cc65/libsrc/tgi/tgi_load.c

/*****************************************************************************/
/*                                                                           */
/*                                tgi_load.c                                 */
/*                                                                           */
/*                       Loader module for TGI drivers                       */
/*                                                                           */
/*                                                                           */
/*                                                                           */
/* (C) 2002      Ullrich von Bassewitz                                       */
/*               Wacholderweg 14                                             */
/*               D-70597 Stuttgart                                           */
/* EMail:        uz@musoftware.de                                            */
/*                                                                           */
/*                                                                           */
/* This software is provided 'as-is', without any expressed or implied       */
/* warranty.  In no event will the authors be held liable for any damages    */
/* arising from the use of this software.                                    */
/*                                                                           */
/* Permission is granted to anyone to use this software for any purpose,     */
/* including commercial applications, and to alter it and redistribute it    */
/* freely, subject to the following restrictions:                            */
/*                                                                           */
/* 1. The origin of this software must not be misrepresented; you must not   */
/*    claim that you wrote the original software. If you use this software   */
/*    in a product, an acknowledgment in the product documentation would be  */
/*    appreciated but is not required.                                       */
/* 2. Altered source versions must be plainly marked as such, and must not   */
/*    be misrepresented as being the original software.                      */
/* 3. This notice may not be removed or altered from any source              */
/*    distribution.                                                          */
/*                                                                           */
/*****************************************************************************/



#include <stdio.h>
#include <string.h>
#include <modload.h>
#include <tgi.h>
#include <tgi/tgi-kernel.h>



static unsigned char ReadInputBlock (struct mod_ctrl* C, void* Buf, unsigned Size)
{
    return (fread (Buf, 1, Size, C->callerdata) != Size);
}



void __fastcall__ tgi_load (unsigned char mode)
/* Install the matching driver for the given mode. Will just load the driver
 * and check if loading was successul. Will not switch to gaphics mode.
 */
{
    const char* name = tgi_map_mode (mode);
    if (name == 0) {
        /* No driver for this mode */
        tgi_error = TGI_ERR_NO_DRIVER;
    } else {
        /* Laod the driver */
        tgi_load_driver (name);
    }
}



void __fastcall__ tgi_load_driver (const char* name)
/* Install the given driver. This function is identical to tgi_load with the
 * only difference that the name of the driver is specified explicitly. You
 * should NOT use this function in most cases, use tgi_load() instead.
 */
{
    static const unsigned char marker[4] = { 0x74, 0x67, 0x69, 0x00 };

    static struct mod_ctrl ctrl = {
        ReadInputBlock           /* read_block */
    };
    unsigned Res;

    /* Check if we do already have a driver loaded. If so, remove it. */
    if (tgi_drv != 0) {
        tgi_unload ();
    }

    /* Now open the file */
    ctrl.callerdata = fopen (name, "r");
    if (ctrl.callerdata == 0) {
        tgi_error = TGI_ERR_CANNOT_LOAD;
        return;
    }

    /* Load the module */
    Res = mod_load (&ctrl);

    /* Close the input file */
    fclose (ctrl.callerdata);

    /* Check the return code */
    if (Res == MLOAD_OK) {

        /* Get a pointer to the loaded driver */
        tgi_drv = (tgi_drv_header*) ctrl.module;

        /* Check the header */
        if (memcmp (tgi_drv, marker, sizeof (marker)) != 0) {
            /* Invalid driver */
            mod_free (tgi_drv);
            tgi_drv = 0;
            tgi_error = TGI_ERR_INV_DRIVER;
        } else {
            /* Driver is ok do setup */
            tgi_setup ();
        }

    } else {

        /* Error loading the driver */
        tgi_error = TGI_ERR_CANNOT_LOAD;

    }
}