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From: | Paolo Bonzini |
Subject: | Re: [Qemu-devel] [RFC][PATCH] signrom: Speed up checksum calculation |
Date: | Tue, 24 Jan 2012 09:39:53 +0100 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0 |
On 01/23/2012 07:38 PM, Jan Kiszka wrote:
nums=`od -A n -t u1 -v -N $size "$1"` -for i in ${nums}; do - # add each byte's value to sum - sum=`expr \( $sum + $i \) % 256` -done - -sum=$(( (256 - $sum) % 256 ))
We have a bashism here, so why not do sum=$(( ($sum + $i) % 256 ))and do the same with a one-line patch (two line if you change the header to #!/bin/bash)? It should be just as fast as awk.
Paolo
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