423 lines
13 KiB
PHP
423 lines
13 KiB
PHP
<?php
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/**
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* Created by PhpStorm.
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* User: Ashot
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* Date: 3/25/15
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* Time: 11:51
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*/
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/*
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* Copyright 2007 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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namespace Zxing\Common;
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/**
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* <p>A simple, fast array of bits, represented compactly by an array of ints internally.</p>
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*
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* @author Sean Owen
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*/
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final class BitArray
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{
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private $bits;
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private $size;
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public function __construct($bits = [], $size = 0)
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{
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if (!$bits && !$size) {
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$this->$size = 0;
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$this->bits = [];
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} elseif ($bits && !$size) {
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$this->size = $bits;
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$this->bits = $this->makeArray($bits);
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} else {
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$this->bits = $bits;
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$this->size = $size;
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}
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}
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private static function makeArray($size)
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{
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return [];
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}
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public function getSize()
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{
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return $this->size;
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}
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public function getSizeInBytes()
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{
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return ($this->size + 7) / 8;
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}
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/**
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* Sets bit i.
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*
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* @param i bit to set
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*/
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public function set($i)
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{
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$this->bits[(int)($i / 32)] |= 1 << ($i & 0x1F);
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$this->bits[(int)($i / 32)] = ($this->bits[(int)($i / 32)]);
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}
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/**
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* Flips bit i.
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*
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* @param i bit to set
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*/
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public function flip($i)
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{
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$this->bits[(int)($i / 32)] ^= 1 << ($i & 0x1F);
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$this->bits[(int)($i / 32)] = ($this->bits[(int)($i / 32)]);
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}
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/**
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* @param from first bit to check
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*
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* @return index of first bit that is set, starting from the given index, or size if none are set
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* at or beyond this given index
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* @see #getNextUnset(int)
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*/
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public function getNextSet($from)
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{
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if ($from >= $this->size) {
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return $this->size;
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}
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$bitsOffset = (int)($from / 32);
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$currentBits = (int)$this->bits[$bitsOffset];
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// mask off lesser bits first
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$currentBits &= ~((1 << ($from & 0x1F)) - 1);
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while ($currentBits == 0) {
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if (++$bitsOffset == count($this->bits)) {
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return $this->size;
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}
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$currentBits = $this->bits[$bitsOffset];
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}
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$result = ($bitsOffset * 32) + numberOfTrailingZeros($currentBits); //numberOfTrailingZeros
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return $result > $this->size ? $this->size : $result;
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}
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/**
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* @param from index to start looking for unset bit
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*
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* @return index of next unset bit, or {@code size} if none are unset until the end
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* @see #getNextSet(int)
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*/
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public function getNextUnset($from)
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{
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if ($from >= $this->size) {
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return $this->size;
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}
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$bitsOffset = (int)($from / 32);
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$currentBits = ~$this->bits[$bitsOffset];
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// mask off lesser bits first
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$currentBits &= ~((1 << ($from & 0x1F)) - 1);
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while ($currentBits == 0) {
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if (++$bitsOffset == count($this->bits)) {
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return $this->size;
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}
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$currentBits = (~$this->bits[$bitsOffset]);
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}
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$result = ($bitsOffset * 32) + numberOfTrailingZeros($currentBits);
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return $result > $this->size ? $this->size : $result;
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}
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/**
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* Sets a block of 32 bits, starting at bit i.
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*
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* @param i first bit to set
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* @param newBits the new value of the next 32 bits. Note again that the least-significant bit
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* corresponds to bit i, the next-least-significant to i+1, and so on.
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*/
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public function setBulk($i, $newBits)
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{
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$this->bits[(int)($i / 32)] = $newBits;
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}
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/**
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* Sets a range of bits.
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*
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* @param start start of range, inclusive.
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* @param end end of range, exclusive
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*/
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public function setRange($start, $end)
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{
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if ($end < $start) {
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throw new \InvalidArgumentException();
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}
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if ($end == $start) {
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return;
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}
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$end--; // will be easier to treat this as the last actually set bit -- inclusive
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$firstInt = (int)($start / 32);
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$lastInt = (int)($end / 32);
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for ($i = $firstInt; $i <= $lastInt; $i++) {
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$firstBit = $i > $firstInt ? 0 : $start & 0x1F;
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$lastBit = $i < $lastInt ? 31 : $end & 0x1F;
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$mask = 0;
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if ($firstBit == 0 && $lastBit == 31) {
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$mask = -1;
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} else {
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$mask = 0;
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for ($j = $firstBit; $j <= $lastBit; $j++) {
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$mask |= 1 << $j;
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}
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}
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$this->bits[$i] = ($this->bits[$i] | $mask);
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}
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}
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/**
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* Clears all bits (sets to false).
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*/
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public function clear()
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{
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$max = count($this->bits);
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for ($i = 0; $i < $max; $i++) {
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$this->bits[$i] = 0;
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}
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}
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/**
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* Efficient method to check if a range of bits is set, or not set.
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*
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* @param start start of range, inclusive.
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* @param end end of range, exclusive
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* @param value if true, checks that bits in range are set, otherwise checks that they are not set
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*
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* @return true iff all bits are set or not set in range, according to value argument
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* @throws InvalidArgumentException if end is less than or equal to start
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*/
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public function isRange($start, $end, $value)
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{
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if ($end < $start) {
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throw new \InvalidArgumentException();
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}
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if ($end == $start) {
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return true; // empty range matches
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}
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$end--; // will be easier to treat this as the last actually set bit -- inclusive
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$firstInt = (int)($start / 32);
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$lastInt = (int)($end / 32);
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for ($i = $firstInt; $i <= $lastInt; $i++) {
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$firstBit = $i > $firstInt ? 0 : $start & 0x1F;
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$lastBit = $i < $lastInt ? 31 : $end & 0x1F;
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$mask = 0;
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if ($firstBit == 0 && $lastBit == 31) {
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$mask = -1;
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} else {
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$mask = 0;
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for ($j = $firstBit; $j <= $lastBit; $j++) {
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$mask = ($mask | (1 << $j));
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}
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}
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// Return false if we're looking for 1s and the masked bits[i] isn't all 1s (that is,
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// equals the mask, or we're looking for 0s and the masked portion is not all 0s
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if (($this->bits[$i] & $mask) != ($value ? $mask : 0)) {
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return false;
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}
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}
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return true;
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}
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/**
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* Appends the least-significant bits, from value, in order from most-significant to
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* least-significant. For example, appending 6 bits from 0x000001E will append the bits
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* 0, 1, 1, 1, 1, 0 in that order.
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*
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* @param value {@code int} containing bits to append
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* @param numBits bits from value to append
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*/
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public function appendBits($value, $numBits)
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{
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if ($numBits < 0 || $numBits > 32) {
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throw new \InvalidArgumentException("Num bits must be between 0 and 32");
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}
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$this->ensureCapacity($this->size + $numBits);
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for ($numBitsLeft = $numBits; $numBitsLeft > 0; $numBitsLeft--) {
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$this->appendBit((($value >> ($numBitsLeft - 1)) & 0x01) == 1);
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}
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}
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private function ensureCapacity($size)
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{
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if ($size > count($this->bits) * 32) {
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$newBits = $this->makeArray($size);
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$newBits = arraycopy($this->bits, 0, $newBits, 0, count($this->bits));
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$this->bits = $newBits;
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}
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}
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public function appendBit($bit)
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{
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$this->ensureCapacity($this->size + 1);
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if ($bit) {
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$this->bits[(int)($this->size / 32)] |= 1 << ($this->size & 0x1F);
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}
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$this->size++;
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}
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public function appendBitArray($other)
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{
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$otherSize = $other->size;
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$this->ensureCapacity($this->size + $otherSize);
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for ($i = 0; $i < $otherSize; $i++) {
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$this->appendBit($other->get($i));
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}
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}
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public function _xor($other)
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{
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if (count($this->bits) !== count($other->bits)) {
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throw new \InvalidArgumentException("Sizes don't match");
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}
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$count = count($this->bits);
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for ($i = 0; $i < $count; $i++) {
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// The last byte could be incomplete (i.e. not have 8 bits in
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// it) but there is no problem since 0 XOR 0 == 0.
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$this->bits[$i] ^= $other->bits[$i];
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}
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}
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/**
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*
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* @param bitOffset first bit to start writing
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* @param array array to write into. Bytes are written most-significant byte first. This is the opposite
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* of the internal representation, which is exposed by {@link #getBitArray()}
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* @param offset position in array to start writing
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* @param numBytes how many bytes to write
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*/
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public function toBytes($bitOffset, &$array, $offset, $numBytes)
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{
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for ($i = 0; $i < $numBytes; $i++) {
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$theByte = 0;
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for ($j = 0; $j < 8; $j++) {
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if ($this->get($bitOffset)) {
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$theByte |= 1 << (7 - $j);
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}
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$bitOffset++;
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}
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$array[(int)($offset + $i)] = $theByte;
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}
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}
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/**
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* @param $i ; bit to get
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*
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* @return true iff bit i is set
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*/
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public function get($i)
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{
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$key = (int)($i / 32);
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return ($this->bits[$key] & (1 << ($i & 0x1F))) != 0;
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}
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/**
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* @return array underlying array of ints. The first element holds the first 32 bits, and the least
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* significant bit is bit 0.
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*/
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public function getBitArray()
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{
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return $this->bits;
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}
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/**
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* Reverses all bits in the array.
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*/
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public function reverse()
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{
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$newBits = [];
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// reverse all int's first
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$len = (($this->size - 1) / 32);
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$oldBitsLen = $len + 1;
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for ($i = 0; $i < $oldBitsLen; $i++) {
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$x = $this->bits[$i];/*
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$x = (($x >> 1) & 0x55555555L) | (($x & 0x55555555L) << 1);
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$x = (($x >> 2) & 0x33333333L) | (($x & 0x33333333L) << 2);
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$x = (($x >> 4) & 0x0f0f0f0fL) | (($x & 0x0f0f0f0fL) << 4);
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$x = (($x >> 8) & 0x00ff00ffL) | (($x & 0x00ff00ffL) << 8);
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$x = (($x >> 16) & 0x0000ffffL) | (($x & 0x0000ffffL) << 16);*/
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$x = (($x >> 1) & 0x55555555) | (($x & 0x55555555) << 1);
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$x = (($x >> 2) & 0x33333333) | (($x & 0x33333333) << 2);
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$x = (($x >> 4) & 0x0f0f0f0f) | (($x & 0x0f0f0f0f) << 4);
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$x = (($x >> 8) & 0x00ff00ff) | (($x & 0x00ff00ff) << 8);
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$x = (($x >> 16) & 0x0000ffff) | (($x & 0x0000ffff) << 16);
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$newBits[(int)$len - $i] = (int)$x;
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}
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// now correct the int's if the bit size isn't a multiple of 32
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if ($this->size != $oldBitsLen * 32) {
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$leftOffset = $oldBitsLen * 32 - $this->size;
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$mask = 1;
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for ($i = 0; $i < 31 - $leftOffset; $i++) {
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$mask = ($mask << 1) | 1;
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}
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$currentInt = ($newBits[0] >> $leftOffset) & $mask;
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for ($i = 1; $i < $oldBitsLen; $i++) {
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$nextInt = $newBits[$i];
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$currentInt |= $nextInt << (32 - $leftOffset);
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$newBits[(int)($i) - 1] = $currentInt;
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$currentInt = ($nextInt >> $leftOffset) & $mask;
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}
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$newBits[(int)($oldBitsLen) - 1] = $currentInt;
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}
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// $bits = $newBits;
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}
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public function equals($o)
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{
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if (!($o instanceof BitArray)) {
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return false;
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}
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$other = $o;
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return $this->size == $other->size && $this->bits === $other->bits;
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}
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public function hashCode()
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{
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return 31 * $this->size + hashCode($this->bits);
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}
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public function toString()
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{
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$result = '';
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for ($i = 0; $i < $this->size; $i++) {
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if (($i & 0x07) == 0) {
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$result .= ' ';
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}
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$result .= ($this->get($i) ? 'X' : '.');
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}
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return (string)$result;
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}
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public function _clone()
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{
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return new BitArray($this->bits, $this->size);
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}
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}
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