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=head1 NAME |
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AnyEvent::GPSD - event based interface to GPSD |
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=head1 SYNOPSIS |
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use AnyEvent::GPSD; |
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|
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=head1 DESCRIPTION |
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|
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This module is an L<AnyEvent> user, you need to make sure that you use and |
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run a supported event loop. |
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This module implements an interface to GPSD (http://gpsd.berlios.de/). |
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You need to consult the GPSD protocol desription in the manpage to make |
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better sense of this module. |
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|
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=head2 METHODS |
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|
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=over 4 |
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|
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=cut |
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|
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package AnyEvent::GPSD; |
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|
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use strict; |
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no warnings; |
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|
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use Carp (); |
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use Errno (); |
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use Scalar::Util (); |
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use Geo::Forward (); |
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|
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use AnyEvent (); |
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use AnyEvent::Util (); |
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use AnyEvent::Socket (); |
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use AnyEvent::Handle (); |
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|
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our $VERSION = '1.0'; |
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|
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=item $gps = new AnyEvent::GPSD [key => value...] |
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|
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Creates a (virtual) connection to the GPSD. If the C<"hostname:port"> |
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argument is missing then C<localhost:2947> will be used. |
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|
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If the connection cannot be established, then it will retry every |
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second. Otherwise, the connection is put into watcher mode. |
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|
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You can specify various configuration parameters, most of them callbacks: |
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|
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=over 4 |
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|
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=item host => $hostname |
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The host to connect to, default is C<locahost>. |
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|
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=item port => $port |
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The port to connect to, default is C<2947>. |
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=item on_error => $cb->($gps) |
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Called on every connection or protocol failure, reason is in C<$!> |
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(protocl errors are signalled via EBADMSG). Can be used to bail out if you |
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are not interested in retries. |
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|
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=item on_connect => $cb->($gps) |
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Nornormally used: Called on every successful connection establish. |
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|
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=item on_response => $cb->($gps, $type, $data, $time) |
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Not normally used: Called on every response received from GPSD. C<$type> |
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is the single letter type and C<$data> is the data portion, if |
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any. C<$time> is the timestamp that this message was received at. |
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|
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=item on_satellite_info => $cb->($gps, {satellite-info}...) |
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|
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Called each time the satellite info changes, also on first connect. Each |
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C<satellite-info> hash contains at least the following members (mnemonic: |
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all keys have three letters): |
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|
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C<prn> holds the satellite PRN (1..32 GPS, anything higher is |
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wASS/EGNOS/MCAS etc, see L<GPS::PRN>). |
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|
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C<ele>, C<azi> contain the elevation (0..90) and azimuth (0..359) of the satellite. |
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C<snr> contains the signal strength in decibals (28+ is usually the |
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minimum value for a good fix). |
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C<fix> contains either C<1> to indicate that this satellite was used for |
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the last position fix, C<0> otherwise. EGNOS/WAAS etc. satellites will |
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always show as C<0>, even if their correction info was used. |
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|
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The passed hash references are read-only. |
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|
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=item on_fix => $cb->({point}) |
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Called regularly (usually about once/second), even when there is no |
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connection to the GPSD (so is useful to update your idea of the current |
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position). The passed hash reference must I<not> be modified in any way. |
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|
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If C<mode> is C<2> or C<3>, then the C<{point}> hash contains at least the |
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following members, otherwise it is undefined which members exist. Members |
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whose values are not known are C<undef> (usually the error values, speed |
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and so on). |
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|
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time when this fix was received (s) |
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|
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lat latitude (S -90..90 N) |
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lon longitude (W -180..180 E) |
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alt altitude |
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|
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herr estimated horizontal error (m) |
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verr estimated vertical error (m) |
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|
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bearing bearing over ground (0..360) |
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berr estimated error in bearing (degrees) |
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speed speed over ground (m/s) |
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serr estimated error in speed over ground (m/s) |
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vspeed vertical velocity, positive = upwards (m/s) |
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vserr estimated error in vspeed (m/s) |
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|
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mode 1 = no fix, 2 = 2d fix, 3 = 3d fix |
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|
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=back |
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=cut |
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sub new { |
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my $class = shift; |
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my $self = bless { |
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@_, |
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interval => 1, |
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fix => { time => AnyEvent->now, mode => 1 }, |
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}, $class; |
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$self->interval_timer; |
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$self->connect; |
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|
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$self |
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} |
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|
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sub event { |
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my $event = splice @_, 1, 1, (); |
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|
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warn "event<$event,@_>\n";#d# |
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if ($event = $_[0]{"on_$event"}) { |
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&$event; |
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} |
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} |
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sub retry { |
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my ($self) = @_; |
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delete $self->{fh}; |
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Scalar::Util::weaken $self; |
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$self->{retry_w} = AnyEvent->timer (after => 1, cb => sub { |
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delete $self->{retry_w}; |
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$self->connect; |
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}); |
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} |
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# make sure we send "no fix" updates when we lose connectivity |
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sub interval_timer { |
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my ($self) = @_; |
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$self->{interval_w} = AnyEvent->timer (after => $self->{interval}, cb => sub { |
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if (AnyEvent->now - $self->{fix}{time} > $self->{interval} * 1.9) { |
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$self->{fix}{mode} = 1; |
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$self->event (fix => $self->{fix}); |
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} |
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$self->interval_timer; |
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}); |
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Scalar::Util::weaken $self; |
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} |
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sub connect { |
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my ($self) = @_; |
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return if $self->{fh}; |
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AnyEvent::Socket::tcp_connect $self->{host} || "localhost", $self->{port} || 2947, sub { |
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my ($fh) = @_; |
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return unless $self; |
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if ($fh) { |
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# unbelievable, but true: gpsd does not support command pipelining. |
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# it's an immensely shitty piece of software, actually, as it blocks |
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# randomly and for extended periods of time, has a surprisingly broken |
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# and non-configurable baud autoconfiguration system (it does stuff |
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# like switching to read-only mode when my bluetooth gps mouse temporarily |
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# loses the connection etc.) and uses rather idiotic and wasteful |
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# programming methods. |
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$self->{fh} = new AnyEvent::Handle |
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fh => $fh, |
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low_delay => 1, |
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on_error => sub { |
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$self->event ("error"); |
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$self->retry; |
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}, |
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on_eof => sub { |
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$! = &Errno::EPIPE; |
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$self->event ("error"); |
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$self->retry; |
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}, |
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on_read => sub { |
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$_[0]{rbuf} =~ s/^([^\015\012]*)\015\012// |
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or return; |
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$self->feed ($1); |
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}, |
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; |
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$self->send ("w"); |
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$self->send ("o"); |
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$self->send ("y"); |
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$self->send ("c"); |
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$self->event ("connect"); |
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} else { |
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$self->event ("error"); |
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} |
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}; |
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Scalar::Util::weaken $self; |
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} |
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sub drain_wbuf { |
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my ($self) = @_; |
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$self->{fh}->push_write (join "", @{ $self->{command}[0] }); |
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} |
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sub send { |
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my ($self, $command, $args) = @_; |
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# curse them, we simply expect that each comamnd will result in a response using |
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# the same letter |
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push @{ $self->{command} }, [uc $command, $args]; |
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$self->drain_wbuf if @{ $self->{command} } == 1; |
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} |
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sub feed { |
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my ($self, $line) = @_; |
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$self->{now} = AnyEvent->now; |
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unless ($line =~ /^GPSD,(.)=(.*)$/) { |
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$! = &Errno::EBADMSG; |
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$self->event ("error"); |
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return $self->retry; |
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} |
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my ($type, $data) = ($1, $2); |
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$self->{state}{$type} = [$data => $self->{now}]; |
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if ($type eq "O") { |
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my @data = split /\s+/, $data; |
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my $fix = $self->{fix}; |
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$fix->{time} = $self->{now}; |
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if (@data > 3) { |
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# the gpsd time is virtually useless as it is truncated :/ |
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for (qw(tag _time _terr lat lon alt herr verr bearing speed vspeed berr serr vserr mode)) { |
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$type = shift @data; |
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$fix->{$_} = $type eq "?" ? undef : $type; |
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} |
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$fix->{mode} = 2 if $fix->{mode} eq "?"; # arbitrary choice |
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} else { |
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$fix->{mode} = 1; |
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} |
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$self->event (fix => $fix); |
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} elsif ($type eq "Y") { |
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my (undef, @sats) = split /:/, $data; |
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$self->{satellite_info} = [map { |
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my @sat = split /\s+/; |
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{ |
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prn => $sat[0], |
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ele => $sat[1], |
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azi => $sat[2], |
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snr => $sat[3], |
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fix => $sat[4], |
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} |
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} @sats]; |
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$self->event (satellite_update => $self->{satellite_info}); |
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|
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} elsif ($type eq "C") { |
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$self->{interval} = $data >= 1 ? $data * 1 : 1; |
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} |
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# we (wrongly) assume that gpsd responses are always in response |
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# to an earlier command |
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if (@{ $self->{command} } && $self->{command}[0][0] eq $type) { |
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shift @{ $self->{command} }; |
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$self->drain_wbuf if @{ $self->{command} }; |
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} |
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} |
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=item ($lat, $lon) = $gps->estimate ([$max_seconds]) |
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This returns an estimate of the current position based on the last fix and |
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the time passed since then. Useful for interactive applications where you |
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want more frequent updates, but not very useful to store, as the next fix |
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might well be totally off. |
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|
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If the fix is older then C<$max_seconds> (default: C<1.9> times the update |
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interval, i.e. usually C<1.9> seconds) or if no fix is available, returns |
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the empty list. |
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|
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=cut |
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|
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sub estimate { |
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my ($self, $max) = @_; |
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|
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$max ||= 1.9 * $self->{interval} unless defined $max; |
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|
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my $geo = $self->{geo_forward} ||= new Geo::Forward; |
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|
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my $fix = $self->{fix} or return; |
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$fix->{mode} >= 2 or return; |
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|
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my $diff = AnyEvent->time - $fix->{time}; |
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|
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$diff <= $max or return; |
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|
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if ($fix->{speed} > $fix->{serr}) { |
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my ($lat, $lon) = $geo->forward ($fix->{lat}, $fix->{lon}, $fix->{bearing}, $fix->{speed} * $diff); |
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($lat, $lon) |
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|
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} else { |
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# if we likely have zero speed, return the point itself |
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($fix->{lat}, $fix->{lon}) |
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} |
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} |
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|
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=back |
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|
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=head1 SEE ALSO |
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|
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L<AnyEvent>. |
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|
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=head1 AUTHOR |
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|
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Marc Lehmann <schmorp@schmorp.de> |
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http://home.schmorp.de/ |
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|
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=cut |
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|
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1 |
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