/*++
Copyright (c) 2006 Microsoft Corporation

Module Name:

    vector.h

Abstract:
    Dynamic array implementation. 
    Remarks:

    - Empty arrays consume only sizeof(T *) bytes.

    - There is the option of disabling the destructor invocation for elements stored in the vector.
    This is useful for vectors of int.

Author:

    Leonardo de Moura (leonardo) 2006-09-11.

Revision History:

--*/
#ifndef _VECTOR_H_
#define _VECTOR_H_

#include"debug.h"
#include<algorithm>
#include<memory.h>
#include"memory_manager.h"
#include"hash.h"

// disable warning for constant 'if' expressions.
// these are used heavily in templates.
#ifdef _MSC_VER
#pragma warning(disable:4127)
#endif

template<typename T, bool CallDestructors=true>
class vector {
#define SIZE_IDX     -1
#define CAPACITY_IDX -2
    T * m_data;

    void destroy_elements() {
        iterator it = begin();
        iterator e  = end();
        for (; it != e; ++it) {
            it->~T();
        }
    }

    void free_memory() { 
        memory::deallocate(reinterpret_cast<char*>(reinterpret_cast<unsigned*>(m_data) - 2));
    }

    void expand_vector() {
        if (m_data == 0) {
            unsigned capacity = 2;
            unsigned * mem    = reinterpret_cast<unsigned*>(memory::allocate(sizeof(T) * capacity + sizeof(unsigned) * 2));
            *mem              = capacity; 
            mem++;
            *mem              = 0;        
            mem++;
            m_data            = reinterpret_cast<T *>(mem);
        }
        else {
            SASSERT(capacity() > 0);
            unsigned old_capacity = reinterpret_cast<unsigned *>(m_data)[CAPACITY_IDX];
            unsigned new_capacity = (3 * old_capacity + 1) >> 1;
            unsigned size         = reinterpret_cast<unsigned *>(m_data)[SIZE_IDX];
            unsigned * mem        = reinterpret_cast<unsigned*>(memory::allocate(sizeof(T) * new_capacity + sizeof(unsigned) * 2));
            *mem                  = new_capacity; 
            mem ++;
            *mem                  = size;         
            mem++;
            memcpy(mem, m_data, size * sizeof(T));
            free_memory();
            m_data                = reinterpret_cast<T *>(mem);
        }
    }

    void copy_core(vector const & source) {
        unsigned size      = source.size();
        unsigned capacity  = source.capacity();
        unsigned * mem     = reinterpret_cast<unsigned*>(memory::allocate(sizeof(T) * capacity + sizeof(unsigned) * 2));
        *mem = capacity; 
        mem++;
        *mem = size; 
        mem++;
        m_data             = reinterpret_cast<T *>(mem);
        const_iterator it  = source.begin();
        iterator it2       = begin();
        SASSERT(it2 == m_data);
        const_iterator e   = source.end();
        for (; it != e; ++it, ++it2) {
            new (it2) T(*it); 
        }
    }

    void destroy() {
        if (m_data) { 
            if (CallDestructors) {
                destroy_elements(); 
            }
            free_memory(); 
        } 
    }

public:
    typedef T data;
    typedef T * iterator;
    typedef const T * const_iterator;

    vector():
        m_data(0) {
    }

    vector(unsigned s) {
        unsigned * mem = reinterpret_cast<unsigned*>(memory::allocate(sizeof(T) * s + sizeof(unsigned) * 2));
        *mem = s; 
        mem++;
        *mem = s; 
        mem++;
        m_data = reinterpret_cast<T *>(mem);
        // initialize elements
        iterator it = begin();
        iterator e  = end();
        for (; it != e; ++it) {
            new (it) T(); 
        }
    }

    vector(unsigned s, T const & elem):
        m_data(0) {
        resize(s, elem);
    }

    vector(vector const & source):
        m_data(0) {
        if (source.m_data) {
            copy_core(source);
        }
        SASSERT(size() == source.size());
    }

    vector(unsigned s, T const * data):
        m_data(0) {
        for (unsigned i = 0; i < s; i++) {
            push_back(data[i]);
        }
    }

    vector(T const & e) : 
        m_data(0) { 
        push_back(e); 
    }

    vector(T const & t1, T const & t2) : 
        m_data(0) { 
        push_back(t1); 
        push_back(t2); 
    }

    vector(T const & t1, T const & t2, T const & t3) : 
        m_data(0) { 
        push_back(t1); 
        push_back(t2); 
        push_back(t3); 
    }
 
    ~vector() { 
        destroy();
    } 

    void finalize() {
        destroy();
        m_data = 0;
    }

    vector & operator=(vector const & source) {
        destroy();
        if (source.m_data) {
            copy_core(source);
        }
        else {
            m_data = 0;
        }
        return *this;
    }

    void reset() { 
        if (m_data) {
            if (CallDestructors) {
                destroy_elements();
            }
            reinterpret_cast<unsigned *>(m_data)[SIZE_IDX] = 0;
        }
    }

    bool empty() const { 
        return m_data == 0 || reinterpret_cast<unsigned *>(m_data)[SIZE_IDX] == 0; 
    }

    unsigned size() const { 
        if (m_data == 0) {
            return 0;  
        }
        return reinterpret_cast<unsigned *>(m_data)[SIZE_IDX]; 
    }

    unsigned capacity() const { 
        if (m_data == 0) {
            return 0;
        }
        return reinterpret_cast<unsigned *>(m_data)[CAPACITY_IDX]; 
    }

    iterator begin() { 
        return m_data; 
    }

    iterator end() { 
        return m_data + size();
    }

    const_iterator begin() const { 
        return m_data; 
    }

    const_iterator end() const { 
        return m_data + size(); 
    }

    void set_end(iterator it) {
        if (m_data) {
            unsigned new_sz = static_cast<unsigned>(it - m_data);
            if (CallDestructors) {
                iterator e = end();
                for(; it != e; ++it) {
                    it->~T();
                }
            }
            reinterpret_cast<unsigned *>(m_data)[SIZE_IDX] = new_sz;
        }
        else {
            SASSERT(it == 0);
        }
    }

    T & operator[](unsigned idx) { 
        SASSERT(idx < size()); 
        return m_data[idx]; 
    }

    T const & operator[](unsigned idx) const { 
        SASSERT(idx < size()); 
        return m_data[idx];
    }

    T & get(unsigned idx) { 
        SASSERT(idx < size()); 
        return m_data[idx]; 
    }

    T const & get(unsigned idx) const { 
        SASSERT(idx < size()); 
        return m_data[idx];
    }

    void set(unsigned idx, T const & val) { 
        SASSERT(idx < size()); 
        m_data[idx] = val;
    }

    T & back() { 
        SASSERT(!empty()); 
        return operator[](size() - 1); 
    }

    T const & back() const { 
        SASSERT(!empty()); 
        return operator[](size() - 1); 
    }

    void pop_back() { 
        SASSERT(!empty()); 
        if (CallDestructors) {
            back().~T(); 
        }
        reinterpret_cast<unsigned *>(m_data)[SIZE_IDX]--; 
    }

    void push_back(T const & elem) {
        if (m_data == 0 || reinterpret_cast<unsigned *>(m_data)[SIZE_IDX] == reinterpret_cast<unsigned *>(m_data)[CAPACITY_IDX]) {
            expand_vector();
        }
        new (m_data + reinterpret_cast<unsigned *>(m_data)[SIZE_IDX]) T(elem); 
        reinterpret_cast<unsigned *>(m_data)[SIZE_IDX]++;
    }

    void insert(T const & elem) {
        push_back(elem);
    }

    void erase(iterator pos) {
        SASSERT(pos >= begin() && pos < end());
        iterator prev = pos;
        ++pos;
        iterator e    = end();
        for(; pos != e; ++pos, ++prev) {
            *prev = *pos;
        }
        reinterpret_cast<unsigned *>(m_data)[SIZE_IDX]--;
    }

    void erase(T const & elem) {
        iterator it = std::find(begin(), end(), elem);
        if (it != end()) {
            erase(it);
        }
    }

    void shrink(unsigned s) {
        if (m_data) {
            SASSERT(s <= reinterpret_cast<unsigned *>(m_data)[SIZE_IDX]);
            if (CallDestructors) {
                iterator it = m_data + s;
                iterator e  = end();
                for(; it != e; ++it) {
                    it->~T();
                }
            }
            reinterpret_cast<unsigned *>(m_data)[SIZE_IDX] = s;
        }
        else {
            SASSERT(s == 0);
        }
    }

    void resize(unsigned s, T const & elem=T()) {
        unsigned sz = size();
        if (s <= sz) { shrink(s); return; }
        while (s > capacity()) {
            expand_vector();
        }
        SASSERT(m_data != 0);
        reinterpret_cast<unsigned *>(m_data)[SIZE_IDX] = s;
        iterator it  = m_data + sz;
        iterator end = m_data + s;
        for(; it != end; ++it) {
            new (it) T(elem);
        }
    }

    void append(vector<T, CallDestructors> const & other) {
        for(unsigned i = 0; i < other.size(); ++i) {
            push_back(other[i]);
        }
    }

    void append(unsigned sz, T const * data) {
        for(unsigned i = 0; i < sz; ++i) {
            push_back(data[i]);
        }
    }

    T * c_ptr() const {
        return m_data;
    }

    void swap(vector & other) {
        std::swap(m_data, other.m_data);
    }

    void reverse() {
        unsigned sz = size();
        for (unsigned i = 0; i < sz/2; ++i) {
           std::swap(m_data[i], m_data[sz-i-1]);
       }
    }

    void fill(T const & elem) {
        iterator i = begin();
        iterator e = end();
        for (; i != e; ++i) {
            *i = elem;
        }
    }

    bool contains(T const & elem) const {
        const_iterator it  = begin();
        const_iterator e = end();
        for (; it != e; ++it) {
            if (*it == elem) {
                return true;
            }
        }
        return false;
    }

    // set pos idx with elem. If idx >= size, then expand using default.
    void setx(unsigned idx, T const & elem, T const & d) {
        if (idx >= size()) {
            resize(idx+1, d);
        }
        m_data[idx] = elem;
    }

    // return element at position idx, if idx >= size, then return default
    T const & get(unsigned idx, T const & d) const {
        if (idx >= size()) {
            return d;
        }
        return m_data[idx];
    }

    void reserve(unsigned s, T const & d = T()) {
        if (s > size())
            resize(s, d);
    }
};

template<typename T>
class ptr_vector : public vector<T *, false> {
public:
    ptr_vector():vector<T *, false>() {}
    ptr_vector(unsigned s):vector<T *, false>(s) {}
    ptr_vector(unsigned s, T * elem):vector<T *, false>(s, elem) {}
    ptr_vector(ptr_vector const & source):vector<T *, false>(source) {}
    ptr_vector(unsigned s, T * const * data):vector<T *, false>(s, const_cast<T**>(data)) {}
};

template<typename T>
class svector : public vector<T, false> {
public:
    svector():vector<T, false>() {}
    svector(unsigned s):vector<T, false>(s) {}
    svector(unsigned s, T const & elem):vector<T, false>(s, elem) {}
    svector(svector const & source):vector<T, false>(source) {}
    svector(unsigned s, T const * data):vector<T, false>(s, data) {}
};

typedef svector<int> int_vector;
typedef svector<unsigned> unsigned_vector;
typedef svector<char> char_vector;
typedef svector<double> double_vector;

template<typename Hash>
struct vector_hash {
    Hash m_hash;
    typedef vector<typename Hash::data> data;

    unsigned operator()(data const& v, unsigned idx) const { return m_hash(v[idx]); }

    vector_hash(Hash const& h = Hash()):m_hash(h) {}

    unsigned operator()(data const& v) const {
        if (v.empty()) {
            return 778;
        }
        return get_composite_hash<data, default_kind_hash_proc<data>, vector_hash>(v, v.size());
    }

};


#endif /* _VECTOR_H_ */