--- /dev/null
+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.HashMap;
+import java.util.Map;
+
+/**
+ * Abstract base class for performing read operations of Lucene's low-level
+ * data types.
+ */
+public abstract class DataInput implements Cloneable {
+
+ private boolean preUTF8Strings; // true if we are reading old (modified UTF8) string format
+
+ /** Call this if readString should read characters stored
+ * in the old modified UTF8 format (length in java chars
+ * and java's modified UTF8 encoding). This is used for
+ * indices written pre-2.4 See LUCENE-510 for details. */
+ public void setModifiedUTF8StringsMode() {
+ preUTF8Strings = true;
+ }
+
+ /** Reads and returns a single byte.
+ * @see DataOutput#writeByte(byte)
+ */
+ public abstract byte readByte() throws IOException;
+
+ /** Reads a specified number of bytes into an array at the specified offset.
+ * @param b the array to read bytes into
+ * @param offset the offset in the array to start storing bytes
+ * @param len the number of bytes to read
+ * @see DataOutput#writeBytes(byte[],int)
+ */
+ public abstract void readBytes(byte[] b, int offset, int len)
+ throws IOException;
+
+ /** Reads a specified number of bytes into an array at the
+ * specified offset with control over whether the read
+ * should be buffered (callers who have their own buffer
+ * should pass in "false" for useBuffer). Currently only
+ * {@link BufferedIndexInput} respects this parameter.
+ * @param b the array to read bytes into
+ * @param offset the offset in the array to start storing bytes
+ * @param len the number of bytes to read
+ * @param useBuffer set to false if the caller will handle
+ * buffering.
+ * @see DataOutput#writeBytes(byte[],int)
+ */
+ public void readBytes(byte[] b, int offset, int len, boolean useBuffer)
+ throws IOException
+ {
+ // Default to ignoring useBuffer entirely
+ readBytes(b, offset, len);
+ }
+
+ /** Reads two bytes and returns a short.
+ * @see DataOutput#writeByte(byte)
+ */
+ public short readShort() throws IOException {
+ return (short) (((readByte() & 0xFF) << 8) | (readByte() & 0xFF));
+ }
+
+ /** Reads four bytes and returns an int.
+ * @see DataOutput#writeInt(int)
+ */
+ public int readInt() throws IOException {
+ return ((readByte() & 0xFF) << 24) | ((readByte() & 0xFF) << 16)
+ | ((readByte() & 0xFF) << 8) | (readByte() & 0xFF);
+ }
+
+ /** Reads an int stored in variable-length format. Reads between one and
+ * five bytes. Smaller values take fewer bytes. Negative numbers are not
+ * supported.
+ * @see DataOutput#writeVInt(int)
+ */
+ public int readVInt() throws IOException {
+ /* This is the original code of this method,
+ * but a Hotspot bug (see LUCENE-2975) corrupts the for-loop if
+ * readByte() is inlined. So the loop was unwinded!
+ byte b = readByte();
+ int i = b & 0x7F;
+ for (int shift = 7; (b & 0x80) != 0; shift += 7) {
+ b = readByte();
+ i |= (b & 0x7F) << shift;
+ }
+ return i;
+ */
+ byte b = readByte();
+ int i = b & 0x7F;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7F) << 7;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7F) << 14;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7F) << 21;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ assert (b & 0x80) == 0;
+ return i | ((b & 0x7F) << 28);
+ }
+
+ /** Reads eight bytes and returns a long.
+ * @see DataOutput#writeLong(long)
+ */
+ public long readLong() throws IOException {
+ return (((long)readInt()) << 32) | (readInt() & 0xFFFFFFFFL);
+ }
+
+ /** Reads a long stored in variable-length format. Reads between one and
+ * nine bytes. Smaller values take fewer bytes. Negative numbers are not
+ * supported. */
+ public long readVLong() throws IOException {
+ /* This is the original code of this method,
+ * but a Hotspot bug (see LUCENE-2975) corrupts the for-loop if
+ * readByte() is inlined. So the loop was unwinded!
+ byte b = readByte();
+ long i = b & 0x7F;
+ for (int shift = 7; (b & 0x80) != 0; shift += 7) {
+ b = readByte();
+ i |= (b & 0x7FL) << shift;
+ }
+ return i;
+ */
+ byte b = readByte();
+ long i = b & 0x7FL;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7FL) << 7;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7FL) << 14;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7FL) << 21;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7FL) << 28;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7FL) << 35;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7FL) << 42;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ i |= (b & 0x7FL) << 49;
+ if ((b & 0x80) == 0) return i;
+ b = readByte();
+ assert (b & 0x80) == 0;
+ return i | ((b & 0x7FL) << 56);
+ }
+
+ /** Reads a string.
+ * @see DataOutput#writeString(String)
+ */
+ public String readString() throws IOException {
+ if (preUTF8Strings)
+ return readModifiedUTF8String();
+ int length = readVInt();
+ final byte[] bytes = new byte[length];
+ readBytes(bytes, 0, length);
+ return new String(bytes, 0, length, "UTF-8");
+ }
+
+ private String readModifiedUTF8String() throws IOException {
+ int length = readVInt();
+ final char[] chars = new char[length];
+ readChars(chars, 0, length);
+ return new String(chars, 0, length);
+ }
+
+ /** Reads Lucene's old "modified UTF-8" encoded
+ * characters into an array.
+ * @param buffer the array to read characters into
+ * @param start the offset in the array to start storing characters
+ * @param length the number of characters to read
+ * @see DataOutput#writeChars(String,int,int)
+ * @deprecated -- please use readString or readBytes
+ * instead, and construct the string
+ * from those utf8 bytes
+ */
+ @Deprecated
+ public void readChars(char[] buffer, int start, int length)
+ throws IOException {
+ final int end = start + length;
+ for (int i = start; i < end; i++) {
+ byte b = readByte();
+ if ((b & 0x80) == 0)
+ buffer[i] = (char)(b & 0x7F);
+ else if ((b & 0xE0) != 0xE0) {
+ buffer[i] = (char)(((b & 0x1F) << 6)
+ | (readByte() & 0x3F));
+ } else {
+ buffer[i] = (char)(((b & 0x0F) << 12)
+ | ((readByte() & 0x3F) << 6)
+ | (readByte() & 0x3F));
+ }
+ }
+ }
+
+ /** Returns a clone of this stream.
+ *
+ * <p>Clones of a stream access the same data, and are positioned at the same
+ * point as the stream they were cloned from.
+ *
+ * <p>Expert: Subclasses must ensure that clones may be positioned at
+ * different points in the input from each other and from the stream they
+ * were cloned from.
+ */
+ @Override
+ public Object clone() {
+ DataInput clone = null;
+ try {
+ clone = (DataInput)super.clone();
+ } catch (CloneNotSupportedException e) {}
+
+ return clone;
+ }
+
+ public Map<String,String> readStringStringMap() throws IOException {
+ final Map<String,String> map = new HashMap<String,String>();
+ final int count = readInt();
+ for(int i=0;i<count;i++) {
+ final String key = readString();
+ final String val = readString();
+ map.put(key, val);
+ }
+
+ return map;
+ }
+}
fnp / pylucene.git / blobdiff