/*
* 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 hivemall.utils.codec;
import hivemall.utils.io.FastByteArrayInputStream;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* First 1 bit of each byte is flag to judge whether more lookahead is required or not.
*
* @link http://www.cs.otago.ac.nz/cosc463/2005/compress.htm
*/
public final class VariableByteCodec {
public VariableByteCodec() {}
public static int requiredBytes(long val) {
int i = 1;
while (val > 0x7FL) {
val >>= 7;
i++;
}
return i;
}
public static int requiredBytes(int val) {
int i = 1;
while (val > 0x7F) {
val >>= 7;
i++;
}
return i;
}
public static byte[] encodeUnsignedLong(long val) {
if (val < 0) {
throw new IllegalArgumentException("Illegal value: " + val);
}
final byte[] buf = new byte[9];
int i = 0;
while (val > 0x7FL) {
buf[i++] = (byte) ((val & 0x7F) | 0x80);
val >>= 7;
}
buf[i++] = (byte) val;
final byte[] rbuf = new byte[i];
System.arraycopy(buf, 0, rbuf, 0, i);
return rbuf;
}
public static void encodeUnsignedLong(long val, final byte[] out, int offset) {
if (val < 0) {
throw new IllegalArgumentException("Illegal value: " + val);
}
while (val > 0x7FL) {
out[offset++] = (byte) ((val & 0x7F) | 0x80);
val >>= 7;
}
out[offset++] = (byte) val;
}
public static void encodeUnsignedLong(long val, final OutputStream os) throws IOException {
if (val < 0) {
throw new IllegalArgumentException("Illegal value: " + val);
}
while (val > 0x7FL) {
final byte b = (byte) ((val & 0x7F) | 0x80);
os.write(b);
val >>= 7;
}
final byte b = (byte) val;
os.write(b);
}
public static void encodeUnsignedLong(long val, final DataOutput out) throws IOException {
if (val < 0) {
throw new IllegalArgumentException("Illegal value: " + val);
}
while (val > 0x7FL) {
final byte b = (byte) ((val & 0x7F) | 0x80);
out.write(b);
val >>= 7;
}
final byte b = (byte) val;
out.write(b);
}
public static long decodeUnsignedLong(final byte[] val) {
return decodeUnsignedLong(val, 0);
}
public static long decodeUnsignedLong(final byte[] val, final int from) {
long x = 0;
long b = 0;
int shift = 0;
final int vlen = val.length;
for (int i = from; i < vlen; i++) {
b = val[i];
final long more = b & 0x80L;
x |= (b & 0x7FL) << shift;
if (more != 0x80L) {
break;
}
shift += 7;
}
return x;
}
public static long decodeUnsignedLong(final InputStream is) throws IOException {
long x = 0;
long b = 0;
int shift = 0;
while (true) {
b = is.read();
x |= (b & 0x7FL) << shift;
final long more = b & 0x80L;
if (more != 0x80L) {
break;
}
shift += 7;
}
return x;
}
public static long decodeUnsignedLong(final DataInput in) throws IOException {
long x = 0;
long b = 0;
int shift = 0;
while (true) {
b = in.readByte();
x |= (b & 0x7FL) << shift;
final long more = b & 0x80L;
if (more != 0x80L) {
break;
}
shift += 7;
}
return x;
}
public static void encodeUnsignedInt(int val, final OutputStream os) throws IOException {
if (val < 0) {
throw new IllegalArgumentException("Illegal value: " + val);
}
while (val > 0x7F) {
final byte b = (byte) ((val & 0x7F) | 0x80);
os.write(b);
val >>= 7;
}
final byte b = (byte) val;
os.write(b);
}
public static void encodeUnsignedInt(int val, final DataOutput out) throws IOException {
if (val < 0) {
throw new IllegalArgumentException("Illegal value: " + val);
}
while (val > 0x7F) {
final byte b = (byte) ((val & 0x7F) | 0x80);
out.write(b);
val >>= 7;
}
final byte b = (byte) val;
out.write(b);
}
public static int decodeUnsignedInt(final byte[] val) {
return decodeUnsignedInt(val, 0);
}
public static int decodeUnsignedInt(final byte[] val, final int from) {
int x = 0;
int b = 0;
int shift = 0;
final int vlen = val.length;
for (int i = from; i < vlen; i++) {
b = val[i];
x |= (b & 0x7F) << shift;
if ((b & 0x80) != 0x80) {
break;
}
shift += 7;
}
return x;
}
public static int decodeUnsignedInt(final InputStream is) throws IOException {
int x = 0;
int b = 0;
int shift = 0;
while (true) {
b = is.read();
x |= (b & 0x7F) << shift;
if ((b & 0x80) != 0x80) {
break;
}
shift += 7;
}
return x;
}
public static int decodeUnsignedInt(final DataInput in) throws IOException {
int x = 0;
int b = 0;
int shift = 0;
while (true) {
b = in.readByte();
x |= (b & 0x7F) << shift;
if ((b & 0x80) != 0x80) {
break;
}
shift += 7;
}
return x;
}
public static int decodeUnsignedInt(final InputStream is, int b) throws IOException {
int x = 0;
int shift = 0;
while (true) {
x |= (b & 0x7F) << shift;
if ((b & 0x80) != 0x80) {
break;
}
shift += 7;
b = is.read();
}
return x;
}
public static int decodeUnsignedInt(final FastByteArrayInputStream is) {
int x = 0;
int b = 0;
int shift = 0;
while (true) {
b = is.read();
x |= (b & 0x7F) << shift;
if ((b & 0x80) != 0x80) {
break;
}
shift += 7;
}
return x;
}
}