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nagios4/nsutils.h

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+#ifndef LIBNAGIOS_nsutils_h__
+#define LIBNAGIOS_nsutils_h__
+#include <sys/types.h>
+
+/**
+ * @file nsutils.h
+ * @brief Non-Standard (or Nagios) utility functions and macros.
+ *
+ * This is where we house all helpers and macros that fall outside
+ * the "standard-ish" norm. The prefixes "nsu_" and NSU_ are
+ * reserved for this purpose, so we avoid clashing with other
+ * applications that may have similarly-acting functions with
+ * identical names.
+ *
+ * The functions already here lack the nsu_ prefix for backwards
+ * compatibility reasons. It's possible we'll have to fix that
+ * some day, but let's leave that for later.
+ *
+ * @{
+ */
+
+/** Macro for dynamically increasing vector lengths */
+#define alloc_nr(x) (((x)+16)*3/2)
+
+/**
+ * Check if a number is a power of 2
+ * @param x The number to check
+ * @return 1 if the number is a power of 2, 0 if it's not
+ */
+static inline int nsu_ispow2(unsigned int x)
+{
+	return x > 1 ? !(x & (x - 1)) : 0;
+}
+
+/**
+ * Round up to a power of 2
+ * Yes, this is the most cryptic function name in all of Nagios, but I
+ * like it, so shush.
+ * @param r The number to round up
+ * @return r, rounded up to the nearest power of 2.
+ */
+static inline unsigned int rup2pof2(unsigned int r)
+{
+	r--;
+	if (!r)
+		return 2;
+	r |= r >> 1;
+	r |= r >> 2;
+	r |= r >> 4;
+	r |= r >> 8;
+	r |= r >> 16;
+
+	return r + 1;
+}
+
+/**
+ * Grab a random unsigned int in the range between low and high.
+ * Note that the PRNG has to be seeded prior to calling this.
+ * @param low The lower bound, inclusive
+ * @param high The higher bound, inclusive
+ * @return An unsigned integer in the mathematical range [low, high]
+ */
+static inline unsigned int ranged_urand(unsigned int low, unsigned int high)
+{
+	return low + (rand() * (1.0 / (RAND_MAX + 1.0)) * (high - low));
+}
+
+/**
+ * Get number of online cpus
+ * @return Active cpu cores detected on success. 0 on failure.
+ */
+extern int real_online_cpus(void);
+
+/**
+ * Wrapper for real_online_cpus(), returning 1 in case we can't
+ * detect any active cpus.
+ * @return Number of active cpu cores on success. 1 on failure.
+ */
+extern int online_cpus(void);
+
+/**
+ * Create a short-lived string in stack-allocated memory
+ * The number and size of strings is limited (currently to 256 strings of
+ * 32 bytes each), so beware and use this sensibly. Intended for
+ * number-to-string conversion and other short strings.
+ * @note The returned string must *not* be free()'d!
+ * @param[in] fmt The format string
+ * @return A pointer to the formatted string on success. Undefined on errors
+ */
+extern const char *mkstr(const char *fmt, ...)
+	__attribute__((__format__(__printf__, 1, 2)));
+
+/**
+ * Calculate the millisecond delta between two timeval structs
+ * @param[in] start The start time
+ * @param[in] stop The stop time
+ * @return The millisecond delta between the two structs
+ */
+extern int tv_delta_msec(const struct timeval *start, const struct timeval *stop);
+
+
+/**
+ * Get timeval delta as seconds
+ * @param start The start time
+ * @param stop The stop time
+ * @return time difference in fractions of seconds
+ */
+extern float tv_delta_f(const struct timeval *start, const struct timeval *stop);
+
+/** @} */
+#endif /* LIBNAGIOS_nsutils_h__ */