| # Gaudi Framework, version v21r6 |

Home |  | Generated: 11 Nov 2009

# Gaudi::StringKey Class Reference

`#include <StringKey.h>`

List of all members.

## Detailed Description

The helper class to represent the efficient "key" for access.

Essentially it is a bit modified version ("boost-free") of the original class stringKey by Gerhard Raven, which is heavily used now in HLT

Attention:
  NEVER use the actual hash value for anything stored in files, as it is not guaranteed that the hashing scheme will remain the same.

Author:
  Vanya BELYAEV Ivan.Belyaev@nikhef.nl

Date:
  2009-04-08

Definition at line 35 of file StringKey.h.

## Public Member Functions
| StringKey (const std::string &key="")
| constructor from the string, perform hashing
const std::string & | str () const
| the actual string
| operator const std::string & () const
| implicit cast to std::string
bool | empty () const
| empty key?
bool | operator! () const
| empty key?
bool | operator== (const StringKey &o) const
| equality Key for efficiency reason compare the hash-values first
bool | operator== (const std::string &o) const
| equality, without hashing string rely on the native string equality
bool | operator!= (const StringKey &o) const
| non equality Key
bool | operator!= (const std::string &o) const
| non-equality string
bool | operator< (const StringKey &o) const
| less key It can be used as a key for std::map, e.g.
bool | operator> (const StringKey &o) const
| greater key
bool | operator<= (const StringKey &o) const
| less or equal key
bool | operator>= (const StringKey &o) const
| greater or equal key
std::size_t | __hash__ () const
| the actual access to the hash
std::string | __str__ () const
| the representation of the object
std::string | __repr__ () const
| the representation of the object
bool | __eq__ (const StringKey &right) const
| equality operator for python
bool | __eq__ (const std::string &right) const
| equality operators for python
bool | __neq__ (const StringKey &right) const
| non-equality operator for python
bool | __neq__ (const std::string &right) const
| non-equality operator for python
std::string | toString () const
| string representation (for properties)
## Private Attributes
std::string | m_str
| the actual string:
std::size_t | m_hash
| the hash:

## Constructor & Destructor Documentation

Gaudi::StringKey::StringKey | ( | const std::string & | key = `""` | ) |

constructor from the string, perform hashing

Definition at line 25 of file StringKey.cpp.

    00026   : m_str  ( key )
    00027   , m_hash ( boost::hash_value( key ) )  // NB! hashing here!!!
    00028 {}

## Member Function Documentation

const std::string& Gaudi::StringKey::str | ( |  | ) | const`[inline]`

the actual string

Definition at line 45 of file StringKey.h.

    00045 { return m_str ;  }

Gaudi::StringKey::operator const std::string & | ( |  | ) | const`[inline]`

implicit cast to std::string

Definition at line 47 of file StringKey.h.

    00047 { return str() ;  }

bool Gaudi::StringKey::empty | ( | void |  | ) | const`[inline]`

empty key?

Definition at line 49 of file StringKey.h.

    00049 { return m_str.empty() ; }

bool Gaudi::StringKey::operator! | ( |  | ) | const`[inline]`

empty key?

Definition at line 51 of file StringKey.h.

    00051 { return       empty() ; }

bool Gaudi::StringKey::operator== | ( | const StringKey & | o | ) | const`[inline]`

equality Key for efficiency reason compare the hash-values first

Definition at line 58 of file StringKey.h.

    00059     { return m_hash == o.m_hash && m_str == o.m_str ; }

bool Gaudi::StringKey::operator== | ( | const std::string & | o | ) | const`[inline]`

equality, without hashing string rely on the native string equality

Definition at line 63 of file StringKey.h.

    00063 { return m_str == o ; }

bool Gaudi::StringKey::operator!= | ( | const StringKey & | o | ) | const`[inline]`

non equality Key

Definition at line 68 of file StringKey.h.

    00068 { return !(*this==o) ; }

bool Gaudi::StringKey::operator!= | ( | const std::string & | o | ) | const`[inline]`

non-equality string

Definition at line 70 of file StringKey.h.

    00070 { return !(*this==o) ; }

bool Gaudi::StringKey::operator< | ( | const StringKey & | o | ) | const`[inline]`

less key It can be used as a key for std::map, e.g.

`std::map<StringKey,double>` Note that with such maps one can gain if using prehashed key:

       typedef std::map<StringKey,double> MAP ;

       const StringKey& key = ...  ;

       const MAP& m = ... ;

       // EFFICIENT:
      MAP::const_iterator i1 = m.find ( key ) ;

      // CAN BE VERY INEFICIENT:
      MAP::const_iterator i2 = m_find( "SomeLongKey,_e.g._TES_Locaiton" );

Definition at line 94 of file StringKey.h.

    00095     { return m_hash == o.m_hash ? m_str < o.m_str : m_hash < o.m_hash   ; }

bool Gaudi::StringKey::operator> | ( | const StringKey & | o | ) | const`[inline]`

greater key

Definition at line 97 of file StringKey.h.

    00097 { return    o < *this  ; }

bool Gaudi::StringKey::operator<= | ( | const StringKey & | o | ) | const`[inline]`

less or equal key

Definition at line 99 of file StringKey.h.

    00099 { return !(*this > o ) ; }

bool Gaudi::StringKey::operator>= | ( | const StringKey & | o | ) | const`[inline]`

greater or equal key

Definition at line 101 of file StringKey.h.

    00101 { return !(*this < o ) ; }

std::size_t Gaudi::StringKey::__hash__ | ( |  | ) | const`[inline]`

the actual access to the hash

Attention:
  NEVER use the actual hash value for anything stored in files, as it is not guaranteed that the hashing scheme will remain the same. The two reason for this function are:
  - transparent usage of this object for hashmap-like containers
  - Python the actual hash value

Definition at line 114 of file StringKey.h.

    00114 { return m_hash ; }

std::string Gaudi::StringKey::__str__ | ( |  | ) | const

the representation of the object

Definition at line 37 of file StringKey.cpp.

    00037 { return toString() ; }

std::string Gaudi::StringKey::__repr__ | ( |  | ) | const

the representation of the object

Definition at line 41 of file StringKey.cpp.

    00041 { return toString() ; }

bool Gaudi::StringKey::__eq__ | ( | const StringKey & | right | ) | const

equality operator for python

Definition at line 44 of file StringKey.cpp.

    00045 { return this == &right || *this == right ; }

bool Gaudi::StringKey::__eq__ | ( | const std::string & | right | ) | const

equality operators for python

Definition at line 49 of file StringKey.cpp.

    00050 { return *this == right ; }

bool Gaudi::StringKey::__neq__ | ( | const StringKey & | right | ) | const

non-equality operator for python

Definition at line 54 of file StringKey.cpp.

    00055 { return this != &right && *this != right ; }

bool Gaudi::StringKey::__neq__ | ( | const std::string & | right | ) | const

non-equality operator for python

Definition at line 59 of file StringKey.cpp.

    00060 { return *this != right ; }

std::string Gaudi::StringKey::toString | ( |  | ) | const

string representation (for properties)

Definition at line 32 of file StringKey.cpp.

    00033 { return Gaudi::Utils::toString ( m_str ) ; }

## Member Data Documentation

std::string Gaudi::StringKey::m_str`[private]`

the actual string:

Definition at line 137 of file StringKey.h.

std::size_t Gaudi::StringKey::m_hash`[private]`

the hash:

Definition at line 139 of file StringKey.h.

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

- /afs/cern.ch/sw/Gaudi/releases/GAUDI/GAUDI_v21r6/GaudiKernel/GaudiKernel/StringKey.h
- /afs/cern.ch/sw/Gaudi/releases/GAUDI/GAUDI_v21r6/GaudiKernel/src/Lib/StringKey.cpp