Refactored vector

Grzegorz Jabłoński
1 parent dea455b3
Showing 1 changed file with 44 additions and 49 deletions
examples11/04-vectortmpl/vector.h
@@ -18,6 +18,42 @@ private:
     return ++w;
   };
+  void destroy_array(C *ptr, unsigned int s) {
+    for (unsigned j = 0; j < s; ++j)
+      (ptr + j)->~C();
+    free(ptr);
+  }
+
+  void resize_before_push() {
+    if (size >= cap) {
+      if (cap > std::numeric_limits<decltype(size)>::max() / (2 * sizeof(C)))
+        throw bad_alloc();
+      unsigned int newcap = (cap == 0) ? 1 : 2 * cap;
+      C *newdata;
+      if constexpr (!std::is_trivially_copyable<C>()) {
+        newdata = static_cast<C *>(
+            std::aligned_alloc(alignof(C), newcap * sizeof(C)));
+        if (!newdata)
+          throw bad_alloc();
+        unsigned i;
+        try {
+          for (i = 0; i < size; i++)
+            new (newdata + i) C(std::move(data[i]));
+        } catch (...) {
+          destroy_array(newdata, i);
+          throw;
+        }
+        destroy_array(data, size);
+      } else {
+        newdata = static_cast<C *>(std::realloc(data, newcap * sizeof(C)));
+        if (!newdata)
+          throw bad_alloc();
+      }
+      data = newdata;
+      cap = newcap;
+    }
+  }
+
 public:
   class index_out_of_range {};
   explicit vector(unsigned s) {
@@ -34,23 +70,19 @@ public:
       for (i = 0; i < size; i++)
         new (data + i) C();
     } catch (...) {
-      for (unsigned j = 0; j < i; ++j)
-        (data + j)->~C();
-      free(data);
+      destroy_array(data, i);
       throw;
     }
   }
-  ~vector() {
-    for (unsigned j = 0; j < size; ++j)
-      (data + j)->~C();
-    free(data);
-  }
+  ~vector() { destroy_array(data, size); }
+
   C &operator[](unsigned int pos) {
     if (pos >= size)
       throw index_out_of_range();
     return data[pos];
   }
+
   C operator[](unsigned int pos) const {
     if (pos >= size)
       throw index_out_of_range();
@@ -68,9 +100,7 @@ public:
       for (i = 0; i < size; i++)
         new (data + i) C(s.data[i]);
     } catch (...) {
-      for (unsigned j = 0; j < i; ++j)
-        (data + j)->~C();
-      free(data);
+      destroy_array(data, i);
       throw;
     }
   }
@@ -105,44 +135,9 @@ public:
   }
   void push_back(const C &s) {
-    if (size < cap) {
-      new (data + size) C(s);
-      ++size;
-    } else {
-      if (cap > std::numeric_limits<decltype(size)>::max() / (2*sizeof(C)))
-        throw bad_alloc();
-      unsigned int newcap = (cap == 0) ? 1 : 2 * cap;
-      C *newdata;
-      if constexpr (!std::is_trivially_copyable<C>()) {
-        newdata = static_cast<C *>(
-            std::aligned_alloc(alignof(C), newcap * sizeof(C)));
-        if (!newdata)
-          throw bad_alloc();
-        unsigned i;
-        try {
-          for (i = 0; i < size; i++)
-            new (newdata + i) C(std::move(data[i]));
-        } catch (...) {
-          for (unsigned j = 0; j < i; ++j)
-            (newdata + j)->~C();
-          free(newdata);
-          throw;
-        }
-        new (newdata + size) C(s);
-        for (unsigned j = 0; j < size; ++j)
-          (data + j)->~C();
-        free(data);
-      } else {
-        newdata = static_cast<C *>(std::realloc(data, newcap * sizeof(C)));
-        if (!newdata)
-          throw bad_alloc();
-        new (newdata + size) C(s);
-      }
-
-      ++size;
-      data = newdata;
-      cap = newcap;
-    }
+    resize_before_push();
+    new (data + size) C(s);
+    ++size;
   }
 };
 #endif /* __VECTOR_H__ */