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/*
*
* Template Numerical Toolkit (TNT)
*
* Mathematical and Computational Sciences Division
* National Institute of Technology,
* Gaithersburg, MD USA
*
*
* This software was developed at the National Institute of Standards and
* Technology (NIST) by employees of the Federal Government in the course
* of their official duties. Pursuant to title 17 Section 105 of the
* United States Code, this software is not subject to copyright protection
* and is in the public domain. NIST assumes no responsibility whatsoever for
* its use by other parties, and makes no guarantees, expressed or implied,
* about its quality, reliability, or any other characteristic.
*
*/
#ifndef TNT_ARRAY1D_H
#define TNT_ARRAY1D_H
#include <cstdlib>
#include <iostream>
#ifdef TNT_BOUNDS_CHECK
#include <assert.h>
#endif
namespace TNT
{
/**
Tempplated one-dimensional, numerical array which
looks like a conventional C array.
Elements are accessed via the familiar A[i] notation.
<p>
Array assignment is by reference (i.e. shallow assignment).
That is, B=A implies that the A and B point to the
same array, so modifications to the elements of A
will be reflected in B. If an independent copy
is required, then B = A.copy() can be used. Note
that this facilitates returning arrays from functions
without relying on compiler optimizations to eliminate
extensive data copying.
<p>
The indexing and layout of this array object makes
it compatible with C and C++ algorithms that utilize
the familiar C[i] notation. This includes numerous
textbooks, such as Numercial Recipes, and various
public domain codes.
<p>
This class employs its own garbage collection via
the use of reference counts. That is, whenever
an internal array storage no longer has any references
to it, it is destoryed.
*/
template <class T>
class Array1D
{
private:
T* v_;
int n_;
int *ref_count_;
void initialize_(int n);
void copy_(T* p, const T* q, int len) const;
void set_(const T& val);
void destroy_();
inline const T* begin_() const;
inline T* begin_();
public:
typedef T value_type;
Array1D();
explicit Array1D(int n);
Array1D(int n, T *a);
Array1D(int n, const T &a);
inline Array1D(const Array1D &A);
inline Array1D & operator=(const T &a);
inline Array1D & operator=(const Array1D &A);
inline Array1D & ref(const Array1D &A);
Array1D copy() const;
Array1D & inject(const Array1D & A);
inline T& operator[](int i);
inline const T& operator[](int i) const;
inline int dim1() const;
inline int dim() const;
inline int ref_count() const;
~Array1D();
};
/**
Null constructor. Creates a 0-length (NULL) array.
(Reference count is also zero.)
*/
template <class T>
Array1D<T>::Array1D() : v_(0), n_(0), ref_count_(0)
{
ref_count_ = new int;
*ref_count_ = 1;
}
/**
Copy constructor. Array data is NOT copied, but shared.
Thus, in Array1D B(A), subsequent changes to A will
be reflected in B. For an indepent copy of A, use
Array1D B(A.copy()), or B = A.copy(), instead.
*/
template <class T>
Array1D<T>::Array1D(const Array1D<T> &A) : v_(A.v_),
n_(A.n_), ref_count_(A.ref_count_)
{
(*ref_count_)++;
}
/**
Create a new array (vector) of length <b>n</b>,
WIHOUT initializing array elements.
To create an initialized array of constants, see Array1D(n,value).
<p>
This version avoids the O(n) initialization overhead and
is used just before manual assignment.
@param n the dimension (length) of the new matrix.
*/
template <class T>
Array1D<T>::Array1D(int n) : v_(0), n_(n), ref_count_(0)
{
initialize_(n);
ref_count_ = new int;
*ref_count_ = 1;
}
/**
Create a new array of length <b>n</b>, initializing array elements to
constant specified by argument. Most often used to
create an array of zeros, as in A(n, 0.0).
@param n the dimension (length) of the new matrix.
@param val the constant value to set all elements of the new array to.
*/
template <class T>
Array1D<T>::Array1D(int n, const T &val) : v_(0), n_(n) ,
ref_count_(0)
{
initialize_(n);
set_(val);
ref_count_ = new int;
*ref_count_ = 1;
}
/**
Create a new n-length array, as a view of an existing one-dimensional
C array. (Note that the storage for this pre-existing array will
never be destroyed by the Aray1DRef class.)
@param n the dimension (length) of the new matrix.
@param a the one dimensional C array to use as data storage for
the array.
*/
template <class T>
Array1D<T>::Array1D(int n, T *a) : v_(a), n_(n) ,
ref_count_(0)
{
ref_count_ = new int;
*ref_count_ = 2; /* this avoid destorying original data. */
}
/**
A[i] indexes the ith element of A. The first element is
A[0]. If TNT_BOUNDS_CHECK is defined, then the index is
checked that it falls within the array bounds.
*/
template <class T>
inline T& Array1D<T>::operator[](int i)
{
#ifdef TNT_BOUNDS_CHECK
assert(i>= 0);
assert(i < n_);
#endif
return v_[i];
}
/**
A[i] indexes the ith element of A. The first element is
A[0]. If TNT_BOUNDS_CHECK is defined, then the index is
checked that it fall within the array bounds.
*/
template <class T>
inline const T& Array1D<T>::operator[](int i) const
{
#ifdef TNT_BOUNDS_CHECK
assert(i>= 0);
assert(i < n_);
#endif
return v_[i];
}
/**
Assign all elemnts of A to a constant scalar.
*/
template <class T>
Array1D<T> & Array1D<T>::operator=(const T &a)
{
set_(a);
return *this;
}
/**
Create a new of existing matrix. Used in B = A.copy()
or in the construction of B, e.g. Array1D B(A.copy()),
to create a new array that does not share data.
*/
template <class T>
Array1D<T> Array1D<T>::copy() const
{
Array1D A( n_);
copy_(A.begin_(), begin_(), n_);
return A;
}
/**
Copy the elements to from one array to another, in place.
That is B.inject(A), both A and B must conform (i.e. have
identical row and column dimensions).
This differs from B = A.copy() in that references to B
before this assignment are also affected. That is, if
we have
<pre>
Array1D A(n);
Array1D C(n);
Array1D B(C); // elements of B and C are shared.
</pre>
then B.inject(A) affects both and C, while B=A.copy() creates
a new array B which shares no data with C or A.
@param A the array from which elements will be copied
@return an instance of the modifed array. That is, in B.inject(A),
it returns B. If A and B are not conformat, no modifications to
B are made.
*/
template <class T>
Array1D<T> & Array1D<T>::inject(const Array1D &A)
{
if (A.n_ == n_)
copy_(begin_(), A.begin_(), n_);
return *this;
}
/**
Create a reference (shallow assignment) to another existing array.
In B.ref(A), B and A shared the same data and subsequent changes
to the array elements of one will be reflected in the other.
<p>
This is what operator= calls, and B=A and B.ref(A) are equivalent
operations.
@return The new referenced array: in B.ref(A), it returns B.
*/
template <class T>
Array1D<T> & Array1D<T>::ref(const Array1D<T> &A)
{
if (this != &A)
{
(*ref_count_) --;
if ( *ref_count_ < 1)
{
destroy_();
}
n_ = A.n_;
v_ = A.v_;
ref_count_ = A.ref_count_;
(*ref_count_) ++ ;
}
return *this;
}
/**
B = A is shorthand notation for B.ref(A).
*/
template <class T>
Array1D<T> & Array1D<T>::operator=(const Array1D<T> &A)
{
return ref(A);
}
/**
@return the dimension (number of elements) of the array.
This is equivalent to dim() and dim1().
*/
template <class T>
inline int Array1D<T>::dim1() const { return n_; }
/**
@return the dimension (number of elements) of the array.
This is equivalent to dim1() and dim1().
*/
template <class T>
inline int Array1D<T>::dim() const { return n_; }
/**
@return the number of arrays that share the same storage area
as this one. (Must be at least one.)
*/
template <class T>
inline int Array1D<T>::ref_count() const
{
return *ref_count_;
}
template <class T>
Array1D<T>::~Array1D()
{
(*ref_count_) --;
if (*ref_count_ < 1)
destroy_();
}
/* private internal functions */
template <class T>
void Array1D<T>::initialize_(int n)
{
v_ = new T[n];
n_ = n;
}
template <class T>
void Array1D<T>::set_(const T& a)
{
T *begin = &(v_[0]);
T *end = begin+ n_;
for (T* p=begin; p<end; p++)
*p = a;
}
template <class T>
void Array1D<T>::copy_(T* p, const T* q, int len) const
{
T *end = p + len;
while (p<end )
*p++ = *q++;
}
template <class T>
void Array1D<T>::destroy_()
{
if (v_ != 0)
{
delete[] (v_);
}
if (ref_count_ != 0)
delete ref_count_;
}
/**
@returns location of first element, i.e. A[0] (mutable).
*/
template <class T>
const T* Array1D<T>::begin_() const { return &(v_[0]); }
/**
@returns location of first element, i.e. A[0] (mutable).
*/
template <class T>
T* Array1D<T>::begin_() { return &(v_[0]); }
} /* namespace TNT */
#endif
/* TNT_ARRAY1D_H */
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