1 files changed, 105 insertions, 0 deletions
diff --git a/src/timings.c b/src/timings.c
new file mode 100644
index 000000000..a1eecc01a
--- /dev/null
+++ b/src/timings.c
@@ -0,0 +1,105 @@
+typedef struct TimeStamp {
+	u64    start;
+	u64    finish;
+	String label;
+} TimeStamp;
+
+typedef struct Timings {
+	TimeStamp        total;
+	Array(TimeStamp) sections;
+	u64              freq;
+} Timings;
+
+
+u64 win32_time_stamp_time_now(void) {
+	LARGE_INTEGER counter;
+	QueryPerformanceCounter(&counter);
+	return counter.QuadPart;
+}
+
+u64 win32_time_stamp__freq(void) {
+	gb_local_persist LARGE_INTEGER win32_perf_count_freq = {0};
+	if (!win32_perf_count_freq.QuadPart) {
+		QueryPerformanceFrequency(&win32_perf_count_freq);
+		GB_ASSERT(win32_perf_count_freq.QuadPart != 0);
+	}
+
+	return win32_perf_count_freq.QuadPart;
+}
+
+u64 time_stamp_time_now(void) {
+#if defined(GB_SYSTEM_WINDOWS)
+	return win32_time_stamp_time_now();
+#else
+#error time_stamp_time_now
+#endif
+}
+
+u64 time_stamp__freq(void) {
+#if defined(GB_SYSTEM_WINDOWS)
+	return win32_time_stamp__freq();
+#else
+#error time_stamp__freq
+#endif
+}
+
+TimeStamp make_time_stamp(String label) {
+	TimeStamp ts = {0};
+	ts.start = time_stamp_time_now();
+	ts.label = label;
+	return ts;
+}
+
+void timings_init(Timings *t, String label, isize buffer_size) {
+	array_init_reserve(&t->sections, heap_allocator(), buffer_size);
+	t->total = make_time_stamp(label);
+	t->freq  = time_stamp__freq();
+}
+
+void timings_destroy(Timings *t) {
+	array_free(&t->sections);
+}
+
+void timings__stop_current_section(Timings *t) {
+	if (t->sections.count > 0) {
+		t->sections.e[t->sections.count-1].finish = time_stamp_time_now();
+	}
+}
+
+void timings_start_section(Timings *t, String label) {
+	timings__stop_current_section(t);
+	array_add(&t->sections, make_time_stamp(label));
+}
+
+f64 time_stamp_as_ms(TimeStamp ts, u64 freq) {
+	GB_ASSERT_MSG(ts.finish >= ts.start, "time_stamp_as_ms - %.*s", LIT(ts.label));
+	return 1000.0 * cast(f64)(ts.finish - ts.start) / cast(f64)freq;
+}
+
+void timings_print_all(Timings *t) {
+	timings__stop_current_section(t);
+	t->total.finish = time_stamp_time_now();
+
+	char const SPACES[] = "                                                                ";
+
+	isize max_len = t->total.label.len;
+	for_array(i, t->sections) {
+		TimeStamp ts = t->sections.e[i];
+		max_len = gb_max(max_len, ts.label.len);
+	}
+
+	GB_ASSERT(max_len <= gb_size_of(SPACES)-1);
+
+	gb_printf("%.*s%.*s - %.3f ms\n",
+	          LIT(t->total.label),
+	          cast(int)(max_len-t->total.label.len), SPACES,
+	          time_stamp_as_ms(t->total, t->freq));
+
+	for_array(i, t->sections) {
+		TimeStamp ts = t->sections.e[i];
+		gb_printf("%.*s%.*s - %.3f ms\n",
+		          LIT(ts.label),
+	              cast(int)(max_len-ts.label.len), SPACES,
+		          time_stamp_as_ms(ts, t->freq));
+	}
+}