/*
* SIP Communicator, the OpenSource Java VoIP and Instant Messaging client.
*
* Distributable under LGPL license.
* See terms of license at gnu.org.
*/
package net.java.sip.communicator.impl.media.transform;
/**
* When using TransformConnector, a RTP/RTCP packet is represented using
* RawPacket. RawPacket stores the buffer holding the RTP/RTCP packet, as well
* as the inner offset and length of RTP/RTCP packet data.
*
* After transformation, data is also store in RawPacket objects, either the
* original RawPacket (in place transformation), or a newly created RawPacket.
*
* Besides packet info storage, RawPacket also provides some other operations
* such as readInt() to ease the development process.
*
* @author Werner Dittmann (Werner.Dittmann@t-online.de)
* @author Bing SU (nova.su@gmail.com)
*/
public class RawPacket
{
/**
* Byte array storing the content of this Packet
*/
protected byte[] buffer;
/**
* Start offset of the packet data inside buffer.
* Usually this value would be 0. But in order to be compatible with
* RTPManager we store this info. (Not assuming the offset is always zero)
*/
protected int offset;
/**
* Length of this packet's data
*/
protected int length;
/**
* Construct a RawPacket using specified value.
*
* @param buffer Byte array holding the content of this Packet
* @param offset Start offset of packet content inside buffer
* @param length Length of the packet's data
*/
public RawPacket(byte[] buffer, int offset, int length)
{
this.buffer = buffer;
this.offset = offset;
this.length = length;
}
/**
* Get buffer containing the content of this packet
*
* @return buffer containing the content of this packet
*/
public byte[] getBuffer()
{
return this.buffer;
}
/**
* Get the length of this packet's data
*
* @return length of this packet's data
*/
public int getLength()
{
return this.length;
}
/**
* Get the start offset of this packet's data inside storing buffer
*
* @return start offset of this packet's data inside storing buffer
*/
public int getOffset()
{
return this.offset;
}
/**
* Read a integer from this packet at specified offset
*
* @param off start offset of the integer to be read
* @return the integer to be read
*/
public int readInt(int off)
{
return (this.buffer[this.offset + off + 0] << 24) |
((this.buffer[this.offset + off + 1] & 0xff) << 16) |
((this.buffer[this.offset + off + 2] & 0xff) << 8) |
(this.buffer[this.offset + off + 3] & 0xff);
}
/**
* Read a short from this packet at specified offset
*
* @param off start offset of this short
* @return short value at offset
*/
public short readShort(int off)
{
return (short) ((this.buffer[this.offset + off + 0] << 8) |
(this.buffer[this.offset + off + 1] & 0xff));
}
/**
* Read an unsigned short at specified offset as a int
*
* @param off start offset of the unsigned short
* @return the int value of the unsigned short at offset
*/
public int readUnsignedShortAsInt(int off)
{
int b1 = (0x000000FF & (this.buffer[this.offset + off + 0]));
int b2 = (0x000000FF & (this.buffer[this.offset + off + 1]));
int val = b1 << 8 | b2;
return val;
}
/**
* Read a byte from this packet at specified offset
*
* @param off start offset of the byte
* @return byte at offset
*/
public byte readByte(int off)
{
return buffer[offset + off];
}
/**
* Read an unsigned integer as long at specified offset
*
* @param off start offset of this unsigned integer
* @return unsigned integer as long at offset
*/
public long readUnsignedIntAsLong(int off)
{
int b0 = (0x000000FF & (this.buffer[this.offset + off + 0]));
int b1 = (0x000000FF & (this.buffer[this.offset + off + 1]));
int b2 = (0x000000FF & (this.buffer[this.offset + off + 2]));
int b3 = (0x000000FF & (this.buffer[this.offset + off + 3]));
return ((b0 << 24 | b1 << 16 | b2 << 8 | b3)) & 0xFFFFFFFFL;
}
/**
* Read a byte region from specified offset with specified length
*
* @param off start offset of the region to be read
* @param len length of the region to be read
* @return byte array of [offset, offset + length)
*/
public byte[] readRegion(int off, int len)
{
int startOffset = this.offset + off;
if (off < 0 || len <= 0
|| startOffset + len > this.buffer.length)
{
return null;
}
byte[] region = new byte[len];
System.arraycopy(this.buffer, startOffset, region, 0, len);
return region;
}
/**
* Read a byte region from specified offset with specified length in given buffer
*
* @param off start offset of the region to be read
* @param len length of the region to be read
* @param outBuff output buffer
*/
public void readRegionToBuff(int off, int len, byte[] outBuff)
{
int startOffset = this.offset + off;
if (off < 0 || len <= 0
|| startOffset + len > this.buffer.length)
{
return;
}
if (outBuff.length < len)
{
return;
}
System.arraycopy(this.buffer, startOffset, outBuff, 0, len);
}
/**
* Append a byte array to then end of the packet. This will change the data
* buffer of this packet.
*
* @param data byte array to append
* @param len the number of bytes to append
*/
public void append(byte[] data, int len)
{
if (data == null || len == 0)
{
return;
}
byte[] newBuffer = new byte[this.length + len];
System.arraycopy(this.buffer, this.offset, newBuffer, 0, this.length);
System.arraycopy(data, 0, newBuffer, this.length, len);
this.offset = 0;
this.length = this.length + len;
this.buffer = newBuffer;
}
/**
* Shrink the buffer of this packet by specified length
*
* @param len length to shrink
*/
public void shrink(int len)
{
if (len <= 0)
{
return;
}
this.length -= len;
if (this.length < 0)
{
this.length = 0;
}
}
}