ueficon.c

/*
 * PROJECT:     FreeLoader UEFI Support
 * LICENSE:     GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later)
 * PURPOSE:     Console output
 * COPYRIGHT:   Copyright 2022 Justin Miller <justinmiller100@gmail.com>
 */

#include <uefildr.h>

#define CHAR_WIDTH  8
#define CHAR_HEIGHT 16

/* GLOBALS ********************************************************************/

extern EFI_SYSTEM_TABLE* GlobalSystemTable;
static unsigned CurrentCursorX = 0;
static unsigned CurrentCursorY = 0;
static unsigned CurrentAttr = 0x0f;
static EFI_INPUT_KEY Key;
static BOOLEAN ExtendedKey = FALSE;
static char ExtendedScanCode = 0;

/* FUNCTIONS ******************************************************************/

VOID
UefiConsPutChar(int c)
{
    ULONG Width, Height, Unused;
    BOOLEAN NeedScroll;

    UefiVideoGetDisplaySize(&Width, &Height, &Unused);

    NeedScroll = (CurrentCursorY >= Height);
    if (NeedScroll)
    {
        UefiVideoScrollUp();
        --CurrentCursorY;
    }
    if (c == '\r')
    {
        CurrentCursorX = 0;
    }
    else if (c == '\n')
    {
        CurrentCursorX = 0;

        if (!NeedScroll)
            ++CurrentCursorY;
    }
    else if (c == '\t')
    {
        CurrentCursorX = (CurrentCursorX + 8) & ~7;
    }
    else
    {
        UefiVideoPutChar(c, CurrentAttr, CurrentCursorX, CurrentCursorY);
        CurrentCursorX++;
    }
    if (CurrentCursorX >= Width)
    {
        CurrentCursorX = 0;
        CurrentCursorY++;
    }
}

static
UCHAR
ConvertToBiosExtValue(UCHAR KeyIn)
{
    switch (KeyIn)
    {
        case SCAN_UP:
            return KEY_UP;
        case SCAN_DOWN:
            return KEY_DOWN;
        case SCAN_RIGHT:
            return KEY_RIGHT;
        case SCAN_LEFT:
            return KEY_LEFT;
        case SCAN_F1:
            return KEY_F1;
        case SCAN_F2:
            return KEY_F2;
        case SCAN_F3:
            return KEY_F3;
        case SCAN_F4:
            return KEY_F4;
        case SCAN_F5:
            return KEY_F5;
        case SCAN_F6:
            return KEY_F6;
        case SCAN_F7:
            return KEY_F7;
        case SCAN_F8:
            return KEY_F8;
        case SCAN_F9:
            return KEY_F9;
        case SCAN_F10:
            return KEY_F10;
        case SCAN_ESC:
            return KEY_ESC;
        case SCAN_DELETE:
            return KEY_DELETE;
    }
    return 0;
}

BOOLEAN
UefiConsKbHit(VOID)
{
    return (GlobalSystemTable->ConIn->ReadKeyStroke(GlobalSystemTable->ConIn, &Key) != EFI_NOT_READY);
}

int
UefiConsGetCh(VOID)
{
    UCHAR KeyOutput = 0;

    /* If an extended key press was detected the last time we were called
     * then return the scan code of that key. */
    if (ExtendedKey)
    {
        ExtendedKey = FALSE;
        return ExtendedScanCode;
    }

    if (Key.UnicodeChar != 0)
    {
        KeyOutput = Key.UnicodeChar;
    }
    else
    {
        ExtendedKey = TRUE;
        ExtendedScanCode = ConvertToBiosExtValue(Key.ScanCode);
        KeyOutput = KEY_EXTENDED;
    }

    /* UEFI will stack input requests, we have to clear it */
    Key.UnicodeChar = 0;
    Key.ScanCode = 0;
    return KeyOutput;
}