Need efficient way to read file in reverse
Dave Jenks
jetfuel at csusac.csus.edu
Wed Sep 19 15:58:46 AEST 1990
In article <1990Sep18.152818.1303 at phri.nyu.edu> roy at alanine.phri.nyu.edu (Roy Smith) writes:
> Is there a standard, portable, efficient way to read a file in
>reverse? I'm doing random seeks in a file and occassionally want to be able
>to find the beginning of the line into the middle of which I just seeked.
>Right now, I'm using a simple-minded revgetc() I wrote which is basically:
I had to do the very same thing a number of years ago. The most
efficient method was to read using read(2) for BLKSIZ bytes (#defined
in <stdio.h> or <stand.h> or someplace like that) and search the
buffer manually. With a simple searching algorithm, this can be very
fast - even with a poor algorithm, it'll still be much faster than
asking for i/o for each character. It's even portable.
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