+/** Compute the minimum of \a x and \a y. */
+#define PARA_MIN(x, y) ({ \
+ typeof(x) _min1 = (x); \
+ typeof(y) _min2 = (y); \
+ (void) (&_min1 == &_min2); \
+ _min1 < _min2 ? _min1 : _min2; })
+
+/** Compute the maximum of \a x and \a y. */
+#define PARA_MAX(x, y) ({ \
+ typeof(x) _max1 = (x); \
+ typeof(y) _max2 = (y); \
+ (void) (&_max1 == &_max2); \
+ _max1 < _max2 ? _max2 : _max1; })
+
+/** Compute the absolute value of \a x. */
+#define PARA_ABS(x) ({ \
+ typeof(x) _x = (x); \
+ _x > 0? _x : -_x; })
+
+
+extern __printf_2_3 void (*para_log)(int, const char*, ...);
+/**
+ * Define a standard log function that always writes to stderr.
+ *
+ * \param funcname The name of the function to be defined.
+ *
+ * \param loglevel_barrier If the loglevel of the current message
+ * is less than that, the message is going to be ignored.
+ *
+ */
+#define DEFINE_STDERR_LOGGER(funcname, loglevel_barrier) \
+ __printf_2_3 void funcname(int ll, const char* fmt,...) \
+ { \
+ va_list argp; \
+ if (ll < loglevel_barrier) \
+ return; \
+ va_start(argp, fmt); \
+ vfprintf(stderr, fmt, argp); \
+ va_end(argp); \
+ }
+#define INIT_STDERR_LOGGING(loglevel_barrier) \
+ DEFINE_STDERR_LOGGER(stderr_log, loglevel_barrier); \
+ __printf_2_3 void (*para_log)(int, const char*, ...) = stderr_log;
+
+/** Sent by para_client to initiate the authentication procedure. */
+#define AUTH_REQUEST_MSG "auth rsa "
+/** Sent by para_server for commands that expect a data file. */
+#define AWAITING_DATA_MSG "\nAwaiting Data."
+/** Sent by para_server if authentication was successful. */
+#define PROCEED_MSG "Proceed."
+/** Length of the \p PROCEED_MSG string. */
+#define PROCEED_MSG_LEN strlen(PROCEED_MSG)
+/** Sent by para_client to indicate the end of the command line. */
+#define EOC_MSG "\nEnd of Command."
+
+/* exec */
+int para_exec_cmdline_pid(pid_t *pid, const char *cmdline, int *fds);
+
+/* time */
+int tv_diff(const struct timeval *b, const struct timeval *a, struct timeval *diff);
+long unsigned tv2ms(const struct timeval*);
+void d2tv(double, struct timeval*);
+void tv_add(const struct timeval*, const struct timeval *, struct timeval *);
+void tv_scale(const unsigned long, const struct timeval *, struct timeval *);
+void tv_divide(const unsigned long divisor, const struct timeval *tv,
+ struct timeval *result);
+int tv_convex_combination(const long a, const struct timeval *tv1,
+ const long b, const struct timeval *tv2,
+ struct timeval *result);
+void ms2tv(const long unsigned n, struct timeval *tv);
+void compute_chunk_time(long unsigned chunk_num,
+ struct timeval *chunk_tv, struct timeval *stream_start,
+ struct timeval *result);
+
+/** The enum of all status items. */
+enum status_items {STATUS_ITEM_ENUM NUM_STAT_ITEMS};
+extern const char *status_item_list[];
+/** Loop over each status item. */
+#define FOR_EACH_STATUS_ITEM(i) for (i = 0; i < NUM_STAT_ITEMS; i++)
+int for_each_stat_item(char *item_buf, size_t num_bytes,
+ int (*item_handler)(int, char *));
+
+
+/**
+ * Return a random non-negative integer in an interval.
+ *
+ * \param max Determines maximal possible return value.
+ *
+ * \return An integer between zero and \p max - 1, inclusively.
+ */
+_static_inline_ long int para_random(unsigned max)
+{
+ return ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
+}
+
+/** Round up x to next multiple of y. */
+#define ROUND_UP(x, y) ({ \
+ const typeof(y) _divisor = y; \
+ ((x) + _divisor - 1) / _divisor * _divisor; })
+
+/** Round down x to multiple of y. */
+#define ROUND_DOWN(x, y) ({ \
+ const typeof(y) _divisor = y; \
+ (x) / _divisor * _divisor; })
+
+/** Divide and round up to next integer. */
+#define DIV_ROUND_UP(x, y) ({ \
+ typeof(y) _divisor = y; \
+ ((x) + _divisor - 1) / _divisor; })
+
+/**
+ * Assert a build-time dependency, as an expression.
+ *
+ * \param cond The compile-time condition which must be true.
+ *
+ * Compilation will fail if the condition isn't true, or can't be evaluated by
+ * the compiler. This can be used in an expression: its value is "0".
+ *
+ * Taken from ccan.
+ */
+#define EXPR_BUILD_ASSERT(cond) (sizeof(char [1 - 2 * !(cond)]) - 1)
+
+/** &a[0] degrades to a pointer: a different type from an array */
+#define _array_size_chk(arr) EXPR_BUILD_ASSERT(\
+ !__builtin_types_compatible_p(typeof(arr), typeof(&(arr)[0])))
+/** Get the size of an array */
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + _array_size_chk(arr))