IdDictFieldImplementation Class Reference

IdDictFieldImplementation is used to capture the specification of a single field of an Identifier. More...

#include <IdDictFieldImplementation.h>

Collaboration diagram for IdDictFieldImplementation:

Public Types
enum	bit_defs { NBITS = sizeof(value_type) * 8, MAX_BIT = (static_cast<value_type>(1) << (NBITS - 1)), ALL_BITS = ~(static_cast<value_type>(0)) }
typedef Identifier::value_type	value_type
typedef Identifier::size_type	size_type

Public Member Functions
	IdDictFieldImplementation ()
int	unpack (Identifier id) const
	Identifier manipulation methods. More...
size_type	unpackToIndex (Identifier id) const
	Unpack a single field index of the id. More...
void	pack (int value, Identifier &id) const
void	reset (Identifier &id) const
const IdDictRange *	range () const
	Accessors. More...
const Range::field &	field () const
const Range::field &	ored_field () const
size_type	bits () const
size_type	bits_offset () const
size_type	mask () const
value_type	zeroing_mask () const
size_type	shift () const
bool	decode_index () const
void	set_range (const IdDictRange *range)
	Modifiers. More...
void	set_field (const Range::field &field)
void	set_ored_field (const Range::field &ored_field)
void	set_bits_offset (size_type bits_offset)
void	set_bits (size_type bits, size_type bits_offset)
void	set_decode_index (bool decode_index)
void	optimize (void)
void	show (void) const
std::string	show_to_string (void) const

Private Member Functions
void	initialize ()

Private Attributes
const IdDictRange *	m_range
Range::field	m_field
Range::field	m_ored_field
size_type	m_bits
size_type	m_bits_offset
size_type	m_mask
value_type	m_zeroing_mask
size_type	m_shift
bool	m_decode_index

Detailed Description

IdDictFieldImplementation is used to capture the specification of a single field of an Identifier.

This class is primarily used to extract or set the field of an identifier:

int unpack (Identifier id) const; // access to field value size_type unpackToIndex (Identifier id) const; // access to field index, i.e. from 0 void pack (int value, Identifier& id) const; void reset (Identifier& id) const; // reset field bits

This class is normally filled during the parsing of the identifier dictionary. The parsing uses the set_ored_field method where the the internal variables are set to optimize the calculations. One may also build a new object by simply using:

void set_bits (size_type bits, size_type bits_offset);

This as well sets all internal variables.

The meaning of the varibles is:

size_type bits() - number of bits for this field size_type bits_offset() - bits offset relative to 1st field size_type mask() - mask: (xxx >> shift) & mask value_type zeroing_mask() - used to reset field to 0 size_type shift() - shift: (xxx >> shift) & mask bool decode_index() - true == need to lookup value

// Primarily for internal use: const IdDictRange* range() - points to the generating IdDictRange Range::field field() - derived from IdDictRange Range::field ored_field() - "expanded" field to account for other overlapping fields

Definition at line 57 of file IdDictFieldImplementation.h.

Member Typedef Documentation

size_type

typedef Identifier::size_type IdDictFieldImplementation::size_type

Definition at line 62 of file IdDictFieldImplementation.h.

value_type

typedef Identifier::value_type IdDictFieldImplementation::value_type

Definition at line 61 of file IdDictFieldImplementation.h.

Member Enumeration Documentation

bit_defs

enum IdDictFieldImplementation::bit_defs

Enumerator
NBITS
MAX_BIT
ALL_BITS

Definition at line 64 of file IdDictFieldImplementation.h.

    { 
        NBITS   = sizeof(value_type) * 8, // bits per byte
        MAX_BIT = (static_cast<value_type>(1) << (NBITS - 1)),
        ALL_BITS  = ~(static_cast<value_type>(0))
    } bit_defs; 

Constructor & Destructor Documentation

IdDictFieldImplementation()

IdDictFieldImplementation::IdDictFieldImplementation ( )

inline

Definition at line 124 of file IdDictFieldImplementation.h.

    :
    m_range(0), 
    m_field(0), 
    m_ored_field(0), 
    m_bits(0), 
    m_bits_offset(0), 
    m_mask(0), 
    m_zeroing_mask(0), 
    m_shift(0), 
    m_decode_index(0)
{}

Member Function Documentation

bits()

IdDictFieldImplementation::size_type IdDictFieldImplementation::bits ( ) const

inline

Definition at line 202 of file IdDictFieldImplementation.h.

{ return (m_bits); } 

bits_offset()

IdDictFieldImplementation::size_type IdDictFieldImplementation::bits_offset ( ) const

inline

Definition at line 208 of file IdDictFieldImplementation.h.

{ return (m_bits_offset); } 

decode_index()

bool IdDictFieldImplementation::decode_index ( ) const

inline

Definition at line 231 of file IdDictFieldImplementation.h.

{ return (m_decode_index); }

field()

const Range::field & IdDictFieldImplementation::field ( ) const

inline

Definition at line 191 of file IdDictFieldImplementation.h.

{ return (m_field); } 

initialize()

void IdDictFieldImplementation::initialize ( )

inlineprivate

Definition at line 236 of file IdDictFieldImplementation.h.

{
    // Initialize masks and shift 
    m_mask = (static_cast<size_type>(1) << m_bits) - 1;
    m_shift = IdDictFieldImplementation::NBITS - m_bits - m_bits_offset;
 
    // Shifting by NBITS is undefined behavior.
    if (m_shift < IdDictFieldImplementation::NBITS)
      m_zeroing_mask = (m_mask << m_shift) ^ IdDictFieldImplementation::ALL_BITS;
    else
      m_zeroing_mask = IdDictFieldImplementation::ALL_BITS;
}

mask()

IdDictFieldImplementation::size_type IdDictFieldImplementation::mask ( ) const

inline

Definition at line 214 of file IdDictFieldImplementation.h.

{ return (m_mask); } 

optimize()

void IdDictFieldImplementation::optimize ( void  )

inline

Definition at line 294 of file IdDictFieldImplementation.h.

{
    m_ored_field.optimize(); // optimize for decoding
}

ored_field()

const Range::field & IdDictFieldImplementation::ored_field ( ) const

inline

Definition at line 196 of file IdDictFieldImplementation.h.

{ return (m_ored_field); } 

pack()

void IdDictFieldImplementation::pack ( int  value, Identifier &  id  ) const

inline

Definition at line 173 of file IdDictFieldImplementation.h.

{
    // Pack value into this field
    size_type index = (size_type)value;
    if (m_decode_index) index = m_ored_field.get_value_index (value); 
    id |= (index << m_shift); 
}

range()

const IdDictRange * IdDictFieldImplementation::range

(

)

const

Accessors.

@fileIdDictFieldImplementation.cxx

Date

2003-09-04 08:55:25

Author

schaffer

Definition at line 20 of file IdDictFieldImplementation.cxx.

{return(m_range);}

reset()

void IdDictFieldImplementation::reset ( Identifier &  id ) const

inline

Definition at line 183 of file IdDictFieldImplementation.h.

{
    // Reset field to 0
    id &= m_zeroing_mask;
}

set_bits()

void IdDictFieldImplementation::set_bits ( size_type  bits, size_type  bits_offset  )

inline

Definition at line 278 of file IdDictFieldImplementation.h.

{
    // Set bits, offset and init
    m_bits        = bits;
    m_bits_offset = bits_offset;
    initialize();
}

set_bits_offset()

void IdDictFieldImplementation::set_bits_offset ( size_type  bits_offset )

inline

Definition at line 269 of file IdDictFieldImplementation.h.

{
    // Set offset and init
    m_bits_offset = bits_offset;
    initialize();
}

set_decode_index()

void IdDictFieldImplementation::set_decode_index ( bool  decode_index )

inline

Definition at line 288 of file IdDictFieldImplementation.h.

{
    m_decode_index = decode_index;
}

set_field()

void IdDictFieldImplementation::set_field ( const Range::field &  field )

inline

Definition at line 251 of file IdDictFieldImplementation.h.

{
    m_field = field;
}

set_ored_field()

void IdDictFieldImplementation::set_ored_field ( const Range::field &  ored_field )

inline

Definition at line 259 of file IdDictFieldImplementation.h.

{
    // Set ored field and bits, and init
    m_ored_field = ored_field;
    m_bits       = m_ored_field.get_bits();
    initialize();
}

set_range()

void IdDictFieldImplementation::set_range

(

const IdDictRange *

range

)

Modifiers.

Definition at line 23 of file IdDictFieldImplementation.cxx.

                                                             {
  m_range = range;
}

shift()

IdDictFieldImplementation::size_type IdDictFieldImplementation::shift ( ) const

inline

Definition at line 226 of file IdDictFieldImplementation.h.

{ return (m_shift); } 

show()

void IdDictFieldImplementation::show

(

void

)

const

Definition at line 28 of file IdDictFieldImplementation.cxx.

                                      {
  std::cout << show_to_string() << std::endl;
}

show_to_string()

std::string IdDictFieldImplementation::show_to_string

(

void

)

const

Definition at line 32 of file IdDictFieldImplementation.cxx.

                                                          {
  // Build the indexes list once
  const auto& idx = m_ored_field.get_indexes();
  std::string indexes;
  indexes.reserve(idx.size() * 3);
  for (std::size_t i = 0; i < idx.size(); ++i) {
    if (i) indexes.push_back(' ');
    indexes += std::to_string(idx[i]);
  }
  // Mode string
  std::string_view mode =
      m_ored_field.isBounded()     ? "both_bounded"
    : m_ored_field.isEnumerated()  ? "enumerated"
                                   : "unknown";
  try{
    return std::format(
        "decode {:d} vals {:<15} "
        "mask/zero mask/shift/bits/offset {:<3x} {:<3x} {:<3} {:<3} {:<3} "
        "indexes {:<20} mode  {}  ",
        m_decode_index,
        static_cast<std::string>(m_ored_field),
        m_mask,
        m_zeroing_mask,
        m_shift,
        m_bits,
        m_bits_offset,
        indexes,
        mode);
  } catch (std::format_error & ){
    return {};
  }
}

unpack()

int IdDictFieldImplementation::unpack ( Identifier  id ) const

inline

Identifier manipulation methods.

Unpack a single field of the bits32 id.

One specifies the pointer to the field implementation to be used for decoding. The first_field_index is normally 0. It is non-zero when fields 0 to first_field_index -1 are missing from the compact

Definition at line 147 of file IdDictFieldImplementation.h.

{
    // Unpack field
    size_type index = id.extract(m_shift, m_mask);
    int field = index;
    if (m_decode_index) field = m_ored_field.get_value_at (index); 
    return (field);
}

unpackToIndex()

Identifier::size_type IdDictFieldImplementation::unpackToIndex ( Identifier  id ) const

inline

Unpack a single field index of the id.

The value unpacked above may differ from the index if the values are enumerated rather than simply 0 to N-1.

Definition at line 164 of file IdDictFieldImplementation.h.

{
    // Unpack field
    size_type index = id.extract(m_shift, m_mask);
    return (index);
}

zeroing_mask()

IdDictFieldImplementation::value_type IdDictFieldImplementation::zeroing_mask ( ) const

inline

Definition at line 220 of file IdDictFieldImplementation.h.

{ return (m_zeroing_mask); } 

Member Data Documentation

m_bits

size_type IdDictFieldImplementation::m_bits

private

Definition at line 111 of file IdDictFieldImplementation.h.

m_bits_offset

size_type IdDictFieldImplementation::m_bits_offset

private

Definition at line 112 of file IdDictFieldImplementation.h.

m_decode_index

bool IdDictFieldImplementation::m_decode_index

private

Definition at line 116 of file IdDictFieldImplementation.h.

m_field

Range::field IdDictFieldImplementation::m_field

private

Definition at line 109 of file IdDictFieldImplementation.h.

m_mask

size_type IdDictFieldImplementation::m_mask

private

Definition at line 113 of file IdDictFieldImplementation.h.

m_ored_field

Range::field IdDictFieldImplementation::m_ored_field

private

Definition at line 110 of file IdDictFieldImplementation.h.

m_range

const IdDictRange* IdDictFieldImplementation::m_range

private

Definition at line 108 of file IdDictFieldImplementation.h.

m_shift

size_type IdDictFieldImplementation::m_shift

private

Definition at line 115 of file IdDictFieldImplementation.h.

m_zeroing_mask

value_type IdDictFieldImplementation::m_zeroing_mask

private

Definition at line 114 of file IdDictFieldImplementation.h.

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The documentation for this class was generated from the following files:

• IdDictFieldImplementation.h
• IdDictFieldImplementation.cxx