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/*
 * Copyright 2004-2014 ICEsoft Technologies Canada Corp.
 *
 * 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.
 */

/*
 * 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 org.icefaces.ace.util.zxing.common;

/**
 * 

A simple, fast array of bits, represented compactly by an array of ints internally.

* * @author Sean Owen */ public final class BitArray { // I have changed these members to be public so ProGuard can inline get() and set(). Ideally // they'd be private and we'd use the -allowaccessmodification flag, but Dalvik rejects the // resulting binary at runtime on Android. If we find a solution to this, these should be changed // back to private. public int[] bits; public int size; public BitArray() { this.size = 0; this.bits = new int[1]; } public BitArray(int size) { this.size = size; this.bits = makeArray(size); } public int getSize() { return size; } public int getSizeInBytes() { return (size + 7) >> 3; } private void ensureCapacity(int size) { if (size > bits.length << 5) { int[] newBits = makeArray(size); System.arraycopy(bits, 0, newBits, 0, bits.length); this.bits = newBits; } } /** * @param i bit to get * @return true iff bit i is set */ public boolean get(int i) { return (bits[i >> 5] & (1 << (i & 0x1F))) != 0; } /** * Sets bit i. * * @param i bit to set */ public void set(int i) { bits[i >> 5] |= 1 << (i & 0x1F); } /** * Flips bit i. * * @param i bit to set */ public void flip(int i) { bits[i >> 5] ^= 1 << (i & 0x1F); } /** * Sets a block of 32 bits, starting at bit i. * * @param i first bit to set * @param newBits the new value of the next 32 bits. Note again that the least-significant bit * corresponds to bit i, the next-least-significant to i+1, and so on. */ public void setBulk(int i, int newBits) { bits[i >> 5] = newBits; } /** * Clears all bits (sets to false). */ public void clear() { int max = bits.length; for (int i = 0; i < max; i++) { bits[i] = 0; } } /** * Efficient method to check if a range of bits is set, or not set. * * @param start start of range, inclusive. * @param end end of range, exclusive * @param value if true, checks that bits in range are set, otherwise checks that they are not set * @return true iff all bits are set or not set in range, according to value argument * @throws IllegalArgumentException if end is less than or equal to start */ public boolean isRange(int start, int end, boolean value) { if (end < start) { throw new IllegalArgumentException(); } if (end == start) { return true; // empty range matches } end--; // will be easier to treat this as the last actually set bit -- inclusive int firstInt = start >> 5; int lastInt = end >> 5; for (int i = firstInt; i <= lastInt; i++) { int firstBit = i > firstInt ? 0 : start & 0x1F; int lastBit = i < lastInt ? 31 : end & 0x1F; int mask; if (firstBit == 0 && lastBit == 31) { mask = -1; } else { mask = 0; for (int j = firstBit; j <= lastBit; j++) { mask |= 1 << j; } } // Return false if we're looking for 1s and the masked bits[i] isn't all 1s (that is, // equals the mask, or we're looking for 0s and the masked portion is not all 0s if ((bits[i] & mask) != (value ? mask : 0)) { return false; } } return true; } public void appendBit(boolean bit) { ensureCapacity(size + 1); if (bit) { bits[size >> 5] |= (1 << (size & 0x1F)); } size++; } /** * Appends the least-significant bits, from value, in order from most-significant to * least-significant. For example, appending 6 bits from 0x000001E will append the bits * 0, 1, 1, 1, 1, 0 in that order. */ public void appendBits(int value, int numBits) { if (numBits < 0 || numBits > 32) { throw new IllegalArgumentException("Num bits must be between 0 and 32"); } ensureCapacity(size + numBits); for (int numBitsLeft = numBits; numBitsLeft > 0; numBitsLeft--) { appendBit(((value >> (numBitsLeft - 1)) & 0x01) == 1); } } public void appendBitArray(BitArray other) { int otherSize = other.getSize(); ensureCapacity(size + otherSize); for (int i = 0; i < otherSize; i++) { appendBit(other.get(i)); } } public void xor(BitArray other) { if (bits.length != other.bits.length) { throw new IllegalArgumentException("Sizes don't match"); } for (int i = 0; i < bits.length; i++) { // The last byte could be incomplete (i.e. not have 8 bits in // it) but there is no problem since 0 XOR 0 == 0. bits[i] ^= other.bits[i]; } } /** * * @param bitOffset first bit to start writing * @param array array to write into. Bytes are written most-significant byte first. This is the opposite * of the internal representation, which is exposed by {@link #getBitArray()} * @param offset position in array to start writing * @param numBytes how many bytes to write */ public void toBytes(int bitOffset, byte[] array, int offset, int numBytes) { for (int i = 0; i < numBytes; i++) { int theByte = 0; for (int j = 0; j < 8; j++) { if (get(bitOffset)) { theByte |= 1 << (7 - j); } bitOffset++; } array[offset + i] = (byte) theByte; } } /** * @return underlying array of ints. The first element holds the first 32 bits, and the least * significant bit is bit 0. */ public int[] getBitArray() { return bits; } /** * Reverses all bits in the array. */ public void reverse() { int[] newBits = new int[bits.length]; int size = this.size; for (int i = 0; i < size; i++) { if (get(size - i - 1)) { newBits[i >> 5] |= 1 << (i & 0x1F); } } bits = newBits; } private static int[] makeArray(int size) { return new int[(size + 31) >> 5]; } public String toString() { StringBuffer result = new StringBuffer(size); for (int i = 0; i < size; i++) { if ((i & 0x07) == 0) { result.append(' '); } result.append(get(i) ? 'X' : '.'); } return result.toString(); } }




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