Bug#308256: kaffe-common: OutputStreamWriter crashes

[Tuukka Hastrup]

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Package: kaffe-common
Version: 2:1.1.5-3
Severity: normal


There is a bug in how KaffeEncoder manages its character buffer. In the
corner case, the bug results in an exception when an application program
uses functionality that is implemented using this class. A simple test
program prints 4096 stars and one dot on other JVMs but throws an
exception on Kaffe:

import java.io.OutputStreamWriter;

class KaffeWriterBug {
    public static void main(String args[]) throws Exception {
	OutputStreamWriter w = new OutputStreamWriter(System.out);
	for (int i=0; i<4096; i++)
	    w.write("*");
	w.write('.');
	w.flush();
    }
}

The buggy case is the use of the method write(char) after a call to the
method write(String) that has filled the character buffer in
KaffeEncoder (4096 characters). A simple fix is to ensure in both
methods adding to the buffer that the buffer isn't full when the method
returns. It seems that after the release of 1.1.5 the source file in
question has been removed from the upstream CVS, the functionality 
re-implemented with java.nio.

Attached is a patch that makes write(String) flush the buffer also when 
the write would fill the buffer but not overflow it. 


-- System Information:
Debian Release: 3.1
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)
Kernel: Linux 2.6.8-2-686
Locale: LANG=fi_FI@euro, LC_CTYPE=fi_FI@euro (charmap=ISO-8859-15)

Versions of packages kaffe-common depends on:
ii  java-common                   0.22       Base of all Java packages

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diff -Naur kaffe-1.1.5/kaffe-1.1.5/libraries/javalib/gnu/java/io/encode/KaffeEncoder.java kaffe-1.1.5-writerfix/kaffe-1.1.5/libraries/javalib/gnu/java/io/encode/KaffeEncoder.java
--- kaffe-1.1.5/kaffe-1.1.5/libraries/javalib/gnu/java/io/encode/KaffeEncoder.java	2005-05-09 02:46:54.161378288 +0300
+++ kaffe-1.1.5-writerfix/kaffe-1.1.5/libraries/javalib/gnu/java/io/encode/KaffeEncoder.java	2005-05-09 03:35:41.461361048 +0300
@@ -151,7 +151,7 @@
 write(char[] buf, int offset, int len) throws IOException
 {
     synchronized (lock) {
-        if (len > buffer.length - ptr) {
+        if (len >= buffer.length - ptr) {
             localFlush();
             _write(buf, offset, len);
         } else if (len == 1) {

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