MemoryPool

The MemoryPool class, provides by the underlining mbed OS, is used for managing the fixed-size momory pools. For more information about MemoryPool, please visit MbedOS

Assembly

Arduino.h

Summary

Constructors
MEMORY_POOL - template<typename T, uint32_t pool_sz> class rtos::MemoryPool< T, pool_sz >
Methods
alloc - T* alloc (void)
calloc - T* calloc (void)
free - osStatus free (T *block)

Constructors

MEMORY_POOL

template<typename T, uint32_t pool_sz> rtos::MemoryPool<T, pool_sz>::MemoryPool()

Parameters

Type Name Description
typename T Data type of the object in memory pool.
uint32_t pool_sz Size of the memory pool.

Methods

alloc

template<typename T, uint32_t pool_sz> T* rtos::MemoryPool< T, pool_sz >::alloc(void)

Allocate a memory block of type T from a memory pool.

Return value

address of the allocated memory block or NULL in case of no memory available.

calloc

template<typename T, uint32_t pool_sz> T* rtos::MemoryPool< T, pool_sz >::calloc(void)

Allocate a memory block of type T from a memory pool and set memory block to zero.

Return value

address of the allocated memory block or NULL in case of no memory available.

free

template<typename T, uint32_t pool_sz> osStatus rtos::MemoryPool< T, pool_sz >::free(T* block)

Free a memory block.

Parameters

Type Name Description
typename block address of the allocated memory block to be freed.

Return value

osOK on successful deallocation, osErrorParameter if given memory block id is NULL or invalid, or osErrorResource if given memory block is in an invalid memory pool state.

Sample code


typedef struct {
    float    voltage;   /* AD result of measured voltage */
    float    current;   /* AD result of measured current */
    int counter;        /* A counter value               */
} message_t;

MemoryPool<message_t, 16> mpool;
Queue<message_t, 16> queue;
Thread thread;

void send_thread (void) {
    int i = 0;
    while (true) {
        i++; // fake data update
        message_t *message = mpool.alloc();
        message->voltage = (i * 0.1) * 33; 
        message->current = (i * 0.1) * 11;
        message->counter = i;
        queue.put(message);
        delay(1000);
    }
}

void setup() {
	Serial.begin(115200);
	thread.start(callback(send_thread));
}

void loop() {
    osEvent evt = queue.get();
    if (evt.status == osEventMessage) {
        message_t *message = (message_t*)evt.value.p;          
        Serial.printf("\nVoltage: %.2f V\n\r"   , message->voltage);
        Serial.printf("Current: %.2f A\n\r"     , message->current);
        Serial.printf("Number of cycles: %d\n\r", message->counter);            
        mpool.free(message);
    }
}