qmk-firmware/quantum/process_keycode/process_unicodemap.c

/* Copyright 2017 Jack Humbert
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "process_unicodemap.h"

__attribute__((weak)) uint16_t unicodemap_index(uint16_t keycode) {
    if (keycode >= QK_UNICODEMAP_PAIR) {
        // Keycode is a pair: extract index based on Shift / Caps Lock state
        uint16_t index = keycode - QK_UNICODEMAP_PAIR;

        bool shift = unicode_saved_mods & MOD_MASK_SHIFT, caps = IS_HOST_LED_ON(USB_LED_CAPS_LOCK);
        if (shift ^ caps) {
            index >>= 7;
        }

        return index & 0x7F;
    } else {
        // Keycode is a regular index
        return keycode - QK_UNICODEMAP;
    }
}

bool process_unicodemap(uint16_t keycode, keyrecord_t *record) {
    if (keycode >= QK_UNICODEMAP && keycode <= QK_UNICODEMAP_PAIR_MAX && record->event.pressed) {
        unicode_input_start();

        uint32_t code       = pgm_read_dword(unicode_map + unicodemap_index(keycode));
        uint8_t  input_mode = get_unicode_input_mode();

        if (code > 0x10FFFF || (code > 0xFFFF && input_mode == UC_WIN)) {
            // Character is out of range supported by the platform
            unicode_input_cancel();
        } else if (code > 0xFFFF && input_mode == UC_MAC) {
            // Convert to UTF-16 surrogate pair on Mac
            code -= 0x10000;
            uint32_t lo = code & 0x3FF, hi = (code & 0xFFC00) >> 10;
            register_hex32(hi + 0xD800);
            register_hex32(lo + 0xDC00);
            unicode_input_finish();
        } else {
            register_hex32(code);
            unicode_input_finish();
        }
    }
    return true;
}