Re: Large binary data manipulation

From: Khamis (khamis_at_wellcode.com)
Date: 08/26/04 

Date: Thu, 26 Aug 2004 00:31:24 +0200

Wellcode wrote:

> Hi Derek
>
> you have two problems in your example:
>
> your first problem is the reading 2 bytes every step. this causes alot
> of io operations. The second problem, that you don't use the append
> command, your method reallocates the buffer every time you set a new
> variable value.
> Just read larger buffers and the routines get alot faster.
>
> set data [read $file_handle 10240]
> set len [string length $data]
> set left_data ""
> set right_data ""
> for {set i 0} {$i < $len} {incr i 4} {
> append left_data [string range $data $i [expr $i+1]]
> append right_data [string range $data [expr $i+2] [expr $i+3]]
> }
>
> regards

This sounds for me a good solution, but if I think on my programs in c
source code, I would never use i++ if the variable is not set.
So "set i 0" must be placed somewhere in your source code before calling
"incr i" and you don't need to validate it's exist.

It sounds like tcl is more saver than bad c source code :-)

regards 

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