benchfn dependencies reduced to only timefn

benchfn used to rely on mem.h, and util,
which in turn relied on platform.h.
Using benchfn outside of zstd required to bring all these dependencies.

Now, dependency is reduced to timefn only.
This required to create a separate timefn from util,
and rewrite benchfn and timefn to no longer need mem.h.

Separating timefn from util has a wide effect accross the code base,
as usage of time functions is widespread.
A lot of build scripts had to be updated to also include timefn.

programs/timefn.c

@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) 2019-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+/* ===  Dependencies  === */
+
+#include "timefn.h"
+
+
+/*-****************************************
+*  Time functions
+******************************************/
+
+#if defined(_WIN32)   /* Windows */
+
+UTIL_time_t UTIL_getTime(void) { UTIL_time_t x; QueryPerformanceCounter(&x); return x; }
+
+PTime UTIL_getSpanTimeMicro(UTIL_time_t clockStart, UTIL_time_t clockEnd)
+{
+    static LARGE_INTEGER ticksPerSecond;
+    static int init = 0;
+    if (!init) {
+        if (!QueryPerformanceFrequency(&ticksPerSecond))
+            UTIL_DISPLAYLEVEL(1, "ERROR: QueryPerformanceFrequency() failure\n");
+        init = 1;
+    }
+    return 1000000ULL*(clockEnd.QuadPart - clockStart.QuadPart)/ticksPerSecond.QuadPart;
+}
+
+PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd)
+{
+    static LARGE_INTEGER ticksPerSecond;
+    static int init = 0;
+    if (!init) {
+        if (!QueryPerformanceFrequency(&ticksPerSecond))
+            UTIL_DISPLAYLEVEL(1, "ERROR: QueryPerformanceFrequency() failure\n");
+        init = 1;
+    }
+    return 1000000000ULL*(clockEnd.QuadPart - clockStart.QuadPart)/ticksPerSecond.QuadPart;
+}
+
+#elif defined(__APPLE__) && defined(__MACH__)
+
+UTIL_time_t UTIL_getTime(void) { return mach_absolute_time(); }
+
+PTime UTIL_getSpanTimeMicro(UTIL_time_t clockStart, UTIL_time_t clockEnd)
+{
+    static mach_timebase_info_data_t rate;
+    static int init = 0;
+    if (!init) {
+        mach_timebase_info(&rate);
+        init = 1;
+    }
+    return (((clockEnd - clockStart) * (PTime)rate.numer) / ((PTime)rate.denom))/1000ULL;
+}
+
+PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd)
+{
+    static mach_timebase_info_data_t rate;
+    static int init = 0;
+    if (!init) {
+        mach_timebase_info(&rate);
+        init = 1;
+    }
+    return ((clockEnd - clockStart) * (PTime)rate.numer) / ((PTime)rate.denom);
+}
+
+#elif (PLATFORM_POSIX_VERSION >= 200112L) \
+   && (defined(__UCLIBC__)                \
+      || (defined(__GLIBC__)              \
+          && ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 17) \
+             || (__GLIBC__ > 2))))
+
+UTIL_time_t UTIL_getTime(void)
+{
+    UTIL_time_t time;
+    if (clock_gettime(CLOCK_MONOTONIC, &time))
+        UTIL_DISPLAYLEVEL(1, "ERROR: Failed to get time\n");   /* we could also exit() */
+    return time;
+}
+
+UTIL_time_t UTIL_getSpanTime(UTIL_time_t begin, UTIL_time_t end)
+{
+    UTIL_time_t diff;
+    if (end.tv_nsec < begin.tv_nsec) {
+        diff.tv_sec = (end.tv_sec - 1) - begin.tv_sec;
+        diff.tv_nsec = (end.tv_nsec + 1000000000ULL) - begin.tv_nsec;
+    } else {
+        diff.tv_sec = end.tv_sec - begin.tv_sec;
+        diff.tv_nsec = end.tv_nsec - begin.tv_nsec;
+    }
+    return diff;
+}
+
+PTime UTIL_getSpanTimeMicro(UTIL_time_t begin, UTIL_time_t end)
+{
+    UTIL_time_t const diff = UTIL_getSpanTime(begin, end);
+    PTime micro = 0;
+    micro += 1000000ULL * diff.tv_sec;
+    micro += diff.tv_nsec / 1000ULL;
+    return micro;
+}
+
+PTime UTIL_getSpanTimeNano(UTIL_time_t begin, UTIL_time_t end)
+{
+    UTIL_time_t const diff = UTIL_getSpanTime(begin, end);
+    PTime nano = 0;
+    nano += 1000000000ULL * diff.tv_sec;
+    nano += diff.tv_nsec;
+    return nano;
+}
+
+#else   /* relies on standard C (note : clock_t measurements can be wrong when using multi-threading) */
+
+UTIL_time_t UTIL_getTime(void) { return clock(); }
+PTime UTIL_getSpanTimeMicro(UTIL_time_t clockStart, UTIL_time_t clockEnd) { return 1000000ULL * (clockEnd - clockStart) / CLOCKS_PER_SEC; }
+PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd) { return 1000000000ULL * (clockEnd - clockStart) / CLOCKS_PER_SEC; }
+
+#endif
+
+/* returns time span in microseconds */
+PTime UTIL_clockSpanMicro(UTIL_time_t clockStart )
+{
+    UTIL_time_t const clockEnd = UTIL_getTime();
+    return UTIL_getSpanTimeMicro(clockStart, clockEnd);
+}
+
+/* returns time span in microseconds */
+PTime UTIL_clockSpanNano(UTIL_time_t clockStart )
+{
+    UTIL_time_t const clockEnd = UTIL_getTime();
+    return UTIL_getSpanTimeNano(clockStart, clockEnd);
+}
+
+void UTIL_waitForNextTick(void)
+{
+    UTIL_time_t const clockStart = UTIL_getTime();
+    UTIL_time_t clockEnd;
+    do {
+        clockEnd = UTIL_getTime();
+    } while (UTIL_getSpanTimeNano(clockStart, clockEnd) == 0);
+}