perf tools: Add time-based utility functions

Add function to parse a user time string of the form <start>,<stop>
where start and stop are time in sec.nsec format. Both start and stop
times are optional.

Add function to determine if a sample time is within a given time
time window of interest.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1480439746-42695-2-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/Build

@@ -87,6 +87,7 @@ libperf-y += help-unknown-cmd.o
 libperf-y += mem-events.o
 libperf-y += vsprintf.o
 libperf-y += drv_configs.o
+libperf-y += time-utils.o
 
 libperf-$(CONFIG_LIBBPF) += bpf-loader.o
 libperf-$(CONFIG_BPF_PROLOGUE) += bpf-prologue.o

tools/perf/util/time-utils.c

@@ -0,0 +1,85 @@
+#include <string.h>
+#include <sys/time.h>
+#include <time.h>
+#include <errno.h>
+#include <inttypes.h>
+
+#include "perf.h"
+#include "debug.h"
+#include "time-utils.h"
+#include "util.h"
+
+static int parse_timestr_sec_nsec(struct perf_time_interval *ptime,
+				  char *start_str, char *end_str)
+{
+	if (start_str && (*start_str != '\0') &&
+	    (parse_nsec_time(start_str, &ptime->start) != 0)) {
+		return -1;
+	}
+
+	if (end_str && (*end_str != '\0') &&
+	    (parse_nsec_time(end_str, &ptime->end) != 0)) {
+		return -1;
+	}
+
+	return 0;
+}
+
+int perf_time__parse_str(struct perf_time_interval *ptime, const char *ostr)
+{
+	char *start_str, *end_str;
+	char *d, *str;
+	int rc = 0;
+
+	if (ostr == NULL || *ostr == '\0')
+		return 0;
+
+	/* copy original string because we need to modify it */
+	str = strdup(ostr);
+	if (str == NULL)
+		return -ENOMEM;
+
+	ptime->start = 0;
+	ptime->end = 0;
+
+	/* str has the format: <start>,<stop>
+	 * variations: <start>,
+	 *             ,<stop>
+	 *             ,
+	 */
+	start_str = str;
+	d = strchr(start_str, ',');
+	if (d) {
+		*d = '\0';
+		++d;
+	}
+	end_str = d;
+
+	rc = parse_timestr_sec_nsec(ptime, start_str, end_str);
+
+	free(str);
+
+	/* make sure end time is after start time if it was given */
+	if (rc == 0 && ptime->end && ptime->end < ptime->start)
+		return -EINVAL;
+
+	pr_debug("start time %" PRIu64 ", ", ptime->start);
+	pr_debug("end time %" PRIu64 "\n", ptime->end);
+
+	return rc;
+}
+
+bool perf_time__skip_sample(struct perf_time_interval *ptime, u64 timestamp)
+{
+	/* if time is not set don't drop sample */
+	if (timestamp == 0)
+		return false;
+
+	/* otherwise compare sample time to time window */
+	if ((ptime->start && timestamp < ptime->start) ||
+	    (ptime->end && timestamp > ptime->end)) {
+		return true;
+	}
+
+	return false;
+}

tools/perf/util/time-utils.h

@@ -0,0 +1,12 @@
+#ifndef _TIME_UTILS_H_
+#define _TIME_UTILS_H_
+
+struct perf_time_interval {
+	u64 start, end;
+};
+
+int perf_time__parse_str(struct perf_time_interval *ptime, const char *ostr);
+
+bool perf_time__skip_sample(struct perf_time_interval *ptime, u64 timestamp);
+
+#endif