package org.apache.lucene.store;
/**
* 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.
*/
import java.io.IOException;
import java.util.Map;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.UnicodeUtil;
/**
* Abstract base class for performing write operations of Lucene's low-level
* data types.
*/
public abstract class DataOutput {
/** Writes a single byte.
* @see IndexInput#readByte()
*/
public abstract void writeByte(byte b) throws IOException;
/** Writes an array of bytes.
* @param b the bytes to write
* @param length the number of bytes to write
* @see DataInput#readBytes(byte[],int,int)
*/
public void writeBytes(byte[] b, int length) throws IOException {
writeBytes(b, 0, length);
}
/** Writes an array of bytes.
* @param b the bytes to write
* @param offset the offset in the byte array
* @param length the number of bytes to write
* @see DataInput#readBytes(byte[],int,int)
*/
public abstract void writeBytes(byte[] b, int offset, int length) throws IOException;
/** Writes an int as four bytes.
* @see DataInput#readInt()
*/
public void writeInt(int i) throws IOException {
writeByte((byte)(i >> 24));
writeByte((byte)(i >> 16));
writeByte((byte)(i >> 8));
writeByte((byte) i);
}
/** Writes an int in a variable-length format. Writes between one and
* five bytes. Smaller values take fewer bytes. Negative numbers are not
* supported.
* @see DataInput#readVInt()
*/
public void writeVInt(int i) throws IOException {
while ((i & ~0x7F) != 0) {
writeByte((byte)((i & 0x7f) | 0x80));
i >>>= 7;
}
writeByte((byte)i);
}
/** Writes a long as eight bytes.
* @see DataInput#readLong()
*/
public void writeLong(long i) throws IOException {
writeInt((int) (i >> 32));
writeInt((int) i);
}
/** Writes an long in a variable-length format. Writes between one and five
* bytes. Smaller values take fewer bytes. Negative numbers are not
* supported.
* @see DataInput#readVLong()
*/
public void writeVLong(long i) throws IOException {
while ((i & ~0x7F) != 0) {
writeByte((byte)((i & 0x7f) | 0x80));
i >>>= 7;
}
writeByte((byte)i);
}
/** Writes a string.
* @see DataInput#readString()
*/
public void writeString(String s) throws IOException {
final BytesRef utf8Result = new BytesRef(10);
UnicodeUtil.UTF16toUTF8(s, 0, s.length(), utf8Result);
writeVInt(utf8Result.length);
writeBytes(utf8Result.bytes, 0, utf8Result.length);
}
/** Writes a sub sequence of characters from s as the old
* format (modified UTF-8 encoded bytes).
* @param s the source of the characters
* @param start the first character in the sequence
* @param length the number of characters in the sequence
* @deprecated -- please pre-convert to utf8 bytes
* instead or use {@link #writeString}
*/
@Deprecated
public void writeChars(String s, int start, int length)
throws IOException {
final int end = start + length;
for (int i = start; i < end; i++) {
final int code = s.charAt(i);
if (code >= 0x01 && code <= 0x7F)
writeByte((byte)code);
else if (((code >= 0x80) && (code <= 0x7FF)) || code == 0) {
writeByte((byte)(0xC0 | (code >> 6)));
writeByte((byte)(0x80 | (code & 0x3F)));
} else {
writeByte((byte)(0xE0 | (code >>> 12)));
writeByte((byte)(0x80 | ((code >> 6) & 0x3F)));
writeByte((byte)(0x80 | (code & 0x3F)));
}
}
}
/** Writes a sub sequence of characters from char[] as
* the old format (modified UTF-8 encoded bytes).
* @param s the source of the characters
* @param start the first character in the sequence
* @param length the number of characters in the sequence
* @deprecated -- please pre-convert to utf8 bytes instead or use {@link #writeString}
*/
@Deprecated
public void writeChars(char[] s, int start, int length)
throws IOException {
final int end = start + length;
for (int i = start; i < end; i++) {
final int code = s[i];
if (code >= 0x01 && code <= 0x7F)
writeByte((byte)code);
else if (((code >= 0x80) && (code <= 0x7FF)) || code == 0) {
writeByte((byte)(0xC0 | (code >> 6)));
writeByte((byte)(0x80 | (code & 0x3F)));
} else {
writeByte((byte)(0xE0 | (code >>> 12)));
writeByte((byte)(0x80 | ((code >> 6) & 0x3F)));
writeByte((byte)(0x80 | (code & 0x3F)));
}
}
}
private static int COPY_BUFFER_SIZE = 16384;
private byte[] copyBuffer;
/** Copy numBytes bytes from input to ourself. */
public void copyBytes(DataInput input, long numBytes) throws IOException {
assert numBytes >= 0: "numBytes=" + numBytes;
long left = numBytes;
if (copyBuffer == null)
copyBuffer = new byte[COPY_BUFFER_SIZE];
while(left > 0) {
final int toCopy;
if (left > COPY_BUFFER_SIZE)
toCopy = COPY_BUFFER_SIZE;
else
toCopy = (int) left;
input.readBytes(copyBuffer, 0, toCopy);
writeBytes(copyBuffer, 0, toCopy);
left -= toCopy;
}
}
public void writeStringStringMap(Map<String,String> map) throws IOException {
if (map == null) {
writeInt(0);
} else {
writeInt(map.size());
for(final Map.Entry<String, String> entry: map.entrySet()) {
writeString(entry.getKey());
writeString(entry.getValue());
}
}
}
}