Created
December 7, 2012 09:33
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Lazy Variable Template
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#pragma once | |
/*! | |
* @brief template class for inertial variable | |
* @note class T must implement operator=(T), operator+(T), and operator/(float). | |
* | |
* @usage | |
* Lazy<float> value(SIZE); | |
* value = 0; | |
* cout << value << endl; // 0 | |
* for(int i = 1; i <= SIZE; ++i) { | |
* value = 10; | |
* cout << value << endl; // 10*i/SIZE | |
* } | |
*/ | |
#include <vector> | |
template<typename T> | |
class Lazy | |
{ | |
public: | |
Lazy<T>(int size=1):length_(size){} | |
Lazy<T>(int size, const T& initial):length_(size){add(initial);} | |
void setSize(unsigned int size) { | |
while(buf_.size() > size) { | |
buf_.erase(buf_.begin()); | |
} | |
length_ = size; | |
} | |
operator T&() { | |
return cache_; | |
} | |
const T& operator =(const T& t) { | |
return add(t); | |
} | |
void clear() { buf_.clear(); } | |
void reset(const T& t) { clear(); add(t); } | |
private: | |
const T& get() const { return cache_; } | |
const T& add(const T& t) { | |
if(buf_.size() == length_) { | |
buf_.erase(buf_.begin()); | |
buf_.push_back(t); | |
} | |
else { | |
while(buf_.size() < length_) { | |
buf_.push_back(t); | |
} | |
} | |
switch(length_) { | |
case 1: | |
cache_ = t; | |
break; | |
case 2: | |
cache_ = (buf_[0]+t)/2.f; | |
break; | |
default: { | |
vector<T>::iterator it = buf_.begin(); | |
cache_ = *it++; | |
while(it != buf_.end()) { | |
cache_ = cache_ + *it++; | |
} | |
cache_ = cache_ / (float)length_; | |
} break; | |
} | |
return cache_; | |
} | |
private: | |
unsigned int length_; | |
std::vector<T> buf_; | |
T cache_; | |
}; | |
/* EOF */ |
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