mirror of
https://github.com/zxing/zxing.git
synced 2025-02-20 18:47:38 -08:00
7616c4d06d
git-svn-id: https://zxing.googlecode.com/svn/trunk@2558 59b500cc-1b3d-0410-9834-0bbf25fbcc57
382 lines
9.5 KiB
C#
Executable file
382 lines
9.5 KiB
C#
Executable file
using System;
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using System.Collections;
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using System.Text;
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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 com.google.zxing.common
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{
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/// <summary>
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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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/// </summary>
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public sealed class BitArray
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{
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private int[] bits;
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private int size;
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public BitArray()
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{
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this.size = 0;
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this.bits = new int[1];
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}
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public BitArray(int size)
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{
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this.size = size;
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this.bits = makeArray(size);
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}
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public int Size
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{
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get
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{
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return size;
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}
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}
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public int SizeInBytes
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{
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get
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{
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return (size + 7) >> 3;
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}
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}
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private void ensureCapacity(int size)
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{
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if (size > bits.Length << 5)
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{
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int[] newBits = makeArray(size);
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Array.Copy(bits, 0, newBits, 0, bits.Length);
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this.bits = newBits;
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}
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}
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/// <param name="i"> bit to get </param>
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/// <returns> true iff bit i is set </returns>
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public bool get(int i)
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{
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return (bits[i >> 5] & (1 << (i & 0x1F))) != 0;
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}
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/// <summary>
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/// Sets bit i.
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/// </summary>
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/// <param name="i"> bit to set </param>
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public void set(int i)
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{
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bits[i >> 5] |= 1 << (i & 0x1F);
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}
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/// <summary>
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/// Flips bit i.
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/// </summary>
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/// <param name="i"> bit to set </param>
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public void flip(int i)
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{
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bits[i >> 5] ^= 1 << (i & 0x1F);
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}
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/// <param name="from"> first bit to check </param>
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/// <returns> 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 </returns>
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/// <seealso cref= #getNextUnset(int) </seealso>
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public int getNextSet(int from)
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{
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if (from >= size)
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{
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return size;
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}
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int bitsOffset = from >> 5;
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int currentBits = 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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{
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if (++bitsOffset == bits.Length)
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{
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return size;
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}
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currentBits = bits[bitsOffset];
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}
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//int result = (bitsOffset << 5) + int.numberOfTrailingZeros(currentBits);
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int result = (bitsOffset << 5) + currentBits.NumberOfTrailingZeros();
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return result > size ? size : result;
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}
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/// <seealso cref= #getNextSet(int) </seealso>
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public int getNextUnset(int from)
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{
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if (from >= size)
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{
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return size;
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}
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int bitsOffset = from >> 5;
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int currentBits = ~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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{
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if (++bitsOffset == bits.Length)
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{
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return size;
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}
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currentBits = ~bits[bitsOffset];
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}
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//int result = (bitsOffset << 5) + int.numberOfTrailingZeros(currentBits);
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int result = (bitsOffset << 5) + currentBits.NumberOfTrailingZeros();
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return result > size ? size : result;
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}
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/// <summary>
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/// Sets a block of 32 bits, starting at bit i.
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/// </summary>
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/// <param name="i"> first bit to set </param>
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/// <param name="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. </param>
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public void setBulk(int i, int newBits)
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{
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bits[i >> 5] = newBits;
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}
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/// <summary>
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/// Sets a range of bits.
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/// </summary>
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/// <param name="start"> start of range, inclusive. </param>
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/// <param name="end"> end of range, exclusive </param>
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public void setRange(int start, int end)
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{
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if (end < start)
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{
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throw new System.ArgumentException();
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}
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if (end == start)
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{
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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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int firstInt = start >> 5;
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int lastInt = end >> 5;
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for (int i = firstInt; i <= lastInt; i++)
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{
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int firstBit = i > firstInt ? 0 : start & 0x1F;
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int lastBit = i < lastInt ? 31 : end & 0x1F;
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int mask;
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if (firstBit == 0 && lastBit == 31)
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{
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mask = -1;
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}
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else
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{
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mask = 0;
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for (int j = firstBit; j <= lastBit; j++)
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{
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mask |= 1 << j;
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}
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}
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bits[i] |= mask;
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}
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}
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/// <summary>
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/// Clears all bits (sets to false).
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/// </summary>
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public void clear()
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{
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int max = bits.Length;
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for (int i = 0; i < max; i++)
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{
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bits[i] = 0;
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}
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}
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/// <summary>
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/// Efficient method to check if a range of bits is set, or not set.
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/// </summary>
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/// <param name="start"> start of range, inclusive. </param>
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/// <param name="end"> end of range, exclusive </param>
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/// <param name="value"> if true, checks that bits in range are set, otherwise checks that they are not set </param>
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/// <returns> true iff all bits are set or not set in range, according to value argument </returns>
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/// <exception cref="IllegalArgumentException"> if end is less than or equal to start </exception>
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public bool isRange(int start, int end, bool value)
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{
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if (end < start)
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{
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throw new System.ArgumentException();
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}
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if (end == start)
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{
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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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int firstInt = start >> 5;
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int lastInt = end >> 5;
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for (int i = firstInt; i <= lastInt; i++)
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{
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int firstBit = i > firstInt ? 0 : start & 0x1F;
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int lastBit = i < lastInt ? 31 : end & 0x1F;
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int mask;
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if (firstBit == 0 && lastBit == 31)
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{
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mask = -1;
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}
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else
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{
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mask = 0;
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for (int j = firstBit; j <= lastBit; j++)
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{
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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 ((bits[i] & mask) != (value ? mask : 0))
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{
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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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public void appendBit(bool bit)
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{
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ensureCapacity(size + 1);
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if (bit)
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{
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bits[size >> 5] |= 1 << (size & 0x1F);
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}
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size++;
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}
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/// <summary>
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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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/// </summary>
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public void appendBits(int value, int numBits)
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{
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if (numBits < 0 || numBits > 32)
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{
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throw new System.ArgumentException("Num bits must be between 0 and 32");
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}
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ensureCapacity(size + numBits);
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for (int numBitsLeft = numBits; numBitsLeft > 0; numBitsLeft--)
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{
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appendBit(((value >> (numBitsLeft - 1)) & 0x01) == 1);
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}
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}
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public void appendBitArray(BitArray other)
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{
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int otherSize = other.size;
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ensureCapacity(size + otherSize);
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for (int i = 0; i < otherSize; i++)
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{
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appendBit(other.get(i));
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}
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}
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public void xor(BitArray other)
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{
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if (bits.Length != other.bits.Length)
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{
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throw new System.ArgumentException("Sizes don't match");
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}
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for (int i = 0; i < bits.Length; i++)
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{
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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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bits[i] ^= other.bits[i];
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}
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}
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///
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/// <param name="bitOffset"> first bit to start writing </param>
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/// <param name="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 <seealso cref="#getBitArray()"/> </param>
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/// <param name="offset"> position in array to start writing </param>
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/// <param name="numBytes"> how many bytes to write </param>
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public void toBytes(int bitOffset, sbyte[] array, int offset, int numBytes)
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{
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for (int i = 0; i < numBytes; i++)
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{
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int theByte = 0;
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for (int j = 0; j < 8; j++)
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{
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if (get(bitOffset))
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{
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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[offset + i] = (sbyte) theByte;
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}
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}
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/// <returns> underlying array of ints. The first element holds the first 32 bits, and the least
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/// significant bit is bit 0. </returns>
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public int[] BitArrayBits
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{
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get
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{
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return bits;
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}
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}
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/// <summary>
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/// Reverses all bits in the array.
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/// </summary>
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public void reverse()
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{
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int[] newBits = new int[bits.Length];
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int size = this.size;
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for (int i = 0; i < size; i++)
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{
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if (get(size - i - 1))
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{
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newBits[i >> 5] |= 1 << (i & 0x1F);
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}
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}
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bits = newBits;
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}
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private static int[] makeArray(int size)
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{
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return new int[(size + 31) >> 5];
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}
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public override string ToString()
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{
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StringBuilder result = new StringBuilder(size);
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for (int i = 0; i < size; i++)
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{
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if ((i & 0x07) == 0)
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{
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result.Append(' ');
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}
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result.Append(get(i) ? 'X' : '.');
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}
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return result.ToString();
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}
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}
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} |