/*
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* Copyright 2012 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#import "ZXAbstractRSSReader.h"
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#import "ZXIntArray.h"
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static float ZX_RSS_MAX_AVG_VARIANCE = 0.2f;
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static float ZX_RSS_MAX_INDIVIDUAL_VARIANCE = 0.45f;
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float const ZX_RSS_MIN_FINDER_PATTERN_RATIO = 9.5f / 12.0f;
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float const ZX_RSS_MAX_FINDER_PATTERN_RATIO = 12.5f / 14.0f;
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#define ZX_RSS14_FINDER_PATTERNS_LEN 9
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#define ZX_RSS14_FINDER_PATTERNS_SUB_LEN 4
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const int ZX_RSS14_FINDER_PATTERNS[ZX_RSS14_FINDER_PATTERNS_LEN][ZX_RSS14_FINDER_PATTERNS_SUB_LEN] = {
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{3,8,2,1},
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{3,5,5,1},
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{3,3,7,1},
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{3,1,9,1},
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{2,7,4,1},
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{2,5,6,1},
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{2,3,8,1},
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{1,5,7,1},
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{1,3,9,1},
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};
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#define ZX_RSS_EXPANDED_FINDER_PATTERNS_LEN 6
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#define ZX_RSS_EXPANDED_FINDER_PATTERNS_SUB_LEN 4
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const int ZX_RSS_EXPANDED_FINDER_PATTERNS[ZX_RSS_EXPANDED_FINDER_PATTERNS_LEN][ZX_RSS_EXPANDED_FINDER_PATTERNS_SUB_LEN] = {
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{1,8,4,1}, // A
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{3,6,4,1}, // B
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{3,4,6,1}, // C
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{3,2,8,1}, // D
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{2,6,5,1}, // E
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{2,2,9,1} // F
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};
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@implementation ZXAbstractRSSReader
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- (id)init {
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if (self = [super init]) {
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_decodeFinderCounters = [[ZXIntArray alloc] initWithLength:4];
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_dataCharacterCounters = [[ZXIntArray alloc] initWithLength:8];
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_oddRoundingErrorsLen = 4;
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_oddRoundingErrors = (float *)malloc(_oddRoundingErrorsLen * sizeof(float));
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memset(_oddRoundingErrors, 0, _oddRoundingErrorsLen * sizeof(float));
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_evenRoundingErrorsLen = 4;
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_evenRoundingErrors = (float *)malloc(_evenRoundingErrorsLen * sizeof(float));
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memset(_evenRoundingErrors, 0, _evenRoundingErrorsLen * sizeof(float));
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_oddCounts = [[ZXIntArray alloc] initWithLength:_dataCharacterCounters.length / 2];
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_evenCounts = [[ZXIntArray alloc] initWithLength:_dataCharacterCounters.length / 2];
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}
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return self;
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}
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- (void)dealloc {
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if (_oddRoundingErrors != NULL) {
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free(_oddRoundingErrors);
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_oddRoundingErrors = NULL;
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}
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if (_evenRoundingErrors != NULL) {
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free(_evenRoundingErrors);
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_evenRoundingErrors = NULL;
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}
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}
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+ (int)parseFinderValue:(ZXIntArray *)counters finderPatternType:(ZX_RSS_PATTERNS)finderPatternType {
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switch (finderPatternType) {
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case ZX_RSS_PATTERNS_RSS14_PATTERNS:
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for (int value = 0; value < ZX_RSS14_FINDER_PATTERNS_LEN; value++) {
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if ([self patternMatchVariance:counters pattern:ZX_RSS14_FINDER_PATTERNS[value] maxIndividualVariance:ZX_RSS_MAX_INDIVIDUAL_VARIANCE] < ZX_RSS_MAX_AVG_VARIANCE) {
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return value;
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}
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}
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break;
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case ZX_RSS_PATTERNS_RSS_EXPANDED_PATTERNS:
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for (int value = 0; value < ZX_RSS_EXPANDED_FINDER_PATTERNS_LEN; value++) {
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if ([self patternMatchVariance:counters pattern:ZX_RSS_EXPANDED_FINDER_PATTERNS[value] maxIndividualVariance:ZX_RSS_MAX_INDIVIDUAL_VARIANCE] < ZX_RSS_MAX_AVG_VARIANCE) {
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return value;
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}
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}
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break;
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default:
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break;
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}
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return -1;
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}
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+ (int)count:(ZXIntArray *)array {
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return [array sum];
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}
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+ (void)increment:(ZXIntArray *)array errors:(float *)errors {
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int index = 0;
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float biggestError = errors[0];
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for (int i = 1; i < array.length; i++) {
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if (errors[i] > biggestError) {
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biggestError = errors[i];
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index = i;
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}
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}
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array.array[index]++;
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}
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+ (void)decrement:(ZXIntArray *)array errors:(float *)errors {
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int index = 0;
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float biggestError = errors[0];
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for (int i = 1; i < array.length; i++) {
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if (errors[i] < biggestError) {
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biggestError = errors[i];
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index = i;
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}
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}
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array.array[index]--;
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}
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+ (BOOL)isFinderPattern:(ZXIntArray *)counters {
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int32_t *array = counters.array;
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int firstTwoSum = array[0] + array[1];
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int sum = firstTwoSum + array[2] + array[3];
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float ratio = (float)firstTwoSum / (float)sum;
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if (ratio >= ZX_RSS_MIN_FINDER_PATTERN_RATIO && ratio <= ZX_RSS_MAX_FINDER_PATTERN_RATIO) {
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int minCounter = INT_MAX;
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int maxCounter = INT_MIN;
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for (int i = 0; i < counters.length; i++) {
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int counter = array[i];
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if (counter > maxCounter) {
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maxCounter = counter;
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}
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if (counter < minCounter) {
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minCounter = counter;
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}
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}
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return maxCounter < 10 * minCounter;
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}
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return NO;
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}
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@end
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