BitSource

src/common/BitSource.java

@@ -1,111 +0,0 @@
-/*
- * Copyright 2007 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.
- */
-
-package com.google.zxing.common;
-
-/**
- * <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 thread-safe but not reentrant -- unless the caller modifies the bytes array
- * it passed in, in which case all bets are off.</p>
- *
- * @author Sean Owen
- */
-public final class BitSource {
-
-  private final byte[] bytes;
-  private int byteOffset;
-  private int bitOffset;
-
-  /**
-   * @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.
-   */
-  public BitSource(byte[] bytes) {
-    this.bytes = bytes;
-  }
-
-  /**
-   * @return index of next bit in current byte which would be read by the next call to {@link #readBits(int)}.
-   */
-  public int getBitOffset() {
-    return bitOffset;
-  }
-
-  /**
-   * @return index of next byte in input byte array which would be read by the next call to {@link #readBits(int)}.
-   */
-  public 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] or more than is available
-   */
-  public int readBits(int numBits) {
-    if (numBits < 1 || numBits > 32 || numBits > available()) {
-      throw new IllegalArgumentException(String.valueOf(numBits));
-    }
-
-    int result = 0;
-
-    // First, read remainder from current byte
-    if (bitOffset > 0) {
-      int bitsLeft = 8 - bitOffset;
-      int toRead = Math.min(numBits, bitsLeft);
-      int bitsToNotRead = bitsLeft - toRead;
-      int mask = (0xFF >> (8 - toRead)) << bitsToNotRead;
-      result = (bytes[byteOffset] & mask) >> bitsToNotRead;
-      numBits -= toRead;
-      bitOffset += toRead;
-      if (bitOffset == 8) {
-        bitOffset = 0;
-        byteOffset++;
-      }
-    }
-
-    // Next read whole bytes
-    if (numBits > 0) {
-      while (numBits >= 8) {
-        result = (result << 8) | (bytes[byteOffset] & 0xFF);
-        byteOffset++;
-        numBits -= 8;
-      }
-
-      // Finally read a partial byte
-      if (numBits > 0) {
-        int bitsToNotRead = 8 - numBits;
-        int mask = (0xFF >> bitsToNotRead) << bitsToNotRead;
-        result = (result << numBits) | ((bytes[byteOffset] & mask) >> bitsToNotRead);
-        bitOffset += numBits;
-      }
-    }
-
-    return result;
-  }
-
-  /**
-   * @return number of bits that can be read successfully
-   */
-  public int available() {
-    return 8 * (bytes.length - byteOffset) - bitOffset;
-  }
-
-}