src/jdk.jfr/share/classes/jdk/jfr/internal/consumer/RecordingInput.java
changeset 50113 caf115bb98ad
child 57360 5d043a159d5c
child 58863 c16ac7a2eba4
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.jfr/share/classes/jdk/jfr/internal/consumer/RecordingInput.java	Tue May 15 20:24:34 2018 +0200
@@ -0,0 +1,339 @@
+/*
+ * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.internal.consumer;
+
+import java.io.DataInput;
+import java.io.EOFException;
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.charset.Charset;
+
+public final class RecordingInput implements DataInput, AutoCloseable {
+
+    public static final byte STRING_ENCODING_NULL = 0;
+    public static final byte STRING_ENCODING_EMPTY_STRING = 1;
+    public static final byte STRING_ENCODING_CONSTANT_POOL = 2;
+    public static final byte STRING_ENCODING_UTF8_BYTE_ARRAY = 3;
+    public static final byte STRING_ENCODING_CHAR_ARRAY = 4;
+    public static final byte STRING_ENCODING_LATIN1_BYTE_ARRAY = 5;
+
+    private final static int DEFAULT_BLOCK_SIZE = 16 * 1024 * 1024;
+    private final static Charset UTF8 = Charset.forName("UTF-8");
+    private final static Charset LATIN1 = Charset.forName("ISO-8859-1");
+
+    private static final class Block {
+        private byte[] bytes = new byte[0];
+        private long blockPosition;
+
+        boolean contains(long position) {
+            return position >= blockPosition && position < blockPosition + bytes.length;
+        }
+
+        public void read(RandomAccessFile file, int amount) throws IOException {
+            blockPosition = file.getFilePointer();
+            // reuse byte array, if possible
+            if (amount != bytes.length) {
+                bytes = new byte[amount];
+            }
+            file.readFully(bytes);
+        }
+
+        public byte get(long position) {
+            return bytes[(int) (position - blockPosition)];
+        }
+    }
+
+    private final RandomAccessFile file;
+    private final long size;
+    private Block currentBlock = new Block();
+    private Block previousBlock = new Block();
+    private long position;
+    private final int blockSize;
+
+    private RecordingInput(File f, int blockSize) throws IOException {
+        this.size = f.length();
+        this.blockSize = blockSize;
+        this.file = new RandomAccessFile(f, "r");
+        if (size < 8) {
+            throw new IOException("Not a valid Flight Recorder file. File length is only " + size + " bytes.");
+        }
+    }
+
+    public RecordingInput(File f) throws IOException {
+        this(f, DEFAULT_BLOCK_SIZE);
+    }
+
+    @Override
+    public final byte readByte() throws IOException {
+        if (!currentBlock.contains(position)) {
+            position(position);
+        }
+        return currentBlock.get(position++);
+    }
+
+    @Override
+    public final void readFully(byte[] dest, int offset, int length) throws IOException {
+        // TODO: Optimize, use Arrays.copy if all bytes are in current block
+        // array
+        for (int i = 0; i < length; i++) {
+            dest[i + offset] = readByte();
+        }
+    }
+
+    @Override
+    public final void readFully(byte[] dst) throws IOException {
+        readFully(dst, 0, dst.length);
+    }
+
+    public final short readRawShort() throws IOException {
+        // copied from java.io.Bits
+        byte b0 = readByte();
+        byte b1 = readByte();
+        return (short) ((b1 & 0xFF) + (b0 << 8));
+    }
+
+    @Override
+    public final double readDouble() throws IOException {
+        // copied from java.io.Bits
+        return Double.longBitsToDouble(readRawLong());
+    }
+
+    @Override
+    public final float readFloat() throws IOException {
+        // copied from java.io.Bits
+        return Float.intBitsToFloat(readRawInt());
+    }
+
+    public final int readRawInt() throws IOException {
+        // copied from java.io.Bits
+        byte b0 = readByte();
+        byte b1 = readByte();
+        byte b2 = readByte();
+        byte b3 = readByte();
+        return ((b3 & 0xFF)) + ((b2 & 0xFF) << 8) + ((b1 & 0xFF) << 16) + ((b0) << 24);
+    }
+
+    public final long readRawLong() throws IOException {
+        // copied from java.io.Bits
+        byte b0 = readByte();
+        byte b1 = readByte();
+        byte b2 = readByte();
+        byte b3 = readByte();
+        byte b4 = readByte();
+        byte b5 = readByte();
+        byte b6 = readByte();
+        byte b7 = readByte();
+        return ((b7 & 0xFFL)) + ((b6 & 0xFFL) << 8) + ((b5 & 0xFFL) << 16) + ((b4 & 0xFFL) << 24) + ((b3 & 0xFFL) << 32) + ((b2 & 0xFFL) << 40) + ((b1 & 0xFFL) << 48) + (((long) b0) << 56);
+    }
+
+    public final long position() throws IOException {
+        return position;
+    }
+
+    public final void position(long newPosition) throws IOException {
+        if (!currentBlock.contains(newPosition)) {
+            if (!previousBlock.contains(newPosition)) {
+                if (newPosition > size()) {
+                    throw new EOFException("Trying to read at " + newPosition + ", but file is only " + size() + " bytes.");
+                }
+                long blockStart = trimToFileSize(calculateBlockStart(newPosition));
+                file.seek(blockStart);
+                // trim amount to file size
+                long amount = Math.min(size() - blockStart, blockSize);
+                previousBlock.read(file, (int) amount);
+            }
+            // swap previous and current
+            Block tmp = currentBlock;
+            currentBlock = previousBlock;
+            previousBlock = tmp;
+        }
+        position = newPosition;
+    }
+
+    private final long trimToFileSize(long position) throws IOException {
+        return Math.min(size(), Math.max(0, position));
+    }
+
+    private final long calculateBlockStart(long newPosition) {
+        // align to end of current block
+        if (currentBlock.contains(newPosition - blockSize)) {
+            return currentBlock.blockPosition + currentBlock.bytes.length;
+        }
+        // align before current block
+        if (currentBlock.contains(newPosition + blockSize)) {
+            return currentBlock.blockPosition - blockSize;
+        }
+        // not near current block, pick middle
+        return newPosition - blockSize / 2;
+    }
+
+    public final long size() throws IOException {
+        return size;
+    }
+
+    public final void close() throws IOException {
+        file.close();
+    }
+
+    @Override
+    public final int skipBytes(int n) throws IOException {
+        long position = position();
+        position(position + n);
+        return (int) (position() - position);
+    }
+
+    @Override
+    public final boolean readBoolean() throws IOException {
+        return readByte() != 0;
+    }
+
+    @Override
+    public int readUnsignedByte() throws IOException {
+        return readByte() & 0x00FF;
+    }
+
+    @Override
+    public int readUnsignedShort() throws IOException {
+        return readShort() & 0xFFFF;
+    }
+
+    @Override
+    public final String readLine() throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    // NOTE, this method should really be called readString
+    // but can't be renamed without making RecordingInput a
+    // public class.
+    //
+    // This method DOES Not read as expected (s2 + utf8 encoded character)
+    // instead it read:
+    // byte encoding
+    // int size
+    // data (byte or char)
+    //
+    // where encoding
+    //
+    // 0, means null
+    // 1, means UTF8 encoded byte array
+    // 2, means char array
+    // 3, means latin-1 (ISO-8859-1) encoded byte array
+    // 4, means ""
+    @Override
+    public String readUTF() throws IOException {
+        return readEncodedString(readByte());
+    }
+
+    public String readEncodedString(byte encoding) throws IOException {
+        if (encoding == STRING_ENCODING_NULL) {
+            return null;
+        }
+        if (encoding == STRING_ENCODING_EMPTY_STRING) {
+            return "";
+        }
+        int size = readInt();
+        if (encoding == STRING_ENCODING_CHAR_ARRAY) {
+            char[] c = new char[size];
+            for (int i = 0; i < size; i++) {
+                c[i] = readChar();
+            }
+            return new String(c);
+        }
+        byte[] bytes = new byte[size];
+        readFully(bytes); // TODO: optimize, check size, and copy only if needed
+        if (encoding == STRING_ENCODING_UTF8_BYTE_ARRAY) {
+            return new String(bytes, UTF8);
+        }
+
+        if (encoding == STRING_ENCODING_LATIN1_BYTE_ARRAY) {
+            return new String(bytes, LATIN1);
+        }
+        throw new IOException("Unknown string encoding " + encoding);
+    }
+
+    @Override
+    public char readChar() throws IOException {
+        return (char) readLong();
+    }
+
+    @Override
+    public short readShort() throws IOException {
+        return (short) readLong();
+    }
+
+    @Override
+    public int readInt() throws IOException {
+        return (int) readLong();
+    }
+
+    @Override
+    public long readLong() throws IOException {
+        // can be optimized by branching checks, but will do for now
+        byte b0 = readByte();
+        long ret = (b0 & 0x7FL);
+        if (b0 >= 0) {
+            return ret;
+        }
+        int b1 = readByte();
+        ret += (b1 & 0x7FL) << 7;
+        if (b1 >= 0) {
+            return ret;
+        }
+        int b2 = readByte();
+        ret += (b2 & 0x7FL) << 14;
+        if (b2 >= 0) {
+            return ret;
+        }
+        int b3 = readByte();
+        ret += (b3 & 0x7FL) << 21;
+        if (b3 >= 0) {
+            return ret;
+        }
+        int b4 = readByte();
+        ret += (b4 & 0x7FL) << 28;
+        if (b4 >= 0) {
+            return ret;
+        }
+        int b5 = readByte();
+        ret += (b5 & 0x7FL) << 35;
+        if (b5 >= 0) {
+            return ret;
+        }
+        int b6 = readByte();
+        ret += (b6 & 0x7FL) << 42;
+        if (b6 >= 0) {
+            return ret;
+        }
+        int b7 = readByte();
+        ret += (b7 & 0x7FL) << 49;
+        if (b7 >= 0) {
+            return ret;
+        }
+        int b8 = readByte(); // read last byte raw
+        return ret + (((long) (b8 & 0XFF)) << 56);
+    }
+}