From 20d7d03a0d923591f012dfbfc97786074e133da7 Mon Sep 17 00:00:00 2001
From: Jan Mulder <jlmulder@xs4all.nl>
Date: Mon, 13 Nov 2017 10:02:43 +0100
Subject: [PATCH] OSTC: initialize initial CNS from header

As the OSTC does not report a CNS value on the first sample, we need to
initialize it differently. This can be solved by using the initial CNS
value form the dive header, and storing that value in the first sample.
The resulting patch is very similar to 44f629f03a91a3b3.

Signed-off-by: Jan Mulder <jlmulder@xs4all.nl>
---
 src/hw_ostc_parser.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/hw_ostc_parser.c b/src/hw_ostc_parser.c
index a1dc0c3..d01f087 100644
--- a/src/hw_ostc_parser.c
+++ b/src/hw_ostc_parser.c
@@ -98,6 +98,7 @@ typedef struct hw_ostc_parser_t {
 	unsigned int nfixed;
 	unsigned int initial;
 	unsigned int initial_setpoint;
+	unsigned int initial_cns;
 	hw_ostc_gasmix_t gasmix[NGASMIXES];
 } hw_ostc_parser_t;
 
@@ -222,9 +223,11 @@ hw_ostc_parser_cache (hw_ostc_parser_t *parser)
 	}
 
 	// Get all the gas mixes, the index of the inital mix,
-	// and the initial setpoint (used in the fixed setpoint mode).
+	// the initial setpoint (used in the fixed setpoint CCR mode),
+	// and the initial CNS from the header
 	unsigned int initial = UNDEFINED;
 	unsigned int initial_setpoint = UNDEFINED;
+	unsigned int initial_cns = UNDEFINED;
 	unsigned int ngasmixes = 0;
 	hw_ostc_gasmix_t gasmix[NGASMIXES] = {{0}};
 	if (version == 0x22) {
@@ -250,6 +253,8 @@ hw_ostc_parser_cache (hw_ostc_parser_t *parser)
 		if (data[82] == OSTC3_CC) {
 			initial_setpoint = data[60];
 		}
+		// Initial CNS
+		initial_cns = array_uint16_le (data + 53);
 	} else {
 		ngasmixes = 5;
 		if (data[31] != 0xFF) {
@@ -278,6 +283,7 @@ hw_ostc_parser_cache (hw_ostc_parser_t *parser)
 	parser->nfixed = ngasmixes;
 	parser->initial = initial;
 	parser->initial_setpoint = initial_setpoint;
+	parser->initial_cns = initial_cns;
 	for (unsigned int i = 0; i < ngasmixes; ++i) {
 		parser->gasmix[i] = gasmix[i];
 	}
@@ -312,6 +318,7 @@ hw_ostc_parser_create_internal (dc_parser_t **out, dc_context_t *context, unsign
 	parser->nfixed = 0;
 	parser->initial = 0;
 	parser->initial_setpoint = 0;
+	parser->initial_cns = 0;
 	for (unsigned int i = 0; i < NGASMIXES; ++i) {
 		parser->gasmix[i].oxygen = 0;
 		parser->gasmix[i].helium = 0;
@@ -349,6 +356,7 @@ hw_ostc_parser_set_data (dc_parser_t *abstract, const unsigned char *data, unsig
 	parser->nfixed = 0;
 	parser->initial = 0;
 	parser->initial_setpoint = 0;
+	parser->initial_cns = 0;
 	for (unsigned int i = 0; i < NGASMIXES; ++i) {
 		parser->gasmix[i].oxygen = 0;
 		parser->gasmix[i].helium = 0;
@@ -663,6 +671,12 @@ hw_ostc_parser_samples_foreach (dc_parser_t *abstract, dc_sample_callback_t call
 			if (callback) callback (DC_SAMPLE_SETPOINT, sample, userdata);
 		}
 
+		// Initial CNS (%).
+		if (time == samplerate && parser->initial_cns != UNDEFINED) {
+			sample.cns = parser->initial_cns / 100.0;
+			if (callback) callback (DC_SAMPLE_CNS, sample, userdata);
+		}
+
 		// Depth (mbar).
 		unsigned int depth = array_uint16_le (data + offset);
 		sample.depth = (depth * BAR / 1000.0) / hydrostatic;