/IronPython_Main/Runtime/Tests/LinqDlrTests/testenv/perl/lib/Search/Dict.pm

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;

	<FH> if $mid;			# probably a partial line

	$_ = <FH>;

	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;

    <FH> if $min;

    for (;;) {

	$min = tell(FH);

	defined($_ = <FH>)

	    or last;

	chop;

	s/[^\w\s]//g if $dict;

	$_ = lc $_ if $fold;

	last if $_ ge $key;

    }

    seek(FH,$min,0);

    $min;

}



1;