/AI_Patch/src/public/tier1/utlcommon.h
C++ Header | 345 lines | 205 code | 62 blank | 78 comment | 11 complexity | 06904101b8f6077f8014367531d31b53 MD5 | raw file
Possible License(s): BSD-3-Clause
- //========= Copyright Valve Corporation, All rights reserved. ============//
- //
- // Purpose: common helpers for reuse among various Utl containers
- //
- // $NoKeywords: $
- //
- //=============================================================================//
-
- #ifndef UTLCOMMON_H
- #define UTLCOMMON_H
- #pragma once
-
- //-----------------------------------------------------------------------------
- // Henry Goffin (henryg) was here. Questions? Bugs? Go slap him around a bit.
- //-----------------------------------------------------------------------------
-
- // empty_t is the canonical "no-value" type which is fully defined but empty.
- struct empty_t {};
-
- // undefined_t is the canonical "undefined" type, used mostly for typedefs;
- // parameters of type undefined_t will not compile, which is actually useful
- // behavior when it comes to template programming. Google "SFINAE" for info.
- struct undefined_t;
-
- // CTypeSelect<sel,A,B>::type is a typedef of A if sel is nonzero, else B
- template <int sel, typename A, typename B>
- struct CTypeSelect { typedef A type; };
-
- template <typename A, typename B>
- struct CTypeSelect<0, A, B> { typedef B type; };
-
- // CTypeEquals<A, B>::value is nonzero if A and B are the same type
- template <typename A, typename B, bool bIgnoreConstVolatile = false, bool bIgnoreReference = false>
- struct CTypeEquals { enum { value = 0 }; };
-
- template <typename Same>
- struct CTypeEquals<Same, Same, false, false> { enum { value = 1 }; };
-
- template <typename A, typename B>
- struct CTypeEquals<A, B, true, true> : CTypeEquals< const volatile A&, const volatile B& > {};
-
- template <typename A, typename B>
- struct CTypeEquals<A, B, true, false> : CTypeEquals< const volatile A, const volatile B > {};
-
- template <typename A, typename B>
- struct CTypeEquals<A, B, false, true> : CTypeEquals< A&, B& > {};
-
- // CUtlKeyValuePair is intended for use with key-lookup containers.
- // Because it is specialized for "empty_t" values, one container can
- // function as either a set of keys OR a key-value dictionary while
- // avoiding storage waste or padding for the empty_t value objects.
- template <typename K, typename V>
- class CUtlKeyValuePair
- {
- public:
- typedef V ValueReturn_t;
- K m_key;
- V m_value;
-
- CUtlKeyValuePair() {}
-
- template < typename KInit >
- explicit CUtlKeyValuePair( const KInit &k ) : m_key( k ) {}
-
- template < typename KInit, typename VInit >
- CUtlKeyValuePair( const KInit &k, const VInit &v ) : m_key( k ), m_value( v ) {}
-
- V &GetValue() { return m_value; }
- const V &GetValue() const { return m_value; }
- };
-
- template <typename K>
- class CUtlKeyValuePair<K, empty_t>
- {
- public:
- typedef const K ValueReturn_t;
- K m_key;
-
- CUtlKeyValuePair() {}
-
- template < typename KInit >
- explicit CUtlKeyValuePair( const KInit &k ) : m_key( k ) {}
-
- template < typename KInit >
- CUtlKeyValuePair( const KInit &k, empty_t ) : m_key( k ) {}
-
- CUtlKeyValuePair( const K &k, const empty_t& ) : m_key( k ) {}
- const K &GetValue() const { return m_key; }
- };
-
-
- // Default functors. You can specialize these if your type does
- // not implement operator== or operator< in an efficient way for
- // some odd reason.
- template <typename T> struct DefaultLessFunctor;
- template <typename T> struct DefaultEqualFunctor;
-
- // Hashing functor used by hash tables. You can either specialize
- // for types which are widely used, or plug a custom functor directly
- // into the hash table. If you do roll your own, please read up on
- // bit-mixing and the avalanche property; be sure that your values
- // are reasonably well-distributed across the entire 32-bit range.
- // http://en.wikipedia.org/wiki/Avalanche_effect
- // http://home.comcast.net/~bretm/hash/5.html
- //
- template <typename T> struct DefaultHashFunctor;
-
- // Argument type information. Struct currently contains one or two typedefs:
- // typename Arg_t = primary argument type. Usually const T&, sometimes T.
- // typename Alt_t = optional alternate type. Usually *undefined*.
- //
- // Any specializations should be implemented via simple inheritance
- // from ArgumentTypeInfoImpl< BestArgType, [optional] AlternateArgType >
- //
- template <typename T> struct ArgumentTypeInfo;
-
-
- // Some fundamental building-block functors...
- struct StringLessFunctor { bool operator()( const char *a, const char *b ) const { return Q_strcmp( a, b ) < 0; } };
- struct StringEqualFunctor { bool operator()( const char *a, const char *b ) const { return Q_strcmp( a, b ) == 0; } };
- struct CaselessStringLessFunctor { bool operator()( const char *a, const char *b ) const { return Q_strcasecmp( a, b ) < 0; } };
- struct CaselessStringEqualFunctor { bool operator()( const char *a, const char *b ) const { return Q_strcasecmp( a, b ) == 0; } };
-
- struct Mix32HashFunctor { unsigned int operator()( uint32 s ) const; };
- struct StringHashFunctor { unsigned int operator()( const char* s ) const; };
- struct CaselessStringHashFunctor { unsigned int operator()( const char* s ) const; };
-
- struct PointerLessFunctor { bool operator()( const void *a, const void *b ) const { return a < b; } };
- struct PointerEqualFunctor { bool operator()( const void *a, const void *b ) const { return a == b; } };
- struct PointerHashFunctor { unsigned int operator()( const void* s ) const { return Mix32HashFunctor()((uint32)POINTER_TO_INT(s)); } };
-
-
- // Generic implementation of Less and Equal functors
- template < typename T >
- struct DefaultLessFunctor
- {
- bool operator()( typename ArgumentTypeInfo< T >::Arg_t a, typename ArgumentTypeInfo< T >::Arg_t b ) const { return a < b; }
- bool operator()( typename ArgumentTypeInfo< T >::Alt_t a, typename ArgumentTypeInfo< T >::Arg_t b ) const { return a < b; }
- bool operator()( typename ArgumentTypeInfo< T >::Arg_t a, typename ArgumentTypeInfo< T >::Alt_t b ) const { return a < b; }
- };
-
- template < typename T >
- struct DefaultEqualFunctor
- {
- bool operator()( typename ArgumentTypeInfo< T >::Arg_t a, typename ArgumentTypeInfo< T >::Arg_t b ) const { return a == b; }
- bool operator()( typename ArgumentTypeInfo< T >::Alt_t a, typename ArgumentTypeInfo< T >::Arg_t b ) const { return a == b; }
- bool operator()( typename ArgumentTypeInfo< T >::Arg_t a, typename ArgumentTypeInfo< T >::Alt_t b ) const { return a == b; }
- };
-
- // Hashes for basic types
- template <> struct DefaultHashFunctor<char> : Mix32HashFunctor { };
- template <> struct DefaultHashFunctor<signed char> : Mix32HashFunctor { };
- template <> struct DefaultHashFunctor<unsigned char> : Mix32HashFunctor { };
- template <> struct DefaultHashFunctor<signed short> : Mix32HashFunctor { };
- template <> struct DefaultHashFunctor<unsigned short> : Mix32HashFunctor { };
- template <> struct DefaultHashFunctor<signed int> : Mix32HashFunctor { };
- template <> struct DefaultHashFunctor<unsigned int> : Mix32HashFunctor { };
- template <> struct DefaultHashFunctor<signed long> : Mix32HashFunctor { };
- template <> struct DefaultHashFunctor<unsigned long> : Mix32HashFunctor { };
- template <> struct DefaultHashFunctor<void*> : PointerHashFunctor { };
- template <> struct DefaultHashFunctor<const void*> : PointerHashFunctor { };
- #if !defined(_MSC_VER) || defined(_NATIVE_WCHAR_T_DEFINED)
- template <> struct DefaultHashFunctor<wchar_t> : Mix32HashFunctor { };
- #endif
-
- // String specializations. If you want to operate on raw values, use
- // PointerLessFunctor and friends from the "building-block" section above
- template <> struct DefaultLessFunctor<char*> : StringLessFunctor { };
- template <> struct DefaultLessFunctor<const char*> : StringLessFunctor { };
- template <> struct DefaultEqualFunctor<char*> : StringEqualFunctor { };
- template <> struct DefaultEqualFunctor<const char*> : StringEqualFunctor { };
- template <> struct DefaultHashFunctor<char*> : StringHashFunctor { };
- template <> struct DefaultHashFunctor<const char*> : StringHashFunctor { };
-
- // CUtlString/CUtlConstString are specialized here and not in utlstring.h
- // because I consider string datatypes to be fundamental, and don't feel
- // comfortable making that header file dependent on this one. (henryg)
- class CUtlString;
- template < typename T > class CUtlConstStringBase;
-
- template <> struct DefaultLessFunctor<CUtlString> : StringLessFunctor { };
- template <> struct DefaultHashFunctor<CUtlString> : StringHashFunctor { };
- template < typename T > struct DefaultLessFunctor< CUtlConstStringBase<T> > : StringLessFunctor { };
- template < typename T > struct DefaultHashFunctor< CUtlConstStringBase<T> > : StringHashFunctor { };
-
-
- // Helpers to deduce if a type defines a public AltArgumentType_t typedef:
- template < typename T >
- struct HasClassAltArgumentType
- {
- template < typename X > static long Test( typename X::AltArgumentType_t* );
- template < typename X > static char Test( ... );
- enum { value = ( sizeof( Test< T >( NULL ) ) != sizeof( char ) ) };
- };
-
- template < typename T, bool = HasClassAltArgumentType< T >::value >
- struct GetClassAltArgumentType { typedef typename T::AltArgumentType_t Result_t; };
-
- template < typename T >
- struct GetClassAltArgumentType< T, false > { typedef undefined_t Result_t; };
-
- // Unwrap references; reference types don't have member typedefs.
- template < typename T >
- struct GetClassAltArgumentType< T&, false > : GetClassAltArgumentType< T > { };
-
- // ArgumentTypeInfoImpl is the base for all ArgumentTypeInfo specializations.
- template < typename ArgT, typename AltT = typename GetClassAltArgumentType<ArgT>::Result_t >
- struct ArgumentTypeInfoImpl
- {
- enum { has_alt = 1 };
- typedef ArgT Arg_t;
- typedef AltT Alt_t;
- };
-
- // Handle cases where AltArgumentType_t is typedef'd to undefined_t
- template < typename ArgT >
- struct ArgumentTypeInfoImpl< ArgT, undefined_t >
- {
- enum { has_alt = 0 };
- typedef ArgT Arg_t;
- typedef undefined_t Alt_t;
- };
-
- // Handle cases where AltArgumentType_t is typedef'd to the primary type
- template < typename ArgT >
- struct ArgumentTypeInfoImpl< ArgT, ArgT >
- {
- enum { has_alt = 0 };
- typedef ArgT Arg_t;
- typedef undefined_t Alt_t;
- };
-
-
- // By default, everything is passed via const ref and doesn't define an alternate type.
- template <typename T> struct ArgumentTypeInfo : ArgumentTypeInfoImpl< const T& > { };
-
- // Small native types are most efficiently passed by value.
- template <> struct ArgumentTypeInfo< bool > : ArgumentTypeInfoImpl< bool > { };
- template <> struct ArgumentTypeInfo< char > : ArgumentTypeInfoImpl< char > { };
- template <> struct ArgumentTypeInfo< signed char > : ArgumentTypeInfoImpl< signed char > { };
- template <> struct ArgumentTypeInfo< unsigned char > : ArgumentTypeInfoImpl< unsigned char > { };
- template <> struct ArgumentTypeInfo< signed short > : ArgumentTypeInfoImpl< signed short > { };
- template <> struct ArgumentTypeInfo< unsigned short > : ArgumentTypeInfoImpl< unsigned short > { };
- template <> struct ArgumentTypeInfo< signed int > : ArgumentTypeInfoImpl< signed int > { };
- template <> struct ArgumentTypeInfo< unsigned int > : ArgumentTypeInfoImpl< unsigned int > { };
- template <> struct ArgumentTypeInfo< signed long > : ArgumentTypeInfoImpl< signed long > { };
- template <> struct ArgumentTypeInfo< unsigned long > : ArgumentTypeInfoImpl< unsigned long > { };
- template <> struct ArgumentTypeInfo< signed long long > : ArgumentTypeInfoImpl< signed long long > { };
- template <> struct ArgumentTypeInfo< unsigned long long > : ArgumentTypeInfoImpl< unsigned long long > { };
- template <> struct ArgumentTypeInfo< float > : ArgumentTypeInfoImpl< float > { };
- template <> struct ArgumentTypeInfo< double > : ArgumentTypeInfoImpl< double > { };
- template <> struct ArgumentTypeInfo< long double > : ArgumentTypeInfoImpl< long double > { };
- #if !defined(_MSC_VER) || defined(_NATIVE_WCHAR_T_DEFINED)
- template <> struct ArgumentTypeInfo< wchar_t > : ArgumentTypeInfoImpl< wchar_t > { };
- #endif
-
- // Pointers are also most efficiently passed by value.
- template < typename T > struct ArgumentTypeInfo< T* > : ArgumentTypeInfoImpl< T* > { };
-
-
- // Specializations to unwrap const-decorated types and references
- template <typename T> struct ArgumentTypeInfo<const T> : ArgumentTypeInfo<T> { };
- template <typename T> struct ArgumentTypeInfo<volatile T> : ArgumentTypeInfo<T> { };
- template <typename T> struct ArgumentTypeInfo<const volatile T> : ArgumentTypeInfo<T> { };
- template <typename T> struct ArgumentTypeInfo<T&> : ArgumentTypeInfo<T> { };
-
- template <typename T> struct DefaultLessFunctor<const T> : DefaultLessFunctor<T> { };
- template <typename T> struct DefaultLessFunctor<volatile T> : DefaultLessFunctor<T> { };
- template <typename T> struct DefaultLessFunctor<const volatile T> : DefaultLessFunctor<T> { };
- template <typename T> struct DefaultLessFunctor<T&> : DefaultLessFunctor<T> { };
-
- template <typename T> struct DefaultEqualFunctor<const T> : DefaultEqualFunctor<T> { };
- template <typename T> struct DefaultEqualFunctor<volatile T> : DefaultEqualFunctor<T> { };
- template <typename T> struct DefaultEqualFunctor<const volatile T> : DefaultEqualFunctor<T> { };
- template <typename T> struct DefaultEqualFunctor<T&> : DefaultEqualFunctor<T> { };
-
- template <typename T> struct DefaultHashFunctor<const T> : DefaultHashFunctor<T> { };
- template <typename T> struct DefaultHashFunctor<volatile T> : DefaultHashFunctor<T> { };
- template <typename T> struct DefaultHashFunctor<const volatile T> : DefaultHashFunctor<T> { };
- template <typename T> struct DefaultHashFunctor<T&> : DefaultHashFunctor<T> { };
-
-
- // Hash all pointer types as raw pointers by default
- template <typename T> struct DefaultHashFunctor< T * > : PointerHashFunctor { };
-
-
- // Here follow the useful implementations.
-
- // Bob Jenkins's 32-bit mix function.
- inline unsigned int Mix32HashFunctor::operator()( uint32 n ) const
- {
- // Perform a mixture of the bits in n, where each bit
- // of the input value has an equal chance to affect each
- // bit of the output. This turns tightly clustered input
- // values into a smooth distribution.
- //
- // This takes 16-20 cycles on modern x86 architectures;
- // that's roughly the same cost as a mispredicted branch.
- // It's also reasonably efficient on PPC-based consoles.
- //
- // If you're still thinking, "too many instructions!",
- // do keep in mind that reading one byte of uncached RAM
- // is about 30x slower than executing this code. It pays
- // to have a good hash function which minimizes collisions
- // (and therefore long lookup chains).
- n = ( n + 0x7ed55d16 ) + ( n << 12 );
- n = ( n ^ 0xc761c23c ) ^ ( n >> 19 );
- n = ( n + 0x165667b1 ) + ( n << 5 );
- n = ( n + 0xd3a2646c ) ^ ( n << 9 );
- n = ( n + 0xfd7046c5 ) + ( n << 3 );
- n = ( n ^ 0xb55a4f09 ) ^ ( n >> 16 );
- return n;
- }
-
- // Based on the widely-used FNV-1A string hash with a final
- // mixing step to improve dispersion for very small and very
- // large hash table sizes.
- inline unsigned int StringHashFunctor::operator()( const char* s ) const
- {
- uint32 h = 2166136261u;
- for ( ; *s; ++s )
- {
- uint32 c = (unsigned char) *s;
- h = (h ^ c) * 16777619;
- }
- return (h ^ (h << 17)) + (h >> 21);
- }
-
- // Equivalent to StringHashFunctor on lower-case strings.
- inline unsigned int CaselessStringHashFunctor::operator()( const char* s ) const
- {
- uint32 h = 2166136261u;
- for ( ; *s; ++s )
- {
- uint32 c = (unsigned char) *s;
- // Brutally fast branchless ASCII tolower():
- // if ((c >= 'A') && (c <= 'Z')) c += ('a' - 'A');
- c += (((('A'-1) - c) & (c - ('Z'+1))) >> 26) & 32;
- h = (h ^ c) * 16777619;
- }
- return (h ^ (h << 17)) + (h >> 21);
- }
-
-
- #endif // UTLCOMMON_H