EPICS_base/pva2pva
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more AnyScalar

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This commit is contained in:
Michael Davidsaver
2017-09-13 11:29:17 -05:00
parent 9cf062df22
commit 7de37e57bc
2 changed files with 87 additions and 16 deletions
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57
common/anyscalar.h
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@ -17,9 +17,12 @@
namespace detail {
// special mangling for AnyScalar ctor to map from argument type to storage type
// special mangling for AnyScalar ctor to map from argument type to storage type.
// allow construction from constants.
template <typename T>
struct any_storage_type { typedef T type; };
template<> struct any_storage_type<int> { typedef epics::pvData::int32 type; };
template<> struct any_storage_type<unsigned> { typedef epics::pvData::uint32 type; };
template<> struct any_storage_type<char*> { typedef std::string type; };
template<> struct any_storage_type<const char*> { typedef std::string type; };
@ -53,12 +56,17 @@ private:
typename std::aligned_storage<sizeof(std::string), alignof(std::string)>::type blob[1];
} _wrap;
#else
union wrap_t {
char blob[sizeof(std::string)];
double align_f; // assume std::string alignment <= 8
struct wrap_t {
union blob_t {
char data[sizeof(std::string)];
double align_f; // assume std::string alignment <= 8
} blob[1];
} _wrap;
#endif
// assumed largest non-string type
typedef double _largest_blob;
template<typename T>
inline T& _as() {
return *reinterpret_cast<T*>(_wrap.blob);
@ -90,8 +98,8 @@ public:
{
if(o._stype==epics::pvData::pvString) {
new (_wrap.blob) std::string(o._as<std::string>());
} else {
memcpy(_wrap.blob, o._wrap.blob, sizeof(_wrap.blob));
} else if(o._stype!=(ScalarType)-1) {
memcpy(_wrap.blob, o._wrap.blob, sizeof(_largest_blob));
}
}
@ -99,10 +107,13 @@ public:
AnyScalar(AnyScalar&& o)
:_stype(o._stype)
{
typedef std::string string;
if(o._stype==epics::pvData::pvString) {
new (_wrap.blob) std::string();
_as<std::string>() = std::move(o._as<std::string>());
} else {
memcpy(_wrap.blob, o._wrap.blob, sizeof(_wrap.blob));
o._as<string>().~string();
} else if(o._stype!=(ScalarType)-1) {
memcpy(_wrap.blob, o._wrap.blob, sizeof(_largest_blob));
}
o._stype = (ScalarType)-1;
}
@ -111,7 +122,7 @@ public:
~AnyScalar() {
if(_stype==epics::pvData::pvString) {
typedef std::string string;
(&_as<string>())->~string();
_as<string>().~string();
}
// other types need no cleanup
}
@ -127,7 +138,19 @@ public:
return *this;
}
inline void swap(AnyScalar& o) {
#if __cplusplus>=201103L
AnyScalar& operator=(AnyScalar&& o) {
if(_stype==epics::pvData::pvString) {
typedef std::string string;
_as<string>().~string();
}
_stype = (ScalarType)-1;
swap(o);
return *this;
}
#endif
void swap(AnyScalar& o) {
typedef std::string string;
switch((unsigned)_stype) {
case -1:
@ -143,7 +166,7 @@ public:
break;
default:
// nil <-> non-string
memcpy(_wrap.blob, o._wrap.blob, sizeof(_wrap.blob));
memcpy(_wrap.blob, o._wrap.blob, sizeof(_largest_blob));
break;
}
break;
@ -166,7 +189,7 @@ public:
_as<std::string>().~string();
memcpy(_wrap.blob, o._wrap.blob, sizeof(_wrap.blob));
memcpy(_wrap.blob, o._wrap.blob, sizeof(_largest_blob));
new (o._wrap.blob) std::string();
temp.swap(o._as<std::string>());
@ -178,7 +201,7 @@ public:
switch((unsigned)o._stype) {
case -1:
// non-string <-> nil
memcpy(o._wrap.blob, _wrap.blob, sizeof(_wrap.blob));
memcpy(o._wrap.blob, _wrap.blob, sizeof(_largest_blob));
break;
case epics::pvData::pvString: {
// non-string <-> string
@ -187,7 +210,7 @@ public:
o._as<std::string>().~string();
memcpy(o._wrap.blob, _wrap.blob, sizeof(_wrap.blob));
memcpy(o._wrap.blob, _wrap.blob, sizeof(_largest_blob));
new (_wrap.blob) std::string();
temp.swap(_as<std::string>());
@ -195,7 +218,11 @@ public:
break;
default:
// non-string <-> non-string
std::swap(o._wrap.blob, _wrap.blob);
_largest_blob temp;
memcpy(&temp, _wrap.blob, sizeof(_largest_blob));
memcpy(_wrap.blob, o._wrap.blob, sizeof(_largest_blob));
memcpy(o._wrap.blob, &temp, sizeof(_largest_blob));
// std::swap(o._wrap.blob, _wrap.blob); // gcc <=4.3 doesn't like this
break;
}
break;