perl/RingBuf.pm

   1 #
   2 # Finite size ring buffer creation and access routines
   3 #
   4 # Copyright (c) - 1998 Dirk Koopman G1TLH
   5 #
   6 # $Id$
   7 #
   8
   9 use strict;
  10
  11 package RingBuf;
  12
  13 use vars qw($VERSION $BRANCH);
  14 $VERSION = sprintf( "%d.%03d", q$Revision$ =~ /(\d+)\.(\d+)/ );
  15 $BRANCH = sprintf( "%d.%03d", q$Revision$ =~ /\d+\.\d+\.(\d+)\.(\d+)/  || (0,0));
  16 $main::build += $VERSION;
  17 $main::branch += $BRANCH;
  18
  19
  20 sub new
  21 {
  22         my $pkg = shift;
  23         my $size = shift;
  24         return bless [$size, 0, 0, 0, 0, []], (ref $pkg || $pkg);
  25 }
  26
  27 sub write
  28 {
  29         my $self = shift;
  30
  31         $self->[5]->[$self->[2]++] = shift;
  32         $self->[2] = 0 if $self->[2] >= $self->[0];
  33         if ($self->[1] < $self->[0]) {
  34                 $self->[1] = ++$self->[1];
  35         }
  36         $self->[2] = $self->[2];
  37         if ($self->[1] == $self->[0] && $self->[2] == $self->[3]) {
  38                 $self->[3] = $self->[2]+1;
  39                 $self->[3] = 0 if $self->[3] >= $self->[0];
  40         }
  41 }
  42
  43 sub read
  44 {
  45         my $self = shift;
  46         return unless $self->[1];
  47         my $r;
  48
  49         if ($self->[4] != $self->[2]) {
  50                 $r = $self->[5]->[$self->[4]++];
  51                 $self->[4] = 0 if $self->[4] >= $self->[0];
  52         }
  53         return $r;
  54 }
  55
  56 sub rewind
  57 {
  58         my $self = shift;
  59         $self->[4] = $self->[3];
  60 }
  61
  62 sub lth
  63 {
  64         my $self = shift;
  65         return $self->[1];
  66 }
  67
  68 sub readall
  69 {
  70         my $self = shift;
  71         my @out;
  72
  73         $self->rewind;
  74         while (my $r = $self->read) {
  75                 push @out, $r;
  76         }
  77         return @out;
  78 }
  79 1;