/*
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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 "ZXEAN13Writer.h"
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#import "ZXUPCAWriter.h"
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@implementation ZXUPCAWriter
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- (ZXEAN13Writer *)subWriter {
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static ZXEAN13Writer *subWriter = nil;
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static dispatch_once_t onceToken;
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dispatch_once(&onceToken, ^{
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subWriter = [[ZXEAN13Writer alloc] init];
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});
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return subWriter;
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}
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- (ZXBitMatrix *)encode:(NSString *)contents format:(ZXBarcodeFormat)format width:(int)width height:(int)height error:(NSError **)error {
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return [self encode:contents format:format width:width height:height hints:nil error:error];
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}
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- (ZXBitMatrix *)encode:(NSString *)contents format:(ZXBarcodeFormat)format width:(int)width height:(int)height hints:(ZXEncodeHints *)hints error:(NSError **)error {
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if (format != kBarcodeFormatUPCA) {
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@throw [NSException exceptionWithName:NSInvalidArgumentException
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reason:[NSString stringWithFormat:@"Can only encode UPC-A, but got %d", format]
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userInfo:nil];
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}
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return [self.subWriter encode:[self preencode:contents] format:kBarcodeFormatEan13 width:width height:height hints:hints error:error];
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}
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/**
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* Transform a UPC-A code into the equivalent EAN-13 code, and add a check digit if it is not
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* already present.
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*/
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- (NSString *)preencode:(NSString *)contents {
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NSUInteger length = [contents length];
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if (length == 11) {
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int sum = 0;
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for (int i = 0; i < 11; ++i) {
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sum += ([contents characterAtIndex:i] - '0') * (i % 2 == 0 ? 3 : 1);
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}
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contents = [contents stringByAppendingFormat:@"%d", (1000 - sum) % 10];
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} else if (length != 12) {
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@throw [NSException exceptionWithName:NSInvalidArgumentException
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reason:[NSString stringWithFormat:@"Requested contents should be 11 or 12 digits long, but got %ld", (unsigned long)[contents length]]
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userInfo:nil];
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}
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return [NSString stringWithFormat:@"0%@", contents];
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}
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@end
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