Import format_timespan() from systemd

We also introduce a new couple of files: time-util.{c,h}. For now this is
a verbatim copy from systemd c20db3887569e0c0d9c0e2845c5286e7edf0133a

Signed-off-by: Arnaud Rebillout <[email protected]>

Author: elboulangero

src/meson.build

@@ -3,6 +3,8 @@
 util_sources = files('''
         log.c
         log.h
+        time-util.c
+        time-util.h
         util.c
         util.h
 '''.split())

src/time-util.c

@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include "util.h"
+#include "time-util.h"
+
+char *format_timespan(char *buf, size_t l, usec_t t, usec_t accuracy) {
+        static const struct {
+                const char *suffix;
+                usec_t usec;
+        } table[] = {
+                { "y",     USEC_PER_YEAR   },
+                { "month", USEC_PER_MONTH  },
+                { "w",     USEC_PER_WEEK   },
+                { "d",     USEC_PER_DAY    },
+                { "h",     USEC_PER_HOUR   },
+                { "min",   USEC_PER_MINUTE },
+                { "s",     USEC_PER_SEC    },
+                { "ms",    USEC_PER_MSEC   },
+                { "us",    1               },
+        };
+
+        size_t i;
+        char *p = buf;
+        bool something = false;
+
+        assert(buf);
+        assert(l > 0);
+
+        if (t == USEC_INFINITY) {
+                strncpy(p, "infinity", l-1);
+                p[l-1] = 0;
+                return p;
+        }
+
+        if (t <= 0) {
+                strncpy(p, "0", l-1);
+                p[l-1] = 0;
+                return p;
+        }
+
+        /* The result of this function can be parsed with parse_sec */
+
+        for (i = 0; i < ELEMENTSOF(table); i++) {
+                int k = 0;
+                size_t n;
+                bool done = false;
+                usec_t a, b;
+
+                if (t <= 0)
+                        break;
+
+                if (t < accuracy && something)
+                        break;
+
+                if (t < table[i].usec)
+                        continue;
+
+                if (l <= 1)
+                        break;
+
+                a = t / table[i].usec;
+                b = t % table[i].usec;
+
+                /* Let's see if we should shows this in dot notation */
+                if (t < USEC_PER_MINUTE && b > 0) {
+                        usec_t cc;
+                        signed char j;
+
+                        j = 0;
+                        for (cc = table[i].usec; cc > 1; cc /= 10)
+                                j++;
+
+                        for (cc = accuracy; cc > 1; cc /= 10) {
+                                b /= 10;
+                                j--;
+                        }
+
+                        if (j > 0) {
+                                k = snprintf(p, l,
+                                             "%s"USEC_FMT".%0*"PRI_USEC"%s",
+                                             p > buf ? " " : "",
+                                             a,
+                                             j,
+                                             b,
+                                             table[i].suffix);
+
+                                t = 0;
+                                done = true;
+                        }
+                }
+
+                /* No? Then let's show it normally */
+                if (!done) {
+                        k = snprintf(p, l,
+                                     "%s"USEC_FMT"%s",
+                                     p > buf ? " " : "",
+                                     a,
+                                     table[i].suffix);
+
+                        t = b;
+                }
+
+                n = MIN((size_t) k, l);
+
+                l -= n;
+                p += n;
+
+                something = true;
+        }
+
+        *p = 0;
+
+        return buf;
+}

src/time-util.h

@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#ifndef footimeutilfoo
+#define footimeutilfoo
+
+typedef uint64_t usec_t;
+typedef uint64_t nsec_t;
+
+#define PRI_NSEC PRIu64
+#define PRI_USEC PRIu64
+#define NSEC_FMT "%" PRI_NSEC
+#define USEC_FMT "%" PRI_USEC
+
+#define USEC_INFINITY ((usec_t) -1)
+#define NSEC_INFINITY ((nsec_t) -1)
+
+#define MSEC_PER_SEC  1000ULL
+#define USEC_PER_SEC  ((usec_t) 1000000ULL)
+#define USEC_PER_MSEC ((usec_t) 1000ULL)
+//#define NSEC_PER_SEC  ((nsec_t) 1000000000ULL) already defined in util.h
+#define NSEC_PER_MSEC ((nsec_t) 1000000ULL)
+#define NSEC_PER_USEC ((nsec_t) 1000ULL)
+
+#define USEC_PER_MINUTE ((usec_t) (60ULL*USEC_PER_SEC))
+#define NSEC_PER_MINUTE ((nsec_t) (60ULL*NSEC_PER_SEC))
+#define USEC_PER_HOUR ((usec_t) (60ULL*USEC_PER_MINUTE))
+#define NSEC_PER_HOUR ((nsec_t) (60ULL*NSEC_PER_MINUTE))
+#define USEC_PER_DAY ((usec_t) (24ULL*USEC_PER_HOUR))
+#define NSEC_PER_DAY ((nsec_t) (24ULL*NSEC_PER_HOUR))
+#define USEC_PER_WEEK ((usec_t) (7ULL*USEC_PER_DAY))
+#define NSEC_PER_WEEK ((nsec_t) (7ULL*NSEC_PER_DAY))
+#define USEC_PER_MONTH ((usec_t) (2629800ULL*USEC_PER_SEC))
+#define NSEC_PER_MONTH ((nsec_t) (2629800ULL*NSEC_PER_SEC))
+#define USEC_PER_YEAR ((usec_t) (31557600ULL*USEC_PER_SEC))
+#define NSEC_PER_YEAR ((nsec_t) (31557600ULL*NSEC_PER_SEC))
+
+char *format_timespan(char *buf, size_t l, usec_t t, usec_t accuracy);
+
+#endif