working basic vector implementation

octa/vector.h

@@ -6,66 +6,153 @@
 #ifndef OCTA_VECTOR_H
 #define OCTA_VECTOR_H
 
+#include <string.h>
+
 #include "octa/new.h"
 #include "octa/traits.h"
 
 namespace octa {
     template<typename T>
     class Vector {
-        T *buf;
-        size_t length, capacity;
+        T *p_buf;
+        size_t p_len, p_cap;
 
     public:
-        explicit vector(): buf(NULL), length(0), capacity(0) {}
+        enum { MIN_SIZE = 8 };
 
-        vector(const vector &v): buf(NULL), length(0), capacity(0) {
+        explicit Vector(): p_buf(NULL), p_len(0), p_cap(0) {}
+
+        Vector(const Vector &v): p_buf(NULL), p_len(0), p_cap(0) {
             *this = v;
         }
 
-        ~vector() {
-            resize(0);
-            if (buf) delete[] (unsigned char *)buf;
+        Vector(size_t n, const T &val = T()): Vector() {
+            p_buf = new uchar[n * sizeof(T)];
+            p_len = p_cap = n;
+            T *cur = p_buf, *last = p_buf + n;
+            while (cur != last) new (cur++) T(val);
         }
 
-        vector<T> &operator=(const vector<T> &v) {
-            resize(0);
-            if (v.length() > capacity) resize(v.length());
-            for (size_t i = 0; i < v.length(); ++i) push(v[i]);
+        ~Vector() {
+            clear();
+        }
+
+        void clear() {
+            if (p_cap > 0) {
+                if (octa::IsClass<T>::value) {
+                    T *cur = p_buf, *last = p_buf + p_len;
+                }
+                delete[] (uchar *)p_buf;
+                p_buf = NULL;
+                p_len = p_cap = 0;
+            }
+        }
+
+        Vector<T> &operator=(const Vector<T> &v) {
+            if (this == &v) return *this;
+
+            if (p_cap >= v.p_cap) {
+                if (octa::IsClass<T>::value) {
+                    T *cur = p_buf, *last = p_buf + p_len;
+                    while (cur != last) (*cur++).~T();
+                }
+                p_len = v.p_len;
+            } else {
+                clear();
+                p_len = v.p_len;
+                p_cap = v.p_cap;
+                p_buf = (T *)new uchar[p_cap * sizeof(T)];
+            }
+
+            if (!octa::IsClass<T>::value) {
+                memcpy(p_buf, v.p_buf, p_len * sizeof(T));
+            } else {
+                T *cur = p_buf, *last = p_buf + p_len;
+                T *vbuf = v.p_buf;
+                while (cur != last) {
+                    new (cur++) T(*vbuf++);
+                }
+            }
+
             return *this;
         }
 
+        void resize(size_t n, const T &v = T()) {
+            size_t len = p_len;
+            reserve(n);
+            p_len = n;
+            if (!octa::IsClass<T>::value) {
+                for (size_t i = len; i < p_len; ++i) {
+                    p_buf[i] = T(v);
+                }
+            } else {
+                T *first = p_buf + len;
+                T *last  = p_buf + p_len;
+                while (first != last) new (first++) T(v);
+            }
+        }
+
+        void reserve(size_t n) {
+            if (n <= p_len) {
+                if (n == p_len) return;
+                while (p_len > n) pop();
+                return;
+            }
+            size_t oc = p_cap;
+            if (!oc) {
+                p_cap = (n > MIN_SIZE) ? n : MIN_SIZE;
+            } else {
+                while (p_cap < n) p_cap *= 2;
+            }
+            T *tmp = (T *)new uchar[p_cap * sizeof(T)];
+            if (oc > 0) {
+                if (!octa::IsClass<T>::value) {
+                    memcpy(tmp, p_buf, p_len * sizeof(T));
+                } else {
+                    T *cur = p_buf, *tcur = tmp, *last = tmp + p_len;
+                    while (tcur != last) {
+                        new (tcur++) T(*cur);
+                        (*cur).~T();
+                        ++cur;
+                    }
+                }
+                delete[] (uchar *)p_buf;
+            }
+            p_buf = tmp;
+        }
+
+        T &operator[](size_t i) { return p_buf[i]; }
+        const T &operator[](size_t i) const { return p_buf[i]; }
+
+        T &at(size_t i) { return p_buf[i]; }
+        const T &at(size_t i) const { return p_buf[i]; }
+
         T &push(const T &v) {
-            if (length == capacity) resize(length + 1);
-            new (&buf[length]) T(v);
-            return buf[length++];
+            if (p_len == p_cap) reserve(p_len + 1);
+            new (&p_buf[p_len]) T(v);
+            return p_buf[p_len++];
         }
 
         T &push() {
-            if (length == capacity) resize(length + 1);
-            new (&buf[length]) T;
-            return buf[length++];
+            if (p_len == p_cap) reserve(p_len + 1);
+            new (&p_buf[p_len]) T;
+            return p_buf[p_len++];
         }
 
-        void resize(size_t n) {
-            if (n <= length) {
-                if (n == length) return;
-                while (length > n) pop();
-                return;
+        void pop() {
+            if (octa::IsClass<T>::value) {
+                p_buf[--p_len].~T();
+            } else {
+                --p_len;
             }
-            int old = capacity;
-            if (!old)
-                capacity = max(n, 8);
-            else
-                while (capacity < n) capacity += (capacity / 2);
-            if (capacity <= old)
-                return;
-            unsigned char *nbuf = new unsigned char[capacity * sizeof(T)];
-            if (old > 0) {
-                if (length > 0) memcpy(nbuf, (void *)buf, length * sizeof(T));
-                delete[] (unsigned char *)buf;
-            }
-            buf = (T *)buf;
         }
+
+        T *get() { return p_buf; }
+
+        size_t length() const { return p_len; }
+        size_t capacity() const { return p_cap; }
+
+        bool empty() const { return (p_len == 0); }
     };
 }