Luna/kernel/src/misc/Scancodes.cpp

#include "misc/Scancodes.h"

#define SCANCODE_EXTENDED 0xE0

bool scancode_filter_released(unsigned char* scancode)
{
    if (*scancode > 0x80)
    {
        *scancode -= 0x80;
        return true;
    }
    return false;
}

static bool next_key_ignored = false; // FIXME: Do not ignore extended scancodes.

static bool left_shifted = false;
static bool right_shifted = false;
static bool capslock = false;

static bool should_shift()
{
    if (capslock) return !(left_shifted || right_shifted);
    return left_shifted || right_shifted;
}

#define SCANCODE_LEFT_SHIFT 0x2A
#define SCANCODE_RIGHT_SHIFT 0x36
#define SCANCODE_CAPS_LOCK 0x3A

#define SCANCODE_LEFT_CONTROL 0x1D
#define SCANCODE_TAB 0x0F
#define SCANCODE_LEFT_ALT 0x38
#define SCANCODE_F11 0x57
#define SCANCODE_F12 0x58

static bool should_ignore_key(char scancode)
{
    return (scancode > 0x3A && scancode < 0x47) || scancode == SCANCODE_LEFT_CONTROL || scancode == SCANCODE_TAB ||
           scancode == SCANCODE_LEFT_ALT || scancode == SCANCODE_F11 || scancode == SCANCODE_F12;
}

char keys_normal[] = {
    '\0',
    '\1', // escape
    '1',  '2', '3', '4', '5', '6', '7', '8', '9', '0', '-',  '=', '\b',
    '\0', // tab
    'q',  'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '[',  ']', '\n',
    '\0', // left ctrl
    'a',  's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '\'', '`',
    '\0', // left shift
    '\\', 'z', 'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/',
    '\0', // right shift
    '*',  // keypad *
    '\0', // left alt
    ' ',
    '\0', // caps lock
    '\0', // f1
    '\0', // f2
    '\0', // f3
    '\0', // f4
    '\0', // f5
    '\0', // f6
    '\0', // f7
    '\0', // f8
    '\0', // f9
    '\0', // f10
    '\0', // num lock
    '\0', // scroll lock
    '7',  // keypad 7
    '8',  // keypad 8
    '9',  // keypad 9
    '-',  // keypad -
    '4',  // keypad 4
    '5',  // keypad 5
    '6',  // keypad 6
    '+',  // keypad +
    '1',  // keypad 1
    '2',  // keypad 2
    '3',  // keypad 3
    '0',  // keypad 0
    '.',  // keypad .
};

char keys_shifted[] = {
    '\0',
    '\1', // escape
    '!',  '@', '#', '$', '%', '^', '&', '*', '(', ')', '_', '+', '\b',
    '\0', // tab
    'Q',  'W', 'E', 'R', 'T', 'Y', 'U', 'I', 'O', 'P', '{', '}', '\n',
    '\0', // left ctrl
    'A',  'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', '"', '~',
    '\0', // left shift
    '|',  'Z', 'X', 'C', 'V', 'B', 'N', 'M', '<', '>', '?',
    '\0', // right shift
    '*',  // keypad *
    '\0', // left alt
    ' ',
    '\0', // caps lock
    '\0', // f1
    '\0', // f2
    '\0', // f3
    '\0', // f4
    '\0', // f5
    '\0', // f6
    '\0', // f7
    '\0', // f8
    '\0', // f9
    '\0', // f10
    '\0', // num lock
    '\0', // scroll lock
    '7',  // keypad 7
    '8',  // keypad 8
    '9',  // keypad 9
    '-',  // keypad -
    '4',  // keypad 4
    '5',  // keypad 5
    '6',  // keypad 6
    '+',  // keypad +
    '1',  // keypad 1
    '2',  // keypad 2
    '3',  // keypad 3
    '0',  // keypad 0
    '.',  // keypad .
};

char translate_scancode(unsigned char scancode, bool* ignore)
{
    if (next_key_ignored)
    {
        next_key_ignored = false;
        *ignore = true;
        return 0;
    }
    if (scancode == SCANCODE_EXTENDED)
    {
        next_key_ignored = true;
        *ignore = true;
        return 0;
    }
    bool released = scancode_filter_released(&scancode);
    if (scancode == SCANCODE_CAPS_LOCK)
    {
        if (!released) { capslock = !capslock; }
        *ignore = true;
        return 0;
    }
    if (scancode == SCANCODE_LEFT_SHIFT)
    {
        left_shifted = !released;
        *ignore = true;
        return 0;
    }
    if (scancode == SCANCODE_RIGHT_SHIFT)
    {
        right_shifted = !released;
        *ignore = true;
        return 0;
    }
    if (released || should_ignore_key(scancode))
    {
        *ignore = true;
        return 0;
    }
    *ignore = false;
    if (should_shift()) { return keys_shifted[scancode]; }
    return keys_normal[scancode];
}