File content as of revision 0:82ccff71d12a:

#include <mbed.h>

#define POLOLU_ENCODER_EVENT_INC  0b01000000
#define POLOLU_ENCODER_EVENT_DEC  0b10000000
#define POLOLU_ENCODER_EVENT_ERR  0b11000000

#define POLOLU_ENCODER_BUFFER_SIZE 256

typedef uint8_t PololuEncoderEvent;

class PololuEncoderBuffer
{
    private:
    volatile uint32_t consumerIndex;  // The index in the ring buffer that will be consumed next.
    volatile uint32_t producerIndex;  // The index in the ring buffer that will be populated next, which is currently empty.
    volatile uint8_t buffer[POLOLU_ENCODER_BUFFER_SIZE];

    public:
    bool hasEvents() const
    {
        return consumerIndex != producerIndex;
    }
    
    bool hasSpace() const
    {
        return ((producerIndex + 1) % POLOLU_ENCODER_BUFFER_SIZE) != consumerIndex;
    }
    
    uint8_t readEvent()
    {
        uint8_t event = buffer[consumerIndex];
        consumerIndex = (consumerIndex + 1) % POLOLU_ENCODER_BUFFER_SIZE;
        return event;
    }
    
    void writeEvent(uint8_t event)
    {
        buffer[producerIndex] = event;
        producerIndex = (producerIndex + 1) % POLOLU_ENCODER_BUFFER_SIZE;    
    }
};

class PololuEncoder
{
    private:
    InterruptIn pinA;
    InterruptIn pinB;
    PololuEncoderBuffer * buffer;
    uint8_t id;
    
    public:
    PololuEncoder(PinName pinNameA, PinName pinNameB, PololuEncoderBuffer * buffer, uint8_t id)
      : pinA(pinNameA), pinB(pinNameB), buffer(buffer), id(id)
//    PololuEncoder(PinName pinNameA, PinName pinNameB, uint8_t id)
//      : pinA(pinNameA), pinB(pinNameB), id(id)
    {
        pinA.mode(PullUp);        // TODO: move this to the user code
        pinB.mode(PullUp);        // TODO: move this to the user code
        
        pinA.rise(this, &PololuEncoder::isr);
        pinA.fall(this, &PololuEncoder::isr);
        pinB.rise(this, &PololuEncoder::isr);
        pinB.fall(this, &PololuEncoder::isr);
    }
    
    void isr()
    {
        if (buffer->hasSpace())
        {
            buffer->writeEvent(0x23);
        }
    }
};