/*
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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 "ZXBitArray.h"
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#import "ZXDecodeHints.h"
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#import "ZXEANManufacturerOrgSupport.h"
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#import "ZXErrors.h"
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#import "ZXIntArray.h"
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#import "ZXResult.h"
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#import "ZXResultPoint.h"
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#import "ZXResultPointCallback.h"
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#import "ZXUPCEANReader.h"
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#import "ZXUPCEANExtensionSupport.h"
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static float ZX_UPC_EAN_MAX_AVG_VARIANCE = 0.48f;
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static float ZX_UPC_EAN_MAX_INDIVIDUAL_VARIANCE = 0.7f;
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/**
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* Start/end guard pattern.
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*/
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const int ZX_UPC_EAN_START_END_PATTERN_LEN = 3;
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const int ZX_UPC_EAN_START_END_PATTERN[ZX_UPC_EAN_START_END_PATTERN_LEN] = {1, 1, 1};
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/**
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* Pattern marking the middle of a UPC/EAN pattern, separating the two halves.
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*/
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const int ZX_UPC_EAN_MIDDLE_PATTERN_LEN = 5;
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const int ZX_UPC_EAN_MIDDLE_PATTERN[ZX_UPC_EAN_MIDDLE_PATTERN_LEN] = {1, 1, 1, 1, 1};
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/**
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* "Odd", or "L" patterns used to encode UPC/EAN digits.
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*/
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const int ZX_UPC_EAN_L_PATTERNS_LEN = 10;
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const int ZX_UPC_EAN_L_PATTERNS_SUB_LEN = 4;
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const int ZX_UPC_EAN_L_PATTERNS[ZX_UPC_EAN_L_PATTERNS_LEN][ZX_UPC_EAN_L_PATTERNS_SUB_LEN] = {
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{3, 2, 1, 1}, // 0
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{2, 2, 2, 1}, // 1
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{2, 1, 2, 2}, // 2
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{1, 4, 1, 1}, // 3
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{1, 1, 3, 2}, // 4
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{1, 2, 3, 1}, // 5
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{1, 1, 1, 4}, // 6
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{1, 3, 1, 2}, // 7
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{1, 2, 1, 3}, // 8
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{3, 1, 1, 2} // 9
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};
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/**
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* As above but also including the "even", or "G" patterns used to encode UPC/EAN digits.
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*/
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const int ZX_UPC_EAN_L_AND_G_PATTERNS_LEN = 20;
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const int ZX_UPC_EAN_L_AND_G_PATTERNS_SUB_LEN = 4;
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const int ZX_UPC_EAN_L_AND_G_PATTERNS[ZX_UPC_EAN_L_AND_G_PATTERNS_LEN][ZX_UPC_EAN_L_AND_G_PATTERNS_SUB_LEN] = {
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{3, 2, 1, 1}, // 0
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{2, 2, 2, 1}, // 1
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{2, 1, 2, 2}, // 2
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{1, 4, 1, 1}, // 3
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{1, 1, 3, 2}, // 4
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{1, 2, 3, 1}, // 5
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{1, 1, 1, 4}, // 6
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{1, 3, 1, 2}, // 7
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{1, 2, 1, 3}, // 8
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{3, 1, 1, 2}, // 9
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{1, 1, 2, 3}, // 10 reversed 0
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{1, 2, 2, 2}, // 11 reversed 1
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{2, 2, 1, 2}, // 12 reversed 2
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{1, 1, 4, 1}, // 13 reversed 3
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{2, 3, 1, 1}, // 14 reversed 4
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{1, 3, 2, 1}, // 15 reversed 5
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{4, 1, 1, 1}, // 16 reversed 6
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{2, 1, 3, 1}, // 17 reversed 7
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{3, 1, 2, 1}, // 18 reversed 8
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{2, 1, 1, 3} // 19 reversed 9
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};
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@interface ZXUPCEANReader ()
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@property (nonatomic, strong, readonly) NSMutableString *decodeRowNSMutableString;
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@property (nonatomic, strong, readonly) ZXUPCEANExtensionSupport *extensionReader;
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@property (nonatomic, strong, readonly) ZXEANManufacturerOrgSupport *eanManSupport;
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@end
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@implementation ZXUPCEANReader
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- (id)init {
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if (self = [super init]) {
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_decodeRowNSMutableString = [NSMutableString stringWithCapacity:20];
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_extensionReader = [[ZXUPCEANExtensionSupport alloc] init];
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_eanManSupport = [[ZXEANManufacturerOrgSupport alloc] init];
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}
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return self;
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}
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+ (NSRange)findStartGuardPattern:(ZXBitArray *)row error:(NSError **)error {
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BOOL foundStart = NO;
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NSRange startRange = NSMakeRange(NSNotFound, 0);
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int nextStart = 0;
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ZXIntArray *counters = [[ZXIntArray alloc] initWithLength:ZX_UPC_EAN_START_END_PATTERN_LEN];
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while (!foundStart) {
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[counters clear];
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startRange = [self findGuardPattern:row rowOffset:nextStart
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whiteFirst:NO
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pattern:ZX_UPC_EAN_START_END_PATTERN
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patternLen:ZX_UPC_EAN_START_END_PATTERN_LEN
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counters:counters
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error:error];
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if (startRange.location == NSNotFound) {
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return startRange;
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}
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int start = (int)startRange.location;
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nextStart = (int)NSMaxRange(startRange);
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// Make sure there is a quiet zone at least as big as the start pattern before the barcode.
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// If this check would run off the left edge of the image, do not accept this barcode,
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// as it is very likely to be a false positive.
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int quietStart = start - (nextStart - start);
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if (quietStart >= 0) {
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foundStart = [row isRange:quietStart end:start value:NO];
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}
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}
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return startRange;
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}
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- (ZXResult *)decodeRow:(int)rowNumber row:(ZXBitArray *)row hints:(ZXDecodeHints *)hints error:(NSError **)error {
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return [self decodeRow:rowNumber row:row startGuardRange:[[self class] findStartGuardPattern:row error:error] hints:hints error:error];
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}
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- (ZXResult *)decodeRow:(int)rowNumber row:(ZXBitArray *)row startGuardRange:(NSRange)startGuardRange hints:(ZXDecodeHints *)hints error:(NSError **)error {
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id<ZXResultPointCallback> resultPointCallback = hints == nil ? nil : hints.resultPointCallback;
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if (resultPointCallback != nil) {
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[resultPointCallback foundPossibleResultPoint:[[ZXResultPoint alloc] initWithX:(startGuardRange.location + NSMaxRange(startGuardRange)) / 2.0f y:rowNumber]];
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}
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NSMutableString *result = [NSMutableString string];
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int endStart = [self decodeMiddle:row startRange:startGuardRange result:result error:error];
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if (endStart == -1) {
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return nil;
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}
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if (resultPointCallback != nil) {
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[resultPointCallback foundPossibleResultPoint:[[ZXResultPoint alloc] initWithX:endStart y:rowNumber]];
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}
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NSRange endRange = [self decodeEnd:row endStart:endStart error:error];
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if (endRange.location == NSNotFound) {
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return nil;
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}
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if (resultPointCallback != nil) {
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[resultPointCallback foundPossibleResultPoint:[[ZXResultPoint alloc] initWithX:(endRange.location + NSMaxRange(endRange)) / 2.0f y:rowNumber]];
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}
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// Make sure there is a quiet zone at least as big as the end pattern after the barcode. The
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// spec might want more whitespace, but in practice this is the maximum we can count on.
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int end = (int)NSMaxRange(endRange);
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int quietEnd = end + (end - (int)endRange.location);
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if (quietEnd >= [row size] || ![row isRange:end end:quietEnd value:NO]) {
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if (error) *error = ZXNotFoundErrorInstance();
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return nil;
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}
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NSString *resultString = [result description];
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// UPC/EAN should never be less than 8 chars anyway
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if ([resultString length] < 8) {
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if (error) *error = ZXFormatErrorInstance();
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return nil;
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}
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if (![self checkChecksum:resultString error:error]) {
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if (error) *error = ZXChecksumErrorInstance();
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return nil;
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}
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float left = (float)(NSMaxRange(startGuardRange) + startGuardRange.location) / 2.0f;
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float right = (float)(NSMaxRange(endRange) + endRange.location) / 2.0f;
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ZXBarcodeFormat format = [self barcodeFormat];
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ZXResult *decodeResult = [ZXResult resultWithText:resultString
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rawBytes:nil
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resultPoints:@[[[ZXResultPoint alloc] initWithX:left y:(float)rowNumber], [[ZXResultPoint alloc] initWithX:right y:(float)rowNumber]]
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format:format];
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int extensionLength = 0;
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ZXResult *extensionResult = [self.extensionReader decodeRow:rowNumber row:row rowOffset:(int)NSMaxRange(endRange) error:error];
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if (extensionResult) {
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[decodeResult putMetadata:kResultMetadataTypeUPCEANExtension value:extensionResult.text];
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[decodeResult putAllMetadata:[extensionResult resultMetadata]];
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[decodeResult addResultPoints:[extensionResult resultPoints]];
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extensionLength = (int)[extensionResult.text length];
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}
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ZXIntArray *allowedExtensions = hints == nil ? nil : hints.allowedEANExtensions;
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if (allowedExtensions != nil) {
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BOOL valid = NO;
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for (int i = 0; i < allowedExtensions.length; i++) {
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if (extensionLength == allowedExtensions.array[i]) {
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valid = YES;
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break;
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}
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}
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if (!valid) {
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if (error) *error = ZXNotFoundErrorInstance();
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return nil;
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}
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}
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if (format == kBarcodeFormatEan13 || format == kBarcodeFormatUPCA) {
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NSString *countryID = [self.eanManSupport lookupCountryIdentifier:resultString];
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if (countryID != nil) {
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[decodeResult putMetadata:kResultMetadataTypePossibleCountry value:countryID];
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}
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}
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return decodeResult;
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}
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- (BOOL)checkChecksum:(NSString *)s error:(NSError **)error {
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if ([[self class] checkStandardUPCEANChecksum:s]) {
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return YES;
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} else {
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if (error) *error = ZXFormatErrorInstance();
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return NO;
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}
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}
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+ (BOOL)checkStandardUPCEANChecksum:(NSString *)s {
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int length = (int)[s length];
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if (length == 0) {
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return NO;
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}
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int sum = 0;
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for (int i = length - 2; i >= 0; i -= 2) {
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int digit = (int)[s characterAtIndex:i] - (int)'0';
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if (digit < 0 || digit > 9) {
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return NO;
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}
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sum += digit;
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}
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sum *= 3;
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for (int i = length - 1; i >= 0; i -= 2) {
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int digit = (int)[s characterAtIndex:i] - (int)'0';
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if (digit < 0 || digit > 9) {
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return NO;
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}
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sum += digit;
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}
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return sum % 10 == 0;
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}
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- (NSRange)decodeEnd:(ZXBitArray *)row endStart:(int)endStart error:(NSError **)error {
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return [[self class] findGuardPattern:row
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rowOffset:endStart
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whiteFirst:NO
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pattern:ZX_UPC_EAN_START_END_PATTERN
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patternLen:ZX_UPC_EAN_START_END_PATTERN_LEN
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error:error];
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}
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+ (NSRange)findGuardPattern:(ZXBitArray *)row rowOffset:(int)rowOffset whiteFirst:(BOOL)whiteFirst pattern:(const int[])pattern patternLen:(int)patternLen error:(NSError **)error {
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ZXIntArray *counters = [[ZXIntArray alloc] initWithLength:patternLen];
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return [self findGuardPattern:row rowOffset:rowOffset whiteFirst:whiteFirst pattern:pattern patternLen:patternLen counters:counters error:error];
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}
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+ (NSRange)findGuardPattern:(ZXBitArray *)row rowOffset:(int)rowOffset whiteFirst:(BOOL)whiteFirst pattern:(const int[])pattern patternLen:(int)patternLen counters:(ZXIntArray *)counters error:(NSError **)error {
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int patternLength = patternLen;
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int width = row.size;
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BOOL isWhite = whiteFirst;
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rowOffset = whiteFirst ? [row nextUnset:rowOffset] : [row nextSet:rowOffset];
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int counterPosition = 0;
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int patternStart = rowOffset;
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int32_t *array = counters.array;
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for (int x = rowOffset; x < width; x++) {
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if ([row get:x] ^ isWhite) {
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array[counterPosition]++;
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} else {
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if (counterPosition == patternLength - 1) {
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if ([self patternMatchVariance:counters pattern:pattern maxIndividualVariance:ZX_UPC_EAN_MAX_INDIVIDUAL_VARIANCE] < ZX_UPC_EAN_MAX_AVG_VARIANCE) {
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return NSMakeRange(patternStart, x - patternStart);
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}
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patternStart += array[0] + array[1];
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for (int y = 2; y < patternLength; y++) {
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array[y - 2] = array[y];
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}
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array[patternLength - 2] = 0;
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array[patternLength - 1] = 0;
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counterPosition--;
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} else {
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counterPosition++;
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}
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array[counterPosition] = 1;
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isWhite = !isWhite;
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}
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}
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if (error) *error = ZXNotFoundErrorInstance();
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return NSMakeRange(NSNotFound, 0);
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}
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/**
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* Attempts to decode a single UPC/EAN-encoded digit.
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*/
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+ (int)decodeDigit:(ZXBitArray *)row counters:(ZXIntArray *)counters rowOffset:(int)rowOffset patternType:(ZX_UPC_EAN_PATTERNS)patternType error:(NSError **)error {
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if (![self recordPattern:row start:rowOffset counters:counters]) {
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if (error) *error = ZXNotFoundErrorInstance();
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return -1;
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}
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float bestVariance = ZX_UPC_EAN_MAX_AVG_VARIANCE;
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int bestMatch = -1;
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int max = 0;
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switch (patternType) {
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case ZX_UPC_EAN_PATTERNS_L_PATTERNS:
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max = ZX_UPC_EAN_L_PATTERNS_LEN;
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for (int i = 0; i < max; i++) {
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int pattern[counters.length];
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for (int j = 0; j < counters.length; j++){
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pattern[j] = ZX_UPC_EAN_L_PATTERNS[i][j];
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}
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float variance = [self patternMatchVariance:counters pattern:pattern maxIndividualVariance:ZX_UPC_EAN_MAX_INDIVIDUAL_VARIANCE];
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if (variance < bestVariance) {
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bestVariance = variance;
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bestMatch = i;
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}
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}
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break;
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case ZX_UPC_EAN_PATTERNS_L_AND_G_PATTERNS:
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max = ZX_UPC_EAN_L_AND_G_PATTERNS_LEN;
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for (int i = 0; i < max; i++) {
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int pattern[counters.length];
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for (int j = 0; j< counters.length; j++){
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pattern[j] = ZX_UPC_EAN_L_AND_G_PATTERNS[i][j];
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}
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float variance = [self patternMatchVariance:counters pattern:pattern maxIndividualVariance:ZX_UPC_EAN_MAX_INDIVIDUAL_VARIANCE];
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if (variance < bestVariance) {
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bestVariance = variance;
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bestMatch = i;
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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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if (bestMatch >= 0) {
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return bestMatch;
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} else {
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if (error) *error = ZXNotFoundErrorInstance();
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return -1;
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}
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}
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- (ZXBarcodeFormat)barcodeFormat {
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@throw [NSException exceptionWithName:NSInternalInconsistencyException
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reason:[NSString stringWithFormat:@"You must override %@ in a subclass", NSStringFromSelector(_cmd)]
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userInfo:nil];
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}
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- (int)decodeMiddle:(ZXBitArray *)row startRange:(NSRange)startRange result:(NSMutableString *)result error:(NSError **)error {
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@throw [NSException exceptionWithName:NSInternalInconsistencyException
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reason:[NSString stringWithFormat:@"You must override %@ in a subclass", NSStringFromSelector(_cmd)]
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userInfo:nil];
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}
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@end
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