| package com.intellij.util.containers; |
| |
| /** |
| * A single threaded resizable circular byte queue backed by an array. |
| * |
| * @author Sergey Simonchik |
| */ |
| public class ByteArrayQueue { |
| |
| private byte[] myArray; |
| private int mySize; |
| private int myTail; |
| private int myHead; |
| |
| public ByteArrayQueue(int initialSize) { |
| myArray = new byte[initialSize]; |
| mySize = 0; |
| myTail = 0; |
| myHead = 0; |
| } |
| |
| public void add(byte b) { |
| resizeIfNeeded(mySize + 1); |
| doAdd(b); |
| } |
| |
| public void addAll(byte[] buffer) { |
| resizeIfNeeded(mySize + buffer.length); |
| for (byte b : buffer) { |
| doAdd(b); |
| } |
| } |
| |
| private void doAdd(byte b) { |
| myArray[myTail] = b; |
| myTail++; |
| if (myTail >= myArray.length) { |
| myTail = 0; |
| } |
| mySize++; |
| } |
| |
| public int poll() { |
| if (mySize == 0) { |
| return -1; |
| } |
| byte res = myArray[myHead]; |
| myHead++; |
| if (myHead >= myArray.length) { |
| myHead = 0; |
| } |
| mySize--; |
| return res; |
| } |
| |
| public boolean isEmpty() { |
| return mySize == 0; |
| } |
| |
| public int size() { |
| return mySize; |
| } |
| |
| private void resizeIfNeeded(int newSize) { |
| int len = myArray.length; |
| if (newSize > len) { |
| byte[] newArray = new byte[Math.max(len << 1, newSize)]; |
| if (myHead < myTail) { |
| System.arraycopy(myArray, myHead, newArray, 0, myTail - myHead); |
| } |
| else { |
| System.arraycopy(myArray, myHead, newArray, 0, len - myHead); |
| System.arraycopy(myArray, 0, newArray, len - myHead, myTail); |
| } |
| myArray = newArray; |
| myHead = 0; |
| myTail = mySize; |
| } |
| } |
| |
| } |