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 $size = shift;
  24
  25         # 0 - size
  26         # 1 - lth
  27         # 2 - end
  28         # 3 - start
  29         # 4 - pos
  30         # 5 - buffer []
  31         return bless [$size, 0, 0, 0, 0, []], (ref $pkg || $pkg);
  32 }
  33
  34 sub write
  35 {
  36         my $self = shift;
  37
  38         $self->[5]->[$self->[2]++] = shift;
  39         $self->[2] = 0 if $self->[2] >= $self->[0];
  40         if ($self->[1] < $self->[0]) {
  41                 $self->[1] = ++$self->[1];
  42         }
  43         $self->[2] = $self->[2];
  44         if ($self->[1] == $self->[0] && $self->[2] == $self->[3]) {
  45                 $self->[3] = $self->[2]+1;
  46                 $self->[3] = 0 if $self->[3] >= $self->[0];
  47         }
  48 }
  49
  50 sub read
  51 {
  52         my $self = shift;
  53         return unless $self->[1];
  54         my $r;
  55
  56         if ($self->[4] != $self->[2]) {
  57                 $r = $self->[5]->[$self->[4]++];
  58                 $self->[4] = 0 if $self->[4] >= $self->[0];
  59         }
  60         return $r;
  61 }
  62
  63 sub rewind
  64 {
  65         my $self = shift;
  66         $self->[4] = $self->[3];
  67 }
  68
  69 sub lth
  70 {
  71         my $self = shift;
  72         return $self->[1];
  73 }
  74
  75 sub readall
  76 {
  77         my $self = shift;
  78         my @out;
  79
  80         $self->rewind;
  81         while (my $r = $self->read) {
  82                 push @out, $r;
  83         }
  84         return @out;
  85 }
  86 1;