LUMIERA.clone/src/lib/util.hpp

352 lines
8.8 KiB
C++

/*
UTIL.hpp - collection of small helper functions used "everywhere"
Copyright (C) Lumiera.org
2008, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef UTIL_HPP_
#define UTIL_HPP_
#include <set>
#include <string>
#include <algorithm>
namespace util {
using std::string;
template <class NUM>
inline int
sgn (NUM n)
{
return (n==0)? 0 :((n<0)? -1:+1 );
}
template <class N1, class N2>
inline N1
min (N1 n1, N2 n2)
{
return n2 < n1? N1(n2) : n1;
}
template <class N1, class N2>
inline N1
max (N1 n1, N2 n2)
{
return n1 < n2? N1(n2) : n1;
}
/** helper to treat int or long division uniformly */
template<typename I>
struct IDiv;
template<>
struct IDiv<int>
: div_t
{
IDiv<int> (int num, int den)
: div_t(div (num,den))
{ }
};
template<>
struct IDiv<long>
: ldiv_t
{
IDiv<long> (long num, long den)
: ldiv_t(ldiv (num,den))
{ }
};
/** floor function for integer arithmetics.
* Unlike the built-in integer division, this function
* always rounds towards the next \em smaller integer,
* even for negative numbers.
* @warning floor on doubles performs way better
* @see UtilFloordiv_test
*/
template<typename I>
inline I
floordiv (I num, I den)
{
if (0 < (num^den))
return num/den;
else
{ // truncate similar to floor()
IDiv<I> res(num,den);
return (res.rem)? res.quot-1 // negative results truncated towards next smaller int
: res.quot; //..unless the division result not truncated at all
}
}
/** scale wrapping operation.
* Quantises the numerator value into the scale given by the denominator.
* Unlike the built-in integer division, this function always rounds towards
* the next \em smaller integer and also relates the remainder (=modulo) to
* this next lower scale grid point.
* @return quotient and remainder packed into a struct
* @see UtilFloorwarp_test
*/
template<typename I>
inline IDiv<I>
floorwrap (I num, I den)
{
IDiv<I> res(num,den);
if (0 > (num^den) && res.rem)
{ // negative results
// wrapped similar to floor()
--res.quot;
res.rem = den - (-res.rem);
}
return res;
}
/* ======== generic empty check ========= */
/** a family of util functions providing a "no value whatsoever" test.
Works on strings and all STL containers, includes NULL test for pointers */
template <class CONT>
inline bool
isnil (const CONT& container)
{
return container.empty();
}
template <class CONT>
inline bool
isnil (const CONT* pContainer)
{
return !pContainer || pContainer->empty();
}
template <class CONT>
inline bool
isnil (CONT* pContainer)
{
return !pContainer || pContainer->empty();
}
inline bool
isnil (const char* pCStr)
{
return !pCStr || !(*pCStr);
}
/** cut a numeric value to be >=0 */
template <typename NUM>
inline NUM
noneg (NUM val)
{
return (0<val? val : 0);
}
/** shortcut for containment test on a map */
template <typename MAP>
inline bool
contains (MAP& map, typename MAP::key_type const& key)
{
return map.find(key) != map.end();
}
/** shortcut for set value containment test */
template <typename T>
inline bool
contains (std::set<T>& set, T const& val)
{
return set.end() != set.find (val);
}
/** shortcut for string value containment test */
template <typename T>
inline bool
contains (std::string const& str, const T& val)
{
return str.find (val) != std::string::npos;
}
/** shortcut for brute-force containment test
* in any sequential container */
template <typename SEQ>
inline bool
contains (SEQ const& cont, typename SEQ::const_reference val)
{
typename SEQ::const_iterator begin = cont.begin();
typename SEQ::const_iterator end = cont.end();
return end != std::find(begin,end, val);
}
/** fetch value from a Map, or return a default if not found */
template <typename MAP>
inline typename MAP::mapped_type
getValue_or_default (MAP& map, typename MAP::key_type const& key
, typename MAP::mapped_type defaultVal)
{
typename MAP::const_iterator pos = map.find (key);
if (pos != map.end())
return pos->second;
else
return defaultVal;
}
/** shortcut for removing all copies of an Element
* in any sequential collection */
template <typename SEQ>
inline typename SEQ::iterator
removeall (SEQ& coll, typename SEQ::value_type& val)
{
typename SEQ::iterator collEnd = coll.end();
return coll.erase (std::remove (coll.begin(), collEnd, val),
collEnd
);
}
/** remove all elements fulfilling a given predicate
* from a (sorted) set.
* @return true if anything has been removed. */
template<class SET, typename PRD>
bool remove_if (SET& set, PRD test)
{
typedef typename SET::iterator Itor;
bool found = false;
Itor end = set.end();
Itor begin = set.begin();
Itor pos = begin;
while (pos!=end)
{
if (!test (*pos)) ++pos;
else
{
found = true;
if (pos==begin)
{
set.erase(pos);
pos = begin = set.begin();
}
else
{
set.erase(pos--);
++pos;
}
end = set.end();
} }
return found;
}
/** shortcut to save some typing when having to define
* const and non-const variants of member functions
*/
template<class OBJ>
OBJ*
unConst (const OBJ* o)
{
return const_cast<OBJ*> (o);
}
template<class OBJ>
OBJ&
unConst (OBJ const& ro)
{
return const_cast<OBJ&> (ro);
}
/** compare plain object identity,
* bypassing any custom comparison operators.
*/
template<class A, class B>
inline bool
isSameObject (A const& a, B const& b)
{
return static_cast<const void*> (&a)
== static_cast<const void*> (&b);
}
/** produce an identifier based on the given string.
* remove non-standard-chars, reduce sequences of punctuation
* and whitespace to single underscores. The sanitised string
* will start with an alphanumeric character.
*
* @par Example Conversions
\verbatim
"Word" --> 'Word'
"a Sentence" --> 'a_Sentence'
"trailing Withespace \t \n" --> 'trailing_Withespace'
"with a lot \nof Whitespace" --> 'with_a_lot_of_Whitespace'
"with\"much (punctuation)[]!" --> 'withmuch_(punctuation)'
"§&Ω%€ leading garbage" --> 'leading_garbage'
"mixed Ω garbage" --> 'mixed_garbage'
"Bääääh!!" --> 'Bh'
\endverbatim
* @see sanitised-identifier-test.cpp
*/
string sanitise (string const& org);
/** convenience shortcut: conversion to c-String via string.
* usable for printf with objects providing to-string conversion.
*/
inline const char*
cStr (string const& org)
{
return org.c_str();
}
} // namespace util
/* === some common macro definitions === */
/** suppress "warning: unused variable" on vars, which are
* introduced into a scope because of some sideeffect, i.e. Locking
*/
#define SIDEEFFECT __attribute__ ((unused));
/** this macro wraps its parameter into a cstring literal */
#define STRINGIFY(TOKEN) __STRNGFY(TOKEN)
#define __STRNGFY(TOKEN) #TOKEN
/** shortcut for subclass test, intended for assertions only.
* @note it is considered bad style to use such in non-assertion code,
* and we probably will enforce this design rule in future. */
#define INSTANCEOF(CLASS, EXPR) (dynamic_cast<const CLASS*> (EXPR))
/** the inevitable MAX macro, sometimes still necessary in template code */
#ifndef MAX // this is present to make this definition play nice with GLib
#define MAX(A,B) ((A < B) ? (B) : (A))
#endif
#endif /*UTIL_HPP_*/