/*
 * Copyright 2012 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

@class ZXBitMatrix;

/**
 * Encapsulates data masks for the data bits in a QR code, per ISO 18004:2006 6.8. Implementations
 * of this class can un-mask a raw BitMatrix. For simplicity, they will unmask the entire BitMatrix,
 * including areas used for finder patterns, timing patterns, etc. These areas should be unused
 * after the point they are unmasked anyway.
 *
 * Note that the diagram in section 6.8.1 is misleading since it indicates that i is column position
 * and j is row position. In fact, as the text says, i is row position and j is column position.
 */
@interface ZXQRCodeDataMask : NSObject

/**
 * Implementations of this method reverse the data masking process applied to a QR Code and
 * make its bits ready to read.
 *
 * @param bits representation of QR Code bits
 * @param dimension dimension of QR Code, represented by bits, being unmasked
 */
- (void)unmaskBitMatrix:(ZXBitMatrix *)bits dimension:(int)dimension;

- (BOOL)isMasked:(int)i j:(int)j;

/**
 * @param reference a value between 0 and 7 indicating one of the eight possible
 * data mask patterns a QR Code may use
 * @return DataMask encapsulating the data mask pattern
 */
+ (ZXQRCodeDataMask *)forReference:(int)reference;

@end