added float encoding

include/gp/enveloppe/cbor.hpp

@@ -70,7 +70,14 @@ namespace gp {
 		{}
 	};
 
+	struct ieee754_hf final {
+		uint16_t sign : 1;
+		uint16_t exponent : 5;
+		uint16_t mantissa : 10;
+	};
+
 	using cbor_floating_point = gp::fixed_variant<
+		ieee754_hf,
 		float,
 		double
 	>; 
@@ -152,6 +159,30 @@ namespace gp {
 			return gp::vector<gp::pair<cbor_value, cbor_value>>{alloc};
 		}
 
+		static auto encode_float(buffer<std::byte> dest, cbor_floating_point& value) {
+			switch(value.type()) {
+				case cbor_floating_point::alt<ieee754_hf>():{
+					if(dest.size() < 3) return dest.begin();
+					dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::word);
+					(dest.slice_start(3).slice_end(2).cast<gp::endian_wrapper<ieee754_hf, gp::endian::big>>())[0] = value.value<ieee754_hf>();
+					return dest.begin()+3;
+				}
+				case cbor_floating_point::alt<float>():{
+					if(dest.size() < 5) return dest.begin();
+					dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::dword);
+					(dest.slice_start(5).slice_end(4).cast<gp::endian_wrapper<float, gp::endian::big>>())[0] = value.value<float>();
+					return dest.begin()+5;
+				}
+				case cbor_floating_point::alt<double>():{
+					if(dest.size() < 9) return dest.begin();
+					dest[0] = std::byte(((uint8_t)cbor_type::oths << 5u) + (uint8_t)cbor_oths::qword);
+					(dest.slice_start(9).slice_end(8).cast<gp::endian_wrapper<double, gp::endian::big>>())[0] = value.value<double>();
+					return dest.begin()+9;
+				}
+				default: return dest.begin();
+			}
+		}
+
 		static auto encode_length(buffer<std::byte> dest, cbor_type major, uint64_t value) {
 			auto num = value;
 			if(value <= 23) {
@@ -230,7 +261,7 @@ namespace gp {
 					return dest.begin()+1;
 				}
 				case cbor_composite<cbor_value>::alt<cbor_floating_point>(): {
-
+					return encode_float(dest, contents.value<cbor_floating_point>());
 				}
 			}
 		}