/**
* Copyright (c) 2010 Yahoo! Inc. All rights reserved.
*
* 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. See accompanying
* LICENSE file.
*/
package com.yahoo.ycsb;
/**
* A ByteIterator that generates a random sequence of bytes.
*/
public class RandomByteIterator extends ByteIterator {
private long len;
private long off;
private int bufOff;
private byte[] buf;
@Override
public boolean hasNext() {
return (off + bufOff) < len;
}
private void fillBytesImpl(byte[] buffer, int base) {
int bytes = Utils.random().nextInt();
try {
buffer[base+0] = (byte)(((bytes) & 31) + ' ');
buffer[base+1] = (byte)(((bytes >> 5) & 31) + ' ');
buffer[base+2] = (byte)(((bytes >> 10) & 31) + ' ');
buffer[base+3] = (byte)(((bytes >> 15) & 31) + ' ');
buffer[base+4] = (byte)(((bytes >> 20) & 31) + ' ');
buffer[base+5] = (byte)(((bytes >> 25) & 31) + ' ');
} catch (ArrayIndexOutOfBoundsException e) { /* ignore it */ }
}
private void fillBytes() {
if(bufOff == buf.length) {
fillBytesImpl(buf, 0);
bufOff = 0;
off += buf.length;
}
}
public RandomByteIterator(long len) {
this.len = len;
this.buf = new byte[6];
this.bufOff = buf.length;
fillBytes();
this.off = 0;
}
public byte nextByte() {
fillBytes();
bufOff++;
return buf[bufOff-1];
}
@Override
public int nextBuf(byte[] buffer, int bufferOffset) {
int ret;
if(len - off < buffer.length - bufferOffset) {
ret = (int)(len - off);
} else {
ret = buffer.length - bufferOffset;
}
int i;
for(i = 0; i < ret; i+=6) {
fillBytesImpl(buffer, i + bufferOffset);
}
off+=ret;
return ret + bufferOffset;
}
@Override
public long bytesLeft() {
return len - off - bufOff;
}
}