poco库学习--数据类型,字节序,Any/DynamicAny

基础数据类型：
    poco 提供了整数类型头文件 "Poco/type.h"
    并提供了2个宏
        POCO_PTR_IS_64_BIT 
        POCO_LONG_IS_64_BIT
    可以用来判断是否64位环境

#elif defined(__GNUC__) || defined(__clang__)
    //
    // Unix/GCC/Clang
    //
    typedef signed char            Int8;
    typedef unsigned char          UInt8;
    typedef signed short           Int16;
    typedef unsigned short         UInt16;
    typedef signed int Int32;
    typedef unsigned int UInt32;
    #if defined(_WIN64)
        #define POCO_PTR_IS_64_BIT 1
        typedef signed long long   IntPtr;
        typedef unsigned long long UIntPtr;
        typedef signed long long   Int64;
        typedef unsigned long long UInt64;
    #else
        typedef signed long        IntPtr;
        typedef unsigned long      UIntPtr;
        #if defined(__LP64__)
            #define POCO_PTR_IS_64_BIT 1
            #define POCO_LONG_IS_64_BIT 1
            typedef signed long        Int64;
            typedef unsigned long      UInt64;
        #else
            typedef signed long long   Int64;
            typedef unsigned long long UInt64;
        #endif
    #endif
    #define POCO_HAVE_INT64 1
#elif defined(__DECCXX)

字节序：
    poco提供2个宏来判断大/小端字节序，定义在头文件 "Poco/platform.h"
        POCO_ARCH_LITTLE_ENDIAN
        POCO_ARCH_BIG_ENDIAN 
    和一系列的字节序转换函数 "Poco/ByteOrder.h"，包括网络字节序转主机字节序函数接口

class Foundation_API ByteOrder
    /// This class contains a number of static methods
    /// to convert between big-endian and little-endian
    /// integers of various sizes.
{
public:
    static Int16 flipBytes(Int16 value);
    static UInt16 flipBytes(UInt16 value);
    static Int32 flipBytes(Int32 value);
    static UInt32 flipBytes(UInt32 value);
#if defined(POCO_HAVE_INT64)
    static Int64 flipBytes(Int64 value);
    static UInt64 flipBytes(UInt64 value);
#endif

    static Int16 toBigEndian(Int16 value);
    static UInt16 toBigEndian (UInt16 value);
    static Int32 toBigEndian(Int32 value);
    static UInt32 toBigEndian (UInt32 value);

Any：
    #include "Poco/Any.h"
    Poco::Any 实例可以支持各种类型数据，
    Poco::AnyCast()和Poco::RefAnyCast()函数模板用来获取数据值和引用
    AnyCast数据类型不同时会抛出BadCastException 异常
    

Any any(42);
int i = AnyCast<int>(any);

short s = AnyCast<short>(any); // throws BadCastException

DynamicAny：
    

DynamicAny any(42);
int i = any;
std::string s(any.convert<std::string>());
 any.convert(s); // or without the need to cast
const int& ri(any.extract<int>());
short s = any;

short s = any.extract<short>(); // throws BadCastException