Initial implementation of the time module (#1680)

Author: gptsarthak

src/libasr/runtime/lfortran_intrinsics.c

@@ -10,6 +10,10 @@
 #include <limits.h>
 #include <ctype.h>
 
+#if defined(_MSC_VER)
+#  include <winsock2.h>
+#endif
+
 #include <libasr/runtime/lfortran_intrinsics.h>
 #include <libasr/config.h>
 
@@ -1254,6 +1258,22 @@ LFORTRAN_API void _lfortran_i64sys_clock(
 #endif
 }
 
+LFORTRAN_API double _lfortran_time()
+{
+#if defined(_MSC_VER)
+    FILETIME ft;
+    ULARGE_INTEGER uli;
+    GetSystemTimeAsFileTime(&ft);
+    uli.LowPart = ft.dwLowDateTime;
+    uli.HighPart = ft.dwHighDateTime;
+    return (double)uli.QuadPart / 10000000.0 - 11644473600.0;
+#else
+    struct timespec ts;
+    clock_gettime(CLOCK_REALTIME, &ts);
+    return (double)ts.tv_sec + (double)ts.tv_nsec / 1000000000.0;
+#endif
+}
+
 LFORTRAN_API void _lfortran_sp_rand_num(float *x) {
     srand(time(0));
     *x = rand() / (float) RAND_MAX;

src/libasr/runtime/lfortran_intrinsics.h

@@ -211,6 +211,7 @@ LFORTRAN_API void _lfortran_i32sys_clock(
         int32_t *count, int32_t *rate, int32_t *max);
 LFORTRAN_API void _lfortran_i64sys_clock(
         uint64_t *count, int64_t *rate, int64_t *max);
+LFORTRAN_API double _lfortran_time();
 LFORTRAN_API void _lfortran_sp_rand_num(float *x);
 LFORTRAN_API void _lfortran_dp_rand_num(double *x);
 LFORTRAN_API int64_t _lpython_open(char *path, char *flags);

src/runtime/time.py

@@ -0,0 +1,8 @@
+from lpython import f64, ccall
+
+def time() -> f64:
+    return _lfortran_time()
+
+@ccall
+def _lfortran_time() -> f64:
+    pass