text: /*
   * 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.
   */
  #import <UIKit/UIKit.h>
  
  @class ZXByteArray;
  
  /**
   * 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.
   *
   * This class is thread-safe but not reentrant -- unless the caller modifies the bytes array
   * it passed in, in which case all bets are off.
   */
  @interface ZXBitSource : NSObject
  
  /**
   * @return index of next bit in current byte which would be read by the next call to {@link #readBits(int)}.
   */
  @property (nonatomic, assign, readonly) int bitOffset;
  
  /**
   * @return index of next byte in input byte array which would be read by the next call to {@link #readBits(int)}.
   */
  @property (nonatomic, assign, readonly) int byteOffset;
  
  /**
   * @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.
   */
  - (id)initWithBytes:(ZXByteArray *)bytes;
  
  /**
   * @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 NSInvalidArgumentException if numBits isn't in [1,32] or more than is available
   */
  - (int)readBits:(int)numBits;
  
  /**
   * @return number of bits that can be read successfully
   */
  - (int)available;
  
  @end
  