BitSource.h Example File

 #ifndef __BIT_SOURCE_H__
 #define __BIT_SOURCE_H__

 /*
  *  BitSource.h
  *  zxing
  *
  *  Copyright 2010 ZXing authors All rights reserved.
  *
  * 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.
  */

 #include <zxing/common/Array.h>
 #include <zxing/common/Types.h>

 namespace zxing {
 /**
  * <p>This provides an easy abstraction to read bits at a time from a sequence of bytes, where the
  * number of bits read is not often a multiple of 8.</p>
  *
  * <p>This class is not thread-safe.</p>
  *
  * @author srowen@google.com (Sean Owen)
  * @author christian.brunschen@gmail.com (Christian Brunschen)
  */
 class BitSource : public Counted {
 private:
   ArrayRef<byte> bytes_;
   int byteOffset_;
   int bitOffset_;
 public:
   /**
    * @param bytes bytes from which this will read bits. Bits will be read from the first byte first.
    * Bits are read within a byte from most-significant to least-significant bit.
    */
   BitSource(ArrayRef<byte> &bytes) :
       bytes_(bytes), byteOffset_(0), bitOffset_(0) {
   }

   int getBitOffset() {
     return bitOffset_;
   }

   int getByteOffset() {
     return byteOffset_;
   }

   /**
    * @param numBits number of bits to read
    * @return int representing the bits read. The bits will appear as the least-significant
    *         bits of the int
    * @throws IllegalArgumentException if numBits isn't in [1,32]
    */
   int readBits(int numBits);

   /**
    * @return number of bits that can be read successfully
    */
   int available();
 };

 }

 #endif // __BIT_SOURCE_H__