open source----Flexible button按键

一个挺好用的开源的代码…按键
按键对应的开发应该大家都有用过…
这里就先不大概讲解原理，估计很多人都用过。我最近也在用，功能得话包括：单击、双击、多击、组合键，长按、长按hold住、长按松开等，可以调按键时序。直接看代码吧

这两个就是主要的open source，按键灵魂，.c文件这里给到得是确定几个按键、扫描按键状态等信息。

Flexible_button.c

#include "flexible_button.h"

#ifndef NULL
#define NULL 0
#endif

#define EVENT_SET_AND_EXEC_CB(btn, evt)                                        \
    do                                                                         \
    {
                                                                               \
        btn->event = evt;                                                      \
        if(btn->cb)                                                            \
            btn->cb((flex_button_t*)btn);                                      \
    } while(0)

/**
 * BTN_IS_PRESSED
 * 
 * 1: is pressed
 * 0: is not pressed
*/
#define BTN_IS_PRESSED(i) (g_btn_status_reg & (1 << i))

enum FLEX_BTN_STAGE
{
   
    FLEX_BTN_STAGE_DEFAULT = 0,
    FLEX_BTN_STAGE_DOWN    = 1,
    FLEX_BTN_STAGE_MULTIPLE_CLICK = 2
};

typedef uint32_t btn_type_t;

static flex_button_t *btn_head = NULL;

/**
 * g_logic_level
 * 
 * The logic level of the button pressed, 
 * Each bit represents a button.
 * 
 * First registered button, the logic level of the button pressed is 
 * at the low bit of g_logic_level.
*/
btn_type_t g_logic_level = (btn_type_t)0;

/**
 * g_btn_status_reg
 * 
 * The status register of all button, each bit records the pressing state of a button.
 * 
 * First registered button, the pressing state of the button is 
 * at the low bit of g_btn_status_reg.
*/
btn_type_t g_btn_status_reg = (btn_type_t)0;

static uint8_t button_cnt = 0;

/**
 * @brief Register a user button
 * 
 * @param button: button structure instance
 * @return Number of keys that have been registered, or -1 when error
*/
int32_t flex_button_register(flex_button_t *button)
{
   
    flex_button_t *curr = btn_head;
    
    if (!button || (button_cnt > sizeof(btn_type_t) * 8))
    {
   
        return -1;
    }

    while (curr)
    {
   
        if(curr == button)
        {
   
            return -1;  /* already exist. */
        }
        curr = curr->next;
    }

    /**
     * First registered button is at the end of the 'linked list'.
     * btn_head points to the head of the 'linked list'.
    */
    button->next = btn_head;
    button->status = FLEX_BTN_STAGE_DEFAULT;
    button->event = FLEX_BTN_PRESS_NONE;
    button->scan_cnt = 0;
    button->click_cnt = 0;
    button->max_multiple_clicks_interval = MAX_MULTIPLE_CLICKS_INTERVAL;
    btn_head = button;

    /**
     * First registered button, the logic level of the button pressed is 
     * at the low bit of g_logic_level.
    */
    g_logic_level |= (button->pressed_logic_level << button_cnt);
    button_cnt ++;

    return button_cnt;
}

/**
 * @brief Read all key values in one scan cycle
 * 
 * @param void
 * @return none
*/
static void flex_button_read(void)
{
   
    uint8_t i;
    flex_button_t* target;

    /* The button that was registered first, the button value is in the low position of raw_data */
    btn_type_t raw_data = 0;

    for(target = btn_head, i = button_cnt - 1;
        (target != NULL) && (target->usr_button_read != NULL);
        target = target->next, i--)
    {
   
        raw_data = raw_data | ((target->usr_button_read)(target) << i);
    }

    g_btn_status_reg = (~raw_data) ^ g_logic_level;
}

/**
 * @brief Handle all key events in one scan cycle.
 *        Must be used after 'flex_button_read' API
 * 
 * @param void
 * @return Activated button count
*/
static uint8_t flex_button_process(void)
{
   
    uint8_t i;
    uint8_t active_btn_cnt = 0;
    flex_button_t* target;
    
    for (target = btn_head, i = button_cnt - 1; target != NULL; target = target->next, i--)
    {
   
        if (target->status > FLEX_BTN_STAGE_DEFAULT)
        {
   
            target->scan_cnt ++;
            if (target->scan_cnt >= ((1 << (sizeof(target->scan_cnt) * 8)) - 1))
            {
   
                target->scan_cnt = target->long_hold_start_tick;
            }
        }