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/*
 * 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.itextpdf.text.pdf.qrcode;

/**
 * 

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

* * @author Sean Owen * @since 5.0.2 */ public final class BitArray { // TODO: 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 final int size; public BitArray(int size) { if (size < 1) { throw new IllegalArgumentException("size must be at least 1"); } this.size = size; this.bits = makeArray(size); } public int getSize() { return size; } /** * @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; } /** * @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) { int arraySize = size >> 5; if ((size & 0x1F) != 0) { arraySize++; } return new int[arraySize]; } 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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