From 56395b38946d4b7de9e485098e928e8e432ef920 Mon Sep 17 00:00:00 2001
From: Dirk Hohndel <dirk@hohndel.org>
Date: Thu, 29 May 2014 13:13:11 -0700
Subject: [PATCH] Don't assume that pressures are always positive

When planning a dive, the dive could use more gas than is in the cylinder.
So getting a negative end pressure is a useful indication to the user that
there plan might not be a good one.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
---
 dive.c     | 4 ++--
 dive.h     | 2 +-
 helpers.h  | 2 +-
 profile.c  | 4 ++--
 qt-gui.cpp | 2 +-
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/dive.c b/dive.c
index ae07d151a..0d8f48754 100644
--- a/dive.c
+++ b/dive.c
@@ -76,7 +76,7 @@ void remove_event(struct event* event)
 	}
 }
 
-int get_pressure_units(unsigned int mb, const char **units)
+int get_pressure_units(int mb, const char **units)
 {
 	int pressure;
 	const char *unit;
@@ -454,7 +454,7 @@ void per_cylinder_mean_depth(struct dive *dive, struct divecomputer *dc, int *me
 
 static void fixup_pressure(struct dive *dive, struct sample *sample)
 {
-	unsigned int pressure, index;
+	int pressure, index;
 	cylinder_t *cyl;
 
 	pressure = sample->cylinderpressure.mbar;
diff --git a/dive.h b/dive.h
index 50bd2df39..03acea496 100644
--- a/dive.h
+++ b/dive.h
@@ -68,7 +68,7 @@ typedef struct
 	const char *description; /* "integrated", "belt", "ankle" */
 } weightsystem_t;
 
-extern int get_pressure_units(unsigned int mb, const char **units);
+extern int get_pressure_units(int mb, const char **units);
 extern double get_depth_units(int mm, int *frac, const char **units);
 extern double get_volume_units(unsigned int ml, int *frac, const char **units);
 extern double get_temp_units(unsigned int mk, const char **units);
diff --git a/helpers.h b/helpers.h
index e4bc1c6b4..fbcf2895f 100644
--- a/helpers.h
+++ b/helpers.h
@@ -19,7 +19,7 @@ QString get_weight_unit();
 QString get_cylinder_used_gas_string(cylinder_t *cyl, bool showunit = false);
 QString get_temperature_string(temperature_t temp, bool showunit = false);
 QString get_temp_unit();
-QString get_volume_string(volume_t volume, bool showunit = false, unsigned int mbar = 0);
+QString get_volume_string(volume_t volume, bool showunit = false, int mbar = 0);
 QString get_volume_unit();
 QString get_pressure_string(pressure_t pressure, bool showunit = false);
 QString get_pressure_unit();
diff --git a/profile.c b/profile.c
index 26b267dd0..35af28f25 100644
--- a/profile.c
+++ b/profile.c
@@ -683,7 +683,7 @@ struct plot_info calculate_max_limits_new(struct dive *dive, struct divecomputer
 
 	/* Get the per-cylinder maximum pressure if they are manual */
 	for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
-		unsigned int mbar = dive->cylinder[cyl].start.mbar;
+		int mbar = dive->cylinder[cyl].start.mbar;
 		if (mbar > maxpressure)
 			maxpressure = mbar;
 		if (mbar < minpressure)
@@ -964,7 +964,7 @@ static void populate_pressure_information(struct dive *dive, struct divecomputer
 	current = NULL;
 	for (i = 0; i < pi->nr; i++) {
 		struct plot_data *entry = pi->entry + i;
-		unsigned pressure = SENSOR_PRESSURE(entry);
+		int pressure = SENSOR_PRESSURE(entry);
 
 		/* discrete integration of pressure over time to get the SAC rate equivalent */
 		if (current) {
diff --git a/qt-gui.cpp b/qt-gui.cpp
index f342e20e1..3e898b979 100644
--- a/qt-gui.cpp
+++ b/qt-gui.cpp
@@ -286,7 +286,7 @@ QString get_temp_unit()
 		return QString(UTF8_DEGREE "F");
 }
 
-QString get_volume_string(volume_t volume, bool showunit, unsigned int mbar)
+QString get_volume_string(volume_t volume, bool showunit, int mbar)
 {
 	if (prefs.units.volume == units::LITER) {
 		double liter = volume.mliter / 1000.0;