Viewing file: look.pl (1.23 KB) -rw-r--r-- Select action/file-type: (+) | (+) | (+) | Code (+) | Session (+) | (+) | SDB (+) | (+) | (+) | (+) | (+) | (+) |
;# Usage: &look(*FILEHANDLE,$key,$dict,$fold) # # This library is no longer being maintained, and is included for backward # compatibility with Perl 4 programs which may require it. # # In particular, this should not be used as an example of modern Perl # programming techniques. # ;# Sets file position in FILEHANDLE to be first line greater than or equal ;# (stringwise) to $key. Pass flags for dictionary order and case folding.
sub look { local(*FH,$key,$dict,$fold) = @_; local($max,$min,$mid,$_); local($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime, $blksize,$blocks) = stat(FH); $blksize = 8192 unless $blksize; $key =~ s/[^\w\s]//g if $dict; $key = lc $key if $fold; $max = int($size / $blksize); while ($max - $min > 1) { $mid = int(($max + $min) / 2); seek(FH,$mid * $blksize,0); $_ = <FH> if $mid; # probably a partial line $_ = <FH>; chop; s/[^\w\s]//g if $dict; $_ = lc $_ if $fold; if ($_ lt $key) { $min = $mid; } else { $max = $mid; } } $min *= $blksize; seek(FH,$min,0); <FH> if $min; while (<FH>) { chop; s/[^\w\s]//g if $dict; $_ = lc $_ if $fold; last if $_ ge $key; $min = tell(FH); } seek(FH,$min,0); $min; }
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