3 files changed, 22 insertions, 21 deletions
diff --git a/core/dive.c b/core/dive.c
index 84acecb38..54d2a00f4 100644
--- a/core/dive.c
+++ b/core/dive.c
@@ -1172,6 +1172,21 @@ static void sanitize_cylinder_info(struct dive *dive)
 	}
 }
 
+/* Perform isobaric counterdiffusion calculations for gas changes in trimix dives.
+ * Here we use the rule-of-fifths where, during a change involving trimix gas, the increase in nitrogen
+ * should not exceed one fifth of the decrease in helium.
+ * Parameters: 1) pointers to two gas mixes, the gas being switched from and the gas being switched to.
+ *             2) a pointer to an icd_data structure.
+ * Output:     i) The icd_data stucture is filled with the delta_N2 and delta_He numbers (as permille).
+ *            ii) Function returns a boolean indicating an exceeding of the rule-of-fifths. False = no icd problem.
+ */
+bool isobaric_counterdiffusion(struct gasmix *oldgasmix, struct gasmix *newgasmix, struct icd_data *results)
+{
+	results->dN2 = get_he(oldgasmix) + get_o2(oldgasmix) - get_he(newgasmix) - get_o2(newgasmix);
+	results->dHe = get_he(newgasmix) - get_he(oldgasmix);
+	return get_he(oldgasmix) && results->dN2 > 0 && 5 * results->dN2 > -results->dHe;
+}
+
 /* some events should never be thrown away */
 static bool is_potentially_redundant(struct event *event)
 {
diff --git a/core/dive.h b/core/dive.h
index 3532b4a59..c155abbfd 100644
--- a/core/dive.h
+++ b/core/dive.h
@@ -114,6 +114,13 @@ typedef struct
 	const char *description; /* "integrated", "belt", "ankle" */
 } weightsystem_t;
 
+struct icd_data { // This structure provides communication between function isobaric_counterdiffusion() and the calling software.
+	int dN2;      // The change in fraction (permille) of nitrogen during the change
+	int dHe;      // The change in fraction (permille) of helium during the change
+};
+
+extern bool isobaric_counterdiffusion(struct gasmix *oldgasmix, struct gasmix *newgasmix, struct icd_data *results);
+
 /*
  * Events are currently based straight on what libdivecomputer gives us.
  *  We need to wrap these into our own events at some point to remove some of the limitations.
diff --git a/core/plannernotes.c b/core/plannernotes.c
index 4021806ea..1c03d2048 100644
--- a/core/plannernotes.c
+++ b/core/plannernotes.c
@@ -30,27 +30,6 @@ int diveplan_duration(struct diveplan *diveplan)
 	return (duration + 30) / 60;
 }
 
-struct icd_data { // This structure provides communication between function isobaric_counterdiffusion() and the calling software.
-	int dN2;      // The change in fraction (permille) of nitrogen during the change
-	int dHe;      // The change in fraction (permille) of helium during the change
-};
-
-/* Perform isobaric counterdiffusion calculations for gas changes in trimix dives.
- * Here we use the rule-of-fifths where, during a change involving trimix gas, the increase in nitrogen
- * should not exceed one fifth of the decrease in helium.
- * Parameters: 1) Pointer to the dive structure.
- *             2) pointers to two gas mixes, the gas being switched from and the gas being switched to.
- *             3) a pointer to an icd_data structure.
- * Output:     i) The icd_data stucture is filled with the delta_N2 and delta_He numbers (as permille).
- *            ii) Function returns a boolean indicating an exceeding of the rule-of-fifths. False = no icd problem.
- */
-bool isobaric_counterdiffusion(struct gasmix *oldgasmix, struct gasmix *newgasmix, struct icd_data *results)
-{
-	results->dN2 = get_he(oldgasmix) + get_o2(oldgasmix) - get_he(newgasmix) - get_o2(newgasmix);
-	results->dHe = get_he(newgasmix) - get_he(oldgasmix);
-	return get_he(oldgasmix) && results->dN2 > 0 && 5 * results->dN2 > -results->dHe;
-}
-
 /* Add the icd results of one trimix gas change to the dive plan html buffer. Two rows are added to the table, one
  * indicating fractions of gas, the other indication partial pressures of gas. This function makes use of the
  * icd_data structure that was filled with information by the function isobaric_counterdiffusion().