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package com.sun.grizzly.util;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.SelectableChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
/**
* Class contains set of useful operations commonly used in the framework
*
* @author Alexey Stashok
* @author Jean-Francois Arcand
*/
public class Utils {
/**
* Character translation tables.
*/
private static final byte[] toLower = new byte[256];
/**
* Initialize character translation and type tables.
*/
static {
for (int i = 0; i < 256; i++) {
toLower[i] = (byte)i;
}
for (int lc = 'a'; lc <= 'z'; lc++) {
int uc = lc + 'A' - 'a';
toLower[uc] = (byte)lc;
}
}
/**
* Method reads data from {@link SelectableChannel} to
* {@link ByteBuffer}. If data is not immediately available - channel
* will be reregistered on temporary {@link Selector} and wait maximum
* readTimeout milliseconds for data.
*
* @param channel {@link SelectableChannel} to read data from
* @param byteBuffer {@link ByteBuffer} to store read data to
* @param readTimeout maximum time in millis operation will wait for
* incoming data
*
* @return number of bytes were read
* @throws IOException if any error was occured during read
*/
public static int readWithTemporarySelector(SelectableChannel channel,
ByteBuffer byteBuffer, long readTimeout) throws IOException {
int count = 1;
int byteRead = 0;
int preReadInputBBPos = byteBuffer.position();
Selector readSelector = null;
SelectionKey tmpKey = null;
try {
ReadableByteChannel readableChannel = (ReadableByteChannel) channel;
while (count > 0){
count = readableChannel.read(byteBuffer);
if ( count > -1 )
byteRead += count;
else
byteRead = count;
}
if (byteRead == 0 && byteBuffer.position() == preReadInputBBPos) {
readSelector = SelectorFactory.getSelector();
if ( readSelector == null ){
return 0;
}
count = 1;
tmpKey = channel.register(readSelector, SelectionKey.OP_READ);
tmpKey.interestOps(tmpKey.interestOps() | SelectionKey.OP_READ);
int code = readSelector.select(readTimeout);
tmpKey.interestOps(
tmpKey.interestOps() & (~SelectionKey.OP_READ));
if ( code == 0 ){
return 0; // Return on the main Selector and try again.
}
while (count > 0){
count = readableChannel.read(byteBuffer);
if ( count > -1 )
byteRead += count;
else
byteRead = count;
}
} else if (byteRead == 0 && byteBuffer.position() != preReadInputBBPos) {
byteRead += (byteBuffer.position() - preReadInputBBPos);
}
} finally {
if (tmpKey != null)
tmpKey.cancel();
if ( readSelector != null) {
// Bug 6403933
SelectorFactory.selectNowAndReturnSelector(readSelector);
}
}
return byteRead;
}
/**
* Return the bytes contained between the startByte and the endByte. The ByteBuffer
* will be left in the state it was before invoking that method, meaning
* its position and limit will be the same.
*
* @param byteBuffer The bytes.
* @param startByte the first byte to look for
* @param endByte the second byte to look for
* @return The byte[] contained between startByte and endByte
*/
public static byte[] extractBytes(ByteBuffer byteBuffer,
byte startByte, byte endByte) throws IOException{
int curPosition = byteBuffer.position();
int curLimit = byteBuffer.limit();
if (byteBuffer.position() == 0){
throw new IllegalStateException("Invalid state");
}
byteBuffer.position(0);
byteBuffer.limit(curPosition);
int state =0;
int start =0;
int end = 0;
try {
byte c;
// Rule b - try to determine the context-root
while(byteBuffer.hasRemaining()) {
c = byteBuffer.get();
switch(state) {
case 0: // Search for first ' '
if (c == startByte){
state = 1;
start = byteBuffer.position();
}
break;
case 1:
if (c == endByte){
end = byteBuffer.position();
byte[] bytes = new byte[end - start];
byteBuffer.position(start);
byteBuffer.limit(end);
byteBuffer.get(bytes);
return bytes;
}
break;
default:
throw new IllegalArgumentException("Unexpected state");
}
}
throw new IllegalStateException("Unexpected state");
} finally {
byteBuffer.limit(curLimit);
byteBuffer.position(curPosition);
}
}
/**
* Specialized utility method: find a sequence of lower case bytes inside
* a ByteBuffer.
*/
public static int findBytes(ByteBuffer byteBuffer, byte[] b) {
int curPosition = byteBuffer.position();
int curLimit = byteBuffer.limit();
if (byteBuffer.position() == 0){
throw new IllegalStateException("Invalid state");
}
byteBuffer.position(0);
byteBuffer.limit(curPosition);
try {
byte first = b[0];
int start = 0;
int end = curPosition;
// Look for first char
int srcEnd = b.length;
for (int i = start; i <= (end - srcEnd); i++) {
if ((toLower[byteBuffer.get(i) & 0xff] & 0xff) != first) continue;
// found first char, now look for a match
int myPos = i+1;
for (int srcPos = 1; srcPos < srcEnd; ) {
if ((toLower[byteBuffer.get(myPos++) & 0xff] & 0xff) != b[srcPos++])
break;
if (srcPos == srcEnd) return i - start; // found it
}
}
return -1;
} finally {
byteBuffer.limit(curLimit);
byteBuffer.position(curPosition);
}
}
}