Revision 4:8e3de1a314e1, committed 2016-02-22

Comitter:

Overdrivr

Date:

Mon Feb 22 17:55:46 2016 +0000

Parent:

3:37d2d127bc83

Child:

5:cd94bb58e096

Commit message:

Fixed issue (C++ api methods name identically as C api functions were calling themselves rather than calling C api.)

Changed in this revision

--- a/Telemetry.cpp	Mon Feb 22 17:17:52 2016 +0000
+++ b/Telemetry.cpp	Mon Feb 22 17:55:46 2016 +0000
@@ -38,61 +38,58 @@
     pc.baud(bauds);
 }
 
-void Telemetry::publish(const char * topic, char * msg)
+void Telemetry::pub(const char * topic, char * msg)
 {
     publish(topic,msg);
 }
 
-void Telemetry::publish_u8(const char * topic, uint8_t msg)
+void Telemetry::pub_u8(const char * topic, uint8_t msg)
 {
     publish_u8(topic,msg);
 }
 
-void Telemetry::publish_u16(const char * topic, uint16_t msg)
+void Telemetry::pub_u16(const char * topic, uint16_t msg)
 {
     publish_u16(topic,msg);
 }
 
-void Telemetry::publish_u32(const char * topic, uint32_t msg)
+void Telemetry::pub_u32(const char * topic, uint32_t msg)
 {
     publish_u32(topic,msg);
 }
 
-void Telemetry::publish_i8(const char * topic, int8_t msg)
+void Telemetry::pub_i8(const char * topic, int8_t msg)
 {
     publish_i8(topic,msg);
 }
 
-void Telemetry::publish_i16(const char * topic, int16_t msg)
+void Telemetry::pub_i16(const char * topic, int16_t msg)
 {
     publish_i16(topic,msg);
 }
 
-void Telemetry::publish_i32(const char * topic, int32_t msg)
+void Telemetry::pub_i32(const char * topic, int32_t msg)
 {
     publish_i32(topic,msg);
 }
 
-void Telemetry::publish_f32(const char * topic, float msg)
+void Telemetry::pub_f32(const char * topic, float msg)
 {
     publish_f32(topic,msg);
 }
 
-void Telemetry::subscribe(void (*callback)(TM_state * s, TM_msg * m))
-{
-    subscribe(callback);
-}
-
-void Telemetry::set(TM_state* userData)
+void Telemetry::sub(void (*callback)(TM_state * s, TM_msg * m),
+                    TM_state* userData)
 {
     set_state(userData);
+    subscribe(callback);
 }
 
 void Telemetry::update()
 {
     update_telemetry(0);
 }
-
+/*
 uint32_t cast(TM_msg * m, char * buf, size_t bufSize)
 {
     return emplace(m,buf,bufSize);
@@ -132,3 +129,4 @@
 {
     return emplace_f32(m,dst);
 }
+*/

--- a/Telemetry.h	Mon Feb 22 17:17:52 2016 +0000
+++ b/Telemetry.h	Mon Feb 22 17:55:46 2016 +0000
@@ -1,29 +1,28 @@
-#include "c_api/_telemetry.h"
+#include "c_api/telemetry.h"
 
 class Telemetry
 {
     public:
       Telemetry(uint32_t bauds = 9600);
+      // Need different names from C API otherwise calling a method will call
+      // this method again and again
+      void pub(const char * topic, char * msg);
+      void pub_u8(const char * topic, uint8_t msg);
+      void pub_u16(const char * topic, uint16_t msg);
+      void pub_u32(const char * topic, uint32_t msg);
+      void pub_i8(const char * topic, int8_t msg);
+      void pub_i16(const char * topic, int16_t msg);
+      void pub_i32(const char * topic, int32_t msg);
+      void pub_f32(const char * topic, float msg);
 
-      void publish(const char * topic, char * msg);
-      void publish_u8(const char * topic, uint8_t msg);
-      void publish_u16(const char * topic, uint16_t msg);
-      void publish_u32(const char * topic, uint32_t msg);
-      void publish_i8(const char * topic, int8_t msg);
-      void publish_i16(const char * topic, int16_t msg);
-      void publish_i32(const char * topic, int32_t msg);
-      void publish_f32(const char * topic, float msg);
-
-      void subscribe(void (*callback)(TM_state * s, TM_msg * m));
-
-      void set(TM_state* userData);
+      void sub(void (*callback)(TM_state * s, TM_msg * m), TM_state* userData);
 
       void update();
 
     private:
       TM_transport transport;
 };
-
+/*
 uint32_t cast(TM_msg * m, char * buf, size_t bufSize);
 uint32_t cast_u8(TM_msg * m, uint8_t * dst);
 uint32_t cast_u16(TM_msg * m, uint16_t * dst);
@@ -32,3 +31,4 @@
 uint32_t cast_i16(TM_msg * m, int16_t * dst);
 uint32_t cast_i32(TM_msg * m, int32_t * dst);
 uint32_t cast_f32(TM_msg * m, float * dst);
+*/

--- a/c_api/_telemetry.cpp	Mon Feb 22 17:17:52 2016 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,327 +0,0 @@
-#include "_telemetry.h"
-#include "framing.h"
-#include "crc16.h"
-#include "string.h"
-
-static TM_state * statePtr;
-static TM_transport * transportPtr;
-static uint8_t incomingBuffer[INCOMING_BUFFER_SIZE];
-static uint8_t outgoingBuffer[OUTGOING_BUFFER_SIZE];
-static char topicBuffer[TOPIC_BUFFER_SIZE];
-
-static void (*userCallback)(TM_state * s, TM_msg * m);
-
-uint16_t header(TM_type type);
-uint16_t topic(const char * topic, uint16_t crc);
-uint16_t payload(const void * payload, uint32_t size, uint16_t crc);
-void frame(const char * t, TM_type type, const void * data, uint32_t datasize);
-void send(void * buf, uint32_t size);
-void on_incoming_frame(uint8_t * storage, uint32_t size);
-void on_incoming_error(int32_t errCode);
-void emptyCallback(TM_state * s, TM_msg * m);
-
-void init_telemetry(TM_transport * t)
-{
-  statePtr = NULL;
-  transportPtr = t;
-  userCallback = emptyCallback;
-
-  // Setup framing
-  initialize_framing();
-  incoming_storage(incomingBuffer,INCOMING_BUFFER_SIZE);
-  outgoing_storage(outgoingBuffer, OUTGOING_BUFFER_SIZE);
-  set_on_incoming_frame(on_incoming_frame);
-  set_on_incoming_error(on_incoming_error);
-}
-
-uint32_t emplace(TM_msg* m, char * buf, size_t bufSize)
-{
-  if(m->type != TM_string)
-    return 0;
-
-  uint32_t size = m->size;
-
-  if(bufSize - 1 < size)
-    size = bufSize - 1;
-
-  strncpy(buf, (char*)(m->buffer), size);
-  buf[size] = '\0';
-
-  return 1;
-}
-
-uint32_t emplace_u8(TM_msg* m, uint8_t* dst)
-{
-  if(m->type != TM_uint8)
-    return 0;
-
-  memcpy(dst,m->buffer,1);
-  return 1;
-}
-
-uint32_t emplace_u16(TM_msg* m, uint16_t* dst)
-{
-  if(m->type != TM_uint16)
-    return 0;
-
-  memcpy(dst,m->buffer,2);
-  return 1;
-}
-
-uint32_t emplace_u32(TM_msg* m, uint32_t* dst)
-{
-  if(m->type != TM_uint32)
-    return 0;
-
-  memcpy(dst,m->buffer,4);
-  return 1;
-}
-
-uint32_t emplace_i8(TM_msg* m, int8_t* dst)
-{
-  if(m->type != TM_int8)
-    return 0;
-
-  memcpy(dst,m->buffer,1);
-  return 1;
-}
-
-uint32_t emplace_i16(TM_msg* m, int16_t* dst)
-{
-  if(m->type != TM_int16)
-    return 0;
-
-  memcpy(dst,m->buffer,2);
-  return 1;
-}
-
-uint32_t emplace_i32(TM_msg* m, int32_t* dst)
-{
-  if(m->type != TM_int32)
-    return 0;
-
-  memcpy(dst,m->buffer,4);
-  return 1;
-}
-
-uint32_t emplace_f32(TM_msg* m, float* dst)
-{
-  if(m->type != TM_float32)
-    return 0;
-
-  memcpy(dst,m->buffer,4);
-  return 1;
-}
-
-void publish(const char * t, char * msg)
-{
-  frame(t,TM_string,msg,strlen(msg));
-}
-
-void publish_u8(const char * t, uint8_t  msg)
-{
-  void * ptr = (void *)(&msg);
-  frame(t,TM_uint8,ptr,1);
-}
-
-void publish_u16(const char * t, uint16_t msg)
-{
-  void * ptr = (void *)(&msg);
-  frame(t,TM_uint16,ptr,2);
-}
-
-void publish_u32(const char * t, uint32_t msg)
-{
-  void * ptr = (void *)(&msg);
-  frame(t,TM_uint32,ptr,4);
-}
-
-void publish_i8(const char * t, int8_t   msg)
-{
-  void * ptr = (void *)(&msg);
-  frame(t,TM_int8,ptr,1);
-}
-
-void publish_i16(const char * t, int16_t  msg)
-{
-  void * ptr = (void *)(&msg);
-  frame(t,TM_int16,ptr,2);
-}
-
-void publish_i32(const char * t, int32_t  msg)
-{
-  void * ptr = (void *)(&msg);
-  frame(t,TM_int32,ptr,4);
-}
-
-void publish_f32(const char * t, float    msg)
-{
-  void * ptr = (void *)(&msg);
-  frame(t,TM_float32,ptr,4);
-}
-
-void set_state(TM_state * s)
-{
-  statePtr = s;
-}
-
-void subscribe(void (*callback)(TM_state* s, TM_msg* m))
-{
-  userCallback = callback;
-}
-
-void update_telemetry(float elapsedTime)
-{
-  // If user forgot to define transport by calling init_telemetry, abort
-  if(!transportPtr)
-    return;
-
-  uint32_t amount = transportPtr->readable();
-
-  for(uint32_t i = 0 ; i < amount ; i++)
-  {
-    uint8_t c;
-    transportPtr->read(&c,1);
-    feed(c);
-  }
-}
-
-uint16_t header(TM_type type)
-{
-  // header data
-  uint16_t h = type;
-  uint8_t * ptr = (uint8_t*)(&h);
-
-  // add data to frame
-  append2(h);
-
-  // compute crc and return it
-  return crc16(ptr, 2);
-}
-
-uint16_t topic(const char * t, uint16_t crc)
-{
-  const uint8_t * ptr = (uint8_t*)t;
-  for(uint32_t i = 0 ; i < strlen(t) ; i++)
-  {
-    // TODO : Replace with Huffman compression
-    append(ptr[i]);
-    crc = crc16_recursive(ptr[i], crc);
-  }
-  // Add NULL character
-  append(0);
-  return crc16_recursive(0,crc);
-}
-
-uint16_t payload(const void * p, uint32_t size, uint16_t crc)
-{
-  const uint8_t * ptr = (uint8_t*)p;
-  for(uint32_t i = 0 ; i < size ; i++)
-  {
-    append(ptr[i]);
-    crc = crc16_recursive(ptr[i], crc);
-  }
-  return crc;
-}
-
-void frame(const char * t, TM_type type, const void * data, uint32_t datasize)
-{
-  // start new frame
-  begin();
-
-  // header
-  uint16_t crc = header(type);
-
-  // topic
-  crc = topic(t, crc);
-
-  // payload
-  crc = payload(data, datasize, crc);
-
-  // crc
-  append2(crc);
-
-  // complete frame
-  uint32_t bytesAmount = end();
-
-  // send data
-  send(outgoingBuffer, bytesAmount);
-}
-
-void send(void * buf, uint32_t size)
-{
-  // If user forgot to define transport by calling init_telemetry, abort
-  if(!transportPtr)
-    return;
-
-  if(transportPtr->writeable() && size > 0)
-  {
-    transportPtr->write(outgoingBuffer, size);
-  }
-}
-
-void on_incoming_frame(uint8_t * storage, uint32_t size)
-{
-  if(size < 2)
-    return;
-  // Read header
-  uint16_t head;
-  uint8_t * ptr;
-  ptr = (uint8_t*)(&head);
-  memcpy(ptr,storage,2);
-
-  // Read topic
-  uint32_t cursor = 2;
-  uint32_t topicSize = 0;
-  while(cursor < size)
-  {
-    if(storage[cursor] == 0)
-      break;
-    topicSize++;
-    cursor++;
-  }
-
-  if(topicSize == 0)
-    return;
-
-  // payload = total - header - topic - /0 - crc
-  int32_t payloadSize = size - 2 - topicSize - 1 - 2;
-
-  if(payloadSize <= 0)
-    return;
-
-  // Check crc
-  uint16_t expected_crc = crc16(storage, size-2);
-  uint16_t rcv_crc;
-  ptr = (uint8_t*)(&rcv_crc);
-  memcpy(ptr,storage+size-2,2);
-
-  if(expected_crc != rcv_crc)
-    return;
-
-  // Store topic
-  char * t = (char*)(storage);
-  strcpy(topicBuffer, t + 2);
-
-  // ptr to beginning of payload
-  ptr = (uint8_t*)(storage) + (uint32_t)(2 + topicSize + 1);
-
-  TM_msg packet;
-  packet.topic = topicBuffer;
-  packet.type = (TM_type)head;
-  packet.buffer = (void *)(ptr);
-  packet.size = (uint32_t)payloadSize;
-
-  // Call callback
-  userCallback(statePtr,&packet);
-}
-
-void on_incoming_error(int32_t errCode)
-{
-  // TODO : Error management
-}
-
-void emptyCallback(TM_state * s, TM_msg * m)
-{
-  // Called only if the user forgot to subscribe a callback
-}

--- a/c_api/_telemetry.h	Mon Feb 22 17:17:52 2016 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,73 +0,0 @@
-#ifndef TELEMETRY_H_
-#define TELEMETRY_H_
-
-#include "stddef.h"
-#include "stdint.h"
-
-#define INCOMING_BUFFER_SIZE 128
-#define OUTGOING_BUFFER_SIZE 128
-#define TOPIC_BUFFER_SIZE 64
-
-// Forward declaration of user state
-typedef struct TM_state TM_state;
-
-// Enumeration of supported message payloads
-enum TM_type {
-  TM_float32 = 0,
-  TM_uint8 = 1,
-  TM_uint16 = 2,
-  TM_uint32 = 3,
-  TM_int8 = 4,
-  TM_int16 = 5,
-  TM_int32 = 6,
-  TM_string = 7
-};
-typedef enum TM_type TM_type;
-
-// Data structure for received messages
-typedef struct TM_msg TM_msg;
-struct TM_msg {
-  TM_type type;
-  char * topic;
-  void * buffer;
-  uint32_t size;
-};
-
-// Data structure for holding transport interface
-typedef struct TM_transport TM_transport;
-struct TM_transport {
-  int32_t (*read)(void * buf, uint32_t sizeToRead);
-  int32_t (*readable)();
-  int32_t (*write)(void * buf, uint32_t sizeToWrite);
-  int32_t (*writeable)();
-};
-
-void init_telemetry(TM_transport * t);
-
-// Decodes TM_msg buffer and emplaces its value into dst
-// Returns 0 if decoding was successful
-uint32_t emplace(TM_msg * m, char * buf, size_t bufSize);
-uint32_t emplace_u8(TM_msg * m, uint8_t * dst);
-uint32_t emplace_u16(TM_msg * m, uint16_t * dst);
-uint32_t emplace_u32(TM_msg * m, uint32_t * dst);
-uint32_t emplace_i8(TM_msg * m, int8_t * dst);
-uint32_t emplace_i16(TM_msg * m, int16_t * dst);
-uint32_t emplace_i32(TM_msg * m, int32_t * dst);
-uint32_t emplace_f32(TM_msg * m, float * dst);
-
-void publish(const char * topic, char * msg);
-void publish_u8(const char * topic, uint8_t msg);
-void publish_u16(const char * topic, uint16_t msg);
-void publish_u32(const char * topic, uint32_t msg);
-void publish_i8(const char * topic, int8_t msg);
-void publish_i16(const char * topic, int16_t msg);
-void publish_i32(const char * topic, int32_t msg);
-void publish_f32(const char * topic, float msg);
-
-void set_state(TM_state * s);
-
-void subscribe(void (*callback)(TM_state * s, TM_msg * m));
-
-void update_telemetry(float elapsedTime);
-
-#endif

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/c_api/telemetry.cpp	Mon Feb 22 17:55:46 2016 +0000
@@ -0,0 +1,327 @@
+#include "telemetry.h"
+#include "framing.h"
+#include "crc16.h"
+#include "string.h"
+
+static TM_state * statePtr;
+static TM_transport * transportPtr;
+static uint8_t incomingBuffer[INCOMING_BUFFER_SIZE];
+static uint8_t outgoingBuffer[OUTGOING_BUFFER_SIZE];
+static char topicBuffer[TOPIC_BUFFER_SIZE];
+
+static void (*userCallback)(TM_state * s, TM_msg * m);
+
+uint16_t header(TM_type type);
+uint16_t topic(const char * topic, uint16_t crc);
+uint16_t payload(const void * payload, uint32_t size, uint16_t crc);
+void frame(const char * t, TM_type type, const void * data, uint32_t datasize);
+void send(void * buf, uint32_t size);
+void on_incoming_frame(uint8_t * storage, uint32_t size);
+void on_incoming_error(int32_t errCode);
+void emptyCallback(TM_state * s, TM_msg * m);
+
+void init_telemetry(TM_transport * t)
+{
+  statePtr = NULL;
+  transportPtr = t;
+  userCallback = emptyCallback;
+
+  // Setup framing
+  initialize_framing();
+  incoming_storage(incomingBuffer,INCOMING_BUFFER_SIZE);
+  outgoing_storage(outgoingBuffer, OUTGOING_BUFFER_SIZE);
+  set_on_incoming_frame(on_incoming_frame);
+  set_on_incoming_error(on_incoming_error);
+}
+
+uint32_t emplace(TM_msg* m, char * buf, size_t bufSize)
+{
+  if(m->type != TM_string)
+    return 0;
+
+  uint32_t size = m->size;
+
+  if(bufSize - 1 < size)
+    size = bufSize - 1;
+
+  strncpy(buf, (char*)(m->buffer), size);
+  buf[size] = '\0';
+
+  return 1;
+}
+
+uint32_t emplace_u8(TM_msg* m, uint8_t* dst)
+{
+  if(m->type != TM_uint8)
+    return 0;
+
+  memcpy(dst,m->buffer,1);
+  return 1;
+}
+
+uint32_t emplace_u16(TM_msg* m, uint16_t* dst)
+{
+  if(m->type != TM_uint16)
+    return 0;
+
+  memcpy(dst,m->buffer,2);
+  return 1;
+}
+
+uint32_t emplace_u32(TM_msg* m, uint32_t* dst)
+{
+  if(m->type != TM_uint32)
+    return 0;
+
+  memcpy(dst,m->buffer,4);
+  return 1;
+}
+
+uint32_t emplace_i8(TM_msg* m, int8_t* dst)
+{
+  if(m->type != TM_int8)
+    return 0;
+
+  memcpy(dst,m->buffer,1);
+  return 1;
+}
+
+uint32_t emplace_i16(TM_msg* m, int16_t* dst)
+{
+  if(m->type != TM_int16)
+    return 0;
+
+  memcpy(dst,m->buffer,2);
+  return 1;
+}
+
+uint32_t emplace_i32(TM_msg* m, int32_t* dst)
+{
+  if(m->type != TM_int32)
+    return 0;
+
+  memcpy(dst,m->buffer,4);
+  return 1;
+}
+
+uint32_t emplace_f32(TM_msg* m, float* dst)
+{
+  if(m->type != TM_float32)
+    return 0;
+
+  memcpy(dst,m->buffer,4);
+  return 1;
+}
+
+void publish(const char * t, char * msg)
+{
+  frame(t,TM_string,msg,strlen(msg));
+}
+
+void publish_u8(const char * t, uint8_t  msg)
+{
+  void * ptr = (void *)(&msg);
+  frame(t,TM_uint8,ptr,1);
+}
+
+void publish_u16(const char * t, uint16_t msg)
+{
+  void * ptr = (void *)(&msg);
+  frame(t,TM_uint16,ptr,2);
+}
+
+void publish_u32(const char * t, uint32_t msg)
+{
+  void * ptr = (void *)(&msg);
+  frame(t,TM_uint32,ptr,4);
+}
+
+void publish_i8(const char * t, int8_t   msg)
+{
+  void * ptr = (void *)(&msg);
+  frame(t,TM_int8,ptr,1);
+}
+
+void publish_i16(const char * t, int16_t  msg)
+{
+  void * ptr = (void *)(&msg);
+  frame(t,TM_int16,ptr,2);
+}
+
+void publish_i32(const char * t, int32_t  msg)
+{
+  void * ptr = (void *)(&msg);
+  frame(t,TM_int32,ptr,4);
+}
+
+void publish_f32(const char * t, float    msg)
+{
+  void * ptr = (void *)(&msg);
+  frame(t,TM_float32,ptr,4);
+}
+
+void set_state(TM_state * s)
+{
+  statePtr = s;
+}
+
+void subscribe(void (*callback)(TM_state* s, TM_msg* m))
+{
+  userCallback = callback;
+}
+
+void update_telemetry(float elapsedTime)
+{
+  // If user forgot to define transport by calling init_telemetry, abort
+  if(!transportPtr)
+    return;
+
+  uint32_t amount = transportPtr->readable();
+
+  for(uint32_t i = 0 ; i < amount ; i++)
+  {
+    uint8_t c;
+    transportPtr->read(&c,1);
+    feed(c);
+  }
+}
+
+uint16_t header(TM_type type)
+{
+  // header data
+  uint16_t h = type;
+  uint8_t * ptr = (uint8_t*)(&h);
+
+  // add data to frame
+  append2(h);
+
+  // compute crc and return it
+  return crc16(ptr, 2);
+}
+
+uint16_t topic(const char * t, uint16_t crc)
+{
+  const uint8_t * ptr = (uint8_t*)t;
+  for(uint32_t i = 0 ; i < strlen(t) ; i++)
+  {
+    // TODO : Replace with Huffman compression
+    append(ptr[i]);
+    crc = crc16_recursive(ptr[i], crc);
+  }
+  // Add NULL character
+  append(0);
+  return crc16_recursive(0,crc);
+}
+
+uint16_t payload(const void * p, uint32_t size, uint16_t crc)
+{
+  const uint8_t * ptr = (uint8_t*)p;
+  for(uint32_t i = 0 ; i < size ; i++)
+  {
+    append(ptr[i]);
+    crc = crc16_recursive(ptr[i], crc);
+  }
+  return crc;
+}
+
+void frame(const char * t, TM_type type, const void * data, uint32_t datasize)
+{
+  // start new frame
+  begin();
+
+  // header
+  uint16_t crc = header(type);
+
+  // topic
+  crc = topic(t, crc);
+
+  // payload
+  crc = payload(data, datasize, crc);
+
+  // crc
+  append2(crc);
+
+  // complete frame
+  uint32_t bytesAmount = end();
+
+  // send data
+  send(outgoingBuffer, bytesAmount);
+}
+
+void send(void * buf, uint32_t size)
+{
+  // If user forgot to define transport by calling init_telemetry, abort
+  if(!transportPtr)
+    return;
+
+  if(transportPtr->writeable() && size > 0)
+  {
+    transportPtr->write(outgoingBuffer, size);
+  }
+}
+
+void on_incoming_frame(uint8_t * storage, uint32_t size)
+{
+  if(size < 2)
+    return;
+  // Read header
+  uint16_t head;
+  uint8_t * ptr;
+  ptr = (uint8_t*)(&head);
+  memcpy(ptr,storage,2);
+
+  // Read topic
+  uint32_t cursor = 2;
+  uint32_t topicSize = 0;
+  while(cursor < size)
+  {
+    if(storage[cursor] == 0)
+      break;
+    topicSize++;
+    cursor++;
+  }
+
+  if(topicSize == 0)
+    return;
+
+  // payload = total - header - topic - /0 - crc
+  int32_t payloadSize = size - 2 - topicSize - 1 - 2;
+
+  if(payloadSize <= 0)
+    return;
+
+  // Check crc
+  uint16_t expected_crc = crc16(storage, size-2);
+  uint16_t rcv_crc;
+  ptr = (uint8_t*)(&rcv_crc);
+  memcpy(ptr,storage+size-2,2);
+
+  if(expected_crc != rcv_crc)
+    return;
+
+  // Store topic
+  char * t = (char*)(storage);
+  strcpy(topicBuffer, t + 2);
+
+  // ptr to beginning of payload
+  ptr = (uint8_t*)(storage) + (uint32_t)(2 + topicSize + 1);
+
+  TM_msg packet;
+  packet.topic = topicBuffer;
+  packet.type = (TM_type)head;
+  packet.buffer = (void *)(ptr);
+  packet.size = (uint32_t)payloadSize;
+
+  // Call callback
+  userCallback(statePtr,&packet);
+}
+
+void on_incoming_error(int32_t errCode)
+{
+  // TODO : Error management
+}
+
+void emptyCallback(TM_state * s, TM_msg * m)
+{
+  // Called only if the user forgot to subscribe a callback
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/c_api/telemetry.h	Mon Feb 22 17:55:46 2016 +0000
@@ -0,0 +1,73 @@
+#ifndef TELEMETRY_H_
+#define TELEMETRY_H_
+
+#include "stddef.h"
+#include "stdint.h"
+
+#define INCOMING_BUFFER_SIZE 128
+#define OUTGOING_BUFFER_SIZE 128
+#define TOPIC_BUFFER_SIZE 64
+
+// Forward declaration of user state
+typedef struct TM_state TM_state;
+
+// Enumeration of supported message payloads
+enum TM_type {
+  TM_float32 = 0,
+  TM_uint8 = 1,
+  TM_uint16 = 2,
+  TM_uint32 = 3,
+  TM_int8 = 4,
+  TM_int16 = 5,
+  TM_int32 = 6,
+  TM_string = 7
+};
+typedef enum TM_type TM_type;
+
+// Data structure for received messages
+typedef struct TM_msg TM_msg;
+struct TM_msg {
+  TM_type type;
+  char * topic;
+  void * buffer;
+  uint32_t size;
+};
+
+// Data structure for holding transport interface
+typedef struct TM_transport TM_transport;
+struct TM_transport {
+  int32_t (*read)(void * buf, uint32_t sizeToRead);
+  int32_t (*readable)();
+  int32_t (*write)(void * buf, uint32_t sizeToWrite);
+  int32_t (*writeable)();
+};
+
+void init_telemetry(TM_transport * t);
+
+// Decodes TM_msg buffer and emplaces its value into dst
+// Returns 0 if decoding was successful
+uint32_t emplace(TM_msg * m, char * buf, size_t bufSize);
+uint32_t emplace_u8(TM_msg * m, uint8_t * dst);
+uint32_t emplace_u16(TM_msg * m, uint16_t * dst);
+uint32_t emplace_u32(TM_msg * m, uint32_t * dst);
+uint32_t emplace_i8(TM_msg * m, int8_t * dst);
+uint32_t emplace_i16(TM_msg * m, int16_t * dst);
+uint32_t emplace_i32(TM_msg * m, int32_t * dst);
+uint32_t emplace_f32(TM_msg * m, float * dst);
+
+void publish(const char * topic, char * msg);
+void publish_u8(const char * topic, uint8_t msg);
+void publish_u16(const char * topic, uint16_t msg);
+void publish_u32(const char * topic, uint32_t msg);
+void publish_i8(const char * topic, int8_t msg);
+void publish_i16(const char * topic, int16_t msg);
+void publish_i32(const char * topic, int32_t msg);
+void publish_f32(const char * topic, float msg);
+
+void set_state(TM_state * s);
+
+void subscribe(void (*callback)(TM_state * s, TM_msg * m));
+
+void update_telemetry(float elapsedTime);
+
+#endif