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binary key-value-pair serialization format (see http://projects.unbit.it/uwsgi/wiki/uwsgiProtocol)
//========================================================================
//Copyright 2007-2010 David Yu [email protected]
//------------------------------------------------------------------------
//Licensed 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 com.dyuproject.protostuff;
import static com.dyuproject.protostuff.StringSerializer.stringSize;
import java.io.IOException;
import java.io.OutputStream;
/**
* An output for serializing kvp-encoded messages (from a byte array as source).
* A kvp encoding is a binary encoding w/c contains a key-value sequence.
* On the wire, a serialized field (key-value) would look like:
* [key-len][key][value-len][value]
*
* The keys and values are length-delimited (uint16 little endian).
*
* Note that this encoding does not support nested messages.
* This encoding is mostly useful for headers w/c contain information about
* the content it carries (see http://projects.unbit.it/uwsgi/wiki/uwsgiProtocol).
*
* @author David Yu
* @created Nov 30, 2010
*/
public final class KvpOutput extends WriteSession implements Output
{
final byte[] numBuf = new byte[2];
final boolean numeric;
private Schema schema;
public KvpOutput(LinkedBuffer head, Schema schema, boolean numeric)
{
super(head);
this.schema = schema;
this.numeric = numeric;
}
public KvpOutput(LinkedBuffer head, OutputStream out, Schema schema,
boolean numeric)
{
super(head, out);
this.schema = schema;
this.numeric = numeric;
}
public KvpOutput use(Schema schema, boolean clearBuffer)
{
this.schema = schema;
if(clearBuffer)
tail = head.clear();
return this;
}
private LinkedBuffer writeField(final int number, final LinkedBuffer lb)
throws IOException
{
if(numeric)
{
final int len = stringSize(number);
numBuf[0] = (byte)len;
numBuf[1] = (byte)((len >>> 8) & 0xFF);
return sink.writeStrFromInt(
number,
this,
sink.writeByteArray(
numBuf, 0, 2,
this,
lb));
}
return sink.writeStrUTF8FixedDelimited(
schema.getFieldName(number),
true,
this,
lb);
}
private LinkedBuffer writeField(final int number, final int valueLen,
LinkedBuffer lb) throws IOException
{
if(numeric)
{
final int len = stringSize(number);
numBuf[0] = (byte)len;
numBuf[1] = (byte)((len >>> 8) & 0xFF);
lb = sink.writeStrFromInt(
number,
this,
sink.writeByteArray(
numBuf, 0, 2,
this,
lb));
// value len prefix
numBuf[0] = (byte)valueLen;
numBuf[1] = (byte)((valueLen >>> 8) & 0xFF);
return sink.writeByteArray(numBuf, 0, 2, this, lb);
}
// value len prefix
numBuf[0] = (byte)valueLen;
numBuf[1] = (byte)((valueLen >>> 8) & 0xFF);
return sink.writeByteArray(
numBuf, 0, 2,
this,
sink.writeStrUTF8FixedDelimited(
schema.getFieldName(number),
true,
this,
lb));
}
public void writeBool(int fieldNumber, boolean value, boolean repeated) throws IOException
{
tail = sink.writeByte(
(byte)(value ? 0x31 : 0x30),
this,
writeField(
fieldNumber,
1,
tail));
}
public void writeByteArray(int fieldNumber, byte[] value, boolean repeated) throws IOException
{
tail = sink.writeByteArray(
value,
this,
writeField(
fieldNumber,
value.length,
tail));
}
public void writeByteRange(boolean utf8String, int fieldNumber, byte[] value, int offset, int length, boolean repeated) throws IOException
{
tail = sink.writeByteArray(
value, offset, length,
this,
writeField(
fieldNumber,
length,
tail));
}
public void writeBytes(int fieldNumber, ByteString value, boolean repeated) throws IOException
{
writeByteArray(fieldNumber, value.getBytes(), repeated);
}
public void writeDouble(int fieldNumber, double value, boolean repeated) throws IOException
{
// TODO optimize
final String str = Double.toString(value);
tail = sink.writeStrAscii(
str,
this,
writeField(
fieldNumber,
str.length(),
tail));
}
public void writeEnum(int fieldNumber, int value, boolean repeated) throws IOException
{
writeInt32(fieldNumber, value, repeated);
}
public void writeFixed32(int fieldNumber, int value, boolean repeated) throws IOException
{
writeInt32(fieldNumber, value, repeated);
}
public void writeFixed64(int fieldNumber, long value, boolean repeated) throws IOException
{
writeInt64(fieldNumber, value, repeated);
}
public void writeFloat(int fieldNumber, float value, boolean repeated) throws IOException
{
// TODO optimize
final String str = Float.toString(value);
tail = sink.writeStrAscii(
str,
this,
writeField(
fieldNumber,
str.length(),
tail));
}
public void writeInt32(int fieldNumber, int value, boolean repeated) throws IOException
{
final int size = (value < 0) ? stringSize(-value) + 1 : stringSize(value);
tail = sink.writeStrFromInt(
value,
this,
writeField(
fieldNumber,
size,
tail));
}
public void writeInt64(int fieldNumber, long value, boolean repeated) throws IOException
{
final int size = (value < 0) ? stringSize(-value) + 1 : stringSize(value);
tail = sink.writeStrFromLong(
value,
this,
writeField(
fieldNumber,
size,
tail));
}
public void writeObject(int fieldNumber, T value, Schema schema, boolean repeated) throws IOException
{
throw new UnsupportedOperationException();
}
public void writeSFixed32(int fieldNumber, int value, boolean repeated) throws IOException
{
writeInt32(fieldNumber, value, repeated);
}
public void writeSFixed64(int fieldNumber, long value, boolean repeated) throws IOException
{
writeInt64(fieldNumber, value, repeated);
}
public void writeSInt32(int fieldNumber, int value, boolean repeated) throws IOException
{
writeInt32(fieldNumber, value, repeated);
}
public void writeSInt64(int fieldNumber, long value, boolean repeated) throws IOException
{
writeInt64(fieldNumber, value, repeated);
}
public void writeString(int fieldNumber, String value, boolean repeated) throws IOException
{
tail = sink.writeStrUTF8FixedDelimited(
value,
true,
this,
writeField(
fieldNumber,
tail));
}
public void writeUInt32(int fieldNumber, int value, boolean repeated) throws IOException
{
writeInt32(fieldNumber, value, repeated);
}
public void writeUInt64(int fieldNumber, long value, boolean repeated) throws IOException
{
writeInt64(fieldNumber, value, repeated);
}
}