/*
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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 "ZXBitMatrix.h"
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#import "ZXQRCodeDataMask.h"
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/**
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* 000: mask bits for which (x + y) mod 2 == 0
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*/
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@interface ZXDataMask000 : ZXQRCodeDataMask
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@end
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@implementation ZXDataMask000
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- (BOOL)isMasked:(int)i j:(int)j {
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return ((i + j) & 0x01) == 0;
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}
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@end
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/**
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* 001: mask bits for which x mod 2 == 0
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*/
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@interface ZXDataMask001 : ZXQRCodeDataMask
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@end
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@implementation ZXDataMask001
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- (BOOL)isMasked:(int)i j:(int)j {
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return (i & 0x01) == 0;
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}
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@end
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/**
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* 010: mask bits for which y mod 3 == 0
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*/
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@interface ZXDataMask010 : ZXQRCodeDataMask
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@end
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@implementation ZXDataMask010
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- (BOOL)isMasked:(int)i j:(int)j {
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return j % 3 == 0;
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}
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@end
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/**
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* 011: mask bits for which (x + y) mod 3 == 0
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*/
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@interface ZXDataMask011 : ZXQRCodeDataMask
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@end
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@implementation ZXDataMask011
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- (BOOL)isMasked:(int)i j:(int)j {
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return (i + j) % 3 == 0;
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}
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@end
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/**
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* 100: mask bits for which (x/2 + y/3) mod 2 == 0
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*/
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@interface ZXDataMask100 : ZXQRCodeDataMask
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@end
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@implementation ZXDataMask100
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- (BOOL)isMasked:(int)i j:(int)j {
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return (((i / 2) + (j /3)) & 0x01) == 0;
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}
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@end
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/**
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* 101: mask bits for which xy mod 2 + xy mod 3 == 0
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*/
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@interface ZXDataMask101 : ZXQRCodeDataMask
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@end
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@implementation ZXDataMask101
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- (BOOL)isMasked:(int)i j:(int)j {
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int temp = i * j;
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return (temp & 0x01) + (temp % 3) == 0;
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}
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@end
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/**
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* 110: mask bits for which (xy mod 2 + xy mod 3) mod 2 == 0
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*/
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@interface ZXDataMask110 : ZXQRCodeDataMask
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@end
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@implementation ZXDataMask110
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- (BOOL)isMasked:(int)i j:(int)j {
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int temp = i * j;
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return (((temp & 0x01) + (temp % 3)) & 0x01) == 0;
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}
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@end
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/**
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* 111: mask bits for which ((x+y)mod 2 + xy mod 3) mod 2 == 0
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*/
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@interface ZXDataMask111 : ZXQRCodeDataMask
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@end
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@implementation ZXDataMask111
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- (BOOL)isMasked:(int)i j:(int)j {
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return ((((i + j) & 0x01) + ((i * j) % 3)) & 0x01) == 0;
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}
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@end
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@implementation ZXQRCodeDataMask
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/**
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* See ISO 18004:2006 6.8.1
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*/
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static NSArray *DATA_MASKS = nil;
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/**
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* Implementations of this method reverse the data masking process applied to a QR Code and
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* make its bits ready to read.
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*/
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- (void)unmaskBitMatrix:(ZXBitMatrix *)bits dimension:(int)dimension {
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for (int i = 0; i < dimension; i++) {
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for (int j = 0; j < dimension; j++) {
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if ([self isMasked:i j:j]) {
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[bits flipX:j y:i];
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}
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}
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}
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}
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- (BOOL)isMasked:(int)i j:(int)j {
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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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+ (ZXQRCodeDataMask *)forReference:(int)reference {
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if (!DATA_MASKS) {
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DATA_MASKS = @[[[ZXDataMask000 alloc] init],
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[[ZXDataMask001 alloc] init],
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[[ZXDataMask010 alloc] init],
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[[ZXDataMask011 alloc] init],
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[[ZXDataMask100 alloc] init],
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[[ZXDataMask101 alloc] init],
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[[ZXDataMask110 alloc] init],
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[[ZXDataMask111 alloc] init]];
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}
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if (reference < 0 || reference > 7) {
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[NSException raise:NSInvalidArgumentException format:@"Invalid reference value"];
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}
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return DATA_MASKS[reference];
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}
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@end
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