/usr/include/lcm/lcm-cpp.hpp is in liblcm-dev 1.3.1+repack1-1.
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#define __lcm_cpp_hpp__
#include <string>
#include <vector>
#include <cstdio> /* needed for FILE* */
#include "lcm.h"
namespace lcm {
/**
* @defgroup LcmCpp C++ API Reference
*
* THe %LCM C++ API provides classes and data structures for communicating with
* other %LCM clients, as well as reading and writing %LCM log files. It is a
* pure header wrapper around the C API, and has the same linking requirements
* as the C API.
*
* @{
*/
class Subscription;
struct ReceiveBuffer;
/**
* @brief Core communications class for the C++ API.
*
* @headerfile lcm/lcm-cpp.hpp
*/
class LCM {
public:
/**
* @brief Constructor.
*
* Initializes the LCM instance and connects it to the specified LCM
* network. See the documentation on lcm_create() in the C API for
* details on how lcm_url is formatted.
*
* @sa lcm_create()
*/
inline LCM(std::string lcm_url="");
/**
* @brief Constructor.
*
* Initializes the c++ LCM instance from an existing C instance.
*
* @sa lcm_create()
*/
inline LCM(lcm_t * lcm_in);
/**
* @brief Destructor.
*
* Disconnects from the LCM network, and destroys all outstanding
* Subscription objects.
*/
inline ~LCM();
/**
* @brief Checks if initialization succeeded during object
* construction.
*
* @return true if initialization succeeded and the instance appears
* ready for communication, false if not.
*/
inline bool good() const;
/**
* @brief Publishes a raw data message.
*
* @param channel the channel to publish the message on.
* @param data data buffer containing the message to publish
* @param datalen length of the message, in bytes.
*
* @return 0 on success, -1 on failure.
*/
inline int publish(const std::string& channel, const void *data,
unsigned int datalen);
/**
* @brief Publishes a message with automatic message encoding.
*
* This template method is designed for use with C++ classes generated
* by lcm-gen.
*
* @param channel the channel to publish the message on.
* @param msg the message to publish.
*
* @return 0 on success, -1 on failure.
*/
template<class MessageType>
inline int publish(const std::string& channel, const MessageType* msg);
/**
* @brief Returns a file descriptor or socket that can be used with
* @c select(), @c poll(), or other event loops for asynchronous
* notification of incoming messages.
*
* This method is useful when integrating LCM into another event loop,
* such as the Qt event loop (via QSocketNotifier), the GLib event loop
* (via GIOChannel), a custom @c select() @c - or @c poll() @c -based event loop, or any other
* event loop that supports file descriptors.
*
* @todo link to example code.
*
* @return a non-negative file descriptor on success, or -1 if something
* is wrong.
* @sa lcm_get_fileno()
*/
inline int getFileno();
/**
* @brief Waits for and dispatches messages.
*
* @return 0 on success, -1 if something went wrong.
* @sa lcm_handle()
*/
inline int handle();
/**
* @brief Waits for and dispatches messages, with a timeout.
*
* New in LCM 1.1.0.
*
* @return >0 if a message was handled, 0 if the function timed out,
* and <0 if an error occured.
* @sa lcm_handle_timeout()
*/
inline int handleTimeout(int timeout_millis);
/**
* @brief Subscribes a callback method of an object to a channel, with
* automatic message decoding.
*
* This method is designed for use with C++ classes generated by
* @c lcm-gen @c .
*
* The callback method will be invoked on the object when a message
* arrives on the specified channel. Prior to method invocation, LCM
* will attempt to automatically decode the message to the specified
* message type @c MessageType @c , which should be a class generated
* by @c lcm-gen @c . If message
* decoding fails, the callback method is not invoked and an error
* message is printed to stderr.
*
* The callback method is invoked during calls to LCM::handle().
* Callback methods are invoked by the same thread that invokes
* LCM::handle(), in the order that they were subscribed.
*
* For example:
*
* \code
* #include <exlcm/example_t.lcm>
* #include <lcm/lcm-cpp.hpp>
*
* class MyMessageHandler {
* void onMessage(const lcm::ReceiveBuffer* rbuf, const std::string& channel,
* const exlcm::example_t* msg) {
* // do something with the message
* }
* };
*
* int main(int argc, char** argv) {
* lcm::LCM lcm;
* MyMessageHandler handler;
* lcm.subscribe("CHANNEL", &MyMessageHandler::onMessage, &handler);
* while(true)
* lcm.handle();
* return 0;
* }
* \endcode
*
* @param channel The channel to subscribe to. This is treated as a
* regular expression implicitly surrounded by '^' and '$'.
* @param handlerMethod A class method pointer identifying the callback
* method.
* @param handler A class instance that the callback method will be
* invoked on.
*
* @return a Subscription object that can be used to adjust the
* subscription and unsubscribe. The Subscription object is managed by
* the LCM class, and is automatically destroyed when its LCM instance
* is destroyed.
*/
template <class MessageType, class MessageHandlerClass>
Subscription* subscribe(const std::string& channel,
void (MessageHandlerClass::*handlerMethod)(const ReceiveBuffer* rbuf, const std::string& channel, const MessageType* msg),
MessageHandlerClass* handler);
/**
* @brief Subscribe a callback method of an object to a channel,
* without automatic message decoding.
*
* This method is designed for use when automatic message decoding is
* not desired.
*
* The callback method will be invoked on the object when a message
* arrives on the specified channel. Callback methods are invoked
* during calls to LCM::handle(), by the same thread that calls
* LCM::handle(). Callbacks are invoked in the order that they were
* subscribed.
*
* For example:
*
* \code
* #include <lcm/lcm-cpp.hpp>
*
* class MyMessageHandler {
* void onMessage(const lcm::ReceiveBuffer* rbuf, const std::string& channel) {
* // do something with the message. Raw message bytes are
* // accessible via rbuf->data
* }
* };
*
* int main(int argc, char** argv) {
* lcm::LCM lcm;
* MyMessageHandler handler;
* lcm.subscribe("CHANNEL", &MyMessageHandler::onMessage, &handler);
* while(true)
* lcm.handle();
* return 0;
* }
* \endcode
*
* @param channel The channel to subscribe to. This is treated as a
* regular expression implicitly surrounded by '^' and '$'.
* @param handlerMethod A class method pointer identifying the callback
* method.
* @param handler A class instance that the callback method will be
* invoked on.
*
* @return a Subscription object that can be used to adjust the
* subscription and unsubscribe. The Subscription object is managed by
* the LCM class, and is automatically destroyed when its LCM instance
* is destroyed.
*/
template <class MessageHandlerClass>
Subscription* subscribe(const std::string& channel,
void (MessageHandlerClass::*handlerMethod)(const ReceiveBuffer* rbuf, const std::string& channel),
MessageHandlerClass* handler);
/**
* @brief Subscribe a function callback to a channel, with automatic
* message decoding.
*
* This method is designed for use with static member functions and
* C-style functions.
*
* The callback function will be invoked on the object when a message
* arrives on the specified channel. Prior to callback invocation, LCM
* will attempt to automatically decode the message to the specified
* message type @c MessageType @c , which should be a class generated
* by @c lcm-gen @c . If message decoding fails, the callback function
* is not invoked and an error message is printed to stderr.
*
* The callback function is invoked during calls to LCM::handle().
* Callbacks are invoked by the same thread that invokes
* LCM::handle(), in the order that they were subscribed.
*
* For example:
*
* \code
* #include <lcm/lcm-cpp.hpp>
*
* class State {
* public:
* lcm::LCM lcm;
* int usefulVariable;
* };
*
* void onMessage(const lcm::ReceiveBuffer* rbuf, const std::string& channel, const MessageType* msg, State* state) {
* // do something with the message.
* }
*
* int main(int argc, char** argv) {
* State* state = new State;
* state->lcm.subscribe("CHANNEL", onMessage, state);
* while(true)
* state->lcm.handle();
* delete state;
* return 0;
* }
* \endcode
*
* @param channel The channel to subscribe to. This is treated as a
* regular expression implicitly surrounded by '^' and '$'.
* @param handler A function pointer identifying the callback
* function.
* @param context A context variable that will be passed to the
* callback function. This can be used to pass state or other
* information to the callback function. If not needed, then @c
* ContextClass @c can be set to void*, and this argument set to NULL.
*
* @return a Subscription object that can be used to adjust the
* subscription and unsubscribe. The Subscription object is managed by
* the LCM class, and is automatically destroyed when its LCM instance
* is destroyed.
*/
template <class MessageType, class ContextClass>
Subscription* subscribeFunction(const std::string& channel,
void (*handler)(const ReceiveBuffer* rbuf,
const std::string& channel,
const MessageType *msg,
ContextClass context),
ContextClass context);
/**
* @brief Subscribe a function callback to a channel, without automatic
* message decoding.
*
* This method is designed for use when automatic message decoding is
* not desired.
*
* For example:
*
* \code
* #include <lcm/lcm-cpp.hpp>
*
* void onMessage(const lcm::ReceiveBuffer* rbuf, const std::string& channel, void*) {
* // do something with the message. Raw message bytes are
* // accessible via rbuf->data
* }
*
* int main(int argc, char** argv) {
* LCM::lcm lcm;
* lcm.subscribe("CHANNEL", onMessage, NULL);
* while(true)
* lcm.handle();
* return 0;
* }
* \endcode
*
* @param channel The channel to subscribe to. This is treated as a
* regular expression implicitly surrounded by '^' and '$'.
* @param handler A function pointer identifying the callback
* function.
* @param context A context variable that will be passed to the
* callback function. This can be used to pass state or other
* information to the callback function. If not needed, then @c
* ContextClass @c can be set to void*, and this argument set to NULL.
*
* @return a Subscription object that can be used to adjust the
* subscription and unsubscribe. The Subscription object is managed by
* the LCM class, and is automatically destroyed when its LCM instance
* is destroyed.
*/
template <class ContextClass>
Subscription* subscribeFunction(const std::string& channel,
void (*handler)(const ReceiveBuffer* rbuf,
const std::string& channel,
ContextClass context),
ContextClass context);
/**
* @brief Unsubscribes a message handler.
*
* After unsubscription, the callback registered by the original call
* to subscribe() or subscribeFunction() will no longer be invoked when
* messages are received.
* The Subscription object is destroyed by this method.
*
* @param subscription a Subscription object previously returned by a
* call to subscribe() or subscribeFunction().
*
* @return 0 on success, -1 if @p subscription is not a valid
* subscription.
*/
inline int unsubscribe(Subscription* subscription);
/**
* @brief retrives the lcm_t C data structure wrapped by this class.
*
* This method should be used carefully and sparingly. An example use
* case would be extending the subscription mechanism to Boost
* Function objects.
*
* @return the lcm_t instance wrapped by this object.
*
* @sa lcm_t
*/
inline lcm_t* getUnderlyingLCM();
private:
lcm_t *lcm;
bool owns_lcm;
std::vector<Subscription*> subscriptions;
};
/**
* @brief Stores the raw bytes and timestamp of a received message.
*
* @headerfile lcm/lcm-cpp.hpp
*/
struct ReceiveBuffer {
/**
* Message payload data, represented as a raw byte buffer.
*/
void *data;
/**
* Length of message payload, in bytes.
*/
uint32_t data_size;
/**
* Timestamp identifying when the message was received. Specified in
* microseconds since the UNIX epoch.
*/
int64_t recv_utime;
};
/**
* @brief Represents a channel subscription, and can be used to unsubscribe
* and set options.
*
* This class is not meant to be instantiated by the user, and instead is
* constructed and returned by a call to LCM::subscribe() or
* LCM::subscribeFunction().
*
* To unsubscribe, pass the instance to LCM::unsubscribe(). Once unsubscribed,
* the object is destroyed and can not be used anymore.
*
* @headerfile lcm/lcm-cpp.hpp
*/
class Subscription {
public:
virtual ~Subscription() {}
/**
* @brief Adjusts the maximum number of received messages that can be
* queued up for this subscription.
*
* @param num_messages the maximum queue size, in messages. The
* default is 30.
*
* Setting this to a low number may reduce
* overall latency at the expense of dropping more messages.
* Conversely, setting this to a high number may drop fewer messages at
* the expense of increased latency. A value of 0 indicates no limit,
* and should be used very carefully.
*
*/
inline int setQueueCapacity(int num_messages);
friend class LCM;
protected:
Subscription() {};
/**
* The underlying lcm_subscription_t object wrapped by this
* subscription.
*/
lcm_subscription_t *c_subs;
};
/**
* @brief Represents a single event (message) in a log file.
*
*
*
* This struct is the C++ counterpart for lcm_eventlog_event_t.
*
* @sa lcm_eventlog_event_t
*
* @headerfile lcm/lcm-cpp.hpp
*/
struct LogEvent {
/**
* Monotically increasing counter identifying the event number. This field
* is managed by LCM, and there should be no need to ever set it manually.
*/
int64_t eventnum;
/**
* Timestamp identifying when the event was received. Represented in
* microseconds since the UNIX epoch.
*/
int64_t timestamp;
/**
* The LCM channel on which the message was received.
*/
std::string channel;
/**
* The length of the message payload, in bytes
*/
int32_t datalen;
/**
* The message payload.
*/
void* data;
};
/**
* @brief Read and write %LCM log files.
*
* This class is the C++ counterpart for lcm_eventlog_t.
*
* @sa lcm_eventlog_t
*
* @headerfile lcm/lcm-cpp.hpp
*/
class LogFile {
public:
/**
* Constructor. Opens the specified log file for reading or writing.
* @param path the file to open
* @param mode "r" (read mode) or "w" (write mode)
*
* @sa lcm_eventlog_create()
*/
inline LogFile(const std::string & path, const std::string & mode);
/**
* Destructor. Closes the log file.
*/
inline ~LogFile();
/**
* @return true if the log file is ready for reading/writing.
*/
inline bool good() const;
/**
* Reads the next event in the log file. Valid in read mode only.
*
* The LogFile class manages the memory of the read event. The
* returned event is valid until the next call to this method.
*
* @return the next event, or NULL if the end of the log file has been
* reached.
*/
inline const LogEvent* readNextEvent();
/**
* Seek close to the specified timestamp in the log file. Valid
* in read mode only.
*
* @param timestamp the desired seek point in the log file.
*
* @return 0 on success, -1 on error.
* @sa lcm_eventlog_seek_to_timestamp()
*/
inline int seekToTimestamp(int64_t timestamp);
/**
* Writes an event to the log file. Valid in write mode only.
*
* @param event the event to write. The timestamp, channel, datalen,
* and data fields should be filled in. The eventnum field will be
* automatically filled in.
*
* @return 0 on success, -1 on error.
* @sa lcm_eventlog_write_event()
*/
inline int writeEvent(LogEvent* event);
/**
* @brief retrives the underlying FILE* wrapped by this class.
*
* This method should be used carefully and sparingly.
* An example use-case is borrowing to tweak the behavior of the I/O.
* Calls of interest include fflush(), fileno(), setvbuf(), etc
* It is a bad idea to attempt reading or writing on the raw FILE*
*
* @return the FILE* wrapped by this object.
*/
inline FILE* getFilePtr();
private:
LogEvent curEvent;
lcm_eventlog_t* eventlog;
lcm_eventlog_event_t* last_event;
};
/**
* @}
*/
#define __lcm_cpp_impl_ok__
#include "lcm-cpp-impl.hpp"
#undef __lcm_cpp_impl_ok__
}
#endif
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