input

void input(char* str, int x, int y, int width) {
    const unsigned int sc013A[] = { 0xD201D002, 0x422B0009, 0x80010070, 0x013A }; // syscall to display OS cursor
    #define Cursor_SetFlashMode ((void(*)(int))sc013A)
    #define INPUT_BUFFER_SIZE 1024
    char buffer[INPUT_BUFFER_SIZE];
    int run=1, key, i, cursor=0, length=0, displayStart=0;
    buffer[0] = 0;
    Cursor_SetFlashMode(1); // enable OS cursor
    while(run) {
        if (cursor && cursor <= displayStart) displayStart = cursor-1;
        if (cursor-displayStart >= width) displayStart = cursor-width+1;
        locate(x, y);
        PrintLine(buffer + displayStart, x+width-1); // display string
        if (length-displayStart < width) {
            locate(x+length-displayStart, y);
            Print(" "); // clear old last character in case of removal
        }
        locate(x+cursor-displayStart, y); // set position of displayed cursor
        GetKey(&key);
        switch (key) {
            case KEY_CTRL_LEFT:
                if (cursor) cursor--;
                break;
            case KEY_CTRL_RIGHT:
                if (cursor < length) cursor++;
                break;
            case KEY_CTRL_EXE:
                run = 0;
                break;
            case KEY_CTRL_DEL:
                if (cursor) cursor--;
                for (i=cursor ; i<length ; i++)
                    buffer[i] = buffer[i+1];
                if (length) length--;
                break;
            default:
                if (key >= 32 && key < 127 && length+1 < INPUT_BUFFER_SIZE) { // if ASCII char
                    for (i=length ; i>=cursor ; i--)
                        buffer[i+1] = buffer[i];
                    buffer[cursor] = key;
                    cursor++;
                    length++;
                }
        }
    }
    Cursor_SetFlashMode(0);
    for (i=0 ; i<=length ; i++) {
        str[i] = buffer[i];
    }
}