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71 lines
2 KiB
C++
71 lines
2 KiB
C++
#ifndef __BIT_SOURCE_H__
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#define __BIT_SOURCE_H__
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/*
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* BitSource.h
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* zxing
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*
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* Copyright 2010 ZXing authors All rights reserved.
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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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#include <zxing/common/Array.h>
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namespace zxing {
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/**
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* <p>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.</p>
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*
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* <p>This class is not thread-safe.</p>
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*
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* @author srowen@google.com (Sean Owen)
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* @author christian.brunschen@gmail.com (Christian Brunschen)
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*/
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class BitSource : public Counted {
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typedef unsigned char byte;
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private:
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ArrayRef<byte> bytes_;
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int byteOffset_;
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int bitOffset_;
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public:
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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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BitSource(ArrayRef<byte> &bytes) :
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bytes_(bytes), byteOffset_(0), bitOffset_(0) {
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}
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int getByteOffset() {
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return byteOffset_;
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}
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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 IllegalArgumentException if numBits isn't in [1,32]
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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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};
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}
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#endif // __BIT_SOURCE_H__
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