1 files changed, 30 insertions, 0 deletions
diff --git a/src/gas.h b/src/gas.h
new file mode 100644
index 0000000..ca38a8d
--- /dev/null
+++ b/src/gas.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: MIT-0 */
+
+#ifndef GAS_H
+#define GAS_H
+
+#define PO2_MAX_DEFAULT 1.6
+#define END_MAX_DEFAULT 4.01325
+
+extern double PO2_MAX;
+extern double END_MAX;
+
+#define MOD_AUTO 0
+
+/* types */
+typedef struct gas_t {
+    unsigned char o2;
+    unsigned char he;
+    unsigned char n2;
+    double mod;
+} gas_t;
+
+/* functions */
+gas_t gas_new(unsigned char o2, unsigned char he, double mod);
+int gas_equal(const gas_t *g1, const gas_t *g2);
+unsigned char gas_o2(const gas_t *gas);
+unsigned char gas_he(const gas_t *gas);
+unsigned char gas_n2(const gas_t *gas);
+double gas_mod(const gas_t *gas);
+
+#endif /* end of include guard: GAS_H */