Mailing List Archive

commit 31dc27cefcb595b016737d75d4b23e3fbffd01a4
Author: Asad Sajjad Ahmed <asadsa@varnish-software.com>
Date: Tue Sep 28 14:18:50 2021 +0200

vdef: implement vmin[_t], vmax[_t] and vlimit[_t]

This should make the code easier to read and stop us from being inconsistent.

Signed-off-by: Asad Sajjad Ahmed <asadsa@varnish-software.com>

diff --git a/include/vdef.h b/include/vdef.h
index c4004611f..a810be196 100644
--- a/include/vdef.h
+++ b/include/vdef.h
@@ -164,6 +164,55 @@ int __llvm_gcov_flush(void);
#define RDN2(x, y) ((x)&(~((uintptr_t)(y)-1UL))) /* PWR2(y) true */
#define RUP2(x, y) (((x)+((y)-1))&(~((uintptr_t)(y)-1UL))) /* PWR2(y) true */

+/**********************************************************************
+ * Find the minimum or maximum values.
+ * Only evaluate the expression once and perform type checking.
+ */
+
+/* ref: https://stackoverflow.com/a/17624752 */
+
+#define VINDIRECT(a, b, c) a ## b ## c
+#define VCOMBINE(a, b, c) VINDIRECT(a, b, c)
+
+#if defined(__COUNTER__)
+# define VUNIQ_NAME(base) VCOMBINE(base, __LINE__, __COUNTER__)
+#else
+# define VUNIQ_NAME(base) VCOMBINE(base, __LINE__, 0)
+#endif
+
+/* ref: https://gcc.gnu.org/onlinedocs/gcc/Typeof.html */
+
+#define _vmin(a, b, _va, _vb) \
+({ \
+ typeof (a) _va = (a); \
+ typeof (b) _vb = (b); \
+ (void)(&_va == &_vb); \
+ _va < _vb ? _va : _vb; \
+})
+
+#define _vmax(a, b, _va, _vb) \
+({ \
+ typeof (a) _va = (a); \
+ typeof (b) _vb = (b); \
+ (void)(&_va == &_vb); \
+ _va > _vb ? _va : _vb; \
+})
+
+#define vmin(a, b) _vmin((a), (b), VUNIQ_NAME(_vmina), \
+ VUNIQ_NAME(_vminb))
+#define vmax(a, b) _vmax((a), (b), VUNIQ_NAME(_vmaxa), \
+ VUNIQ_NAME(_vmaxb))
+
+#define vmin_t(type, a, b) vmin((type)(a), (type)(b))
+#define vmax_t(type, a, b) vmax((type)(a), (type)(b))
+
+/**********************************************************************
+ * Clamp the value between two limits.
+ */
+
+#define vlimit(a, l, u) vmax((l), vmin((a), (u)))
+#define vlimit_t(type, a, l, u) vmax_t(type, (l), vmin_t(type, (a), (u)))
+
/**********************************************************************
* FlexeLint and compiler shutuppery
*/
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