From 072e404af52f71aabcbd42cf0d1320352635aca5 Mon Sep 17 00:00:00 2001
From: "Robert C. Helling" <helling@atdotde.de>
Date: Tue, 3 Jul 2018 11:25:38 +0200
Subject: Allow to split dives with more than one dive computer

Only the first computer is taken into account to find
surface intervals. All further dive computers are split
according to time.

Signed-off-by: Robert C. Helling <helling@atdotde.de>
---
 core/dive.c | 74 +++++++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 48 insertions(+), 26 deletions(-)

diff --git a/core/dive.c b/core/dive.c
index 2c4539530..78263dfab 100644
--- a/core/dive.c
+++ b/core/dive.c
@@ -3466,36 +3466,56 @@ static int split_dive_at(struct dive *dive, int a, int b)
 	dc2->samples -= b;
 	memmove(dc2->sample, dc2->sample+b, dc2->samples * sizeof(struct sample));
 
+	/* Now the secondary dive computers */
+	t = dc2->sample[0].time.seconds;
+	while ((dc1 = dc1->next))	{
+		i = 0;
+		while (dc1->samples < i && dc1->sample[i].time.seconds <= t)
+			++i;
+		dc1->samples = i;
+	}
+	while ((dc2 = dc2->next)) {
+		i = 0;
+		while (dc2->samples < i && dc2->sample[i].time.seconds < t)
+			++i;
+		dc2->samples -= i;
+		memmove(dc2->sample, dc2->sample + i, dc2->samples * sizeof(struct sample));
+	}
+	dc1 = &d1->dc;
+	dc2 = &d2->dc;
 	/*
 	 * This is where we cut off events from d1,
 	 * and shift everything in d2
 	 */
-	t = dc2->sample[0].time.seconds;
 	d2->when += t;
-	dc2->when += t;
-	for (i = 0; i < dc2->samples; i++)
-		dc2->sample[i].time.seconds -= t;
-
-	/* Remove the events past 't' from d1 */
-	evp = &dc1->events;
-	while ((event = *evp) != NULL && event->time.seconds < t)
-		evp = &event->next;
-	*evp = NULL;
-	while (event) {
-		struct event *next = event->next;
-		free(event);
-		event = next;
-	}
-
-	/* Remove the events before 't' from d2, and shift the rest */
-	evp = &dc2->events;
-	while ((event = *evp) != NULL) {
-		if (event->time.seconds < t) {
-			*evp = event->next;
+	while (dc1 && dc2) {
+		dc2->when += t;
+		for (i = 0; i < dc2->samples; i++)
+			dc2->sample[i].time.seconds -= t;
+
+		/* Remove the events past 't' from d1 */
+		evp = &dc1->events;
+		while ((event = *evp) != NULL && event->time.seconds < t)
+			evp = &event->next;
+		*evp = NULL;
+		while (event) {
+			struct event *next = event->next;
 			free(event);
-		} else {
-			event->time.seconds -= t;
+			event = next;
+		}
+
+		/* Remove the events before 't' from d2, and shift the rest */
+		evp = &dc2->events;
+		while ((event = *evp) != NULL) {
+			if (event->time.seconds < t) {
+				*evp = event->next;
+				free(event);
+			} else {
+				event->time.seconds -= t;
+			}
 		}
+		dc1 = dc1->next;
+		dc2 = dc2->next;
 	}
 
 	force_fixup_dive(d1);
@@ -3540,10 +3560,11 @@ static bool should_split(struct divecomputer *dc, int t1, int t2)
 /*
  * Try to split a dive into multiple dives at a surface interval point.
  *
- * NOTE! We will not split dives with multiple dive computers, and
- * only split when there is at least one surface event that has
+ * NOTE! We will split when there is at least one surface event that has
  * non-surface events on both sides.
  *
+ * The surface interval points are determined using the first dive computer.
+ *
  * In other words, this is a (simplified) reversal of the dive merging.
  */
 int split_dive(struct dive *dive)
@@ -3552,9 +3573,10 @@ int split_dive(struct dive *dive)
 	int at_surface, surface_start;
 	struct divecomputer *dc;
 
-	if (!dive || (dc = &dive->dc)->next)
+	if (!dive)
 		return 0;
 
+	dc = &dive->dc;
 	surface_start = 0;
 	at_surface = 1;
 	for (i = 1; i < dc->samples; i++) {
-- 
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