X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;ds=sidebyside;f=include%2Fbabeltrace%2Ftrace-ir%2Fclock-class-internal.h;h=80147a639f2dc696163a5b25bd48224c0d22c56c;hb=5b9e151d6a8c0327e67bca1706ef16525d1d319d;hp=d91d549f7f4d4558bdfafe00f7bbf862c1703594;hpb=7fcdb0a96f75d66f5ff4f32d3ca78d7ca6067e4c;p=babeltrace.git

diff --git a/include/babeltrace/trace-ir/clock-class-internal.h b/include/babeltrace/trace-ir/clock-class-internal.h
index d91d549f..80147a63 100644
--- a/include/babeltrace/trace-ir/clock-class-internal.h
+++ b/include/babeltrace/trace-ir/clock-class-internal.h
@@ -31,10 +31,14 @@
 #include <babeltrace/compat/uuid-internal.h>
 #include <babeltrace/types.h>
 #include <babeltrace/property-internal.h>
+#include <babeltrace/assert-internal.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <glib.h>
 
+#define NS_PER_S_I	INT64_C(1000000000)
+#define NS_PER_S_U	UINT64_C(1000000000)
+
 struct bt_clock_class {
 	struct bt_object base;
 
@@ -102,4 +106,92 @@ void _bt_clock_class_freeze(const struct bt_clock_class *clock_class);
 BT_HIDDEN
 bt_bool bt_clock_class_is_valid(struct bt_clock_class *clock_class);
 
+static inline
+int bt_clock_class_clock_value_from_ns_from_origin(
+		struct bt_clock_class *cc, int64_t ns_from_origin,
+		uint64_t *raw_value)
+{
+	int ret = 0;
+	int64_t offset_in_ns;
+	uint64_t value_in_ns;
+	uint64_t rem_value_in_ns;
+	uint64_t value_periods;
+	uint64_t value_period_cycles;
+	int64_t ns_to_add;
+
+	BT_ASSERT(cc);
+	BT_ASSERT(raw_value);
+
+	/* Compute offset part of requested value, in nanoseconds */
+	if (!bt_safe_to_mul_int64(cc->offset_seconds, NS_PER_S_I)) {
+		ret = -1;
+		goto end;
+	}
+
+	offset_in_ns = cc->offset_seconds * NS_PER_S_I;
+
+	if (cc->frequency == NS_PER_S_U) {
+		ns_to_add = (int64_t) cc->offset_cycles;
+	} else {
+		if (!bt_safe_to_mul_int64((int64_t) cc->offset_cycles,
+				NS_PER_S_I)) {
+			ret = -1;
+			goto end;
+		}
+
+		ns_to_add = ((int64_t) cc->offset_cycles * NS_PER_S_I) /
+			(int64_t) cc->frequency;
+	}
+
+	if (!bt_safe_to_add_int64(offset_in_ns, ns_to_add)) {
+		ret = -1;
+		goto end;
+	}
+
+	offset_in_ns += ns_to_add;
+
+	/* Value part in nanoseconds */
+	if (ns_from_origin < offset_in_ns) {
+		ret = -1;
+		goto end;
+	}
+
+	value_in_ns = (uint64_t) (ns_from_origin - offset_in_ns);
+
+	/* Number of whole clock periods in `value_in_ns` */
+	value_periods = value_in_ns / NS_PER_S_U;
+
+	/* Remaining nanoseconds in cycles + whole clock periods in cycles */
+	rem_value_in_ns = value_in_ns - value_periods * NS_PER_S_U;
+
+	if (value_periods > UINT64_MAX / cc->frequency) {
+		ret = -1;
+		goto end;
+	}
+
+	if (!bt_safe_to_mul_uint64(value_periods, cc->frequency)) {
+		ret = -1;
+		goto end;
+	}
+
+	value_period_cycles = value_periods * cc->frequency;
+
+	if (!bt_safe_to_mul_uint64(cc->frequency, rem_value_in_ns)) {
+		ret = -1;
+		goto end;
+	}
+
+	if (!bt_safe_to_add_uint64(cc->frequency * rem_value_in_ns / NS_PER_S_U,
+			value_period_cycles)) {
+		ret = -1;
+		goto end;
+	}
+
+	*raw_value = cc->frequency * rem_value_in_ns / NS_PER_S_U +
+		value_period_cycles;
+
+end:
+	return ret;
+}
+
 #endif /* BABELTRACE_TRACE_IR_CLOCK_CLASS_INTERNAL_H */