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. | |
dae35969 S |
5 | # This legacy library is deprecated and will be removed in a future |
6 | # release of perl. | |
a6d71656 GS |
7 | # |
8 | # In particular, this should not be used as an example of modern Perl | |
9 | # programming techniques. | |
dae35969 | 10 | |
a687059c LW |
11 | ;# Sets file position in FILEHANDLE to be first line greater than or equal |
12 | ;# (stringwise) to $key. Pass flags for dictionary order and case folding. | |
13 | ||
14 | sub look { | |
fe14fcc3 | 15 | local(*FH,$key,$dict,$fold) = @_; |
a687059c LW |
16 | local($max,$min,$mid,$_); |
17 | local($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime, | |
18 | $blksize,$blocks) = stat(FH); | |
19 | $blksize = 8192 unless $blksize; | |
20 | $key =~ s/[^\w\s]//g if $dict; | |
55497cff | 21 | $key = lc $key if $fold; |
ac58e20f LW |
22 | $max = int($size / $blksize); |
23 | while ($max - $min > 1) { | |
24 | $mid = int(($max + $min) / 2); | |
25 | seek(FH,$mid * $blksize,0); | |
26 | $_ = <FH> if $mid; # probably a partial line | |
a687059c LW |
27 | $_ = <FH>; |
28 | chop; | |
29 | s/[^\w\s]//g if $dict; | |
55497cff | 30 | $_ = lc $_ if $fold; |
a687059c LW |
31 | if ($_ lt $key) { |
32 | $min = $mid; | |
33 | } | |
34 | else { | |
35 | $max = $mid; | |
36 | } | |
37 | } | |
ac58e20f | 38 | $min *= $blksize; |
a687059c | 39 | seek(FH,$min,0); |
ac58e20f | 40 | <FH> if $min; |
a687059c LW |
41 | while (<FH>) { |
42 | chop; | |
43 | s/[^\w\s]//g if $dict; | |
55497cff | 44 | $_ = lc $_ if $fold; |
a687059c LW |
45 | last if $_ ge $key; |
46 | $min = tell(FH); | |
47 | } | |
48 | seek(FH,$min,0); | |
49 | $min; | |
50 | } | |
51 | ||
52 | 1; |