/*
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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 "ZXErrors.h"
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#import "ZXIntArray.h"
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#import "ZXUPCEReader.h"
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// For an UPC-E barcode, the final digit is represented by the parities used
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// to encode the middle six digits, according to the table below.
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//
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// Parity of next 6 digits
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// Digit 0 1 2 3 4 5
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// 0 Even Even Even Odd Odd Odd
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// 1 Even Even Odd Even Odd Odd
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// 2 Even Even Odd Odd Even Odd
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// 3 Even Even Odd Odd Odd Even
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// 4 Even Odd Even Even Odd Odd
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// 5 Even Odd Odd Even Even Odd
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// 6 Even Odd Odd Odd Even Even
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// 7 Even Odd Even Odd Even Odd
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// 8 Even Odd Even Odd Odd Even
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// 9 Even Odd Odd Even Odd Even
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//
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// The encoding is represented by the following array, which is a bit pattern
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// using Odd = 0 and Even = 1. For example, 5 is represented by:
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//
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// Odd Even Even Odd Odd Even
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// in binary:
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// 0 1 1 0 0 1 == 0x19
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//
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const int CHECK_DIGIT_ENCODINGS[] = {
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0x38, 0x34, 0x32, 0x31, 0x2C, 0x26, 0x23, 0x2A, 0x29, 0x25
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};
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const int ZX_UPCE_MIDDLE_END_PATTERN_LEN = 6;
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/**
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* The pattern that marks the middle, and end, of a UPC-E pattern.
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* There is no "second half" to a UPC-E barcode.
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*/
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const int ZX_UPCE_MIDDLE_END_PATTERN[] = {1, 1, 1, 1, 1, 1};
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/**
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* See ZX_UCPE_L_AND_G_PATTERNS; these values similarly represent patterns of
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* even-odd parity encodings of digits that imply both the number system (0 or 1)
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* used, and the check digit.
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*/
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const int ZX_UCPE_NUMSYS_AND_CHECK_DIGIT_PATTERNS[][10] = {
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{0x38, 0x34, 0x32, 0x31, 0x2C, 0x26, 0x23, 0x2A, 0x29, 0x25},
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{0x07, 0x0B, 0x0D, 0x0E, 0x13, 0x19, 0x1C, 0x15, 0x16, 0x1A}
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};
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@interface ZXUPCEReader ()
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@property (nonatomic, strong, readonly) ZXIntArray *decodeMiddleCounters;
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@end
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@implementation ZXUPCEReader
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- (id)init {
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if (self = [super init]) {
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_decodeMiddleCounters = [[ZXIntArray alloc] initWithLength:4];
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}
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return self;
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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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ZXIntArray *counters = self.decodeMiddleCounters;
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[counters clear];
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int end = [row size];
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int rowOffset = (int)NSMaxRange(startRange);
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int lgPatternFound = 0;
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for (int x = 0; x < 6 && rowOffset < end; x++) {
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int bestMatch = [ZXUPCEANReader decodeDigit:row counters:counters rowOffset:rowOffset patternType:ZX_UPC_EAN_PATTERNS_L_AND_G_PATTERNS error:error];
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if (bestMatch == -1) {
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return -1;
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}
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[result appendFormat:@"%C", (unichar)('0' + bestMatch % 10)];
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rowOffset += [counters sum];
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if (bestMatch >= 10) {
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lgPatternFound |= 1 << (5 - x);
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}
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}
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if (![self determineNumSysAndCheckDigit:result lgPatternFound:lgPatternFound]) {
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if (error) *error = ZXNotFoundErrorInstance();
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return -1;
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}
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return rowOffset;
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}
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- (NSRange)decodeEnd:(ZXBitArray *)row endStart:(int)endStart error:(NSError **)error {
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return [ZXUPCEANReader findGuardPattern:row
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rowOffset:endStart
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whiteFirst:YES
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pattern:ZX_UPCE_MIDDLE_END_PATTERN
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patternLen:sizeof(ZX_UPCE_MIDDLE_END_PATTERN) / sizeof(int)
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error:error];
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}
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- (BOOL)checkChecksum:(NSString *)s error:(NSError **)error {
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return [super checkChecksum:[ZXUPCEReader convertUPCEtoUPCA:s] error:error];
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}
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- (BOOL)determineNumSysAndCheckDigit:(NSMutableString *)resultString lgPatternFound:(int)lgPatternFound {
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for (int numSys = 0; numSys <= 1; numSys++) {
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for (int d = 0; d < 10; d++) {
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if (lgPatternFound == ZX_UCPE_NUMSYS_AND_CHECK_DIGIT_PATTERNS[numSys][d]) {
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[resultString insertString:[NSString stringWithFormat:@"%C", (unichar)('0' + numSys)] atIndex:0];
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[resultString appendFormat:@"%C", (unichar)('0' + d)];
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return YES;
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}
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}
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}
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return NO;
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}
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- (ZXBarcodeFormat)barcodeFormat {
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return kBarcodeFormatUPCE;
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}
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/**
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* Expands a UPC-E value back into its full, equivalent UPC-A code value.
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*
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* @param upce UPC-E code as string of digits
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* @return equivalent UPC-A code as string of digits
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*/
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+ (NSString *)convertUPCEtoUPCA:(NSString *)upce {
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NSString *upceChars = [upce substringWithRange:NSMakeRange(1, 6)];
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NSMutableString *result = [NSMutableString stringWithCapacity:12];
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[result appendFormat:@"%C", [upce characterAtIndex:0]];
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unichar lastChar = [upceChars characterAtIndex:5];
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switch (lastChar) {
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case '0':
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case '1':
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case '2':
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[result appendString:[upceChars substringToIndex:2]];
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[result appendFormat:@"%C", lastChar];
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[result appendString:@"0000"];
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[result appendString:[upceChars substringWithRange:NSMakeRange(2, 3)]];
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break;
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case '3':
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[result appendString:[upceChars substringToIndex:3]];
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[result appendString:@"00000"];
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[result appendString:[upceChars substringWithRange:NSMakeRange(3, 2)]];
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break;
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case '4':
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[result appendString:[upceChars substringToIndex:4]];
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[result appendString:@"00000"];
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[result appendString:[upceChars substringWithRange:NSMakeRange(4, 1)]];
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break;
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default:
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[result appendString:[upceChars substringToIndex:5]];
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[result appendString:@"0000"];
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[result appendFormat:@"%C", lastChar];
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break;
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}
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[result appendFormat:@"%C", [upce characterAtIndex:7]];
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return result;
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}
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@end
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