680a00073e
git-svn-id: svn://svn.code.sf.net/p/loki-lib/code/trunk@1093 7ec92016-0320-0410-acc4-a06ded1c099a
518 lines
26 KiB
C++
518 lines
26 KiB
C++
////////////////////////////////////////////////////////////////////////////////
|
|
// The Loki Library
|
|
// Copyright (c) 2009 by Fedor Pikus & Rich Sposato
|
|
// The copyright on this file is protected under the terms of the MIT license.
|
|
//
|
|
// Permission to use, copy, modify, distribute and sell this software for any
|
|
// purpose is hereby granted without fee, provided that the above copyright
|
|
// notice appear in all copies and that both that copyright notice and this
|
|
// permission notice appear in supporting documentation.
|
|
//
|
|
// The author makes no claims about the suitability of this software for any
|
|
// purpose. It is provided "as is" without express or implied warranty.
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
// $Id$
|
|
|
|
|
|
#ifndef LOKI_INCLUDED_SAFE_BIT_FIELDS_H
|
|
#define LOKI_INCLUDED_SAFE_BIT_FIELDS_H
|
|
|
|
#include <cstdlib>
|
|
#include <assert.h>
|
|
#include <loki/static_check.h>
|
|
|
|
|
|
namespace Loki
|
|
{
|
|
|
|
/*
|
|
==========================================================================================================================================
|
|
SafeBitField - type-safe class for bit fields.
|
|
SafeBitConst - type-safe class for bit constants.
|
|
SafeBitField is designed to be a [almost] drop-in replacement for integer flags and bit fields where individual bits are set and checked
|
|
using symbolic names for flags:
|
|
|
|
typedef unsigned long Labels_t;
|
|
Labels_t labels;
|
|
const Labels_t Label_A = 0x00000001;
|
|
const Labels_t Label_B = 0x00000002;
|
|
...
|
|
labels |= Label_B;
|
|
if ( labels & Label_A ) { ... }
|
|
|
|
Such code offers no protection against mismatching bit constants and bit fields:
|
|
|
|
typedef unsigned long Kinds_t;
|
|
Kinds_t kinds;
|
|
const Kinds_t Kind_A = 0x00000004;
|
|
...
|
|
if ( kinds & Label_A ) { ... } // Error but compiles
|
|
|
|
SafeBitField is a drop-in replacement which generates a unique type for each bit field. Bit fields of different types cannot be applied
|
|
to each other:
|
|
|
|
LOKI_BIT_FIELD( unsigned long ) Labels_t;
|
|
Labels_t labels;
|
|
LOKI_BIT_CONST( Labels_t, Label_A, 1 ); // 0x0001 - 1st bit is set
|
|
LOKI_BIT_CONST( Labels_t, Label_B, 2 ); // 0x0002 - 1st bit is set
|
|
...
|
|
LOKI_BIT_FIELD( unsigned long ) Kinds_t;
|
|
Kinds_t kinds;
|
|
LOKI_BIT_CONST( Kinds_t, Kind_A, 3 ); // 0x0004 - 1st bit is set
|
|
...
|
|
if ( kinds & Label_A ) { ... } // Does not compile
|
|
|
|
Several other kinds of bit field misuse are caught by safe bit fields:
|
|
|
|
if ( kinds & Kind_A == 0 ) { ... }
|
|
if ( kinds && Kind_A ) { ... }
|
|
|
|
There are few cases where drop-in replacement does not work:
|
|
|
|
1. Operations involving bit fields and unnamed integers. Usually the integer in question is 0:
|
|
|
|
Labels_t labels = 0; // No longer compiles
|
|
if ( ( labels & Label_A ) == 0 ) { ... } // Also does not compile
|
|
|
|
The solution is to use named bit constants, including the one for 0:
|
|
|
|
LOKI_BIT_CONST( Labels_t, Label_None, 0 ); // 0x0000 - No bit is set
|
|
Labels_t labels = Label_None; // Or just Labels_t labels; - constructor initializes to 0
|
|
if ( ( labels & Label_A ) == Label_None ) { ... } // // Or just if ( labels & Label_A ) { ... }
|
|
|
|
2. I/O and other operations which require integer variables and cannot be modified:
|
|
|
|
void write_to_db( unsigned int word );
|
|
Labels_t labels;
|
|
write_to_db( labels ); // No longer compiles
|
|
|
|
This problem is solved by reinterpreting the bit fields as an integer, the user is responsible for using the right
|
|
type of integer:
|
|
|
|
write_to_db( *((Labels_t::bit_word_t*)(&labels)) );
|
|
|
|
==========================================================================================================================================
|
|
*/
|
|
|
|
/// @par Non-Templated Initialization.
|
|
/// Not all compilers support template member functions where the template
|
|
/// arguments are not deduced but explicitly specified. For these broken
|
|
/// compilers, a non-template make_bit_const() function is provided instead of
|
|
/// the template one. The only downside is that instead of compile-time checking
|
|
/// of the index argument, it does runtime checking.
|
|
#if defined(__SUNPRO_CC) || ( defined(__GNUC__) && (__GNUC__ < 3) )
|
|
#define LOKI_BIT_FIELD_NONTEMPLATE_INIT
|
|
#endif
|
|
|
|
/// @par Forbidding Conversions.
|
|
/// This incomplete type prevents compilers from instantiating templates for
|
|
/// type conversions which should not happen. This incomplete type must be a
|
|
/// template: if the type is incomplete at the point of template definition,
|
|
/// the template is illegal (although the standard allows compilers to accept
|
|
/// or reject such code, §14.6/, so some compilers will not issue diagnostics
|
|
/// unless template is instantiated). The standard-compliant way is to defer
|
|
/// binding to the point of instantiation by making the incomplete type itself
|
|
/// a template.
|
|
template < typename > struct Forbidden_conversion; // This struct must not be defined!
|
|
|
|
/// Forward declaration of the field type.
|
|
template <
|
|
unsigned int unique_index,
|
|
typename word_t = unsigned long
|
|
> class SafeBitField;
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
/// \class SafeBitConst Bit constants.
|
|
/// This class defines a bit-field constant - a collection of unchanging bits
|
|
/// used to compare to bit-fields. Instances of this class are intended to act
|
|
/// as labels for bit-fields.
|
|
///
|
|
/// \par Safety
|
|
/// - This class provides operations used for comparisons and conversions, but
|
|
/// no operations which may modify the value.
|
|
/// - As a templated class, it provides type-safety so bit values and constants
|
|
/// used for different reasons may not be unknowingly compared to each other.
|
|
/// - The unique_index template parameter insures the unique type of each bit
|
|
/// bit-field. It shares the unique_index with a similar SafeBitField.
|
|
/// - Its operations only allow comparisons to other bit-constants and
|
|
/// bit-fields of the same type.
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
template
|
|
<
|
|
unsigned int unique_index,
|
|
typename word_t = unsigned long
|
|
>
|
|
class SafeBitConst
|
|
{
|
|
public:
|
|
|
|
/// Type of the bit field is available if needed.
|
|
typedef word_t bit_word_t;
|
|
/// Corresponding field type.
|
|
typedef SafeBitField< unique_index, word_t > field_t;
|
|
/// Typedef is not allowed in friendship declaration.
|
|
friend class SafeBitField< unique_index, word_t >;
|
|
|
|
// Static factory constructor, creates a bit constant with one bit set. The position of the bit is given by the template parameter,
|
|
// bit 1 is the junior bit, i.e. make_bit_const<1>() returns 1. Bit index 0 is a special case and returns 0.
|
|
// This function should be used only to initialize the static bit constant objects.
|
|
// This function will not compile if the bit index is outside the vaild range.
|
|
// There is also a compile-time assert to make sure the size of the class is the same as the size of the underlaying integer type.
|
|
// This assert could go into the constructor, but aCC does not seem to understand sizeof(SafeBitConst) in the constructor.
|
|
//
|
|
#ifndef LOKI_BIT_FIELD_NONTEMPLATE_INIT
|
|
template < unsigned int i > static SafeBitConst make_bit_const()
|
|
{
|
|
LOKI_STATIC_CHECK( i <= ( 8 * sizeof(word_t) ), Index_is_beyond_size_of_data );
|
|
LOKI_STATIC_CHECK( sizeof(SafeBitConst) == sizeof(word_t), Object_size_does_not_match_data_size );
|
|
// Why check for ( i > 0 ) again inside the shift if the shift
|
|
// can never be evaluated for i == 0? Some compilers see shift by ( i - 1 )
|
|
// and complain that for i == 0 the number is invalid, without
|
|
// checking that shift needs evaluating.
|
|
return SafeBitConst( ( i > 0 ) ? ( word_t(1) << ( ( i > 0 ) ? ( i - 1 ) : 0 ) ) : 0 );
|
|
}
|
|
#else
|
|
static SafeBitConst make_bit_const( unsigned int i )
|
|
{
|
|
LOKI_STATIC_CHECK( sizeof(SafeBitConst) == sizeof(word_t), Object_size_does_not_match_data_size );
|
|
assert( i <= ( 8 * sizeof(word_t) ) ); // Index is beyond size of data.
|
|
// Why check for ( i > 0 ) again inside the shift if the shift
|
|
// can never be evaluated for i == 0? Some compilers see shift by ( i - 1 )
|
|
// and complain that for i == 0 the number is invalid, without
|
|
// checking that shift needs evaluating.
|
|
return SafeBitConst( ( i > 0 ) ? ( word_t(1) << ( ( i > 0 ) ? ( i - 1 ) : 0 ) ) : 0 );
|
|
}
|
|
#endif
|
|
|
|
/// Default constructor allows client code to construct bit fields on the stack.
|
|
SafeBitConst() : word( 0 ) {}
|
|
|
|
/// Copy constructor.
|
|
SafeBitConst( const SafeBitConst& rhs ) : word( rhs.word ) {}
|
|
|
|
/// Comparison operators which take a constant bit value.
|
|
bool operator == ( const SafeBitConst & rhs ) const { return word == rhs.word; }
|
|
bool operator != ( const SafeBitConst & rhs ) const { return word != rhs.word; }
|
|
bool operator < ( const SafeBitConst & rhs ) const { return word < rhs.word; }
|
|
bool operator > ( const SafeBitConst & rhs ) const { return word > rhs.word; }
|
|
bool operator <= ( const SafeBitConst & rhs ) const { return word <= rhs.word; }
|
|
bool operator >= ( const SafeBitConst & rhs ) const { return word >= rhs.word; }
|
|
|
|
/// Comparision operators for mutable bit fields.
|
|
bool operator == ( const field_t & rhs ) const { return word == rhs.word; }
|
|
bool operator != ( const field_t & rhs ) const { return word != rhs.word; }
|
|
bool operator < ( const field_t & rhs ) const { return word < rhs.word; }
|
|
bool operator > ( const field_t & rhs ) const { return word > rhs.word; }
|
|
bool operator <= ( const field_t & rhs ) const { return word <= rhs.word; }
|
|
bool operator >= ( const field_t & rhs ) const { return word >= rhs.word; }
|
|
|
|
/// Bitwise operations. Operation-assignment operators are not needed,
|
|
/// since bit constants cannot be changed after they are initialized.
|
|
const SafeBitConst operator | ( const SafeBitConst & rhs ) const { return SafeBitConst( word | rhs.word ); }
|
|
const SafeBitConst operator & ( const SafeBitConst & rhs ) const { return SafeBitConst( word & rhs.word ); }
|
|
const SafeBitConst operator ^ ( const SafeBitConst & rhs ) const { return SafeBitConst( word ^ rhs.word ); }
|
|
const SafeBitConst operator ~ ( void ) const { return SafeBitConst( ~word ); }
|
|
|
|
/// These bitwise operators return a bit-field instead of a bit-const.
|
|
field_t operator | ( const field_t & rhs ) const { return field_t( word | rhs.word ); }
|
|
field_t operator & ( const field_t & rhs ) const { return field_t( word & rhs.word ); }
|
|
field_t operator ^ ( const field_t & rhs ) const { return field_t( word ^ rhs.word ); }
|
|
|
|
/// The shift operators move bits inside the bit field. These are useful in
|
|
/// loops which act over bit fields and increment them.
|
|
const SafeBitConst operator << ( unsigned int s ) const { return SafeBitConst( word << s ); }
|
|
const SafeBitConst operator >> ( unsigned int s ) const { return SafeBitConst( word >> s ); }
|
|
|
|
/// Word size is also the maximum number of different bit fields for a given word type.
|
|
static size_t size() { return ( 8 * sizeof( word_t ) ); }
|
|
|
|
private:
|
|
|
|
/// Copy-assignment operator is not implemented since it does not make sense
|
|
/// for a constant object.
|
|
SafeBitConst operator = ( const SafeBitConst & rhs );
|
|
|
|
// Private constructor from an integer type.
|
|
explicit SafeBitConst( word_t init ) : word( init ) {}
|
|
|
|
/// This data stores a single bit value. It is declared const to enforce
|
|
// constness for all functions of this class.
|
|
const word_t word;
|
|
|
|
// Here comes the interesting stuff: all the operators designed to
|
|
// trap unintended conversions and make them not compile.
|
|
// Operators below handle code like this:
|
|
// SafeBitField<1> label1;
|
|
// SafeBitField<2> label2;
|
|
// if ( label1 & label2 ) { ... }
|
|
|
|
// These operators are private, and will not instantiate in any
|
|
// event because of the incomplete Forbidden_conversion struct.
|
|
template < typename T > SafeBitConst & operator|( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitConst & operator&( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitConst & operator^( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitConst & operator|=( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitConst & operator&=( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitConst & operator^=( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
|
|
// And the same thing for comparisons: private and unusable.
|
|
// if ( label1 == label2 ) { ... }
|
|
template < typename T > bool operator==( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator!=( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator<( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator>( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator<=( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator>=( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
};
|
|
|
|
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
/// \class SafeBitConst Bit constants.
|
|
/// This class defines a bit-field constant - a collection of unchanging bits
|
|
/// used to compare to bit-fields. Instances of this class are intended to
|
|
/// store bit values.
|
|
///
|
|
/// \par Safety
|
|
/// - This class provides operations used for comparisons and conversions, and
|
|
/// also operations which may safely modify the value.
|
|
/// - As a templated class, it provides type-safety so bit values and constants
|
|
/// used for different reasons may not be unknowingly compared to each other.
|
|
/// - The unique_index template parameter insures the unique type of each bit
|
|
/// bit-field. It shares the unique_index with a similar SafeBitConst.
|
|
/// - Its operations only allow comparisons to other bit-constants and
|
|
/// bit-fields of the same type.
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
template
|
|
<
|
|
unsigned int unique_index,
|
|
typename word_t
|
|
>
|
|
class SafeBitField
|
|
{
|
|
public:
|
|
|
|
/// Type of the bit field is available if needed.
|
|
typedef word_t bit_word_t;
|
|
/// Corresponding field type.
|
|
typedef SafeBitConst< unique_index, word_t > const_t;
|
|
/// Typedef is not allowed in friendship declaration.
|
|
friend class SafeBitConst<unique_index, word_t>;
|
|
|
|
/// Default constructor allows client code to construct bit fields on the stack.
|
|
SafeBitField() : word( 0 ) {}
|
|
|
|
/// Copy constructor and assignment operators.
|
|
SafeBitField( const SafeBitField & rhs ) : word( rhs.word ) {}
|
|
SafeBitField & operator = ( const SafeBitField & rhs ) { word = rhs.word; return *this; }
|
|
|
|
/// Copy constructor and assignment operators from constant bit fields.
|
|
SafeBitField( const const_t & rhs ) : word( rhs.word ) {}
|
|
SafeBitField & operator = ( const const_t & rhs ) { word = rhs.word; return *this; }
|
|
|
|
/// These comparison operators act on bit-fields of the same type.
|
|
bool operator == ( const SafeBitField & rhs ) const { return word == rhs.word; }
|
|
bool operator != ( const SafeBitField & rhs ) const { return word != rhs.word; }
|
|
bool operator < ( const SafeBitField & rhs ) const { return word < rhs.word; }
|
|
bool operator > ( const SafeBitField & rhs ) const { return word > rhs.word; }
|
|
bool operator <= ( const SafeBitField & rhs ) const { return word <= rhs.word; }
|
|
bool operator >= ( const SafeBitField & rhs ) const { return word >= rhs.word; }
|
|
|
|
/// These comparison operators act on bit-constants of a similar type.
|
|
bool operator == ( const const_t & rhs ) const { return word == rhs.word; }
|
|
bool operator != ( const const_t & rhs ) const { return word != rhs.word; }
|
|
bool operator < ( const const_t & rhs ) const { return word < rhs.word; }
|
|
bool operator > ( const const_t & rhs ) const { return word > rhs.word; }
|
|
bool operator <= ( const const_t & rhs ) const { return word <= rhs.word; }
|
|
bool operator >= ( const const_t & rhs ) const { return word >= rhs.word; }
|
|
|
|
/// Bitwise operations that use bit-fields.
|
|
SafeBitField operator | ( const SafeBitField & rhs ) const { return SafeBitField( word | rhs.word ); }
|
|
SafeBitField operator & ( const SafeBitField & rhs ) const { return SafeBitField( word & rhs.word ); }
|
|
SafeBitField operator ^ ( const SafeBitField & rhs ) const { return SafeBitField( word ^ rhs.word ); }
|
|
SafeBitField operator ~ ( void ) const { return SafeBitField( ~word ); }
|
|
SafeBitField & operator |= ( const SafeBitField & rhs ) { word |= rhs.word; return *this; }
|
|
SafeBitField & operator &= ( const SafeBitField & rhs ) { word &= rhs.word; return *this; }
|
|
SafeBitField & operator ^= ( const SafeBitField & rhs ) { word ^= rhs.word; return *this; }
|
|
|
|
/// Bitwise operators that use bit-constants.
|
|
SafeBitField operator | ( const_t rhs ) const { return SafeBitField( word | rhs.word ); }
|
|
SafeBitField operator & ( const_t rhs ) const { return SafeBitField( word & rhs.word ); }
|
|
SafeBitField operator ^ ( const_t rhs ) const { return SafeBitField( word ^ rhs.word ); }
|
|
SafeBitField & operator |= ( const_t rhs ) { word |= rhs.word; return *this; }
|
|
SafeBitField & operator &= ( const_t rhs ) { word &= rhs.word; return *this; }
|
|
SafeBitField & operator ^= ( const_t rhs ) { word ^= rhs.word; return *this; }
|
|
|
|
// Conversion to bool.
|
|
// This is a major source of headaches, but it's required to support code like this:
|
|
// const static SafeBitConst<1> Label_value = SafeBitConst<1>::make_bit_const<1>();
|
|
// SafeBitField<1> label;
|
|
// if ( label & Label_value ) { ... } // Nice...
|
|
//
|
|
// The downside is that this allows all sorts of nasty conversions. Without additional precautions, bit fields of different types
|
|
// can be converted to bool and then compared or operated on:
|
|
// SafeBitField<1> label1;
|
|
// SafeBitField<2> label2;
|
|
// if ( label1 == label2 ) { ... } // Yuck!
|
|
// if ( label1 & label2 ) { ... } // Blech!
|
|
//
|
|
// It is somewhat safer to convert to a pointer, at least pointers to different types cannot be readilly compared, and there are no
|
|
// bitwise operations on pointers, but the conversion from word_t to a pointer can have run-time cost if they are of different size.
|
|
//
|
|
operator bool() const { return ( 0 != word ); }
|
|
|
|
// Shift operators shift bits inside the bit field. Does not make
|
|
// sense, most of the time, except perhaps to loop over labels and
|
|
// increment them.
|
|
SafeBitField operator << ( unsigned int s ) { return SafeBitField( word << s ); }
|
|
SafeBitField operator >> ( unsigned int s ) { return SafeBitField( word >> s ); }
|
|
SafeBitField & operator <<= ( unsigned int s ) { word <<= s; return *this; }
|
|
SafeBitField & operator >>= ( unsigned int s ) { word >>= s; return *this; }
|
|
|
|
// Word size is also the maximum number of different bit fields for
|
|
// a given word type.
|
|
static size_t size( void ) { return ( 8 * sizeof( word_t ) ); }
|
|
|
|
private:
|
|
|
|
/// Private constructor from an integer type. Don't put too much stock into
|
|
/// explicit declaration, it's better than nothing but does not solve all
|
|
/// problems with undesired conversions because SafeBitField coverts to bool.
|
|
explicit SafeBitField( word_t init ) : word( init ) {}
|
|
|
|
/// This stores the bits.
|
|
word_t word;
|
|
|
|
// Here comes the interesting stuff: all the operators designed to
|
|
// trap unintended conversions and make them not compile.
|
|
// Operators below handle code like this:
|
|
// SafeBitField<1> label1;
|
|
// SafeBitField<2> label2;
|
|
// if ( label1 & label2 ) { ... }
|
|
|
|
// These operators are private, and will not instantiate in any
|
|
// event because of the incomplete Forbidden_conversion struct.
|
|
template < typename T > SafeBitField & operator | ( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitField & operator & ( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitField & operator ^ ( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitField & operator |= ( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitField & operator &= ( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
template < typename T > SafeBitField & operator ^= ( T ) const { Forbidden_conversion< T > wrong; return *this; }
|
|
|
|
// And the same thing for comparisons:
|
|
// if ( label1 == label2 ) { ... }
|
|
template < typename T > bool operator == ( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator != ( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator < ( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator > ( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator <= ( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
template < typename T > bool operator >= ( const T ) const { Forbidden_conversion< T > wrong; return true; }
|
|
};
|
|
|
|
// The above template member operators catch errors when the first
|
|
// argument to a binary operator is a label, but they don't work when
|
|
// the first argument is an integer and the second one is a label: the
|
|
// label converts to bool and the operator is performed on two integers.
|
|
// These operators catch errors like this:
|
|
// SafeBitField<1> label1;
|
|
// SafeBitField<2> label2;
|
|
// if ( !label1 & label2 ) { ... }
|
|
// where the first label is converted to bool (these errors cannot be
|
|
// caught by member operators of SafeBitField class because the first
|
|
// argument is not SafeBitField but bool.
|
|
//
|
|
// If used, these operators will not instantiate because of the
|
|
// incomplete Forbidden_conversion struct.
|
|
|
|
template < unsigned int unique_index, typename word_t >
|
|
inline SafeBitField< unique_index, word_t > operator & ( bool, SafeBitField< unique_index, word_t > rhs )
|
|
{
|
|
Forbidden_conversion<word_t> wrong;
|
|
return rhs;
|
|
}
|
|
|
|
template < unsigned int unique_index, typename word_t >
|
|
inline SafeBitField< unique_index, word_t > operator | ( bool, SafeBitField< unique_index, word_t > rhs )
|
|
{
|
|
Forbidden_conversion< word_t > wrong;
|
|
return rhs;
|
|
}
|
|
|
|
template < unsigned int unique_index, typename word_t >
|
|
inline SafeBitField< unique_index, word_t > operator ^ ( bool, SafeBitField< unique_index, word_t > rhs )
|
|
{
|
|
Forbidden_conversion< word_t > wrong;
|
|
return rhs;
|
|
}
|
|
|
|
template < unsigned int unique_index, typename word_t >
|
|
inline SafeBitField< unique_index, word_t > operator == ( bool, SafeBitField< unique_index, word_t > rhs )
|
|
{
|
|
Forbidden_conversion< word_t > wrong;
|
|
return rhs;
|
|
}
|
|
|
|
template < unsigned int unique_index, typename word_t >
|
|
inline SafeBitField< unique_index, word_t > operator != ( bool, SafeBitField< unique_index, word_t > rhs )
|
|
{
|
|
Forbidden_conversion< word_t > wrong;
|
|
return rhs;
|
|
}
|
|
|
|
// Finally, few macros. All macros are conditionally defined to use the SafeBitField classes if LOKI_SAFE_BIT_FIELD is defined. Otherwise,
|
|
// the macros fall back on the use of typedefs and integer constants. This provides no addititonal safety but allows the code to support the
|
|
// mixture of compilers which are broken to different degrees.
|
|
#define LOKI_SAFE_BIT_FIELD
|
|
|
|
// The first macro helps to declare new bit field types:
|
|
// LOKI_BIT_FIELD( ulong ) field_t;
|
|
// This creates a typedef field_t for SafeBitField<unique_index, ulong> where index is the current line number. Since line numbers __LINE__ are counted
|
|
// separately for all header files, this ends up being the same type in all files using the header which defines field_t.
|
|
#ifdef LOKI_SAFE_BIT_FIELD
|
|
#ifdef __COUNTER__
|
|
#define LOKI_BIT_FIELD( word_t ) typedef ::Loki::SafeBitField<__COUNTER__, word_t>
|
|
#else
|
|
#define LOKI_BIT_FIELD( word_t ) typedef ::Loki::SafeBitField<__LINE__, word_t>
|
|
#endif
|
|
#else
|
|
#define LOKI_BIT_FIELD( word_t ) typedef word_t
|
|
#endif // LOKI_SAFE_BIT_FIELD
|
|
|
|
// The second macro helps to declare static bit constants:
|
|
// LOKI_BIT_CONST( field_t, Label_1, 1 );
|
|
// creates new bit field object named Label_1 of type field_t which represents the field with the 1st (junior) bit set.
|
|
#ifdef LOKI_SAFE_BIT_FIELD
|
|
#ifndef LOKI_BIT_FIELD_NONTEMPLATE_INIT
|
|
#define LOKI_BIT_CONST( field_t, label, bit_index ) \
|
|
static const field_t::const_t label = field_t::const_t::make_bit_const<bit_index>()
|
|
#else
|
|
#define LOKI_BIT_CONST( field_t, label, bit_index ) \
|
|
static const field_t::const_t label = field_t::const_t::make_bit_const( bit_index )
|
|
#endif // LOKI_BIT_FIELD_NONTEMPLATE_INIT
|
|
#else
|
|
inline size_t make_bit_const( size_t i ) { return ( i > 0 ) ? ( size_t(1) << ( ( i > 0 ) ? ( i - 1 ) : 0 ) ) : 0; }
|
|
#define LOKI_BIT_CONST( field_t, label, bit_index ) static const field_t label = make_bit_const( bit_index )
|
|
#endif // LOKI_SAFE_BIT_FIELD
|
|
|
|
// The third macro helps to declare complex bit constants which are combination of several bits:
|
|
// LOKI_BIT_CONSTS( field_t, Label12 ) = Label_1 | Label_2;
|
|
#ifdef LOKI_SAFE_BIT_FIELD
|
|
#define LOKI_BIT_CONSTS( field_t, label ) static const field_t::const_t label
|
|
#else
|
|
#define LOKI_BIT_CONSTS( field_t, label ) static const field_t label
|
|
#endif // LOKI_SAFE_BIT_FIELD
|
|
|
|
// The fourth macro helps to declare the maximum number of bit constants for a given type:
|
|
// static const size_t count = LOKI_BIT_FIELD_COUNT( field_t );
|
|
// declared a variable "count" initialized to field_t::size()
|
|
#ifdef LOKI_SAFE_BIT_FIELD
|
|
#define LOKI_BIT_FIELD_COUNT( field_t ) field_t::size()
|
|
#else
|
|
#define LOKI_BIT_FIELD_COUNT( field_t ) ( 8 * sizeof(field_t) )
|
|
#endif // LOKI_SAFE_BIT_FIELD
|
|
|
|
} // namespace Loki
|
|
|
|
#endif // LOKI_INCLUDED_SAFE_BIT_FIELDS_H
|