view_growbuf_read_until() suggestion

[Roland Illig]

Pavel Tsekov wrote:
> I forgot to attach the patch in the original message.
> 
> On Fri, 5 Aug 2005, Pavel Tsekov wrote:
> 
> 
>>Hello Roland,
>>
>>There is a small "bug" in the new viewer code. When the viewer is used in
>>growing buffer mode it incorrectly displays in the status bar ">= size"
>>even if the data source was exhausted and despite the fact the the
>>size of the whole buffer is known. Please, take a look at the attached
>>patch for a idea how to fix it. Of course you could find a better way to
>>solve this since you know the code better.

I confirm that the "bug" does not look nice. But your code has a little 
problem. It _might_ report a too small file size.

>  	    nread = fread (p, 1, bytesfree, view->ds_stdio_pipe);
> -	    if (nread == 0) {
> +	    if (nread > 0)
> +		view->growbuf_lastindex += nread;
> +	    if (nread < bytesfree) {

Nothing in the C standard prevents fread from always returning only one 
element instead of ''bytesfree''. It's just a "quality of 
implementation" that most system's fread(3) function calls read(2) 
repeatedly until either EOF is reached or the necessary number of bytes 
is read.

I have run the two appended files on NetBSD, Linux, Solaris, IRIX and 
AIX, and all systems have a "greedy" fread(). But this is not mandated 
by the standard.

$ make reader writer
$ ./writer | ./reader
25

I would not be surprised if the output were

$ make reader writer
$ ./writer | ./reader
7
7
7
4

Nevertheless I will fix this "bug".

Roland
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