Add bailout code to prevent infinite loop in deco calculation

This appears to happen if we have impossible dive sequences in the
dive_list (i.e., merging XML files from two different divers with
overlapping trips).

We need to fix the underlying cause for this issue (i.e., only pick the
'right' dives to calculate the residual tissue saturation), but at least
this code prevents the hang in an infinite loop.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/deco.c b/deco.c
index cd8f417d1..841ca3100 100644
--- a/deco.c
+++ b/deco.c
@@ -273,6 +273,7 @@ unsigned int deco_allowed_depth(double tissues_tolerance, double surface_pressur
 	double new_gradient_factor;
 	double pressure_delta = tissues_tolerance - surface_pressure;
 	struct dive_data mydata;
+	int bail = 1000;
 
 	if (pressure_delta > 0) {
 		if (!smooth) {
@@ -291,6 +292,12 @@ unsigned int deco_allowed_depth(double tissues_tolerance, double surface_pressur
 	below_gradient_limit = (new_gradient_factor < actual_gradient_limit(&mydata));
 	while(!below_gradient_limit)
 	{
+		/* we run into bugs where this turns into an infinite loop; so add
+		 * some bailout code that prints a warning but prevents the code from hanging */
+		if (--bail == 0) {
+			printf("WARNING!!!\n==========\nThe deco_allowed_depth() loop appears to hang.\nBailing out.\n");
+			break;
+		}
 		if (!smooth)
 			mydata.pressure += PRESSURE_CHANGE_3M;
 		else