gfx_inkey.c

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/* inkey$ handling */

#include "fb_gfx.h"

#define KEY_BUFFER_LEN          16

static int key_buffer[KEY_BUFFER_LEN], key_head = 0, key_tail = 0;
static int key_buffer_changed = FALSE;

int fb_hGfxInputBufferChanged( void )
{
        int res;

        DRIVER_LOCK();

    res = key_buffer_changed;
    key_buffer_changed = FALSE;

        DRIVER_UNLOCK();

        return res;
}

void fb_hPostKey(int key)
{
        key_buffer[key_tail] = key;
        if (((key_tail + 1) & (KEY_BUFFER_LEN - 1)) == key_head)
                key_head = (key_head + 1) & (KEY_BUFFER_LEN - 1);
    key_tail = (key_tail + 1) & (KEY_BUFFER_LEN - 1);
    key_buffer_changed = TRUE;
}

#ifdef HOST_DOS
void fb_hPostKey_End(void)
{ /* this function is here to get the length of the fb_hPostKey function so
     the DOS gfxlib driver can lock it into physical memory for use in an
     interrupt handler */ }
#endif

static int get_key(void)
{
        int key = 0;

        DRIVER_LOCK();

        if (key_head != key_tail) {
                key = key_buffer[key_head];
                key_head = (key_head + 1) & (KEY_BUFFER_LEN - 1);
        }

    /* Reset the status for "key buffer changed" when a key
     * was removed from the input queue. */
    fb_hGfxInputBufferChanged();

        DRIVER_UNLOCK();

        return key;
}

int fb_GfxGetkey(void)
{
        int key = 0;

        if (!__fb_gfx)
                return 0;

        while ((key = get_key()) == 0) {
                fb_Sleep(20);
        }

        return key;
}

int fb_GfxKeyHit(void)
{
        int res;

        DRIVER_LOCK();

        res = (key_head != key_tail? 1: 0);

        DRIVER_UNLOCK();

        return res;
}

FBSTRING *fb_GfxInkey(void)
{
        FBSTRING *res;
        int ch;

        if (__fb_gfx && (ch = get_key())) {
                res = fb_hMakeInkeyStr( ch );
        } else {
                res = &__fb_ctx.null_desc;
        }

        return res;
}

int fb_GfxIsRedir(int is_input)
{
        return FALSE;
}