/* xutil.c - utility functions for X
 *
 * Raster graphics library
 *
 * Copyright (c) 1997-2003 Alfredo K. Kojima
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <config.h>

#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include <assert.h>

#ifdef XSHM
#include <sys/ipc.h>
#include <sys/shm.h>
#endif				/* XSHM */

#include "wraster.h"

#ifdef XSHM

static int shmError;

static int (*oldErrorHandler)(Display *dpy, XErrorEvent *err);

static int errorHandler(Display * dpy, XErrorEvent * err)
{
	shmError = 1;
	if (err->error_code != BadAccess)
		(*oldErrorHandler) (dpy, err);

	return 0;
}

#endif

RXImage *RCreateXImage(RContext * context, int depth, unsigned width, unsigned height)
{
	RXImage *rximg;
	Visual *visual = context->visual;

	rximg = malloc(sizeof(RXImage));
	if (!rximg) {
		RErrorCode = RERR_NOMEMORY;
		return NULL;
	}
#ifndef XSHM
	rximg->image = XCreateImage(context->dpy, visual, depth, ZPixmap, 0, NULL, width, height, 8, 0);
	if (!rximg->image) {
		free(rximg);
		RErrorCode = RERR_XERROR;
		return NULL;
	}
	rximg->image->data = malloc(rximg->image->bytes_per_line * height);
	if (!rximg->image->data) {
		XDestroyImage(rximg->image);
		free(rximg);
		RErrorCode = RERR_NOMEMORY;
		return NULL;
	}
#else				/* XSHM */
	if (!context->attribs->use_shared_memory) {
 retry_without_shm:

		context->attribs->use_shared_memory = 0;
		rximg->is_shared = 0;
		rximg->image = XCreateImage(context->dpy, visual, depth, ZPixmap, 0, NULL, width, height, 8, 0);
		if (!rximg->image) {
			free(rximg);
			RErrorCode = RERR_XERROR;
			return NULL;
		}
		rximg->image->data = malloc(rximg->image->bytes_per_line * height);
		if (!rximg->image->data) {
			XDestroyImage(rximg->image);
			free(rximg);
			RErrorCode = RERR_NOMEMORY;
			return NULL;
		}
	} else {
		rximg->is_shared = 1;

		rximg->info.readOnly = False;

		rximg->image = XShmCreateImage(context->dpy, visual, depth,
					       ZPixmap, NULL, &rximg->info, width, height);

		rximg->info.shmid = shmget(IPC_PRIVATE, rximg->image->bytes_per_line * height, IPC_CREAT | 0777);
		if (rximg->info.shmid < 0) {
			context->attribs->use_shared_memory = 0;
			perror("wrlib: could not allocate shared memory segment");
			XDestroyImage(rximg->image);
			goto retry_without_shm;
		}

		rximg->info.shmaddr = shmat(rximg->info.shmid, 0, 0);
		if (rximg->info.shmaddr == (void *)-1) {
			context->attribs->use_shared_memory = 0;
			if (shmctl(rximg->info.shmid, IPC_RMID, 0) < 0)
				perror("wrlib: shmctl");
			perror("wrlib: could not allocate shared memory");
			XDestroyImage(rximg->image);
			goto retry_without_shm;
		}

		shmError = 0;
		XSync(context->dpy, False);
		oldErrorHandler = XSetErrorHandler(errorHandler);
		XShmAttach(context->dpy, &rximg->info);
		XSync(context->dpy, False);
		XSetErrorHandler(oldErrorHandler);

		rximg->image->data = rximg->info.shmaddr;
		/*      rximg->image->obdata = &(rximg->info); */

		if (shmError) {
			context->attribs->use_shared_memory = 0;
			XDestroyImage(rximg->image);
			if (shmdt(rximg->info.shmaddr) < 0)
				perror("wrlib: shmdt");
			if (shmctl(rximg->info.shmid, IPC_RMID, 0) < 0)
				perror("wrlib: shmctl");
			/*      printf("wrlib:error attaching shared memory segment to XImage\n");
			 */
			goto retry_without_shm;
		}
	}
#endif				/* XSHM */

	return rximg;
}

void RDestroyXImage(RContext * context, RXImage * rximage)
{
#ifndef XSHM
	XDestroyImage(rximage->image);
#else				/* XSHM */
	if (rximage->is_shared) {
		XSync(context->dpy, False);
		XShmDetach(context->dpy, &rximage->info);
		XDestroyImage(rximage->image);
		if (shmdt(rximage->info.shmaddr) < 0)
			perror("wrlib: shmdt");
		if (shmctl(rximage->info.shmid, IPC_RMID, 0) < 0)
			perror("wrlib: shmctl");
	} else {
		XDestroyImage(rximage->image);
	}
#endif
	free(rximage);
}

static unsigned getDepth(Display * dpy, Drawable d)
{
	Window w;
	int foo;
	unsigned bar;
	unsigned depth;

	XGetGeometry(dpy, d, &w, &foo, &foo, &bar, &bar, &bar, &depth);

	return depth;
}

RXImage *RGetXImage(RContext * context, Drawable d, int x, int y, unsigned width, unsigned height)
{
	RXImage *ximg = NULL;

#ifdef XSHM
	if (context->attribs->use_shared_memory && 0) {
		ximg = RCreateXImage(context, getDepth(context->dpy, d), width, height);

		if (ximg && !ximg->is_shared) {
			RDestroyXImage(context, ximg);
			ximg = NULL;
		}
		if (ximg) {
			XShmGetImage(context->dpy, d, ximg->image, x, y, AllPlanes);
		}
	}
	if (!ximg) {
		ximg = malloc(sizeof(RXImage));
		if (!ximg) {
			RErrorCode = RERR_NOMEMORY;
			return NULL;
		}
		ximg->is_shared = 0;
		ximg->image = XGetImage(context->dpy, d, x, y, width, height, AllPlanes, ZPixmap);
	}
	return ximg;
#else				/* !XSHM */
	ximg = malloc(sizeof(RXImage));
	if (!ximg) {
		RErrorCode = RERR_NOMEMORY;
		return NULL;
	}

	ximg->image = XGetImage(context->dpy, d, x, y, width, height, AllPlanes, ZPixmap);

	return ximg;
#endif				/* !XSHM */
}

void
RPutXImage(RContext * context, Drawable d, GC gc, RXImage * ximage, int src_x,
	   int src_y, int dest_x, int dest_y, unsigned int width, unsigned int height)
{
#ifndef XSHM
	XPutImage(context->dpy, d, gc, ximage->image, src_x, src_y, dest_x, dest_y, width, height);
#else
	if (ximage->is_shared) {
		XShmPutImage(context->dpy, d, gc, ximage->image, src_x, src_y,
			     dest_x, dest_y, width, height, False);
	} else {
		XPutImage(context->dpy, d, gc, ximage->image, src_x, src_y, dest_x, dest_y, width, height);
	}
	XFlush(context->dpy);
#endif				/* XSHM */
}

#ifdef XSHM
Pixmap R_CreateXImageMappedPixmap(RContext * context, RXImage * rximage)
{
	Pixmap pix;

	pix = XShmCreatePixmap(context->dpy, context->drawable,
			       rximage->image->data, &rximage->info,
			       rximage->image->width, rximage->image->height, rximage->image->depth);

	return pix;
}

#endif				/* XSHM */
