org.apache.hadoop.io.WritableUtils Maven / Gradle / Ivy
/**
* 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.hadoop.io;
import java.io.*;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.util.ReflectionUtils;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
@InterfaceAudience.Public
@InterfaceStability.Stable
public final class WritableUtils {
public static byte[] readCompressedByteArray(DataInput in) throws IOException {
int length = in.readInt();
if (length == -1) return null;
byte[] buffer = new byte[length];
in.readFully(buffer); // could/should use readFully(buffer,0,length)?
GZIPInputStream gzi = new GZIPInputStream(new ByteArrayInputStream(buffer, 0, buffer.length));
byte[] outbuf = new byte[length];
ByteArrayOutputStream bos = new ByteArrayOutputStream();
int len;
while((len=gzi.read(outbuf, 0, outbuf.length)) != -1){
bos.write(outbuf, 0, len);
}
byte[] decompressed = bos.toByteArray();
bos.close();
gzi.close();
return decompressed;
}
public static void skipCompressedByteArray(DataInput in) throws IOException {
int length = in.readInt();
if (length != -1) {
skipFully(in, length);
}
}
public static int writeCompressedByteArray(DataOutput out,
byte[] bytes) throws IOException {
if (bytes != null) {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
GZIPOutputStream gzout = new GZIPOutputStream(bos);
try {
gzout.write(bytes, 0, bytes.length);
gzout.close();
gzout = null;
} finally {
IOUtils.closeStream(gzout);
}
byte[] buffer = bos.toByteArray();
int len = buffer.length;
out.writeInt(len);
out.write(buffer, 0, len);
/* debug only! Once we have confidence, can lose this. */
return ((bytes.length != 0) ? (100*buffer.length)/bytes.length : 0);
} else {
out.writeInt(-1);
return -1;
}
}
/* Ugly utility, maybe someone else can do this better */
public static String readCompressedString(DataInput in) throws IOException {
byte[] bytes = readCompressedByteArray(in);
if (bytes == null) return null;
return new String(bytes, "UTF-8");
}
public static int writeCompressedString(DataOutput out, String s) throws IOException {
return writeCompressedByteArray(out, (s != null) ? s.getBytes("UTF-8") : null);
}
/*
*
* Write a String as a Network Int n, followed by n Bytes
* Alternative to 16 bit read/writeUTF.
* Encoding standard is... ?
*
*/
public static void writeString(DataOutput out, String s) throws IOException {
if (s != null) {
byte[] buffer = s.getBytes("UTF-8");
int len = buffer.length;
out.writeInt(len);
out.write(buffer, 0, len);
} else {
out.writeInt(-1);
}
}
/*
* Read a String as a Network Int n, followed by n Bytes
* Alternative to 16 bit read/writeUTF.
* Encoding standard is... ?
*
*/
public static String readString(DataInput in) throws IOException{
int length = in.readInt();
if (length == -1) return null;
byte[] buffer = new byte[length];
in.readFully(buffer); // could/should use readFully(buffer,0,length)?
return new String(buffer,"UTF-8");
}
/*
* Write a String array as a Nework Int N, followed by Int N Byte Array Strings.
* Could be generalised using introspection.
*
*/
public static void writeStringArray(DataOutput out, String[] s) throws IOException{
out.writeInt(s.length);
for(int i = 0; i < s.length; i++) {
writeString(out, s[i]);
}
}
/*
* Write a String array as a Nework Int N, followed by Int N Byte Array of
* compressed Strings. Handles also null arrays and null values.
* Could be generalised using introspection.
*
*/
public static void writeCompressedStringArray(DataOutput out, String[] s) throws IOException{
if (s == null) {
out.writeInt(-1);
return;
}
out.writeInt(s.length);
for(int i = 0; i < s.length; i++) {
writeCompressedString(out, s[i]);
}
}
/*
* Write a String array as a Nework Int N, followed by Int N Byte Array Strings.
* Could be generalised using introspection. Actually this bit couldn't...
*
*/
public static String[] readStringArray(DataInput in) throws IOException {
int len = in.readInt();
if (len == -1) return null;
String[] s = new String[len];
for(int i = 0; i < len; i++) {
s[i] = readString(in);
}
return s;
}
/*
* Write a String array as a Nework Int N, followed by Int N Byte Array Strings.
* Could be generalised using introspection. Handles null arrays and null values.
*
*/
public static String[] readCompressedStringArray(DataInput in) throws IOException {
int len = in.readInt();
if (len == -1) return null;
String[] s = new String[len];
for(int i = 0; i < len; i++) {
s[i] = readCompressedString(in);
}
return s;
}
/*
*
* Test Utility Method Display Byte Array.
*
*/
public static void displayByteArray(byte[] record){
int i;
for(i=0;i < record.length -1; i++){
if (i % 16 == 0) { System.out.println(); }
System.out.print(Integer.toHexString(record[i] >> 4 & 0x0F));
System.out.print(Integer.toHexString(record[i] & 0x0F));
System.out.print(",");
}
System.out.print(Integer.toHexString(record[i] >> 4 & 0x0F));
System.out.print(Integer.toHexString(record[i] & 0x0F));
System.out.println();
}
/**
* Make a copy of a writable object using serialization to a buffer.
* @param orig The object to copy
* @return The copied object
*/
public static T clone(T orig, Configuration conf) {
try {
@SuppressWarnings("unchecked") // Unchecked cast from Class to Class
T newInst = ReflectionUtils.newInstance((Class) orig.getClass(), conf);
ReflectionUtils.copy(conf, orig, newInst);
return newInst;
} catch (IOException e) {
throw new RuntimeException("Error writing/reading clone buffer", e);
}
}
/**
* Make a copy of the writable object using serialization to a buffer
* @param dst the object to copy from
* @param src the object to copy into, which is destroyed
* @throws IOException
* @deprecated use ReflectionUtils.cloneInto instead.
*/
@Deprecated
public static void cloneInto(Writable dst, Writable src) throws IOException {
ReflectionUtils.cloneWritableInto(dst, src);
}
/**
* Serializes an integer to a binary stream with zero-compressed encoding.
* For -112 {@literal <=} i {@literal <=} 127, only one byte is used with the
* actual value.
* For other values of i, the first byte value indicates whether the
* integer is positive or negative, and the number of bytes that follow.
* If the first byte value v is between -113 and -116, the following integer
* is positive, with number of bytes that follow are -(v+112).
* If the first byte value v is between -121 and -124, the following integer
* is negative, with number of bytes that follow are -(v+120). Bytes are
* stored in the high-non-zero-byte-first order.
*
* @param stream Binary output stream
* @param i Integer to be serialized
* @throws java.io.IOException
*/
public static void writeVInt(DataOutput stream, int i) throws IOException {
writeVLong(stream, i);
}
/**
* Serializes a long to a binary stream with zero-compressed encoding.
* For -112 {@literal <=} i {@literal <=} 127, only one byte is used with the
* actual value.
* For other values of i, the first byte value indicates whether the
* long is positive or negative, and the number of bytes that follow.
* If the first byte value v is between -113 and -120, the following long
* is positive, with number of bytes that follow are -(v+112).
* If the first byte value v is between -121 and -128, the following long
* is negative, with number of bytes that follow are -(v+120). Bytes are
* stored in the high-non-zero-byte-first order.
*
* @param stream Binary output stream
* @param i Long to be serialized
* @throws java.io.IOException
*/
public static void writeVLong(DataOutput stream, long i) throws IOException {
if (i >= -112 && i <= 127) {
stream.writeByte((byte)i);
return;
}
int len = -112;
if (i < 0) {
i ^= -1L; // take one's complement'
len = -120;
}
long tmp = i;
while (tmp != 0) {
tmp = tmp >> 8;
len--;
}
stream.writeByte((byte)len);
len = (len < -120) ? -(len + 120) : -(len + 112);
for (int idx = len; idx != 0; idx--) {
int shiftbits = (idx - 1) * 8;
long mask = 0xFFL << shiftbits;
stream.writeByte((byte)((i & mask) >> shiftbits));
}
}
/**
* Reads a zero-compressed encoded long from input stream and returns it.
* @param stream Binary input stream
* @throws java.io.IOException
* @return deserialized long from stream.
*/
public static long readVLong(DataInput stream) throws IOException {
byte firstByte = stream.readByte();
int len = decodeVIntSize(firstByte);
if (len == 1) {
return firstByte;
}
long i = 0;
for (int idx = 0; idx < len-1; idx++) {
byte b = stream.readByte();
i = i << 8;
i = i | (b & 0xFF);
}
return (isNegativeVInt(firstByte) ? (i ^ -1L) : i);
}
/**
* Reads a zero-compressed encoded integer from input stream and returns it.
* @param stream Binary input stream
* @throws java.io.IOException
* @return deserialized integer from stream.
*/
public static int readVInt(DataInput stream) throws IOException {
long n = readVLong(stream);
if ((n > Integer.MAX_VALUE) || (n < Integer.MIN_VALUE)) {
throw new IOException("value too long to fit in integer");
}
return (int)n;
}
/**
* Reads an integer from the input stream and returns it.
*
* This function validates that the integer is between [lower, upper],
* inclusive.
*
* @param stream Binary input stream
* @throws java.io.IOException
* @return deserialized integer from stream
*/
public static int readVIntInRange(DataInput stream, int lower, int upper)
throws IOException {
long n = readVLong(stream);
if (n < lower) {
if (lower == 0) {
throw new IOException("expected non-negative integer, got " + n);
} else {
throw new IOException("expected integer greater than or equal to " +
lower + ", got " + n);
}
}
if (n > upper) {
throw new IOException("expected integer less or equal to " + upper +
", got " + n);
}
return (int)n;
}
/**
* Given the first byte of a vint/vlong, determine the sign
* @param value the first byte
* @return is the value negative
*/
public static boolean isNegativeVInt(byte value) {
return value < -120 || (value >= -112 && value < 0);
}
/**
* Parse the first byte of a vint/vlong to determine the number of bytes
* @param value the first byte of the vint/vlong
* @return the total number of bytes (1 to 9)
*/
public static int decodeVIntSize(byte value) {
if (value >= -112) {
return 1;
} else if (value < -120) {
return -119 - value;
}
return -111 - value;
}
/**
* Get the encoded length if an integer is stored in a variable-length format
* @return the encoded length
*/
public static int getVIntSize(long i) {
if (i >= -112 && i <= 127) {
return 1;
}
if (i < 0) {
i ^= -1L; // take one's complement'
}
// find the number of bytes with non-leading zeros
int dataBits = Long.SIZE - Long.numberOfLeadingZeros(i);
// find the number of data bytes + length byte
return (dataBits + 7) / 8 + 1;
}
/**
* Read an Enum value from DataInput, Enums are read and written
* using String values.
* @param Enum type
* @param in DataInput to read from
* @param enumType Class type of Enum
* @return Enum represented by String read from DataInput
* @throws IOException
*/
public static > T readEnum(DataInput in, Class enumType)
throws IOException{
return T.valueOf(enumType, Text.readString(in));
}
/**
* writes String value of enum to DataOutput.
* @param out Dataoutput stream
* @param enumVal enum value
* @throws IOException
*/
public static void writeEnum(DataOutput out, Enum enumVal)
throws IOException{
Text.writeString(out, enumVal.name());
}
/**
* Skip len number of bytes in input streamin
* @param in input stream
* @param len number of bytes to skip
* @throws IOException when skipped less number of bytes
*/
public static void skipFully(DataInput in, int len) throws IOException {
int total = 0;
int cur = 0;
while ((total 0)) {
total += cur;
}
if (total maxLength) {
throw new IllegalArgumentException("Encoded byte size for String was " + length +
", which is outside of 0.." +
maxLength + " range.");
}
byte [] bytes = new byte[length];
in.readFully(bytes, 0, length);
return Text.decode(bytes);
}
}
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