Adding libglim as an external library

libglim is an Apache-licensed C++ wrapper for lmdb, and rather than
rolling our own it seems prudent to use it.

Note: lmdb is not included in it, and unless something happens as did
with libunbound, should be installed via each OS' package manager or
equivalent.

1 files changed, 51 insertions, 0 deletions

diff --git a/external/glim/NsecTimer.hpp b/external/glim/NsecTimer.hpp
new file mode 100644
index 000000000..e66126410
--- /dev/null
+++ b/external/glim/NsecTimer.hpp
@@ -0,0 +1,51 @@
+#ifndef _NSEC_TIMER_H
+#define _NSEC_TIMER_H
+
+#include <time.h> // clock_gettime, CLOCK_MONOTONIC
+#include <stdint.h>
+#include <string>
+#include <sstream>
+
+namespace glim {
+
+//! Safe nanoseconds timer.
+struct NsecTimer {
+  timespec start;
+  NsecTimer () {restart();}
+  //! Nanoseconds since the creation or restart of the timer.
+  int64_t operator()() const {
+    timespec nsecStop; clock_gettime (CLOCK_MONOTONIC, &nsecStop);
+    return (int64_t) (nsecStop.tv_sec - start.tv_sec) * 1000000000LL + (int64_t) (nsecStop.tv_nsec - start.tv_nsec);
+  }
+  /** Seconds since the creation or restart of the timer. */
+  double sec() const {
+    timespec nsecStop; clock_gettime (CLOCK_MONOTONIC, &nsecStop);
+    double seconds = nsecStop.tv_sec - start.tv_sec;
+    seconds += (double)(nsecStop.tv_nsec - start.tv_nsec) / 1000000000.0;
+    return seconds;
+  }
+  //! Seconds since the creation or restart of the timer.
+  std::string seconds (int precision = 9) const {
+    // The trick is to avoid the scientific notation by printing integers.
+    double sec = this->sec();
+    std::ostringstream buf;
+    int isec = (int) sec;
+    buf << isec;
+
+    sec -= isec;
+    for (int pc = precision; pc; --pc) sec *= 10.0;
+    int ifrac = (int) sec;
+    if (ifrac > 0) {
+      buf << '.';
+      buf.fill ('0'); buf.width (precision);
+      buf << ifrac;
+    }
+    return buf.str();
+  }
+  void restart() {clock_gettime (CLOCK_MONOTONIC, &start);}
+  int64_t getAndRestart() {int64_t tmp = operator()(); restart(); return tmp;}
+};
+
+}
+
+#endif // _NSEC_TIMER_H