package Search::Dict; require 5.000; require Exporter; @ISA = qw(Exporter); @EXPORT = qw(look); =head1 NAME Search::Dict, look - search for key in dictionary file =head1 SYNOPSIS use Search::Dict; look *FILEHANDLE, $key, $dict, $fold; =head1 DESCRIPTION Sets file position in FILEHANDLE to be first line greater than or equal (stringwise) to I<$key>. Returns the new file position, or -1 if an error occurs. The flags specify dictionary order and case folding: If I<$dict> is true, search by dictionary order (ignore anything but word characters and whitespace). If I<$fold> is true, ignore case. =cut sub look { local(*FH,$key,$dict,$fold) = @_; local($_); my(@stat) = stat(FH) or return -1; my($size, $blksize) = @stat[7,11]; $blksize ||= 8192; $key =~ s/[^\w\s]//g if $dict; $key = lc $key if $fold; my($min, $max, $mid) = (0, int($size / $blksize)); while ($max - $min > 1) { $mid = int(($max + $min) / 2); seek(FH, $mid * $blksize, 0) or return -1; if $mid; # probably a partial line $_ = ; chop; s/[^\w\s]//g if $dict; $_ = lc $_ if $fold; if (defined($_) && $_ lt $key) { $min = $mid; } else { $max = $mid; } } $min *= $blksize; seek(FH,$min,0) or return -1; if $min; for (;;) { $min = tell(FH); defined($_ = ) or last; chop; s/[^\w\s]//g if $dict; $_ = lc $_ if $fold; last if $_ ge $key; } seek(FH,$min,0); $min; } 1;