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- /*
- * Copyright 2012 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 "ZXByteMatrix.h"
- #import "ZXQRCode.h"
- #import "ZXQRCodeMaskUtil.h"
-
- // Penalty weights from section 6.8.2.1
- const int ZX_N1 = 3;
- const int ZX_N2 = 3;
- const int ZX_N3 = 40;
- const int ZX_N4 = 10;
-
- @implementation ZXQRCodeMaskUtil
-
- + (int)applyMaskPenaltyRule1:(ZXByteMatrix *)matrix {
- return [self applyMaskPenaltyRule1Internal:matrix isHorizontal:YES] + [self applyMaskPenaltyRule1Internal:matrix isHorizontal:NO];
- }
-
- + (int)applyMaskPenaltyRule2:(ZXByteMatrix *)matrix {
- int penalty = 0;
- int8_t **array = matrix.array;
- int width = matrix.width;
- int height = matrix.height;
-
- for (int y = 0; y < height - 1; y++) {
- for (int x = 0; x < width - 1; x++) {
- int value = array[y][x];
- if (value == array[y][x + 1] && value == array[y + 1][x] && value == array[y + 1][x + 1]) {
- penalty++;
- }
- }
- }
-
- return ZX_N2 * penalty;
- }
-
- + (int)applyMaskPenaltyRule3:(ZXByteMatrix *)matrix {
- int numPenalties = 0;
- int8_t **array = matrix.array;
- int width = matrix.width;
- int height = matrix.height;
- for (int y = 0; y < height; y++) {
- for (int x = 0; x < width; x++) {
- int8_t *arrayY = array[y]; // We can at least optimize this access
- if (x + 6 < width &&
- arrayY[x] == 1 &&
- arrayY[x + 1] == 0 &&
- arrayY[x + 2] == 1 &&
- arrayY[x + 3] == 1 &&
- arrayY[x + 4] == 1 &&
- arrayY[x + 5] == 0 &&
- arrayY[x + 6] == 1 &&
- ([self isWhiteHorizontal:arrayY length:width from:x - 4 to:x] || [self isWhiteHorizontal:arrayY length:width from:x + 7 to:x + 11])) {
- numPenalties++;
- }
- if (y + 6 < height &&
- array[y][x] == 1 &&
- array[y + 1][x] == 0 &&
- array[y + 2][x] == 1 &&
- array[y + 3][x] == 1 &&
- array[y + 4][x] == 1 &&
- array[y + 5][x] == 0 &&
- array[y + 6][x] == 1 &&
- ([self isWhiteVertical:array length:width col:x from:y - 4 to:y] || [self isWhiteVertical:array length:height col:x from:y + 7 to:y + 11])) {
- numPenalties++;
- }
- }
- }
- return numPenalties * ZX_N3;
- }
-
- + (BOOL)isWhiteHorizontal:(int8_t *)rowArray length:(int)length from:(int)from to:(int)to {
- for (int i = from; i < to; i++) {
- if (i >= 0 && i < length && rowArray[i] == 1) {
- return NO;
- }
- }
- return YES;
- }
-
- + (BOOL)isWhiteVertical:(int8_t **)array length:(int)length col:(int)col from:(int)from to:(int)to {
- for (int i = from; i < to; i++) {
- if (i >= 0 && i < length && array[i][col] == 1) {
- return NO;
- }
- }
- return YES;
- }
-
- + (int)applyMaskPenaltyRule4:(ZXByteMatrix *)matrix {
- int numDarkCells = 0;
- int8_t **array = matrix.array;
- int width = matrix.width;
- int height = matrix.height;
- for (int y = 0; y < height; y++) {
- int8_t *arrayY = array[y];
- for (int x = 0; x < width; x++) {
- if (arrayY[x] == 1) {
- numDarkCells++;
- }
- }
- }
- int numTotalCells = [matrix height] * [matrix width];
- int fivePercentVariances = abs(numDarkCells * 2 - numTotalCells) * 10 / numTotalCells;
- return fivePercentVariances * ZX_N4;
- }
-
- + (BOOL)dataMaskBit:(int)maskPattern x:(int)x y:(int)y {
- int intermediate;
- int temp;
- switch (maskPattern) {
- case 0:
- intermediate = (y + x) & 0x1;
- break;
- case 1:
- intermediate = y & 0x1;
- break;
- case 2:
- intermediate = x % 3;
- break;
- case 3:
- intermediate = (y + x) % 3;
- break;
- case 4:
- intermediate = ((y / 2) + (x / 3)) & 0x1;
- break;
- case 5:
- temp = y * x;
- intermediate = (temp & 0x1) + (temp % 3);
- break;
- case 6:
- temp = y * x;
- intermediate = ((temp & 0x1) + (temp % 3)) & 0x1;
- break;
- case 7:
- temp = y * x;
- intermediate = ((temp % 3) + ((y + x) & 0x1)) & 0x1;
- break;
- default:
- [NSException raise:NSInvalidArgumentException format:@"Invalid mask pattern: %d", maskPattern];
- }
- return intermediate == 0;
- }
-
- /**
- * Helper function for applyMaskPenaltyRule1. We need this for doing this calculation in both
- * vertical and horizontal orders respectively.
- */
- + (int)applyMaskPenaltyRule1Internal:(ZXByteMatrix *)matrix isHorizontal:(BOOL)isHorizontal {
- int penalty = 0;
- int iLimit = isHorizontal ? matrix.height : matrix.width;
- int jLimit = isHorizontal ? matrix.width : matrix.height;
- int8_t **array = matrix.array;
- for (int i = 0; i < iLimit; i++) {
- int numSameBitCells = 0;
- int prevBit = -1;
- for (int j = 0; j < jLimit; j++) {
- int bit = isHorizontal ? array[i][j] : array[j][i];
- if (bit == prevBit) {
- numSameBitCells++;
- } else {
- if (numSameBitCells >= 5) {
- penalty += ZX_N1 + (numSameBitCells - 5);
- }
- numSameBitCells = 1; // Include the cell itself.
- prevBit = bit;
- }
- }
- if (numSameBitCells >= 5) {
- penalty += ZX_N1 + (numSameBitCells - 5);
- }
- }
- return penalty;
- }
-
- @end
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