X-Git-Url: https://git.cworth.org/git?p=glaze;a=blobdiff_plain;f=glaze.h;fp=glaze.h;h=9a9115a3a516e33189f737f82f5f2fe1998cd62f;hp=0000000000000000000000000000000000000000;hb=cec0694a7f219bd3590e6a04beba34ca45539540;hpb=0b190cc8fbca0f970eadd8c0f1d5792c41f71cf6

diff --git a/glaze.h b/glaze.h
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+/* Copyright © 2013, Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef GLAZE_H
+#define GLAZE_H
+
+/* Perform dynamic lookup of 'function' within the library specified
+ * by the GLAZE_LIBGL environment variable.
+ */
+void *
+glaze_lookup (char *function);
+
+/* A helper macro for glaze-using wrappers to defer an operation to
+ * the "real" underlying OpenGL function.
+ *
+ * The underlying function to be called will be obtained by calling
+ * glaze_lookup. This lookup will be cached in a local variable
+ * (defined by this macro) named real_<function>.
+ *
+ * NOTE: This macro can only be used a single time within any
+ * function, (due to the locally-defined variable). If this is
+ * inadequate, callers can instead call glaze_lookup manually.
+ */
+#define GLAZE_DEFER(function,...) do {				\
+	static typeof(&function) real_ ## function;		\
+	if (! real_ ## function)				\
+		real_ ## function = glaze_lookup (#function);	\
+	real_ ## function(__VA_ARGS__); 			\
+} while (0);
+
+/* As GLAZE_DEFER, but also set 'ret' to the value returned by the
+ * underlying "real" function. */
+#define GLAZE_DEFER_WITH_RETURN(ret, function,...) do {	\
+	static typeof(&function) real_ ## function;		\
+	if (! real_ ## function)				\
+		real_ ## function = glaze_lookup (#function);	\
+	(ret) = real_ ## function(__VA_ARGS__); 		\
+} while (0);
+
+#endif /* GLAZE_H */