// Copyright (C) 1996 Keith Whitwell.
// This file may only be copied under the terms of the GNU Library General
// Public License - see the file COPYING in the lib3d distribution.

#include <Lib3d/Device.H>

PointerArray<Device> *Device::children = 0;
Exemplar Device::exemplar;

Device::Device( Exemplar, uint capabilities )
    : active(false),
      frameBuf(0),
      capabilities(capabilities)
{
}

Device::Device()
    : active(false),
      frameBuf(0),
      pixelSize(1)
{
}

Device::Device( uint w, uint h, uint )
    : active(false),
      frameBuf(0),
      pixelSize(1)		// meaningless default, must be overriden.
{
    setSize(w, h);
}

void
Device::setSize( uint w, uint h )
{
    width = ((w*pixelSize)&~0x03)/pixelSize;
    oldxmax = xmax = width;
    height = oldymax = ymax = h;
    xmin = 0;
    ymin = 0;
    oldxmin = 0;
    oldymin = 0;
    rowSize = width * pixelSize;
}

Device::~Device()
{
}


Device *
Device::create( uint width, uint height, uint min_depth, uint flags )
{
    if (!children) return 0;

    const char *deviceString;
    PointerArray<Device> &c = *children;
    c.sort( &Device::compare );
    
    if ((deviceString = getenv("R_DEVICE")) != 0) {
	int i = c.getNr(); 
	while (i--) {
	    if (strcmp(deviceString, c[i]->getName()) == 0) {
		if ((c[i]->capabilities & flags) != flags) continue;
		::debug() << "Trying device: " << c[i]->getName() 
		          << endlog;
		Device *dev = c[i]->clone(width,height,min_depth);
		if (dev && dev->isGood() && dev->initialize()) {
		    dev->active = true;
		    return dev;
		}
		delete dev;
	    }
	}
    }
    
    int i = c.getNr(); 
    while (i--) {
	if ((c[i]->capabilities & flags) != flags) continue;
	::debug() << "Trying device: " << c[i]->getName() << endlog;
	Device *dev = c[i]->clone(width,height,min_depth);
	if (dev && dev->isGood() && dev->initialize()) {
	    dev->active = true;
	    return dev;
	}
	delete dev;
    }

    return 0;
}

int
Device::compare( const Device **a,  const Device **b )
{
    return (*a)->estimateSpeed() - (*b)->estimateSpeed();
}

void
Device::registerChildClass( Device *exemplar )
{
    if (children == 0) children = new PointerArray<Device>(1);
    children->nextFree() = exemplar;
}


void
Device::clearBuffer( uint background )
{

    // This approach is reasonable for back buffers which are in
    // off-card ram.  If your backbuffer is on the video card, this
    // approach won't be efficient, and you will probably want to use
    // some on-card acclerated function to clear the back buffer.

    // If you don't have access to such a function, you may find that
    // you get better performance with an off-card back buffer.  This
    // is the reason why FlipDgaDevice is slower than XShmDevice in
    // lib3d-0.1.5, but BlitDgaDevice is faster.

    if_debug {
	debug() << "Cleaning x:"<<xmin<<"-"<<xmax
   	        << " y:"<<ymin<<"-"<<ymax
		<< endlog;
    }

    
    if (xmin < xmax && ymin < ymax) {
	int xn = xmin * pixelSize;
	int xx = xmax * pixelSize;

#if 1	
	// expand to word boundaries.  requires that span lines be
	// a multiple of 4 bytes wide.

	xn &= ~0x03;
	if (xx & 0x03) {
	    xx &= ~0x03;
	    xx += 0x04;
	}
#endif	
	uchar *fb = frameBuf + xn + (ymin * rowSize);
	uint wid = xx - xn;
	uint i = ymax - ymin;

#ifdef __i386	
	// innaccurate without expansion code above.

	wid = wid >> 2;
	asm("cld");
	do {
	    asm ("rep\n\t"
		 "stosl"
		 : /* no output registers */
		 : "c" (wid), "a" (background), "D" (fb)
		 : "%ecx", "%edi" );
	    fb += rowSize;
	} while (--i);
#else
	// I know that linux *has* an inline ARCH_MEMSET, but how do I 
	// get at it?
 	do {
	    memset( fb, background, wid );
	    fb += rowSize;
	} while (--i);
#endif
    }

    oldxmin = xmin;
    oldxmax = xmax;
    oldymin = ymin;
    oldymax = ymax;
    xmin = width;
    xmax = 0;
    ymin = height;
    ymax = 0;
}


bool 
Device::requestResize( uint &, uint & )
{
    return false;
}

void 
Device::notifyResize()
{
    abort();			// If this is called, something's wrong.
}

void
Device::notifyExpose(uint, uint, uint, uint)
{
}

void
Device::processPendingEvents()
{
}


ostream &
Device::print( ostream &out ) const
{
    return Debuggable::print(out)
	<< "\n\twidth:"<<getWidth()<<" height:"<<getHeight()
	<< "\n\trowWidth:"<<getRowWidth()
	<< "\n\tpixelSize:"<<getPixelSize();
}


void 
Device::enableMouseCapability()
{
}

void 
Device::enableKeyboardCapability()
{
}

void 
Device::disableMouseCapability()
{
}

void 
Device::disableKeyboardCapability()
{
}