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+1, 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         $self->[1]++ if $self->[1] < $self->[0];
  41         if ($self->[1] == $self->[0] && $self->[2] == $self->[3]) {
  42                 $self->[3] = $self->[2]+1;
  43                 $self->[3] = 0 if $self->[3] >= $self->[0];
  44         }
  45 }
  46
  47 sub read
  48 {
  49         my $self = shift;
  50         return unless $self->[1];
  51         my $r;
  52
  53         if ($self->[4] != $self->[2]) {
  54                 $r = $self->[5]->[$self->[4]++];
  55                 $self->[4] = 0 if $self->[4] >= $self->[0];
  56         }
  57         return $r;
  58 }
  59
  60 sub rewind
  61 {
  62         my $self = shift;
  63         $self->[4] = $self->[3];
  64 }
  65
  66 sub lth
  67 {
  68         my $self = shift;
  69         return $self->[1];
  70 }
  71
  72 sub readall
  73 {
  74         my $self = shift;
  75         my @out;
  76
  77         $self->rewind;
  78         while (my $r = $self->read) {
  79                 push @out, $r;
  80         }
  81         return @out;
  82 }
  83 1;