Re: Problems with java.io.BufferedReader

[Mark Wielaard]

Hi Thorsten,

I saw nobody ever replied to your message from September.

On Sat, 2005-09-10 at 01:05 +0200, Thorsten Suckow-Homberg wrote:
> right now I have some problems with the java.io.BufferedReader and I hope 
> someone can help out.
> 
> The docblock says about the method  read(char[] buf, int offset, int 
> length):
> 
> * [...]
> * This method can
> * return before reading the number of chars requested.  The actual number
> * of chars read is returned as an int.  A -1 is returned to indicate the
> * end of the stream.
> * [...]
> 
> Does this mean that it can happen that the buffer supplied by the caller 
> doesn't even get filled?

No, our documentation also says:

   * This method will block until some data can be read.

> Because I'm operating on some small files and from my understanding there is 
> a problem with the
> default buffersize (BufferedReader::DEFAULT_BUFFER_SIZE = 8192).
> 
> I'll try to explain:

I'll try to respond to your analysis. But it is easier if you could
supply a self-contained program that doesn't work as you expect with GNU
Classpath. Then we can test the behavior ourselves easily.

> // the buffer-member of bufferedReader gets filled
> // avail is set to -1, since limit equals to 0, and buffer.length-limit
> //equals to buffer.length - ergo, the buffer gets filled with the whole 
> // file-contents
> avail = in.read(buffer, limit, buffer.length - limit);

No. avail is set to the number of bytes read from in. If everything is
read in one go then in.read() returns buffer.length. Only the next call
to in.read() would return -1 in that case.

Cheers,

Mark

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