/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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 org.apache.beam.sdk.util;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Variable-length encoding for integers.
*
* <p>Handles, in a common encoding format, signed bytes, shorts, ints, and longs.
* Takes between 1 and 10 bytes.
* Less efficient than BigEndian{Int,Long} coder for negative or large numbers.
* All negative ints are encoded using 5 bytes, longs take 10 bytes.
*/
public class VarInt {
private static long convertIntToLongNoSignExtend(int v) {
return v & 0xFFFFFFFFL;
}
/**
* Encodes the given value onto the stream.
*/
public static void encode(int v, OutputStream stream) throws IOException {
encode(convertIntToLongNoSignExtend(v), stream);
}
/**
* Encodes the given value onto the stream.
*/
public static void encode(long v, OutputStream stream) throws IOException {
do {
// Encode next 7 bits + terminator bit
long bits = v & 0x7F;
v >>>= 7;
byte b = (byte) (bits | ((v != 0) ? 0x80 : 0));
stream.write(b);
} while (v != 0);
}
/**
* Decodes an integer value from the given stream.
*/
public static int decodeInt(InputStream stream) throws IOException {
long r = decodeLong(stream);
if (r < 0 || r >= 1L << 32) {
throw new IOException("varint overflow " + r);
}
return (int) r;
}
/**
* Decodes a long value from the given stream.
*/
public static long decodeLong(InputStream stream) throws IOException {
long result = 0;
int shift = 0;
int b;
do {
// Get 7 bits from next byte
b = stream.read();
if (b < 0) {
if (shift == 0) {
throw new EOFException();
} else {
throw new IOException("varint not terminated");
}
}
long bits = b & 0x7F;
if (shift >= 64 || (shift == 63 && bits > 1)) {
// Out of range
throw new IOException("varint too long");
}
result |= bits << shift;
shift += 7;
} while ((b & 0x80) != 0);
return result;
}
/**
* Returns the length of the encoding of the given value (in bytes).
*/
public static int getLength(int v) {
return getLength(convertIntToLongNoSignExtend(v));
}
/**
* Returns the length of the encoding of the given value (in bytes).
*/
public static int getLength(long v) {
int result = 0;
do {
result++;
v >>>= 7;
} while (v != 0);
return result;
}
}