/*
* 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.buffer;
import io.netty.util.CharsetUtil;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
/**
* A collection of utility methods that is related with handling {@link ByteBuf}.
*/
public final class ByteBufUtil {
private static final char[] HEXDUMP_TABLE = new char[256 * 4];
static {
final char[] DIGITS = "0123456789abcdef".toCharArray();
for (int i = 0; i < 256; i ++) {
HEXDUMP_TABLE[ i << 1 ] = DIGITS[i >>> 4 & 0x0F];
HEXDUMP_TABLE[(i << 1) + 1] = DIGITS[i & 0x0F];
}
}
/**
* Returns a <a href="http://en.wikipedia.org/wiki/Hex_dump">hex dump</a>
* of the specified buffer's readable bytes.
*/
public static String hexDump(ByteBuf buffer) {
return hexDump(buffer, buffer.readerIndex(), buffer.readableBytes());
}
/**
* Returns a <a href="http://en.wikipedia.org/wiki/Hex_dump">hex dump</a>
* of the specified buffer's sub-region.
*/
public static String hexDump(ByteBuf buffer, int fromIndex, int length) {
if (length < 0) {
throw new IllegalArgumentException("length: " + length);
}
if (length == 0) {
return "";
}
int endIndex = fromIndex + length;
char[] buf = new char[length << 1];
int srcIdx = fromIndex;
int dstIdx = 0;
for (; srcIdx < endIndex; srcIdx ++, dstIdx += 2) {
System.arraycopy(
HEXDUMP_TABLE, buffer.getUnsignedByte(srcIdx) << 1,
buf, dstIdx, 2);
}
return new String(buf);
}
/**
* Calculates the hash code of the specified buffer. This method is
* useful when implementing a new buffer type.
*/
public static int hashCode(ByteBuf buffer) {
final int aLen = buffer.readableBytes();
final int intCount = aLen >>> 2;
final int byteCount = aLen & 3;
int hashCode = 1;
int arrayIndex = buffer.readerIndex();
if (buffer.order() == ByteOrder.BIG_ENDIAN) {
for (int i = intCount; i > 0; i --) {
hashCode = 31 * hashCode + buffer.getInt(arrayIndex);
arrayIndex += 4;
}
} else {
for (int i = intCount; i > 0; i --) {
hashCode = 31 * hashCode + swapInt(buffer.getInt(arrayIndex));
arrayIndex += 4;
}
}
for (int i = byteCount; i > 0; i --) {
hashCode = 31 * hashCode + buffer.getByte(arrayIndex ++);
}
if (hashCode == 0) {
hashCode = 1;
}
return hashCode;
}
/**
* Returns {@code true} if and only if the two specified buffers are
* identical to each other as described in {@code ChannelBuffer#equals(Object)}.
* This method is useful when implementing a new buffer type.
*/
public static boolean equals(ByteBuf bufferA, ByteBuf bufferB) {
final int aLen = bufferA.readableBytes();
if (aLen != bufferB.readableBytes()) {
return false;
}
final int longCount = aLen >>> 3;
final int byteCount = aLen & 7;
int aIndex = bufferA.readerIndex();
int bIndex = bufferB.readerIndex();
if (bufferA.order() == bufferB.order()) {
for (int i = longCount; i > 0; i --) {
if (bufferA.getLong(aIndex) != bufferB.getLong(bIndex)) {
return false;
}
aIndex += 8;
bIndex += 8;
}
} else {
for (int i = longCount; i > 0; i --) {
if (bufferA.getLong(aIndex) != swapLong(bufferB.getLong(bIndex))) {
return false;
}
aIndex += 8;
bIndex += 8;
}
}
for (int i = byteCount; i > 0; i --) {
if (bufferA.getByte(aIndex) != bufferB.getByte(bIndex)) {
return false;
}
aIndex ++;
bIndex ++;
}
return true;
}
/**
* Compares the two specified buffers as described in {@link ByteBuf#compareTo(ByteBuf)}.
* This method is useful when implementing a new buffer type.
*/
public static int compare(ByteBuf bufferA, ByteBuf bufferB) {
final int aLen = bufferA.readableBytes();
final int bLen = bufferB.readableBytes();
final int minLength = Math.min(aLen, bLen);
final int uintCount = minLength >>> 2;
final int byteCount = minLength & 3;
int aIndex = bufferA.readerIndex();
int bIndex = bufferB.readerIndex();
if (bufferA.order() == bufferB.order()) {
for (int i = uintCount; i > 0; i --) {
long va = bufferA.getUnsignedInt(aIndex);
long vb = bufferB.getUnsignedInt(bIndex);
if (va > vb) {
return 1;
}
if (va < vb) {
return -1;
}
aIndex += 4;
bIndex += 4;
}
} else {
for (int i = uintCount; i > 0; i --) {
long va = bufferA.getUnsignedInt(aIndex);
long vb = swapInt(bufferB.getInt(bIndex)) & 0xFFFFFFFFL;
if (va > vb) {
return 1;
}
if (va < vb) {
return -1;
}
aIndex += 4;
bIndex += 4;
}
}
for (int i = byteCount; i > 0; i --) {
short va = bufferA.getUnsignedByte(aIndex);
short vb = bufferB.getUnsignedByte(bIndex);
if (va > vb) {
return 1;
}
if (va < vb) {
return -1;
}
aIndex ++;
bIndex ++;
}
return aLen - bLen;
}
/**
* The default implementation of {@link ByteBuf#indexOf(int, int, byte)}.
* This method is useful when implementing a new buffer type.
*/
public static int indexOf(ByteBuf buffer, int fromIndex, int toIndex, byte value) {
if (fromIndex <= toIndex) {
return firstIndexOf(buffer, fromIndex, toIndex, value);
} else {
return lastIndexOf(buffer, fromIndex, toIndex, value);
}
}
/**
* Toggles the endianness of the specified 16-bit short integer.
*/
public static short swapShort(short value) {
return Short.reverseBytes(value);
}
/**
* Toggles the endianness of the specified 24-bit medium integer.
*/
public static int swapMedium(int value) {
int swapped = value << 16 & 0xff0000 | value & 0xff00 | value >>> 16 & 0xff;
if ((swapped & 0x800000) != 0) {
swapped |= 0xff000000;
}
return swapped;
}
/**
* Toggles the endianness of the specified 32-bit integer.
*/
public static int swapInt(int value) {
return Integer.reverseBytes(value);
}
/**
* Toggles the endianness of the specified 64-bit long integer.
*/
public static long swapLong(long value) {
return Long.reverseBytes(value);
}
/**
* Read the given amount of bytes into a new {@link ByteBuf} that is allocated from the {@link ByteBufAllocator}.
*/
public static ByteBuf readBytes(ByteBufAllocator alloc, ByteBuf buffer, int length) {
boolean release = true;
ByteBuf dst = alloc.buffer(length);
try {
buffer.readBytes(dst);
release = false;
return dst;
} finally {
if (release) {
dst.release();
}
}
}
private static int firstIndexOf(ByteBuf buffer, int fromIndex, int toIndex, byte value) {
fromIndex = Math.max(fromIndex, 0);
if (fromIndex >= toIndex || buffer.capacity() == 0) {
return -1;
}
for (int i = fromIndex; i < toIndex; i ++) {
if (buffer.getByte(i) == value) {
return i;
}
}
return -1;
}
private static int lastIndexOf(ByteBuf buffer, int fromIndex, int toIndex, byte value) {
fromIndex = Math.min(fromIndex, buffer.capacity());
if (fromIndex < 0 || buffer.capacity() == 0) {
return -1;
}
for (int i = fromIndex - 1; i >= toIndex; i --) {
if (buffer.getByte(i) == value) {
return i;
}
}
return -1;
}
/**
* Encode the given {@link CharBuffer} using the given {@link Charset} into a new {@link ByteBuf} which
* is allocated via the {@link ByteBufAllocator}.
*/
public static ByteBuf encodeString(ByteBufAllocator alloc, CharBuffer src, Charset charset) {
final CharsetEncoder encoder = CharsetUtil.getEncoder(charset);
int length = (int) ((double) src.remaining() * encoder.maxBytesPerChar());
boolean release = true;
final ByteBuf dst = alloc.buffer(length);
try {
final ByteBuffer dstBuf = dst.internalNioBuffer(0, length);
final int pos = dstBuf.position();
CoderResult cr = encoder.encode(src, dstBuf, true);
if (!cr.isUnderflow()) {
cr.throwException();
}
cr = encoder.flush(dstBuf);
if (!cr.isUnderflow()) {
cr.throwException();
}
dst.writerIndex(dst.writerIndex() + (dstBuf.position() - pos));
release = false;
return dst;
} catch (CharacterCodingException x) {
throw new IllegalStateException(x);
} finally {
if (release) {
dst.release();
}
}
}
static String decodeString(ByteBuffer src, Charset charset) {
final CharsetDecoder decoder = CharsetUtil.getDecoder(charset);
final CharBuffer dst = CharBuffer.allocate(
(int) ((double) src.remaining() * decoder.maxCharsPerByte()));
try {
CoderResult cr = decoder.decode(src, dst, true);
if (!cr.isUnderflow()) {
cr.throwException();
}
cr = decoder.flush(dst);
if (!cr.isUnderflow()) {
cr.throwException();
}
} catch (CharacterCodingException x) {
throw new IllegalStateException(x);
}
return dst.flip().toString();
}
private ByteBufUtil() { }
}