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#ifndef UTIL_H |
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#define UTIL_H |
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|
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#include <climits> |
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#include <cstddef> |
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#include <vector> |
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|
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#include <ermyth/exception.h> |
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|
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// makes dynamically allocated objects zero-initialised |
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struct zero_initialised |
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{ |
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void *operator new (size_t s) |
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{ |
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void *p = malloc (s); |
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memset (p, 0, s); |
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return p; |
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} |
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|
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void *operator new[] (size_t s) |
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{ |
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void *p = malloc (s); |
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memset (p, 0, s); |
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return p; |
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} |
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|
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void operator delete (void *p, size_t s) |
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{ |
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free (p); |
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} |
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|
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void operator delete[] (void *p, size_t s) |
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{ |
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free (p); |
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} |
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}; |
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|
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/** |
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* Mostly the same as std::vector, but erase can reorder |
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* the elements, making insert/remove O(1) instead of O(n). |
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* |
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* NOTE: only some forms of erase are available |
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* (Taken from Crossfire TRT http://cf.schmorp.de/) |
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*/ |
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template<typename T, typename Alloc = std::allocator<T> > |
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struct unordered_vector : std::vector<T, Alloc> |
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{ |
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typedef typename unordered_vector::iterator iterator; |
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|
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void erase (unsigned pos) |
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{ |
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if (pos < this->size () - 1) |
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(*this)[pos] = (*this)[this->size () - 1]; |
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|
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this->pop_back (); |
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} |
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|
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void erase (iterator pos) |
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{ |
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erase ((unsigned)(pos - this->begin ())); |
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} |
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|
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void insert (T const &val) |
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{ |
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push_back (val); |
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} |
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}; |
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|
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/** |
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* The following templates find a sufficiently large integer type to contain |
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* the given number of bits. |
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* |
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* Usage: |
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* |
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* unsigned_type<16>::type a; // 16-bit unsigned if available (probably unsigned short) |
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* signed_type<8>::type a; // 8-bit signed if available (probably char) |
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*/ |
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|
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// Empty class if everything failed |
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struct empty_base |
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{ |
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}; |
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|
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// To allow inheritance from this and get the integer type out |
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template<typename T> |
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struct identity |
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{ |
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typedef T type; |
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}; |
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|
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/** |
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* The following two templates are a compile-time if-statement. |
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*/ |
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template<bool Cond, class Then, class Else> |
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struct If |
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{ |
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typedef Then ret; |
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}; |
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|
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template<class Then, class Else> |
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struct If<false, Then, Else> |
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{ |
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typedef Else ret; |
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}; |
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|
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// Looks whether the desired type exists |
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template<typename T, std::size_t bits, typename Else> |
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struct type_if_size |
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: If<sizeof (T) * CHAR_BIT >= bits, identity<T>, Else>::ret |
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{ |
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}; |
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|
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template<std::size_t bits> |
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struct unsigned_type |
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: type_if_size<unsigned char, bits, |
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type_if_size<unsigned short, bits, |
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type_if_size<unsigned int, bits, |
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type_if_size<unsigned long, bits, |
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empty_base // No such type |
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> |
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> |
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> |
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> |
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{ |
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}; |
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|
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template<std::size_t bits> |
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struct signed_type |
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: type_if_size<signed char, bits |
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, type_if_size<signed short, bits |
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, type_if_size<signed int, bits |
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, type_if_size<signed long, bits |
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, empty_base // No such type |
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> |
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> |
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> |
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> |
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{ |
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}; |
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|
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template<class T, int T::*index = &T::index, class Alloc = std::allocator<T *> > |
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struct indexing_vector : std::vector<T *, Alloc> |
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{ |
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typedef typename indexing_vector::size_type size_type; |
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typedef typename indexing_vector::iterator iterator; |
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|
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void erase (T *obj) |
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{ |
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size_type pos = obj->*index - 1; |
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obj->*index = 0; |
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|
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if (pos <= this->size ()) |
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{ |
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(*this)[pos] = (*this)[this->size () - 1]; |
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(*this)[pos]->*index = pos; |
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} |
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|
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this->pop_back (); |
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} |
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|
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void insert (T *obj) |
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{ |
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this->push_back (obj); |
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obj->*index = this->size (); |
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} |
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}; |
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|
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struct str_hash |
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{ |
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std::size_t operator () (char const *s) const |
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{ |
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unsigned long hash = 0; |
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|
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// use the one-at-a-time hash function. |
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// see http://burtleburtle.net/bob/hash/doobs.html |
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while (*s) |
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{ |
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hash += *s++; |
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hash += hash << 10; |
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hash ^= hash >> 6; |
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} |
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|
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hash += hash << 3; |
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hash ^= hash >> 11; |
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hash += hash << 15; |
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|
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return hash; |
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} |
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}; |
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|
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struct str_eq |
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{ |
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bool operator () (char const * const s1, char const * const s2) const |
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{ |
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if (s1 == NULL || s2 == NULL) |
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throw nullpointer_exception (); |
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return !strcmp (s1, s2); |
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} |
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}; |
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|
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struct str_lt |
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{ |
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bool operator () (char const * const s1, char const * const s2) const |
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{ |
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if (s1 == NULL || s2 == NULL) |
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throw nullpointer_exception (); |
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return strcmp (s1, s2) < 0; |
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} |
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}; |
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|
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#endif |
