/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you 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 io.netty.handler.codec.http.websocketx;
import io.netty.buffer.
ByteBuf;
import io.netty.buffer.
Unpooled;
import io.netty.handler.codec.base64.
Base64;
import io.netty.util.
CharsetUtil;
import io.netty.util.concurrent.
FastThreadLocal;
import io.netty.util.internal.
PlatformDependent;
import java.security.
MessageDigest;
import java.security.
NoSuchAlgorithmException;
/**
* A utility class mainly for use by web sockets
*/
final class
WebSocketUtil {
private static final
FastThreadLocal<
MessageDigest>
MD5 = new
FastThreadLocal<
MessageDigest>() {
@
Override
protected
MessageDigest initialValue() throws
Exception {
try {
//Try to get a MessageDigest that uses MD5
return
MessageDigest.
getInstance("MD5");
} catch (
NoSuchAlgorithmException e) {
//This shouldn't happen! How old is the computer?
throw new
InternalError("MD5 not supported on this platform - Outdated?");
}
}
};
private static final
FastThreadLocal<
MessageDigest>
SHA1 = new
FastThreadLocal<
MessageDigest>() {
@
Override
protected
MessageDigest initialValue() throws
Exception {
try {
//Try to get a MessageDigest that uses SHA1
return
MessageDigest.
getInstance("SHA1");
} catch (
NoSuchAlgorithmException e) {
//This shouldn't happen! How old is the computer?
throw new
InternalError("SHA-1 not supported on this platform - Outdated?");
}
}
};
/**
* Performs a MD5 hash on the specified data
*
* @param data The data to hash
* @return The hashed data
*/
static byte[]
md5(byte[]
data) {
// TODO(normanmaurer): Create md5 method that not need MessageDigest.
return
digest(
MD5,
data);
}
/**
* Performs a SHA-1 hash on the specified data
*
* @param data The data to hash
* @return The hashed data
*/
static byte[]
sha1(byte[]
data) {
// TODO(normanmaurer): Create sha1 method that not need MessageDigest.
return
digest(
SHA1,
data);
}
private static byte[]
digest(
FastThreadLocal<
MessageDigest>
digestFastThreadLocal, byte[]
data) {
MessageDigest digest =
digestFastThreadLocal.
get();
digest.
reset();
return
digest.
digest(
data);
}
/**
* Performs base64 encoding on the specified data
*
* @param data The data to encode
* @return An encoded string containing the data
*/
static
String base64(byte[]
data) {
ByteBuf encodedData =
Unpooled.
wrappedBuffer(
data);
ByteBuf encoded =
Base64.
encode(
encodedData);
String encodedString =
encoded.
toString(
CharsetUtil.
UTF_8);
encoded.
release();
return
encodedString;
}
/**
* Creates an arbitrary number of random bytes
*
* @param size the number of random bytes to create
* @return An array of random bytes
*/
static byte[]
randomBytes(int
size) {
byte[]
bytes = new byte[
size];
PlatformDependent.
threadLocalRandom().
nextBytes(
bytes);
return
bytes;
}
/**
* Generates a pseudo-random number
*
* @param minimum The minimum allowable value
* @param maximum The maximum allowable value
* @return A pseudo-random number
*/
static int
randomNumber(int
minimum, int
maximum) {
assert
minimum <
maximum;
double
fraction =
PlatformDependent.
threadLocalRandom().
nextDouble();
// the idea here is that nextDouble gives us a random value
//
// 0 <= fraction <= 1
//
// the distance from min to max declared as
//
// dist = max - min
//
// satisfies the following
//
// min + dist = max
//
// taking into account
//
// 0 <= fraction * dist <= dist
//
// we've got
//
// min <= min + fraction * dist <= max
return (int) (
minimum +
fraction * (
maximum -
minimum));
}
/**
* A private constructor to ensure that instances of this class cannot be made
*/
private
WebSocketUtil() {
// Unused
}
}