org.nustaq.serialization.util.FSTInputStream Maven / Gradle / Ivy
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A fast java serialization drop in-replacement and some serialization based utils such as Structs and OffHeap Memory.
/*
* Copyright 2014 Ruediger Moeller.
*
* 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 org.nustaq.serialization.util;
import java.io.IOException;
import java.io.InputStream;
/**
* Created with IntelliJ IDEA.
* User: ruedi
* Date: 27.11.12
* Time: 00:35
* To change this template use File | Settings | File Templates.
*/
public final class FSTInputStream extends InputStream {
public int chunk_size = 8000;
public static ThreadLocal cachedBuffer = new ThreadLocal();
public byte buf[];
public int pos;
public int count; // avaiable valid read bytes
InputStream in;
boolean fullyRead = false; // true if input source has been read til end
public boolean byteBacked = false;
public FSTInputStream(InputStream in) {
initFromStream(in);
}
public void resetForReuse( byte b[], int length ) {
reset();
count = length;
buf = b;
pos = 0;
byteBacked = true;
fullyRead = true;
}
public void initFromStream(InputStream in) {
fullyRead = false;
byteBacked = false;
pos = 0;
this.in = in;
if (buf == null) {
buf = cachedBuffer.get();
if (buf == null) {
buf = new byte[chunk_size];
cachedBuffer.set(buf);
}
}
readNextChunk(in);
}
public boolean isFullyRead() {
return fullyRead && pos >= count;
}
public void readNextChunk(InputStream in) {
int read;
try {
if (buf.length < count + chunk_size) {
ensureCapacity(Math.max( Math.min(Integer.MAX_VALUE-1,buf.length * 2), count + chunk_size)); // at least grab 5kb
}
read = in.read(buf, count, chunk_size);
if (read > 0) {
count += read;
} else {
fullyRead = true;
}
} catch (Exception iex) {
fullyRead = true;
}
}
public void ensureCapacity(int siz) {
if (buf.length < siz && ! fullyRead) {
byte newBuf[] = new byte[siz];
System.arraycopy(buf, 0, newBuf, 0, buf.length);
buf = newBuf;
if (siz < 10 * 1024 * 1024) { // issue 19, don't go overboard with buffer caching
cachedBuffer.set(buf);
}
}
}
public FSTInputStream(byte buf[]) {
this.buf = buf;
this.pos = 0;
this.count = buf.length;
}
public FSTInputStream(byte buf[], int offset, int length) {
this.buf = buf;
this.pos = offset;
this.count = Math.min(offset + length, buf.length);
}
public int read() {
if (pos < count) {
return (buf[pos++] & 0xff);
}
readNextChunk(in);
if (fullyRead)
return -1;
return -1;
}
public int read(byte b[], int off, int len) {
if (isFullyRead())
return -1;
while (! fullyRead && pos + len >= count) {
readNextChunk(in);
}
int avail = count - pos;
if (len > avail) {
len = avail;
}
if (len <= 0) {
return 0;
}
System.arraycopy(buf, pos, b, off, len);
pos += len;
return len;
}
public long skip(long n) {
long k = count - pos;
if (n < k) {
k = n < 0 ? 0 : n;
}
pos += k;
return k;
}
public int available() {
return count - pos;
}
public boolean markSupported() {
return false;
}
public void mark(int readAheadLimit) {
}
public void reset() {
count = 0;
pos = 0;
fullyRead = false;
byteBacked = false;
}
public void close() throws IOException {
if ( in != null )
in.close();
}
public void ensureReadAhead(int bytes) {
if ( byteBacked )
return;
int targetCount = pos + bytes;
while (!fullyRead && count < targetCount) {
readNextChunk(in);
}
}
}
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