pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / store / RAMOutputStream.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/store/RAMOutputStream.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/store/RAMOutputStream.java
new file mode 100644 (file)
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--- /dev/null
+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/store/RAMOutputStream.java
@@ -0,0 +1,185 @@
+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;
+
+/**
+ * A memory-resident {@link IndexOutput} implementation.
+ *
+ * @lucene.internal
+ */
+public class RAMOutputStream extends IndexOutput {
+  static final int BUFFER_SIZE = 1024;
+
+  private RAMFile file;
+
+  private byte[] currentBuffer;
+  private int currentBufferIndex;
+  
+  private int bufferPosition;
+  private long bufferStart;
+  private int bufferLength;
+
+  /** Construct an empty output buffer. */
+  public RAMOutputStream() {
+    this(new RAMFile());
+  }
+
+  public RAMOutputStream(RAMFile f) {
+    file = f;
+
+    // make sure that we switch to the
+    // first needed buffer lazily
+    currentBufferIndex = -1;
+    currentBuffer = null;
+  }
+
+  /** Copy the current contents of this buffer to the named output. */
+  public void writeTo(IndexOutput out) throws IOException {
+    flush();
+    final long end = file.length;
+    long pos = 0;
+    int buffer = 0;
+    while (pos < end) {
+      int length = BUFFER_SIZE;
+      long nextPos = pos + length;
+      if (nextPos > end) {                        // at the last buffer
+        length = (int)(end - pos);
+      }
+      out.writeBytes(file.getBuffer(buffer++), length);
+      pos = nextPos;
+    }
+  }
+
+  /** Resets this to an empty file. */
+  public void reset() {
+    currentBuffer = null;
+    currentBufferIndex = -1;
+    bufferPosition = 0;
+    bufferStart = 0;
+    bufferLength = 0;
+    file.setLength(0);
+  }
+
+  @Override
+  public void close() throws IOException {
+    flush();
+  }
+
+  @Override
+  public void seek(long pos) throws IOException {
+    // set the file length in case we seek back
+    // and flush() has not been called yet
+    setFileLength();
+    if (pos < bufferStart || pos >= bufferStart + bufferLength) {
+      currentBufferIndex = (int) (pos / BUFFER_SIZE);
+      switchCurrentBuffer();
+    }
+
+    bufferPosition = (int) (pos % BUFFER_SIZE);
+  }
+
+  @Override
+  public long length() {
+    return file.length;
+  }
+
+  @Override
+  public void writeByte(byte b) throws IOException {
+    if (bufferPosition == bufferLength) {
+      currentBufferIndex++;
+      switchCurrentBuffer();
+    }
+    currentBuffer[bufferPosition++] = b;
+  }
+
+  @Override
+  public void writeBytes(byte[] b, int offset, int len) throws IOException {
+    assert b != null;
+    while (len > 0) {
+      if (bufferPosition ==  bufferLength) {
+        currentBufferIndex++;
+        switchCurrentBuffer();
+      }
+
+      int remainInBuffer = currentBuffer.length - bufferPosition;
+      int bytesToCopy = len < remainInBuffer ? len : remainInBuffer;
+      System.arraycopy(b, offset, currentBuffer, bufferPosition, bytesToCopy);
+      offset += bytesToCopy;
+      len -= bytesToCopy;
+      bufferPosition += bytesToCopy;
+    }
+  }
+
+  private final void switchCurrentBuffer() throws IOException {
+    if (currentBufferIndex == file.numBuffers()) {
+      currentBuffer = file.addBuffer(BUFFER_SIZE);
+    } else {
+      currentBuffer = file.getBuffer(currentBufferIndex);
+    }
+    bufferPosition = 0;
+    bufferStart = (long) BUFFER_SIZE * (long) currentBufferIndex;
+    bufferLength = currentBuffer.length;
+  }
+
+  private void setFileLength() {
+    long pointer = bufferStart + bufferPosition;
+    if (pointer > file.length) {
+      file.setLength(pointer);
+    }
+  }
+
+  @Override
+  public void flush() throws IOException {
+    file.setLastModified(System.currentTimeMillis());
+    setFileLength();
+  }
+
+  @Override
+  public long getFilePointer() {
+    return currentBufferIndex < 0 ? 0 : bufferStart + bufferPosition;
+  }
+
+  /** Returns byte usage of all buffers. */
+  public long sizeInBytes() {
+    return file.numBuffers() * BUFFER_SIZE;
+  }
+  
+  @Override
+  public void copyBytes(DataInput input, long numBytes) throws IOException {
+    assert numBytes >= 0: "numBytes=" + numBytes;
+
+    while (numBytes > 0) {
+      if (bufferPosition == bufferLength) {
+        currentBufferIndex++;
+        switchCurrentBuffer();
+      }
+
+      int toCopy = currentBuffer.length - bufferPosition;
+      if (numBytes < toCopy) {
+        toCopy = (int) numBytes;
+      }
+      input.readBytes(currentBuffer, bufferPosition, toCopy, false);
+      numBytes -= toCopy;
+      bufferPosition += toCopy;
+    }
+
+  }
+  
+}