type_util.hpp

00001 /*
00002  * Copyright (C) 2014 Pavel Kirienko <pavel.kirienko@gmail.com>
00003  */
00004 
00005 #ifndef UAVCAN_MARSHAL_TYPE_UTIL_HPP_INCLUDED
00006 #define UAVCAN_MARSHAL_TYPE_UTIL_HPP_INCLUDED
00007 
00008 #include <uavcan/build_config.hpp>
00009 #include <uavcan/util/templates.hpp>
00010 #include <uavcan/util/comparison.hpp>
00011 
00012 namespace uavcan
00013 {
00014 /**
00015  * Read the specs to learn more about cast modes.
00016  */
00017 enum CastMode { CastModeSaturate, CastModeTruncate };
00018 
00019 /**
00020  * Read the specs to learn more about tail array optimizations.
00021  */
00022 enum TailArrayOptimizationMode { TailArrayOptDisabled, TailArrayOptEnabled };
00023 
00024 /**
00025  * Compile-time: Returns the number of bits needed to represent an integer value.
00026  */
00027 template <unsigned long Num>
00028 struct IntegerBitLen
00029 {
00030     enum { Result = 1 + IntegerBitLen<(Num >> 1)>::Result };
00031 };
00032 template <>
00033 struct IntegerBitLen<0>
00034 {
00035     enum { Result = 0 };
00036 };
00037 
00038 /**
00039  * Compile-time: Returns the number of bytes needed to contain the given number of bits. Assumes 1 byte == 8 bit.
00040  */
00041 template <unsigned long BitLen>
00042 struct BitLenToByteLen
00043 {
00044     enum { Result = (BitLen + 7) / 8 };
00045 };
00046 
00047 /**
00048  * Compile-time: Helper for integer and float specialization classes. Returns the platform-specific storage type.
00049  */
00050 template <typename T, typename Enable = void>
00051 struct StorageType
00052 {
00053     typedef T Type;
00054 };
00055 template <typename T>
00056 struct StorageType<T, typename EnableIfType<typename T::StorageType>::Type>
00057 {
00058     typedef typename T::StorageType Type;
00059 };
00060 
00061 /**
00062  * Compile-time: Whether T is a primitive type on this platform.
00063  */
00064 template <typename T>
00065 class IsPrimitiveType
00066 {
00067     typedef char Yes;
00068     struct No { Yes dummy[8]; };
00069 
00070     template <typename U>
00071     static typename EnableIf<U::IsPrimitive, Yes>::Type test(int);
00072 
00073     template <typename>
00074     static No test(...);
00075 
00076 public:
00077     enum { Result = sizeof(test<T>(0)) == sizeof(Yes) };
00078 };
00079 
00080 /**
00081  * Streams a given value into YAML string. Please see the specializations.
00082  */
00083 template <typename T>
00084 class UAVCAN_EXPORT YamlStreamer;
00085 
00086 }
00087 
00088 #endif // UAVCAN_MARSHAL_TYPE_UTIL_HPP_INCLUDED