/**************************************************************************\ MODULE: vector SUMMARY: Template class for dynamic-sized vectors. The declaration Vec v; creates a zero-length vector. To grow this vector to length n, execute v.SetLength(n) This causes space to be allocated for (at least) n elements, and also causes the delault constructor for T to be called to initialize these elements. The current length of a vector is available as v.length(). The i-th vector element (counting from 0) is accessed as v[i]. If the macro NTL_RANGE_CHECK is defined, code is emitted to test if 0 <= i < v.length(). This check is not performed by default. For old-time FORTRAN programmers, the i-th vector element (counting from 1) is accessed as v(i). Let n = v.length(). Calling v.SetLength(m) with m <= n sets the current length of v to m (but does not call any destructors or free any space). Calling v.SetLength(m) with m > n will allocate space and initialize as necessary, but will leave the values of the already allocated elements unchanged (although their addresses may change). Initializations are performed using T's default constructor. v.MaxLength() is the largest value of n for which v.SetLength(n) was invoked, and is equal to the number of entries that have been initialized. v.SetMaxLength(n) will allocate space for and initialize up to n elements, without changing v.length(). When v's destructor is called, all constructed elements will be destructed, and all space will be relinquished. Space is managed using malloc, realloc, and free. When a vector is grown, a bit more space may be allocated than was requested for efficiency reasons. Note that when a vector is grown, the space is reallocated using realloc, and thus the addresses of vector elements may change, possibly creating dangling references to vector elements. One has to be especially careful of this when using vectors passed as reference parameters that may alias one another. Because realloc is used to grow a vector, the objects stored in a vector should be "relocatable"---that is, they shouldn't care what their actual address is, which may change over time. Most reasonable objects satisfy this constraint. v.allocated() is the number of elements which have been allocated, which may be more than the number elements initialized. Note that if n <= v.allocated(), then v.SetLength(n) is guaranteed not to cause any memory allocation, or movement of objects. \**************************************************************************/ template class Vec { public: Vec(); // initially length 0 Vec(const Vec& a); // copy constructor; uses the assignment operator of T // for copying into locations that have already been initialized, // and uses the copy constructor for T for initializing new locations. Vec& operator=(const Vec& a); // assignment; uses the assignment operator of T // for copying into locations that have already been initialized, // and uses the copy constructor for T for initializing new locations. ~Vec(); // destructor: calls T's destructor for all initialized // elements in the vector, and then frees the vector itself void SetLength(long n); // set current length to n, growing vector if necessary // new objects are initialized using the default contructor for T void SetLength(long n, const T& a); // set current length to n, growing vector if necessary // new objects are initialized using the copy contructor for T long length() const; // current length T& operator[](long i); const T& operator[](long i) const; // indexing operation, starting from 0. // The first version is applied to non-const Vec, // and returns a non-const reference to a T, while the second version // is applied to a const Vec and returns a const reference to a T. T& operator()(long i); const T& operator()(long i) const; // indexing operation, starting from 1 // The first version is applied to non-const Vec, // and returns a non-const reference to a T, while the second version // is applied to a const Vec and returns a const reference to a T. T* elts(); const T* elts() const; // returns address of first vector element (or 0 if no space has // been allocated for this vector). If a vector potentially has // length 0, it is safer to write v.elts() instead of &v[0]. // The first version is applied to non-const Vec, // and returns a non-const pointer to a T, while the second version // is applied to a const Vec and returns a const reference to a T. void swap(Vec& y); // swap with y (fast: just swaps pointers) void append(const T& a); // append a to end of vector; uses the assignment operator of T // for copying into locations that have already been initialized, // and uses the copy constructor for T for initializing new locations. void append(const Vec& w); // append w to end of vector; uses the assignment operator of T // for copying into locations that have already been initialized, // and uses the copy constructor for T for initializing new locations. // Alternative access interface const T& get(long i) const; // v.get(i) returns v[i] void put(long i, const T& a); // v.put(i, a) equivalent to v[i] = q // Some STL compatibility typedef T value_type; typedef value_type& reference; typedef const value_type& const_reference; typedef value_type *iterator; typedef const value_type *const_iterator; T* data(); const T* data() const; // v.data() same as v.elts() T* begin(); const T* begin() const; // v.begin() same as v.elts() T* end(); const T* end() const; // pointer to last element (or NULL) T& at(long i); const T& at(long i) const; // indexing with range checking // the remaining member functions are a bit esoteric (skip on first // reading) Vec(INIT_SIZE_TYPE, long n); // Vec(INIT_SIZE, n) initializes with an intial length of n. void kill(); // release space and set to length 0 void SetMaxLength(long n); // allocates space and initializes up to n elements. Does not change // current length void FixLength(long n); // sets length to n and prohibits all future length changes. // FixLength may only be invoked immediately after the default // construction or kill. // The kill operation is also subsequently prohibited, and swap is // allowed on fixed length vectors of the same length. // FixLength is provided mainly to implement Mat, to enforce // the restriction that all rows have the same length. long fixed() const; // test if length has been fixed by FixLength(). long MaxLength() const; // maximum length, i.e., number of allocated and initialized elements long allocated() const; // the number of objects for which space has been allocated, but not // necessarily initialized; this may be larger than MaxLength(). T& RawGet(long i); const T& RawGet(long i) const; // indexing with no range checking long position(const T& a) const; // returns position of a in the vector, or -1 if it is not there. // The search is conducted from position 0 to allocated()-1 the vector, // and an error is raised if the object is found at position MaxLength() // or higher (in which case a references an uninitialized object). // Note that if NTL_CLEAN_PTR flag is set, this routine takes // linear time, and otherwise, it takes constant time. long position1(const T& a) const; // returns position of a in the vector, or -1 if it is not there. // The search is conducted from position 0 to length()-1 of the vector. // Note that if NTL_CLEAN_PTR flag is set, this routine takes // linear time, and otherwise, it takes constant time. }; /**************************************************************************\ Some utility routines \**************************************************************************/ template void swap(Vec& x, Vec& y); // swaps x & y; same as x.swap(y) template void append(Vec& v, const T& a); // appends a to the end of v; same as v.append(a) template void append(Vec& v, const Vec& w); // appends w to the end of v; same as v.append(w) /**************************************************************************\ Input/Output The I/O format for a vector v with n elements is: [v[0] v[1] ... v[n-1]] Uses corresponding I/O operators for T \**************************************************************************/ template istream& operator>>(istream&, Vec&); template ostream& operator<<(ostream&, const Vec&); /**************************************************************************\ Equality Testing \**************************************************************************/ template long operator==(const Vec& a, const Vec& b); template long operator!=(const Vec& a, const Vec& b); /**************************************************************************\ Customized Constructors and Destructors Esoteric: skip on first reading...also these interfaces are subject to change When new elements in a vector need to be constructed, one of the following routines is called: void BlockConstruct(T* p, long n); // invokes T() to initialize p[i] for i = 0..n-1 void BlockConstructFromVec(T* p, long n, const T* q); // invokes T(q[i]) to initialize p[i] for i = 0..n-1; // q points to elements from a Vec void BlockConstructFromObj(T* p, long n, const T& q); // invokes T(q) to initialize p[i] for i = 0..n-1 When a vector is destroyed, the following routine is called: void BlockDestroy(T* p, long n); // invokes ~T() on p[i] for i = 0..n-1 The default behavior of these routines may be modified by overloading these functions with a custom implementation. In NTL, these routines are overridden for the ZZ_p and GF2E classes, so that many vector entries will be packed into contiguous storage locations. This reduces the number of invocations of malloc, and increases locality of reference. \**************************************************************************/