Commit | Line | Data |
---|---|---|
a687059c | 1 | ;# Usage: &look(*FILEHANDLE,$key,$dict,$fold) |
a6d71656 GS |
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 LW |
9 | ;# Sets file position in FILEHANDLE to be first line greater than or equal |
10 | ;# (stringwise) to $key. Pass flags for dictionary order and case folding. | |
11 | ||
12 | sub look { | |
fe14fcc3 | 13 | local(*FH,$key,$dict,$fold) = @_; |
a687059c LW |
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 LW |
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 LW |
25 | $_ = <FH>; |
26 | chop; | |
27 | s/[^\w\s]//g if $dict; | |
55497cff | 28 | $_ = lc $_ if $fold; |
a687059c LW |
29 | if ($_ 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 LW |
39 | while (<FH>) { |
40 | chop; | |
41 | s/[^\w\s]//g if $dict; | |
55497cff | 42 | $_ = lc $_ if $fold; |
a687059c LW |
43 | last if $_ ge $key; |
44 | $min = tell(FH); | |
45 | } | |
46 | seek(FH,$min,0); | |
47 | $min; | |
48 | } | |
49 | ||
50 | 1; |