From c43e1ad21b1a042bab96e2b214c6e33a412658d3 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat, 10 Sep 2011 15:27:23 -0700
Subject: [PATCH] Let people manage their cylinders in cuft and psi

If the output units are set to cuft and psi, then we should show the
cylinder size and pressure properly.

NOTE! In the absense of pressure data, we *always* show the cylinder
volume in liter.  There's no way to convert it to imperial units, since
the imperial units are not in physical size, but in air volume
normalized to surface pressure..

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 equipment.c | 58 ++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 42 insertions(+), 16 deletions(-)

diff --git a/equipment.c b/equipment.c
index 151b1f9..caa2958 100644
--- a/equipment.c
+++ b/equipment.c
@@ -12,12 +12,31 @@ static int cylinder_changed;
 static GtkComboBox *cylinder_description;
 static GtkSpinButton *cylinder_size, *cylinder_pressure, *nitrox_value;
 
+static void set_cylinder_spinbuttons(int ml, int mbar)
+{
+	double volume, pressure;
+
+	volume = ml / 1000.0;
+	pressure = mbar / 1000.0;
+	if (mbar) {
+		if (output_units.volume == CUFT) {
+			volume /= 28.3168466;	/* Liters to cuft */
+			volume *= pressure / 1.01325;
+		}
+		if (output_units.pressure == PSI) {
+			pressure *= 14.5037738;	/* Bar to PSI */
+		}
+	}
+
+	gtk_spin_button_set_value(cylinder_size, volume);
+	gtk_spin_button_set_value(cylinder_pressure, pressure);
+}
+
 static void cylinder_cb(GtkComboBox *combo_box, gpointer data)
 {
 	GtkTreeIter iter;
 	GtkTreeModel *model = gtk_combo_box_get_model(combo_box);
 	GValue value1 = {0, }, value2 = {0,};
-	int volume, pressure;
 	cylinder_t *cyl = current_dive->cylinder + 0;
 
 	/* Did the user set it to some non-standard value? */
@@ -43,14 +62,9 @@ static void cylinder_cb(GtkComboBox *combo_box, gpointer data)
 	cylinder_changed = 1;
 
 	gtk_tree_model_get_value(model, &iter, 1, &value1);
-	volume = g_value_get_int(&value1);
 	gtk_tree_model_get_value(model, &iter, 2, &value2);
-	pressure = g_value_get_int(&value2);
 
-	gtk_spin_button_set_value(cylinder_size,
-			volume / 1000.0);
-	gtk_spin_button_set_value(cylinder_pressure,
-			pressure / 1000.0);
+	set_cylinder_spinbuttons(g_value_get_int(&value1), g_value_get_int(&value2));
 }
 
 static gboolean match_cylinder(GtkTreeModel *model,
@@ -79,10 +93,8 @@ void show_dive_equipment(struct dive *dive)
 
 	if (desc)
 		gtk_tree_model_foreach(model, match_cylinder, (gpointer)desc);
-	gtk_spin_button_set_value(cylinder_size,
-			cyl->type.size.mliter / 1000.0);
-	gtk_spin_button_set_value(cylinder_pressure,
-			cyl->type.workingpressure.mbar / 1000.0);
+
+	set_cylinder_spinbuttons(cyl->type.size.mliter, cyl->type.workingpressure.mbar);
 	o2 = cyl->gasmix.o2.permille / 10.0;
 	if (!o2)
 		o2 = 21.0;
@@ -104,12 +116,25 @@ static GtkWidget *create_spinbutton(GtkWidget *vbox, const char *name, double mi
 	return button;
 }
 
-static void fill_cylinder_info(cylinder_t *cyl, const char *desc, int mliter, int mbar, int o2)
+static void fill_cylinder_info(cylinder_t *cyl, const char *desc, double volume, double pressure, int o2)
 {
+	int mbar, ml;
+
+	if (output_units.pressure == PSI)
+		pressure /= 14.5037738;
+
+	if (pressure && output_units.volume == CUFT) {
+		volume *= 28.3168466;	/* CUFT to liter */
+		volume /= pressure / 1.01325;
+	}
+
+	ml = volume * 1000 + 0.5;
+	mbar = pressure * 1000 + 0.5;
+
 	if (o2 < 211)
 		o2 = 0;
 	cyl->type.description = desc;
-	cyl->type.size.mliter = mliter;
+	cyl->type.size.mliter = ml;
 	cyl->type.workingpressure.mbar = mbar;
 	cyl->gasmix.o2.permille = o2;
 }
@@ -118,11 +143,12 @@ static void record_cylinder_changes(struct dive *dive)
 {
 	const gchar *desc;
 	GtkComboBox *box = cylinder_description;
-	int volume, pressure, o2;
+	double volume, pressure;
+	int o2;
 
 	desc = gtk_combo_box_get_active_text(box);
-	volume = gtk_spin_button_get_value(cylinder_size) * 1000 + 0.5;
-	pressure = gtk_spin_button_get_value(cylinder_pressure) * 1000 + 0.5;
+	volume = gtk_spin_button_get_value(cylinder_size);
+	pressure = gtk_spin_button_get_value(cylinder_pressure);
 	o2 = gtk_spin_button_get_value(nitrox_value)*10 + 0.5;
 	fill_cylinder_info(dive->cylinder+0, desc, volume, pressure, o2);
 }
-- 
2.43.0