58 lines
1.9 KiB
Objective-C
58 lines
1.9 KiB
Objective-C
/*
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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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@class ZXByteArray;
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/**
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* This provides an easy abstraction to read bits at a time from a sequence of bytes, where the
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* number of bits read is not often a multiple of 8.
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*
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* This class is thread-safe but not reentrant -- unless the caller modifies the bytes array
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* it passed in, in which case all bets are off.
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*/
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@interface ZXBitSource : NSObject
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/**
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* @return index of next bit in current byte which would be read by the next call to {@link #readBits(int)}.
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*/
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@property (nonatomic, assign, readonly) int bitOffset;
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/**
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* @return index of next byte in input byte array which would be read by the next call to {@link #readBits(int)}.
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*/
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@property (nonatomic, assign, readonly) int byteOffset;
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/**
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* @param bytes bytes from which this will read bits. Bits will be read from the first byte first.
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* Bits are read within a byte from most-significant to least-significant bit.
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*/
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- (id)initWithBytes:(ZXByteArray *)bytes;
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/**
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* @param numBits number of bits to read
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* @return int representing the bits read. The bits will appear as the least-significant
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* bits of the int
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* @throws NSInvalidArgumentException if numBits isn't in [1,32] or more than is available
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*/
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- (int)readBits:(int)numBits;
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/**
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* @return number of bits that can be read successfully
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*/
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- (int)available;
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@end
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