List only the gases used in the Info tab

The equipment tab will still show all defined gases, but the info for
the dive should only list the ones used.

Also change the name of the two gas related boxes to better reflect the
data that is shown.

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

2 files changed, 58 insertions, 8 deletions

diff --git a/qt-ui/maintab.ui b/qt-ui/maintab.ui
index 4bf37e9a3..854e67940 100644
--- a/qt-ui/maintab.ui
+++ b/qt-ui/maintab.ui
@@ -240,7 +240,7 @@
     <item row="0" column="1">
      <widget class="QGroupBox" name="groupBox_3">
       <property name="title">
-       <string>O²/HE</string>
+       <string>Gases Used</string>
       </property>
       <layout class="QHBoxLayout" name="horizontalLayout_4">
        <item>
@@ -335,7 +335,7 @@
     <item row="0" column="2">
      <widget class="QGroupBox" name="groupBox_4">
       <property name="title">
-       <string>Gas Used</string>
+       <string>Gas Consumed</string>
       </property>
       <layout class="QHBoxLayout" name="horizontalLayout_5">
        <item>
diff --git a/statistics.c b/statistics.c
index 411ba1c1f..6459b3802 100644
--- a/statistics.c
+++ b/statistics.c
@@ -290,23 +290,73 @@ volume_t get_gas_used(struct dive *dive)
 	return gas_used;
 }
 
+bool is_gas_used(struct dive *dive, int idx)
+{
+	cylinder_t *cyl = &dive->cylinder[idx];
+	int o2, he;
+	struct divecomputer *dc;
+	bool used = FALSE;
+	bool firstGasExplicit = FALSE;
+	if (cylinder_none(cyl))
+		return FALSE;
+
+	o2 = get_o2(&cyl->gasmix);
+	he = get_he(&cyl->gasmix);
+	dc = &dive->dc;
+	while (dc) {
+		struct event *event = dc->events;
+		while (event) {
+			if (event->value) {
+				if (event->name && !strcmp(event->name, "gaschange")) {
+					unsigned int event_he = event->value >> 16;
+					unsigned int event_o2 = event->value & 0xffff;
+					if (event->time.seconds < 30)
+						firstGasExplicit = TRUE;
+					if (is_air(o2, he)) {
+						if (is_air(event_o2 * 10, event_he * 10))
+							used = TRUE;
+					} else if (he == event_he * 10 && o2 == event_o2 * 10) {
+						used = TRUE;
+					}
+				}
+			}
+			if (used)
+				break;
+			event = event->next;
+		}
+		if (used)
+			break;
+		dc = dc->next;
+	}
+	if (idx == 0 && !firstGasExplicit)
+		used = TRUE;
+	return used;
+}
+
 #define MAXBUF 80
 /* for the O2/He readings just create a list of them */
 char *get_gaslist(struct dive *dive)
 {
 	int idx, offset = 0;
 	static char buf[MAXBUF];
+	int o2, he;
 
 	buf[0] = '\0';
 	for (idx = 0; idx < MAX_CYLINDERS; idx++) {
-		cylinder_t *cyl = &dive->cylinder[idx];
-		if (!cylinder_none(cyl)) {
-			int o2 = get_o2(&cyl->gasmix);
-			int he = get_he(&cyl->gasmix);
+		cylinder_t *cyl;
+		if (!is_gas_used(dive, idx))
+			continue;
+		cyl = &dive->cylinder[idx];
+		o2 = get_o2(&cyl->gasmix);
+		he = get_he(&cyl->gasmix);
+		if (is_air(o2, he))
+			snprintf(buf + offset, MAXBUF - offset, (offset > 0) ? ", %s" : "%s", _("air"));
+		else
 			snprintf(buf + offset, MAXBUF - offset, (offset > 0) ? ", %d/%d" : "%d/%d",
 				 (o2 + 5) / 10, (he + 5) / 10);
-			offset = strlen(buf);
-		}
+		offset = strlen(buf);
 	}
+	if (*buf == '\0')
+		strncpy(buf, _("air"), MAXBUF);
 	return buf;
 }