org.objectweb.asm.ByteVector Maven / Gradle / Ivy
/***
* ASM: a very small and fast Java bytecode manipulation framework
* Copyright (c) 2000-2011 INRIA, France Telecom
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.objectweb.asm;
/**
* A dynamically extensible vector of bytes. This class is roughly equivalent to
* a DataOutputStream on top of a ByteArrayOutputStream, but is more efficient.
*
* @author Eric Bruneton
*/
public class ByteVector {
/**
* The content of this vector.
*/
byte[] data;
/**
* Actual number of bytes in this vector.
*/
int length;
/**
* Constructs a new {@link ByteVector ByteVector} with a default initial
* size.
*/
public ByteVector() {
data = new byte[64];
}
/**
* Constructs a new {@link ByteVector ByteVector} with the given initial
* size.
*
* @param initialSize
* the initial size of the byte vector to be constructed.
*/
public ByteVector(final int initialSize) {
data = new byte[initialSize];
}
/**
* Puts a byte into this byte vector. The byte vector is automatically
* enlarged if necessary.
*
* @param b
* a byte.
* @return this byte vector.
*/
public ByteVector putByte(final int b) {
int length = this.length;
if (length + 1 > data.length) {
enlarge(1);
}
data[length++] = (byte) b;
this.length = length;
return this;
}
/**
* Puts two bytes into this byte vector. The byte vector is automatically
* enlarged if necessary.
*
* @param b1
* a byte.
* @param b2
* another byte.
* @return this byte vector.
*/
ByteVector put11(final int b1, final int b2) {
int length = this.length;
if (length + 2 > data.length) {
enlarge(2);
}
byte[] data = this.data;
data[length++] = (byte) b1;
data[length++] = (byte) b2;
this.length = length;
return this;
}
/**
* Puts a short into this byte vector. The byte vector is automatically
* enlarged if necessary.
*
* @param s
* a short.
* @return this byte vector.
*/
public ByteVector putShort(final int s) {
int length = this.length;
if (length + 2 > data.length) {
enlarge(2);
}
byte[] data = this.data;
data[length++] = (byte) (s >>> 8);
data[length++] = (byte) s;
this.length = length;
return this;
}
/**
* Puts a byte and a short into this byte vector. The byte vector is
* automatically enlarged if necessary.
*
* @param b
* a byte.
* @param s
* a short.
* @return this byte vector.
*/
ByteVector put12(final int b, final int s) {
int length = this.length;
if (length + 3 > data.length) {
enlarge(3);
}
byte[] data = this.data;
data[length++] = (byte) b;
data[length++] = (byte) (s >>> 8);
data[length++] = (byte) s;
this.length = length;
return this;
}
/**
* Puts an int into this byte vector. The byte vector is automatically
* enlarged if necessary.
*
* @param i
* an int.
* @return this byte vector.
*/
public ByteVector putInt(final int i) {
int length = this.length;
if (length + 4 > data.length) {
enlarge(4);
}
byte[] data = this.data;
data[length++] = (byte) (i >>> 24);
data[length++] = (byte) (i >>> 16);
data[length++] = (byte) (i >>> 8);
data[length++] = (byte) i;
this.length = length;
return this;
}
/**
* Puts a long into this byte vector. The byte vector is automatically
* enlarged if necessary.
*
* @param l
* a long.
* @return this byte vector.
*/
public ByteVector putLong(final long l) {
int length = this.length;
if (length + 8 > data.length) {
enlarge(8);
}
byte[] data = this.data;
int i = (int) (l >>> 32);
data[length++] = (byte) (i >>> 24);
data[length++] = (byte) (i >>> 16);
data[length++] = (byte) (i >>> 8);
data[length++] = (byte) i;
i = (int) l;
data[length++] = (byte) (i >>> 24);
data[length++] = (byte) (i >>> 16);
data[length++] = (byte) (i >>> 8);
data[length++] = (byte) i;
this.length = length;
return this;
}
/**
* Puts an UTF8 string into this byte vector. The byte vector is
* automatically enlarged if necessary.
*
* @param s
* a String whose UTF8 encoded length must be less than 65536.
* @return this byte vector.
*/
public ByteVector putUTF8(final String s) {
int charLength = s.length();
if (charLength > 65535) {
throw new IllegalArgumentException();
}
int len = length;
if (len + 2 + charLength > data.length) {
enlarge(2 + charLength);
}
byte[] data = this.data;
// optimistic algorithm: instead of computing the byte length and then
// serializing the string (which requires two loops), we assume the byte
// length is equal to char length (which is the most frequent case), and
// we start serializing the string right away. During the serialization,
// if we find that this assumption is wrong, we continue with the
// general method.
data[len++] = (byte) (charLength >>> 8);
data[len++] = (byte) charLength;
for (int i = 0; i < charLength; ++i) {
char c = s.charAt(i);
if (c >= '\001' && c <= '\177') {
data[len++] = (byte) c;
} else {
int byteLength = i;
for (int j = i; j < charLength; ++j) {
c = s.charAt(j);
if (c >= '\001' && c <= '\177') {
byteLength++;
} else if (c > '\u07FF') {
byteLength += 3;
} else {
byteLength += 2;
}
}
if (byteLength > 65535) {
throw new IllegalArgumentException();
}
data[length] = (byte) (byteLength >>> 8);
data[length + 1] = (byte) byteLength;
if (length + 2 + byteLength > data.length) {
length = len;
enlarge(2 + byteLength);
data = this.data;
}
for (int j = i; j < charLength; ++j) {
c = s.charAt(j);
if (c >= '\001' && c <= '\177') {
data[len++] = (byte) c;
} else if (c > '\u07FF') {
data[len++] = (byte) (0xE0 | c >> 12 & 0xF);
data[len++] = (byte) (0x80 | c >> 6 & 0x3F);
data[len++] = (byte) (0x80 | c & 0x3F);
} else {
data[len++] = (byte) (0xC0 | c >> 6 & 0x1F);
data[len++] = (byte) (0x80 | c & 0x3F);
}
}
break;
}
}
length = len;
return this;
}
/**
* Puts an array of bytes into this byte vector. The byte vector is
* automatically enlarged if necessary.
*
* @param b
* an array of bytes. May be null to put len
* null bytes into this byte vector.
* @param off
* index of the fist byte of b that must be copied.
* @param len
* number of bytes of b that must be copied.
* @return this byte vector.
*/
public ByteVector putByteArray(final byte[] b, final int off, final int len) {
if (length + len > data.length) {
enlarge(len);
}
if (b != null) {
System.arraycopy(b, off, data, length, len);
}
length += len;
return this;
}
/**
* Enlarge this byte vector so that it can receive n more bytes.
*
* @param size
* number of additional bytes that this byte vector should be
* able to receive.
*/
private void enlarge(final int size) {
int length1 = 2 * data.length;
int length2 = length + size;
byte[] newData = new byte[length1 > length2 ? length1 : length2];
System.arraycopy(data, 0, newData, 0, length);
data = newData;
}
}
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