circuitpython/shared-module/keypad/EventQueue.c

/*
 * This file is part of the Micro Python project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2021 Dan Halbert for Adafruit Industries
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "shared-bindings/keypad/Event.h"
#include "shared-bindings/keypad/EventQueue.h"
#include "shared-bindings/supervisor/__init__.h"
#include "shared-module/keypad/EventQueue.h"

// Key number is lower 15 bits of a 16-bit value.
#define EVENT_PRESSED (1 << 15)
#define EVENT_KEY_NUM_MASK ((1 << 15) - 1)

void common_hal_keypad_eventqueue_construct(keypad_eventqueue_obj_t *self, size_t max_events) {
    // Event queue is 16-bit values.
    ringbuf_alloc(&self->encoded_events, max_events * (sizeof(uint16_t) + sizeof(mp_obj_t)));
    self->overflowed = false;
}

bool common_hal_keypad_eventqueue_get_into(keypad_eventqueue_obj_t *self, keypad_event_obj_t *event) {
    int encoded_event = ringbuf_get16(&self->encoded_events);
    if (encoded_event == -1) {
        return false;
    }

    mp_obj_t ticks;
    ringbuf_get_n(&self->encoded_events, (uint8_t *)&ticks, sizeof(ticks));
    // "Construct" using the existing event.
    common_hal_keypad_event_construct(event, encoded_event & EVENT_KEY_NUM_MASK, encoded_event & EVENT_PRESSED, ticks);
    return true;
}

mp_obj_t common_hal_keypad_eventqueue_get(keypad_eventqueue_obj_t *self) {
    keypad_event_obj_t *event = mp_obj_malloc(keypad_event_obj_t, &keypad_event_type);
    bool result = common_hal_keypad_eventqueue_get_into(self, event);
    if (result) {
        return event;
    }
    m_free(event);
    return MP_ROM_NONE;
}

bool common_hal_keypad_eventqueue_get_overflowed(keypad_eventqueue_obj_t *self) {
    return self->overflowed;
}

void common_hal_keypad_eventqueue_set_overflowed(keypad_eventqueue_obj_t *self, bool overflowed) {
    self->overflowed = overflowed;
}

void common_hal_keypad_eventqueue_clear(keypad_eventqueue_obj_t *self) {
    ringbuf_clear(&self->encoded_events);
    common_hal_keypad_eventqueue_set_overflowed(self, false);
}

size_t common_hal_keypad_eventqueue_get_length(keypad_eventqueue_obj_t *self) {
    return ringbuf_num_filled(&self->encoded_events);
}

bool keypad_eventqueue_record(keypad_eventqueue_obj_t *self, mp_uint_t key_number, bool pressed, mp_obj_t timestamp) {
    if (ringbuf_num_empty(&self->encoded_events) == 0) {
        // Queue is full. Set the overflow flag. The caller will decide what else to do.
        common_hal_keypad_eventqueue_set_overflowed(self, true);
        return false;
    }

    uint16_t encoded_event = key_number & EVENT_KEY_NUM_MASK;
    if (pressed) {
        encoded_event |= EVENT_PRESSED;
    }
    ringbuf_put16(&self->encoded_events, encoded_event);
    ringbuf_put_n(&self->encoded_events, (uint8_t *)&timestamp, sizeof(mp_obj_t));

    return true;
}