more efficient entry checking

it's a mess, but should work

1 files changed, 268 insertions, 49 deletions

diff --git a/src/entry.c b/src/entry.c
index 13208ca..a2ad34e 100644
--- a/src/entry.c
+++ b/src/entry.c
@@ -1,22 +1,258 @@
 #include "entry.h"
 
 #include <assert.h>
+#include <limits.h>
 
 static time_t rt;
 
-/* super inefficient, but should best-possible avoid any weird leap
+static inline time_t* sub_seconds(
+	struct entry_s *e,
+	time_t *now, time_t *now_minus_stay, time_t *now_plus_warn,
+	struct tm *t, struct tm *ttmp, struct tm *torig
+)
+{
+	unsigned mul, mul_last;
+	time_t rttmp;
+	struct tm *swap;
+
+	rt = e->start;
+
+	if (rt > *now_plus_warn)
+		return NULL;
+
+	if (rt >= *now_minus_stay)
+		return &rt;
+
+	for (mul = 1;;) {
+		mul_last = mul;
+		mul *= 2;
+
+		if ((int)(mul * e->every.second) <= 0) {
+			mul = ((INT_MAX - 60) / e->every.second);
+		}
+
+		*t = *ttmp;
+
+		ttmp->tm_sec += mul * e->every.second;
+
+		rttmp = rt;
+
+		if (e->local)
+			rt = mktime(ttmp);
+		else
+			rt = timegm(ttmp);
+
+		if (rt == -1)
+			return NULL;
+
+		if (rt >= *now_minus_stay)
+			break;
+
+		if (e->local)
+			swap = localtime(&rt);
+		else
+			swap = gmtime(&rt);
+		if (swap == NULL)
+			return NULL;
+		*ttmp = *swap;
+	}
+
+	rt = rttmp;
+
+	for (mul = mul_last; mul > 1; mul = mul / 2) {
+		*ttmp = *t;
+		ttmp->tm_sec += mul * e->every.second;
+
+		if (e->local)
+			rttmp = mktime(ttmp);
+		else
+			rttmp = timegm(ttmp);
+
+		if (rttmp == -1)
+			return NULL;
+
+		if (rttmp >= *now_minus_stay)
+			continue;
+
+		rt = rttmp;
+		if (e->local)
+			swap = localtime(&rt);
+		else
+			swap = gmtime(&rt);
+		if (swap == NULL)
+			return NULL;
+		*t = *swap;
+	}
+
+	while (true) {
+		*ttmp = *t;
+
+		ttmp->tm_sec += e->every.second;
+
+		if (e->local)
+			rttmp = mktime(ttmp);
+		else
+			rttmp = timegm(ttmp);
+
+		if (rttmp == -1)
+			return NULL;
+
+		if (rttmp > *now_plus_warn)
+			return NULL;
+
+		rt = rttmp;
+
+		if (rt >= *now_minus_stay)
+			return &rt;
+
+		if (e->local)
+			swap = localtime(&rt);
+		else
+			swap = gmtime(&rt);
+		if (swap == NULL)
+			return NULL;
+		*t = *swap;
+	}
+}
+
+static inline time_t* sub_others(
+	struct entry_s *e,
+	time_t *now, time_t *now_minus_stay, time_t *now_plus_warn,
+	struct tm *t, struct tm *ttmp, struct tm *torig
+) {
+	unsigned mul, mul_last, mul_max;
+	time_t rttmp;
+	struct tm *swap;
+
+	mul_max = e->every.year;
+
+	if (e->every.month > mul_max)
+		mul_max = e->every.month;
+	if (e->every.day > mul_max)
+		mul_max = e->every.day;
+	if (e->every.hour > mul_max)
+		mul_max = e->every.hour;
+	if (e->every.minute > mul_max)
+		mul_max = e->every.minute;
+	if (e->every.second > mul_max)
+		mul_max = e->every.second;
+
+	mul_max = (INT_MAX - 365) / mul_max;
+
+	for (mul = 1, mul_last = 1;;) {
+		if (mul == mul_max)
+			return NULL;
+
+		*t = *torig;
+
+		t->tm_year += mul * e->every.year;
+		t->tm_mon  += mul * e->every.month;
+		t->tm_mday += mul * e->every.day;
+		t->tm_hour += mul * e->every.hour;
+		t->tm_min  += mul * e->every.minute;
+		t->tm_sec  += mul * e->every.second;
+
+		if (e->local)
+			rt = mktime(t);
+		else
+			rt = timegm(t);
+
+		if (rt == -1)
+			return NULL;
+
+		if (rt >= *now_minus_stay)
+			break;
+
+		mul_last = mul;
+		mul *= 2;
+
+		if (mul > mul_max || mul <= mul_last)
+			break;
+	}
+
+	for (mul = mul_last;;) {
+		mul++;
+
+		if (mul > mul_max)
+			return NULL;
+
+		*t = *torig;
+
+		t->tm_year += mul * e->every.year;
+		t->tm_mon  += mul * e->every.month;
+		t->tm_mday += mul * e->every.day;
+		t->tm_hour += mul * e->every.hour;
+		t->tm_min  += mul * e->every.minute;
+		t->tm_sec  += mul * e->every.second;
+
+		if (e->local)
+			rt = mktime(t);
+		else
+			rt = timegm(t);
+
+		if (rt == -1)
+			return NULL;
+
+		if (rt > *now_plus_warn)
+			return NULL;
+
+		if (rt >= *now_minus_stay) {
+			if (e->every.second)
+				return &rt;
+
+			if (e->local)
+				swap = localtime(&rt);
+			else
+				swap = gmtime(&rt);
+			if (swap == NULL)
+				return NULL;
+			*ttmp = *swap;
+
+			if (ttmp->tm_sec != torig->tm_sec)
+				continue;
+
+			if (e->every.minute)
+				return &rt;
+
+			if (ttmp->tm_min != torig->tm_min)
+				continue;
+
+			if (e->every.hour)
+				return &rt;
+
+			if (ttmp->tm_hour != torig->tm_hour)
+				continue;
+
+			if (e->every.day)
+				return &rt;
+
+			if (ttmp->tm_mday != torig->tm_mday)
+				continue;
+
+			if (e->every.month)
+				return &rt;
+
+			if (ttmp->tm_mon != torig->tm_mon)
+				continue;
+
+			return &rt;
+		}
+	}
+}
+
+/* super messy, but should best-possible avoid any weird leap
  * years/seconds/dst-problems/other future changes */
 time_t* entry_is_active(struct entry_s *e, time_t now)
 {
-	struct tm t, ttmp, *tmp;
-	time_t rttmp, now_plus_warn, now_minus_stay;
+	struct tm t, ttmp, torig, *swap;
+	time_t now_plus_warn, now_minus_stay;
 	
 	assert(e != NULL);
 
-	tmp = localtime(&now);
-	if (tmp == NULL)
+	swap = localtime(&now);
+	if (swap == NULL)
 		return NULL;
-	t = *tmp;
+	t = *swap;
 	ttmp = t;
 
 	t.tm_year += e->warn.year;
@@ -52,50 +288,33 @@ time_t* entry_is_active(struct entry_s *e, time_t now)
 	if (e->has_end && now_minus_stay > e->end)
 		return NULL;
 
-	tmp = localtime( &(e->start) );
-	if (tmp == NULL)
+	if (e->local)
+		swap = localtime( &(e->start) );
+	else
+		swap = gmtime( &(e->start) );
+	if (swap == NULL)
 		return NULL;
-	t = *tmp;
-
-	for (rt = e->start;;) {
-		if (rt > now_plus_warn)
-			return NULL;
-
-		if (rt >= now_minus_stay)
-			return &rt;
-
-		ttmp = t;
-
-		t.tm_year += e->every.year;
-		t.tm_mon  += e->every.month;
-		t.tm_mday += e->every.day;
-		t.tm_hour += e->every.hour;
-		t.tm_min  += e->every.minute;
-		t.tm_sec  += e->every.second;
-
-		rt = mktime(&t);
-
-		if (rt == -1) {
-			rttmp = mktime(&ttmp);
-			if (rttmp == -1)
-				return NULL;
-
-			tmp = localtime(&rttmp);
-			if (tmp == NULL)
-				return NULL;
-			t = *tmp;
-
-			t.tm_year += e->every.year;
-			t.tm_mon  += e->every.month;
-			t.tm_mday += e->every.day;
-			t.tm_hour += e->every.hour;
-			t.tm_min  += e->every.minute;
-			t.tm_sec  += e->every.second;
-
-			rt = mktime(&t);
+	t = *swap;
+	torig = t;
+	ttmp = t;
 
-			if (rt == -1)
-				return NULL;
-		}
+	if (
+		e->every.year == 0 &&
+		e->every.month == 0 &&
+		e->every.day == 0 &&
+		e->every.hour == 0 &&
+		e->every.minute == 0
+	) {
+		return sub_seconds(
+			e,
+			&now, &now_minus_stay, &now_plus_warn,
+			&t, &ttmp, &torig
+		);
 	}
+
+	return sub_others(
+		e,
+		&now, &now_minus_stay, &now_plus_warn,
+		&t, &ttmp, &torig
+	);
 }