| if (p >= 256) {
| p ^= ZX_MODULO_VALUE;
| }
| }
| }
|
| + (NSString *)encodeECC200:(NSString *)codewords symbolInfo:(ZXDataMatrixSymbolInfo *)symbolInfo {
| if (codewords.length != symbolInfo.dataCapacity) {
| [NSException raise:NSInvalidArgumentException format:@"The number of codewords does not match the selected symbol"];
| }
| NSUInteger capacity = symbolInfo.dataCapacity + symbolInfo.errorCodewords;
| NSMutableString *sb = [NSMutableString stringWithCapacity:capacity];
| [sb appendString:codewords];
| int blockCount = symbolInfo.interleavedBlockCount;
| if (blockCount == 1) {
| NSString *ecc = [self createECCBlock:codewords numECWords:symbolInfo.errorCodewords];
| [sb appendString:ecc];
| } else {
| if (sb.length > capacity) {
| [sb deleteCharactersInRange:NSMakeRange(capacity, sb.length - capacity)];
| }
| while (sb.length < capacity) {
| [sb appendFormat:@"%C", (unichar)0];
| }
| int dataSizes[blockCount];
| int errorSizes[blockCount];
| int startPos[blockCount];
| for (int i = 0; i < blockCount; i++) {
| dataSizes[i] = [symbolInfo dataLengthForInterleavedBlock:i + 1];
| errorSizes[i] = [symbolInfo errorLengthForInterleavedBlock:i + 1];
| startPos[i] = 0;
| if (i > 0) {
| startPos[i] = startPos[i - 1] + dataSizes[i];
| }
| }
| for (int block = 0; block < blockCount; block++) {
| NSMutableString *temp = [NSMutableString stringWithCapacity:dataSizes[block]];
| for (int d = block; d < symbolInfo.dataCapacity; d += blockCount) {
| [temp appendFormat:@"%c", [codewords characterAtIndex:d]];
| }
| NSString *ecc = [self createECCBlock:temp numECWords:errorSizes[block]];
| int pos = 0;
| for (int e = block; e < errorSizes[block] * blockCount; e += blockCount) {
| [sb replaceCharactersInRange:NSMakeRange(symbolInfo.dataCapacity + e, 1)
| withString:[ecc substringWithRange:NSMakeRange(pos++, 1)]];
| }
| }
| }
| return [NSString stringWithString:sb];
| }
|
| + (NSString *)createECCBlock:(NSString *)codewords numECWords:(int)numECWords {
| return [self createECCBlock:codewords start:0 len:(int)codewords.length numECWords:numECWords];
| }
|
| + (NSString *)createECCBlock:(NSString *)codewords start:(int)start len:(int)len numECWords:(int)numECWords {
| int table = -1;
| for (int i = 0; i < sizeof(ZX_FACTOR_SETS) / sizeof(int); i++) {
| if (ZX_FACTOR_SETS[i] == numECWords) {
| table = i;
| break;
| }
| }
| if (table < 0) {
| [NSException raise:NSInvalidArgumentException format:@"Illegal number of error correction codewords specified: %d", numECWords];
| }
| int *poly = (int *)ZX_FACTORS[table];
| unichar ecc[numECWords];
| memset(ecc, 0, numECWords * sizeof(unichar));
| for (int i = start; i < start + len; i++) {
| int m = ecc[numECWords - 1] ^ [codewords characterAtIndex:i];
| for (int k = numECWords - 1; k > 0; k--) {
| if (m != 0 && poly[k] != 0) {
| ecc[k] = (unichar) (ecc[k - 1] ^ ZX_ALOG[(ZX_LOG[m] + ZX_LOG[poly[k]]) % 255]);
| } else {
| ecc[k] = ecc[k - 1];
| }
| }
| if (m != 0 && poly[0] != 0) {
| ecc[0] = (unichar) ZX_ALOG[(ZX_LOG[m] + ZX_LOG[poly[0]]) % 255];
| } else {
| ecc[0] = 0;
| }
| }
| unichar eccReversed[numECWords];
| for (int i = 0; i < numECWords; i++) {
| eccReversed[i] = ecc[numECWords - i - 1];
| }
| return [NSString stringWithCharacters:eccReversed length:numECWords];
| }
|
| @end
|
|
