--- /dev/null
+// FastCharStream.java
+package org.apache.lucene.queryParser.surround.parser;
+/**
+ * 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.*;
+
+/** An efficient implementation of JavaCC's CharStream interface. <p>Note that
+ * this does not do line-number counting, but instead keeps track of the
+ * character position of the token in the input, as required by Lucene's {@link
+ * org.apache.lucene.analysis.Token} API. */
+public final class FastCharStream implements CharStream {
+ char[] buffer = null;
+
+ int bufferLength = 0; // end of valid chars
+ int bufferPosition = 0; // next char to read
+
+ int tokenStart = 0; // offset in buffer
+ int bufferStart = 0; // position in file of buffer
+
+ Reader input; // source of chars
+
+ /** Constructs from a Reader. */
+ public FastCharStream(Reader r) {
+ input = r;
+ }
+
+ public final char readChar() throws IOException {
+ if (bufferPosition >= bufferLength)
+ refill();
+ return buffer[bufferPosition++];
+ }
+
+ private final void refill() throws IOException {
+ int newPosition = bufferLength - tokenStart;
+
+ if (tokenStart == 0) { // token won't fit in buffer
+ if (buffer == null) { // first time: alloc buffer
+ buffer = new char[2048];
+ } else if (bufferLength == buffer.length) { // grow buffer
+ char[] newBuffer = new char[buffer.length*2];
+ System.arraycopy(buffer, 0, newBuffer, 0, bufferLength);
+ buffer = newBuffer;
+ }
+ } else { // shift token to front
+ System.arraycopy(buffer, tokenStart, buffer, 0, newPosition);
+ }
+
+ bufferLength = newPosition; // update state
+ bufferPosition = newPosition;
+ bufferStart += tokenStart;
+ tokenStart = 0;
+
+ int charsRead = // fill space in buffer
+ input.read(buffer, newPosition, buffer.length-newPosition);
+ if (charsRead == -1)
+ throw new IOException("read past eof");
+ else
+ bufferLength += charsRead;
+ }
+
+ public final char BeginToken() throws IOException {
+ tokenStart = bufferPosition;
+ return readChar();
+ }
+
+ public final void backup(int amount) {
+ bufferPosition -= amount;
+ }
+
+ public final String GetImage() {
+ return new String(buffer, tokenStart, bufferPosition - tokenStart);
+ }
+
+ public final char[] GetSuffix(int len) {
+ char[] value = new char[len];
+ System.arraycopy(buffer, bufferPosition - len, value, 0, len);
+ return value;
+ }
+
+ public final void Done() {
+ try {
+ input.close();
+ } catch (IOException e) {
+ System.err.println("Caught: " + e + "; ignoring.");
+ }
+ }
+
+ public final int getColumn() {
+ return bufferStart + bufferPosition;
+ }
+ public final int getLine() {
+ return 1;
+ }
+ public final int getEndColumn() {
+ return bufferStart + bufferPosition;
+ }
+ public final int getEndLine() {
+ return 1;
+ }
+ public final int getBeginColumn() {
+ return bufferStart + tokenStart;
+ }
+ public final int getBeginLine() {
+ return 1;
+ }
+}