Working on bitwise ops for float conversion

1 files changed, 116 insertions, 0 deletions

diff --git a/src/types.c b/src/types.c
new file mode 100644
index 0000000..c9482c1
--- /dev/null
+++ b/src/types.c
@@ -0,0 +1,116 @@
+#include <math.h>
+
+#include "osm/types.h"
+
+OSMFloatBreakdown osm_float_to_break(OSMFloat f)
+{
+	OSMFloatBreakdown out;
+
+	out.sign = f >> 63;
+	out.mantissa = (f >> 52) & 0x7ff;
+	out.fraction = f & 0xfffffffffffff;
+
+	return out;
+}
+
+/*
+ * WARNING: This code assumes that the compiler
+ * supports IEEE 754 floating point numbers.
+ *
+ * Should probably be updated with more formats if I was
+ * feeling frisky.
+ *
+ * Supports half, single, and double precision IEEE 754
+ */
+OSMFloatBreakdown osm_native_float_to_break(double d)
+{
+	OSMFloatBreakdown out = {0};
+
+	switch(sizeof(double))
+	{
+		case 2: {
+			uint16_t bits = *(uint16_t *) &d;
+			out.sign = bits >> 15;
+		} break;
+
+		case 4: {
+			uint32_t bits = * (uint32_t *) &d;
+			out.sign = bits >> 31;
+		} break;
+
+		case 8: {
+			uint64_t bits = * (uint64_t *) &d;
+			out = osm_float_to_break(bits);
+		} break;
+
+		default:
+			break;
+	}
+
+	return out;
+}
+
+OSMFloat osm_break_to_float(OSMFloatBreakdown b)
+{
+	OSMFloat out;
+	
+	if (b.sign)
+		out = 1;
+	out = out << 63;
+
+	out |= (OSMFloat)(b.mantissa & 0x7ff) << 52;
+
+	out |= b.fraction & 0xfffffffffffff;
+
+	return out;
+}
+
+/*
+ * WARNING: This code assumes that the compiler
+ * supports IEEE 754 floating point numbers.
+ *
+ * Should probably be updated with more formats if I was
+ * feeling frisky.
+ */
+double osm_break_to_native_float(OSMFloatBreakdown b)
+{
+	double out = 0;
+
+	switch(sizeof(double))
+	{
+		case 2: {
+		} break;
+		
+		case 4: {
+		} break;
+		
+		case 8: {
+			OSMFloat f = osm_break_to_float(b);
+			out = * (double *) &f;
+		} break;
+		
+		default:
+			break;
+	}
+
+	if (b.sign)
+		out = -out;
+
+	return out;
+}
+
+double osm_float_to_native(OSMFloat f)
+{
+	return
+		osm_break_to_native_float(
+			osm_float_to_break(f)
+		);
+}
+
+OSMFloat osm_native_to_float(double d)
+{
+	return
+		osm_break_to_float(
+			osm_native_float_to_break(d)
+		);
+}