X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Futil.c;h=e02f59fb0a0af60d4a71b3c66d297badc86aa924;hb=2c8fcc9cd6a7bbb948f6c79879e89c7ed791c9b1;hp=1a42376e21216fc0c3a07ea928dd172719f1515e;hpb=44b4d050d4a2c966ed6f4aef2e523f70b6463648;p=openvswitch

diff --git a/lib/util.c b/lib/util.c
index 1a42376e..e02f59fb 100644
--- a/lib/util.c
+++ b/lib/util.c
@@ -16,8 +16,11 @@
 
 #include <config.h>
 #include "util.h"
+#include <assert.h>
 #include <errno.h>
+#include <limits.h>
 #include <stdarg.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -30,6 +33,7 @@ VLOG_DEFINE_THIS_MODULE(util);
 COVERAGE_DEFINE(util_xalloc);
 
 const char *program_name;
+static char *program_version;
 
 void
 out_of_memory(void)
@@ -274,21 +278,41 @@ ovs_retval_to_string(int retval)
     return unknown;
 }
 
-/* Sets program_name based on 'argv0'.  Should be called at the beginning of
- * main(), as "set_program_name(argv[0]);".  */
-void set_program_name(const char *argv0)
+/* Sets global "program_name" and "program_version" variables.  Should
+ * be called at the beginning of main() with "argv[0]" as the argument
+ * to 'argv0'.
+ *
+ * The 'date' and 'time' arguments should likely be called with
+ * "__DATE__" and "__TIME__" to use the time the binary was built.
+ * Alternatively, the "set_program_name" macro may be called to do this
+ * automatically.
+ */
+void
+set_program_name__(const char *argv0, const char *date, const char *time)
 {
     const char *slash = strrchr(argv0, '/');
     program_name = slash ? slash + 1 : argv0;
+
+    free(program_version);
+    program_version = xasprintf("%s (Open vSwitch) "VERSION BUILDNR"\n"
+                                "Compiled %s %s\n",
+                                program_name, date, time);
+}
+
+/* Returns a pointer to a string describing the program version.  The
+ * caller must not modify or free the returned string.
+ */
+const char *
+get_program_version(void)
+{
+    return program_version;
 }
 
 /* Print the version information for the program.  */
 void
-ovs_print_version(char *date, char *time,
-                  uint8_t min_ofp, uint8_t max_ofp)
+ovs_print_version(uint8_t min_ofp, uint8_t max_ofp)
 {
-    printf("%s (Open vSwitch) "VERSION BUILDNR"\n", program_name);
-    printf("Compiled %s %s\n", date, time);
+    printf("%s", program_version);
     if (min_ofp || max_ofp) {
         printf("OpenFlow versions %#x:%#x\n", min_ofp, max_ofp);
     }
@@ -607,3 +631,97 @@ english_list_delimiter(size_t index, size_t total)
             : total > 2 ? ", and "
             : " and ");
 }
+
+/* Given a 32 bit word 'n', calculates floor(log_2('n')).  This is equivalent
+ * to finding the bit position of the most significant one bit in 'n'.  It is
+ * an error to call this function with 'n' == 0. */
+int
+log_2_floor(uint32_t n)
+{
+    assert(n);
+
+#if !defined(UINT_MAX) || !defined(UINT32_MAX)
+#error "Someone screwed up the #includes."
+#elif __GNUC__ >= 4 && UINT_MAX == UINT32_MAX
+    return 31 - __builtin_clz(n);
+#else
+    {
+        int log = 0;
+
+#define BIN_SEARCH_STEP(BITS)                   \
+        if (n >= (1 << BITS)) {                 \
+            log += BITS;                        \
+            n >>= BITS;                         \
+        }
+        BIN_SEARCH_STEP(16);
+        BIN_SEARCH_STEP(8);
+        BIN_SEARCH_STEP(4);
+        BIN_SEARCH_STEP(2);
+        BIN_SEARCH_STEP(1);
+#undef BIN_SEARCH_STEP
+        return log;
+    }
+#endif
+}
+
+/* Returns the number of trailing 0-bits in 'n', or 32 if 'n' is 0. */
+int
+ctz(uint32_t n)
+{
+    if (!n) {
+        return 32;
+    } else {
+#if !defined(UINT_MAX) || !defined(UINT32_MAX)
+#error "Someone screwed up the #includes."
+#elif __GNUC__ >= 4 && UINT_MAX == UINT32_MAX
+        return __builtin_ctz(n);
+#else
+        unsigned int k;
+        int count = 31;
+
+#define CTZ_STEP(X)                             \
+        k = n << (X);                           \
+        if (k) {                                \
+            count -= X;                         \
+            n = k;                              \
+        }
+        CTZ_STEP(16);
+        CTZ_STEP(8);
+        CTZ_STEP(4);
+        CTZ_STEP(2);
+        CTZ_STEP(1);
+#undef CTZ_STEP
+
+        return count;
+#endif
+    }
+}
+
+/* Returns true if the 'n' bytes starting at 'p' are zeros. */
+bool
+is_all_zeros(const uint8_t *p, size_t n)
+{
+    size_t i;
+
+    for (i = 0; i < n; i++) {
+        if (p[i] != 0x00) {
+            return false;
+        }
+    }
+    return true;
+}
+
+/* Returns true if the 'n' bytes starting at 'p' are 0xff. */
+bool
+is_all_ones(const uint8_t *p, size_t n)
+{
+    size_t i;
+
+    for (i = 0; i < n; i++) {
+        if (p[i] != 0xff) {
+            return false;
+        }
+    }
+    return true;
+}
+