extra code in pp_concat, Take 2
[p5sagit/p5-mst-13.2.git] / lib / look.pl
CommitLineData
a687059c 1;# Usage: &look(*FILEHANDLE,$key,$dict,$fold)
a6d71656 2#
3# This library is no longer being maintained, and is included for backward
4# compatibility with Perl 4 programs which may require it.
5#
6# In particular, this should not be used as an example of modern Perl
7# programming techniques.
8#
a687059c 9;# Sets file position in FILEHANDLE to be first line greater than or equal
10;# (stringwise) to $key. Pass flags for dictionary order and case folding.
11
12sub look {
fe14fcc3 13 local(*FH,$key,$dict,$fold) = @_;
a687059c 14 local($max,$min,$mid,$_);
15 local($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,
16 $blksize,$blocks) = stat(FH);
17 $blksize = 8192 unless $blksize;
18 $key =~ s/[^\w\s]//g if $dict;
55497cff 19 $key = lc $key if $fold;
ac58e20f 20 $max = int($size / $blksize);
21 while ($max - $min > 1) {
22 $mid = int(($max + $min) / 2);
23 seek(FH,$mid * $blksize,0);
24 $_ = <FH> if $mid; # probably a partial line
a687059c 25 $_ = <FH>;
26 chop;
27 s/[^\w\s]//g if $dict;
55497cff 28 $_ = lc $_ if $fold;
a687059c 29 if ($_ lt $key) {
30 $min = $mid;
31 }
32 else {
33 $max = $mid;
34 }
35 }
ac58e20f 36 $min *= $blksize;
a687059c 37 seek(FH,$min,0);
ac58e20f 38 <FH> if $min;
a687059c 39 while (<FH>) {
40 chop;
41 s/[^\w\s]//g if $dict;
55497cff 42 $_ = lc $_ if $fold;
a687059c 43 last if $_ ge $key;
44 $min = tell(FH);
45 }
46 seek(FH,$min,0);
47 $min;
48}
49
501;