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From Alexei Fedotov <alexei.fedo...@gmail.com>
Subject Re: [classlib][luni] Performance improvement patch in java.io.unread(byte[] buffer, int offset, int length)
Date Tue, 17 Feb 2009 06:59:48 GMT
Hello Deven,
Thank you for your contribution! It would be nice to see how real-life
applications improved with this fix.

Could you please send the patch via JIRA [1]? We also need your ACQ to
be sent to private@harmony.apache.org (see details at [2]).

[1] https://issues.apache.org/jira/browse/HARMONY
[2] http://harmony.apache.org/contribution_policy.html

2009/2/17 Deven You <devyoudw@gmail.com>:
> Hi,
> the patch is as below:
> Index: src/main/java/java/io/PushbackInputStream.java
> ===================================================================
> --- src/main/java/java/io/PushbackInputStream.java      (Version 743234)
> +++ src/main/java/java/io/PushbackInputStream.java      (Working copy)
> @@ -282,9 +282,11 @@
>              throw new ArrayIndexOutOfBoundsException();
>          }
>
> -        for (int i = offset + length - 1; i >= offset; i--) {
> -            unread(buffer[i]);
> +        if (buf == null) {
> +            throw new IOException();
>          }
> +        System.arraycopy(buffer, offset, buf, pos - length, length);
> +        pos = pos - length;
>      }
>
> I have write a test as below:
>
> import java.io.ByteArrayInputStream;
> import java.io.File;
> import java.io.IOException;
> import java.io.PushbackInputStream;
>
> public class PushbackInputStream_Unread_$BII {
>
>     /**
>      * @param args
>      */
>     public static void main(String[] args) {
>         // setUp
>         String fileString =
> "Test_All_Tests\nTest_java_io_BufferedInputStream\nTest_java_io_BufferedOutputStream\nTest_java_io_ByteArrayInputStream\nTest_java_io_ByteArrayOutputStream\nTest_java_io_DataInputStream\nTest_java_io_File\nTest_java_io_FileDescriptor\nTest_java_io_FileInputStream\nTest_java_io_FileNotFoundException\nTest_java_io_FileOutputStream\nTest_java_io_FilterInputStream\nTest_java_io_FilterOutputStream\nTest_java_io_InputStream\nTest_java_io_IOException\nTest_java_io_OutputStream\nTest_java_io_PrintStream\nTest_java_io_RandomAccessFile\nTest_java_io_SyncFailedException\nTest_java_lang_AbstractMethodError\nTest_java_lang_ArithmeticException\nTest_java_lang_ArrayIndexOutOfBoundsException\nTest_java_lang_ArrayStoreException\nTest_java_lang_Boolean\nTest_java_lang_Byte\nTest_java_lang_Character\nTest_java_lang_Class\nTest_java_lang_ClassCastException\nTest_java_lang_ClassCircularityError\nTest_java_lang_ClassFormatError\nTest_java_lang_ClassLoader\nTest_java_lang_ClassNotFoundException\nTest_java_lang_CloneNotSupportedException\nTest_java_lang_Double\nTest_java_lang_Error\nTest_java_lang_Exception\nTest_java_lang_ExceptionInInitializerError\nTest_java_lang_Float\nTest_java_lang_IllegalAccessError\nTest_java_lang_IllegalAccessException\nTest_java_lang_IllegalArgumentException\nTest_java_lang_IllegalMonitorStateException\nTest_java_lang_IllegalThreadStateException\nTest_java_lang_IncompatibleClassChangeError\nTest_java_lang_IndexOutOfBoundsException\nTest_java_lang_InstantiationError\nTest_java_lang_InstantiationException\nTest_java_lang_Integer\nTest_java_lang_InternalError\nTest_java_lang_InterruptedException\nTest_java_lang_LinkageError\nTest_java_lang_Long\nTest_java_lang_Math\nTest_java_lang_NegativeArraySizeException\nTest_java_lang_NoClassDefFoundError\nTest_java_lang_NoSuchFieldError\nTest_java_lang_NoSuchMethodError\nTest_java_lang_NullPointerException\nTest_java_lang_Number\nTest_java_lang_NumberFormatException\nTest_java_lang_Object\nTest_java_lang_OutOfMemoryError\nTest_java_lang_RuntimeException\nTest_java_lang_SecurityManager\nTest_java_lang_Short\nTest_java_lang_StackOverflowError\nTest_java_lang_String\nTest_java_lang_StringBuffer\nTest_java_lang_StringIndexOutOfBoundsException\nTest_java_lang_System\nTest_java_lang_Thread\nTest_java_lang_ThreadDeath\nTest_java_lang_ThreadGroup\nTest_java_lang_Throwable\nTest_java_lang_UnknownError\nTest_java_lang_UnsatisfiedLinkError\nTest_java_lang_VerifyError\nTest_java_lang_VirtualMachineError\nTest_java_lang_vm_Image\nTest_java_lang_vm_MemorySegment\nTest_java_lang_vm_ROMStoreException\nTest_java_lang_vm_VM\nTest_java_lang_Void\nTest_java_net_BindException\nTest_java_net_ConnectException\nTest_java_net_DatagramPacket\nTest_java_net_DatagramSocket\nTest_java_net_DatagramSocketImpl\nTest_java_net_InetAddress\nTest_java_net_NoRouteToHostException\nTest_java_net_PlainDatagramSocketImpl\nTest_java_net_PlainSocketImpl\nTest_java_net_Socket\nTest_java_net_SocketException\nTest_java_net_SocketImpl\nTest_java_net_SocketInputStream\nTest_java_net_SocketOutputStream\nTest_java_net_UnknownHostException\nTest_java_util_ArrayEnumerator\nTest_java_util_Date\nTest_java_util_EventObject\nTest_java_util_HashEnumerator\nTest_java_util_Hashtable\nTest_java_util_Properties\nTest_java_util_ResourceBundle\nTest_java_util_tm\nTest_java_util_Vector\n";
>
>         int count = 10000000;
>         long time = System.currentTimeMillis();
>         PushbackInputStream pis = new PushbackInputStream(
>                 new ByteArrayInputStream(fileString.getBytes()), 65535);
>         byte[] buf = new byte[100];
>         for (int i = 0; i < count; i++) {
>             try {
>                 pis.read(buf, 0, 100);
>                 pis.unread(buf, 0, 100);
>             } catch (IOException e) {
>                 // ignore
>             }
>         }
>
>         // output
>         time = System.currentTimeMillis() - time;
>
>         System.out.println("======================");
>         System.out.println("Invoke Count: " + count);
>         System.out.println("Total Time: " + time + "ms");
>     }
>
> I have test on Intel(R) Core(TM)2 Duo Cpu 2.4GHZ, 2.98GB Memory machine, the
> result is as below:
> Harmony patch before: 3362 ms
> Harmony patched: 1312 ms
>
>



-- 
С уважением,
Алексей Федотов,
ЗАО <<Телеком Экспресс>>

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