Centralization for Kelvin and Standardization to milliKelvin

This centralizes all occurrences of Kelvin to dive.h and standardizes all
usages to milliKelvin.

[Dirk Hohndel: renamed the constant plus minor white space cleanup]

Signed-off-by: Jan Schubert <Jan.Schubert@GMX.li>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

5 files changed, 15 insertions, 14 deletions

diff --git a/dive.h b/dive.h
index f1b9dcc52..02e6a9e73 100644
--- a/dive.h
+++ b/dive.h
@@ -11,13 +11,14 @@
 #include <libxml/tree.h>
 #include <openssl/sha.h>
 
-#define O2_IN_AIR        209     // permille
-#define N2_IN_AIR        781
-#define O2_DENSITY       1429    // mg/Liter
-#define N2_DENSITY       1251
-#define HE_DENSITY       179
-#define SURFACE_PRESSURE 1013    // mbar
+#define O2_IN_AIR		209     // permille
+#define N2_IN_AIR		781
+#define O2_DENSITY		1429    // mg/Liter
+#define N2_DENSITY		1251
+#define HE_DENSITY		179
+#define SURFACE_PRESSURE	1013    // mbar
 #define SURFACE_PRESSURE_STRING "1013"
+#define ZERO_C_IN_MKELVIN	273150  // mKelvin
 
 
 /*
@@ -161,7 +162,7 @@ static inline int to_feet(depth_t depth)
 
 static inline double mkelvin_to_C(int mkelvin)
 {
-	return (mkelvin - 273150) / 1000.0;
+	return (mkelvin - ZERO_C_IN_MKELVIN) / 1000.0;
 }
 
 static inline double mkelvin_to_F(int mkelvin)
@@ -171,12 +172,12 @@ static inline double mkelvin_to_F(int mkelvin)
 
 static inline unsigned long F_to_mkelvin(double f)
 {
-	return (f-32) * 1000 / 1.8 + 273150.5;
+	return (f-32) * 1000 / 1.8 + ZERO_C_IN_MKELVIN + 0.5;
 }
 
 static inline unsigned long C_to_mkelvin(double c)
 {
-	return c * 1000 + 273150.5;
+	return c * 1000 + ZERO_C_IN_MKELVIN + 0.5;
 }
 
 static inline double psi_to_bar(double psi)
diff --git a/libdivecomputer.c b/libdivecomputer.c
index 8345c859f..3a32c5d97 100644
--- a/libdivecomputer.c
+++ b/libdivecomputer.c
@@ -214,7 +214,7 @@ sample_cb(dc_sample_type_t type, dc_sample_value_t value, void *userdata)
 		sample->cylinderpressure.mbar = value.pressure.value * 1000 + 0.5;
 		break;
 	case DC_SAMPLE_TEMPERATURE:
-		sample->temperature.mkelvin = (value.temperature + 273.15) * 1000 + 0.5;
+		sample->temperature.mkelvin = value.temperature * 1000 + ZERO_C_IN_MKELVIN + 0.5;
 		break;
 	case DC_SAMPLE_EVENT:
 		handle_event(dc, sample, value);
diff --git a/parse-xml.c b/parse-xml.c
index 55b37a9c4..8128f25ee 100644
--- a/parse-xml.c
+++ b/parse-xml.c
@@ -348,7 +348,7 @@ static void temperature(char *buffer, void *_temperature)
 			temperature->mkelvin = val.fp * 1000;
 			break;
 		case CELSIUS:
-			temperature->mkelvin = (val.fp + 273.15) * 1000 + 0.5;
+			temperature->mkelvin = val.fp * 1000 + ZERO_C_IN_MKELVIN + 0.5;
 			break;
 		case FAHRENHEIT:
 			temperature->mkelvin = (val.fp + 459.67) * 5000/9;
diff --git a/save-xml.c b/save-xml.c
index afee34da5..6e33cd5e6 100644
--- a/save-xml.c
+++ b/save-xml.c
@@ -37,7 +37,7 @@ static void show_milli(FILE *f, const char *pre, int value, const char *unit, co
 static void show_temperature(FILE *f, temperature_t temp, const char *pre, const char *post)
 {
 	if (temp.mkelvin)
-		show_milli(f, pre, temp.mkelvin - 273150, " C", post);
+		show_milli(f, pre, temp.mkelvin - ZERO_C_IN_MKELVIN, " C", post);
 }
 
 static void show_depth(FILE *f, depth_t depth, const char *pre, const char *post)
diff --git a/uemis.c b/uemis.c
index 1a09a2c3a..9e6d6c23c 100644
--- a/uemis.c
+++ b/uemis.c
@@ -297,7 +297,7 @@ void uemis_parse_divelog_binary(char *base64, void *datap) {
 
 	datalen = uemis_convert_base64(base64, &data);
 
-	dive->dc.airtemp.mkelvin = *(uint16_t *)(data + 45) * 100 + 273150;
+	dive->dc.airtemp.mkelvin = *(uint16_t *)(data + 45) * 100 + ZERO_C_IN_MKELVIN;
 	dive->dc.surface_pressure.mbar = *(uint16_t *)(data + 43);
 	if (*(uint8_t *)(data + 19))
 		dive->dc.salinity = 10300; /* avg grams per 10l sea water */
@@ -355,7 +355,7 @@ void uemis_parse_divelog_binary(char *base64, void *datap) {
 		sample = prepare_sample(dc);
 		sample->time.seconds = u_sample->dive_time;
 		sample->depth.mm = rel_mbar_to_depth(u_sample->water_pressure, dive);
-		sample->temperature.mkelvin = (u_sample->dive_temperature * 100) + 273150;
+		sample->temperature.mkelvin = (u_sample->dive_temperature * 100) + ZERO_C_IN_MKELVIN;
 		sample->sensor = active;
 		sample->cylinderpressure.mbar =
 			(u_sample->tank_pressure_high * 256 + u_sample->tank_pressure_low) * 10;