| 1 | package Search::Dict; |
| 2 | require 5.000; |
| 3 | require Exporter; |
| 4 | |
| 5 | @ISA = qw(Exporter); |
| 6 | @EXPORT = qw(look); |
| 7 | |
| 8 | =head1 NAME |
| 9 | |
| 10 | Search::Dict, look - search for key in dictionary file |
| 11 | |
| 12 | =head1 SYNOPSIS |
| 13 | |
| 14 | use Search::Dict; |
| 15 | look *FILEHANDLE, $key, $dict, $fold; |
| 16 | |
| 17 | =head1 DESCRIPTION |
| 18 | |
| 19 | Sets file position in FILEHANDLE to be first line greater than or equal |
| 20 | (stringwise) to I<$key>. Returns the new file position, or -1 if an error |
| 21 | occurs. |
| 22 | |
| 23 | The flags specify dictionary order and case folding: |
| 24 | |
| 25 | If I<$dict> is true, search by dictionary order (ignore anything but word |
| 26 | characters and whitespace). |
| 27 | |
| 28 | If I<$fold> is true, ignore case. |
| 29 | |
| 30 | =cut |
| 31 | |
| 32 | sub look { |
| 33 | local(*FH,$key,$dict,$fold) = @_; |
| 34 | local($_); |
| 35 | my(@stat) = stat(FH) |
| 36 | or return -1; |
| 37 | my($size, $blksize) = @stat[7,11]; |
| 38 | $blksize ||= 8192; |
| 39 | $key =~ s/[^\w\s]//g if $dict; |
| 40 | $key = lc $key if $fold; |
| 41 | my($min, $max, $mid) = (0, int($size / $blksize)); |
| 42 | while ($max - $min > 1) { |
| 43 | $mid = int(($max + $min) / 2); |
| 44 | seek(FH, $mid * $blksize, 0) |
| 45 | or return -1; |
| 46 | <FH> if $mid; # probably a partial line |
| 47 | $_ = <FH>; |
| 48 | chop; |
| 49 | s/[^\w\s]//g if $dict; |
| 50 | $_ = lc $_ if $fold; |
| 51 | if (defined($_) && $_ lt $key) { |
| 52 | $min = $mid; |
| 53 | } |
| 54 | else { |
| 55 | $max = $mid; |
| 56 | } |
| 57 | } |
| 58 | $min *= $blksize; |
| 59 | seek(FH,$min,0) |
| 60 | or return -1; |
| 61 | <FH> if $min; |
| 62 | for (;;) { |
| 63 | $min = tell(FH); |
| 64 | $_ = <FH> |
| 65 | or last; |
| 66 | chop; |
| 67 | s/[^\w\s]//g if $dict; |
| 68 | $_ = lc $_ if $fold; |
| 69 | last if $_ ge $key; |
| 70 | } |
| 71 | seek(FH,$min,0); |
| 72 | $min; |
| 73 | } |
| 74 | |
| 75 | 1; |