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
  14 sub new
  15 {
  16         my $pkg = shift;
  17         my $size = shift;
  18
  19         # 0 - size
  20         # 1 - lth
  21         # 2 - end
  22         # 3 - start
  23         # 4 - pos
  24         # 5 - buffer []
  25         return bless [$size+1, 0, 0, 0, 0, []], (ref $pkg || $pkg);
  26 }
  27
  28 sub write
  29 {
  30         my $self = shift;
  31
  32         $self->[5]->[$self->[2]++] = shift;
  33         $self->[2] = 0 if $self->[2] >= $self->[0];
  34         $self->[1]++ if $self->[1] < $self->[0];
  35         if ($self->[1] == $self->[0] && $self->[2] == $self->[3]) {
  36                 $self->[3] = $self->[2]+1;
  37                 $self->[3] = 0 if $self->[3] >= $self->[0];
  38         }
  39 }
  40
  41 sub read
  42 {
  43         my $self = shift;
  44         return unless $self->[1];
  45         my $r;
  46
  47         if ($self->[4] != $self->[2]) {
  48                 $r = $self->[5]->[$self->[4]++];
  49                 $self->[4] = 0 if $self->[4] >= $self->[0];
  50         }
  51         return $r;
  52 }
  53
  54 sub rewind
  55 {
  56         my $self = shift;
  57         $self->[4] = $self->[3];
  58 }
  59
  60 sub lth
  61 {
  62         my $self = shift;
  63         return $self->[1];
  64 }
  65
  66 sub readall
  67 {
  68         my $self = shift;
  69         my @out;
  70
  71         $self->rewind;
  72         while (my $r = $self->read) {
  73                 push @out, $r;
  74         }
  75         return @out;
  76 }
  77 1;