Added a new header file: SDL_loadso.h

It contains the following functions:
	SDL_LoadObject(), SDL_LoadFunction(), SDL_UnloadObject()
The UNIX esd and arts audio code use these to dynamically load
their respective audio libraries.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40295

src/SDL_loadso.c

@@ -0,0 +1,193 @@
+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
+
+    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
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Sam Lantinga
+    slouken@libsdl.org
+*/
+
+#ifdef SAVE_RCSID
+static char rcsid =
+ "@(#) $Id$";
+#endif
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+/* System dependent library loading routines                           */
+
+#include <stdio.h>
+#if defined(USE_DLOPEN)
+# include <dlfcn.h>
+#elif defined(WIN32)
+# include <windows.h>
+#elif defined(__BEOS__)
+# include <be/kernel/image.h>
+#elif defined(macintosh)
+# include <string.h>
+# include <Strings.h>
+# include <CodeFragments.h>
+# include <Errors.h>
+#else
+/*#error Unsupported dynamic link environment*/
+#endif /* system type */
+
+#include "SDL_error.h"
+#include "SDL_loadso.h"
+
+void *SDL_LoadObject(const char *sofile)
+{
+	void *handle = NULL;
+	const char *loaderror = "SDL_LoadObject() not implemented";
+#if defined(USE_DLOPEN)
+/* * */
+	handle = dlopen(sofile, RTLD_NOW);
+	loaderror = (char *)dlerror();
+#elif defined(WIN32)
+/* * */
+	char errbuf[512];
+
+	handle = (void *)LoadLibrary(sofile);
+
+	/* Generate an error message if all loads failed */
+	if ( handle == NULL ) {
+		FormatMessage((FORMAT_MESSAGE_IGNORE_INSERTS |
+					FORMAT_MESSAGE_FROM_SYSTEM),
+				NULL, GetLastError(), 
+				MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+				errbuf, SDL_TABLESIZE(errbuf), NULL);
+		loaderror = errbuf;
+	}
+#elif defined(__BEOS__)
+/* * */
+	image_id library_id;
+
+	library_id = load_add_on(sofile);
+	if ( library_id == B_ERROR ) {
+		loaderror = "BeOS error";
+	} else {
+		handle = (void *)(library_id);
+	}
+#elif defined(macintosh)
+/* * */
+	CFragConnectionID library_id;
+	Ptr mainAddr;
+	Str255 errName;
+	OSErr error;
+	char psofile[512];
+
+	strncpy(psofile, sofile, SDL_TABLESIZE(psofile));
+	psofile[SDL_TABLESIZE(psofile)-1] = '\0';
+	error = GetSharedLibrary(C2PStr(psofile), kCompiledCFragArch,
+			kLoadCFrag, &library_id, &mainAddr, errName);
+	switch (error) {
+		case noErr:
+			break;
+		case cfragNoLibraryErr:
+			loaderror = "Library not found";
+			break;
+		case cfragUnresolvedErr:
+			loaderror = "Unabled to resolve symbols";
+			break;
+		case cfragNoPrivateMemErr:
+		case cfragNoClientMemErr:
+			loaderror = "Out of memory";
+			break;
+		default:
+			loaderror = "Unknown Code Fragment Manager error";
+			break;
+	}
+	if ( loaderror == NULL ) {
+		handle = (void *)(library_id);
+	}
+#endif /* system type */
+
+	if ( handle == NULL ) {
+		SDL_SetError("Failed loading %s: %s", sofile, loaderror);
+	}
+	return(handle);
+}
+
+void *SDL_LoadFunction(void *handle, const char *name)
+{
+	void *symbol = NULL;
+	const char *loaderror = "SDL_LoadFunction not implemented";
+#if defined(USE_DLOPEN)
+/* * */
+	symbol = dlsym(handle, name);
+	if ( symbol == NULL ) {
+		loaderror = (char *)dlerror();
+	}
+#elif defined(WIN32)
+/* * */
+	char errbuf[512];
+
+	symbol = (void *)GetProcAddress((HMODULE)handle, name);
+	if ( symbol == NULL ) {
+		FormatMessage((FORMAT_MESSAGE_IGNORE_INSERTS |
+					FORMAT_MESSAGE_FROM_SYSTEM),
+				NULL, GetLastError(), 
+				MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+				errbuf, SDL_TABLESIZE(errbuf), NULL);
+		loaderror = errbuf;
+	}
+#elif defined(__BEOS__)
+/* * */
+	image_id library_id = (image_id)handle;
+	if ( get_image_symbol(library_id,
+		name, B_SYMBOL_TYPE_TEXT, &symbol) != B_NO_ERROR ) {
+		loaderror = "Symbol not found";
+	}
+#elif defined(macintosh)
+/* * */
+	CFragSymbolClass class;
+	CFragConnectionID library_id = (CFragConnectionID)handle;
+	char pname[512];
+
+	strncpy(pname, name, SDL_TABLESIZE(pname));
+	pname[SDL_TABLESIZE(pname)-1] = '\0';
+	if ( FindSymbol(library_id, C2PStr(pname),
+	                (char **)&symbol, &class) != noErr ) {
+		loaderror = "Symbol not found";
+	}
+#endif /* system type */
+
+	if ( symbol == NULL ) {
+		SDL_SetError("Failed loading %s: %s", name, loaderror);
+	}
+	return(symbol);
+}
+
+void SDL_UnloadObject(void *handle)
+{
+	if ( handle == NULL ) {
+		return;
+	}
+#if defined(USE_DLOPEN)
+/* * */
+	dlclose(handle);
+#elif defined(WIN32)
+/* * */
+	FreeLibrary((HMODULE)handle);
+#elif defined(__BEOS__)
+/* * */
+	image_id library_id = (image_id)handle;
+	unload_add_on(library_id);
+#elif defined(macintosh)
+/* * */
+	CFragConnectionID library_id = (CFragConnectionID)handle;
+	CloseConnection(library_id);
+#endif /* system type */
+}