macro: const'ify MIN/MAX/... macros

[elogind.git] / src / shared / macro.h

diff --git a/src/shared/macro.h b/src/shared/macro.h
index d53b07fea5cdc02c45a7d5367df8cb76ec96e574..11bd8b3a93f097cfa822b74b3e72373f9c20403c 100644 (file)
--- a/src/shared/macro.h
+++ b/src/shared/macro.h
@@ -63,6 +63,10 @@
         _Pragma("GCC diagnostic push");                                 \
         _Pragma("GCC diagnostic ignored \"-Wnonnull\"")
 
+#define DISABLE_WARNING_SHADOW                                          \
+        _Pragma("GCC diagnostic push");                                 \
+        _Pragma("GCC diagnostic ignored \"-Wshadow\"")
+
 #define REENABLE_WARNING                                                \
         _Pragma("GCC diagnostic pop")
 
@@ -100,6 +104,19 @@ static inline size_t ALIGN_TO(size_t l, size_t ali) {
 
 #define ALIGN_TO_PTR(p, ali) ((void*) ALIGN_TO((unsigned long) p, ali))
 
+/* align to next higher power-of-2 (except for: 0 => 0, overflow => 0) */
+static inline unsigned long ALIGN_POWER2(unsigned long u) {
+        /* clz(0) is undefined */
+        if (u == 1)
+                return 1;
+
+        /* left-shift overflow is undefined */
+        if (__builtin_clzl(u - 1UL) < 1)
+                return 0;
+
+        return 1UL << (sizeof(u) * 8 - __builtin_clzl(u - 1UL));
+}
+
 #define ELEMENTSOF(x) (sizeof(x)/sizeof((x)[0]))
 
 /*
@@ -116,40 +133,46 @@ static inline size_t ALIGN_TO(size_t l, size_t ali) {
                 })
 
 #undef MAX
-#define MAX(a,b)                                 \
-        __extension__ ({                         \
-                        typeof(a) _a = (a);      \
-                        typeof(b) _b = (b);      \
-                        _a > _b ? _a : _b;       \
+#define MAX(a,b)                                        \
+        __extension__ ({                                \
+                        const typeof(a) _a = (a);       \
+                        const typeof(b) _b = (b);       \
+                        _a > _b ? _a : _b;              \
                 })
 
-#define MAX3(x,y,z)                              \
-        __extension__ ({                         \
-                        typeof(x) _c = MAX(x,y); \
-                        MAX(_c, z);              \
+#define MAX3(x,y,z)                                     \
+        __extension__ ({                                \
+                        const typeof(x) _c = MAX(x,y);  \
+                        MAX(_c, z);                     \
                 })
 
 #undef MIN
-#define MIN(a,b)                                \
-        __extension__ ({                        \
-                        typeof(a) _a = (a);     \
-                        typeof(b) _b = (b);     \
-                        _a < _b ? _a : _b;      \
+#define MIN(a,b)                                        \
+        __extension__ ({                                \
+                        const typeof(a) _a = (a);       \
+                        const typeof(b) _b = (b);       \
+                        _a < _b ? _a : _b;              \
+                })
+
+#define MIN3(x,y,z)                                     \
+        __extension__ ({                                \
+                        const typeof(x) _c = MIN(x,y);  \
+                        MIN(_c, z);                     \
                 })
 
-#define LESS_BY(A,B)                            \
-        __extension__ ({                        \
-                        typeof(A) _A = (A);     \
-                        typeof(B) _B = (B);     \
-                        _A > _B ? _A - _B : 0;  \
+#define LESS_BY(A,B)                                    \
+        __extension__ ({                                \
+                        const typeof(A) _A = (A);       \
+                        const typeof(B) _B = (B);       \
+                        _A > _B ? _A - _B : 0;          \
                 })
 
 #ifndef CLAMP
 #define CLAMP(x, low, high)                                             \
         __extension__ ({                                                \
-                        typeof(x) _x = (x);                             \
-                        typeof(low) _low = (low);                       \
-                        typeof(high) _high = (high);                    \
+                        const typeof(x) _x = (x);                       \
+                        const typeof(low) _low = (low);                 \
+                        const typeof(high) _high = (high);              \
                         ((_x > _high) ? _high : ((_x < _low) ? _low : _x)); \
                 })
 #endif
@@ -218,6 +241,9 @@ static inline size_t ALIGN_TO(size_t l, size_t ali) {
 #define PTR_TO_UINT64(p) ((uint64_t) ((uintptr_t) (p)))
 #define UINT64_TO_PTR(u) ((void *) ((uintptr_t) (u)))
 
+#define PTR_TO_SIZE(p) ((size_t) ((uintptr_t) (p)))
+#define SIZE_TO_PTR(u) ((void *) ((uintptr_t) (u)))
+
 #define memzero(x,l) (memset((x), 0, (l)))
 #define zero(x) (memzero(&(x), sizeof(x)))