o cleanup

tools/bsnes/lib/nall/vector.hpp

@@ -0,0 +1,162 @@
+#ifndef NALL_VECTOR_HPP
+#define NALL_VECTOR_HPP
+
+#include <new>
+#include <nall/algorithm.hpp>
+#include <nall/bit.hpp>
+#include <nall/utility.hpp>
+
+namespace nall {
+  //linear_vector
+  //memory: O(capacity * 2)
+  //
+  //linear_vector uses placement new + manual destructor calls to create a
+  //contiguous block of memory for all objects. accessing individual elements
+  //is fast, though resizing the array incurs significant overhead.
+  //reserve() overhead is reduced from quadratic time to amortized constant time
+  //by resizing twice as much as requested.
+  //
+  //if objects hold memory address references to themselves (introspection), a
+  //valid copy constructor will be needed to keep pointers valid.
+
+  template<typename T> class linear_vector : noncopyable {
+  protected:
+    T *pool;
+    unsigned poolsize, objectsize;
+
+  public:
+    unsigned size() const { return objectsize; }
+    unsigned capacity() const { return poolsize; }
+
+    void reset() {
+      if(pool) {
+        for(unsigned i = 0; i < objectsize; i++) pool[i].~T();
+        free(pool);
+      }
+      pool = 0;
+      poolsize = 0;
+      objectsize = 0;
+    }
+
+    void reserve(unsigned newsize) {
+      newsize = bit::round(newsize);  //round to nearest power of two (for amortized growth)
+
+      T *poolcopy = (T*)malloc(newsize * sizeof(T));
+      for(unsigned i = 0; i < min(objectsize, newsize); i++) new(poolcopy + i) T(pool[i]);
+      for(unsigned i = 0; i < objectsize; i++) pool[i].~T();
+      free(pool);
+      pool = poolcopy;
+      poolsize = newsize;
+      objectsize = min(objectsize, newsize);
+    }
+
+    void resize(unsigned newsize) {
+      if(newsize > poolsize) reserve(newsize);
+
+      if(newsize < objectsize) {
+        //vector is shrinking; destroy excess objects
+        for(unsigned i = newsize; i < objectsize; i++) pool[i].~T();
+      } else if(newsize > objectsize) {
+        //vector is expanding; allocate new objects
+        for(unsigned i = objectsize; i < newsize; i++) new(pool + i) T;
+      }
+
+      objectsize = newsize;
+    }
+
+    void add(const T data) {
+      if(objectsize + 1 > poolsize) reserve(objectsize + 1);
+      new(pool + objectsize++) T(data);
+    }
+
+    inline T& operator[](unsigned index) {
+      if(index >= objectsize) resize(index + 1);
+      return pool[index];
+    }
+
+    inline const T& operator[](unsigned index) const {
+      if(index >= objectsize) throw "vector[] out of bounds";
+      return pool[index];
+    }
+
+    linear_vector() : pool(0), poolsize(0), objectsize(0) {}
+    ~linear_vector() { reset(); }
+  };
+
+  //pointer_vector
+  //memory: O(1)
+  //
+  //pointer_vector keeps an array of pointers to each vector object. this adds
+  //significant overhead to individual accesses, but allows for optimal memory
+  //utilization.
+  //
+  //by guaranteeing that the base memory address of each objects never changes,
+  //this avoids the need for an object to have a valid copy constructor.
+
+  template<typename T> class pointer_vector : noncopyable {
+  protected:
+    T **pool;
+    unsigned poolsize, objectsize;
+
+  public:
+    unsigned size() const { return objectsize; }
+    unsigned capacity() const { return poolsize; }
+
+    void reset() {
+      if(pool) {
+        for(unsigned i = 0; i < objectsize; i++) { if(pool[i]) delete pool[i]; }
+        free(pool);
+      }
+      pool = 0;
+      poolsize = 0;
+      objectsize = 0;
+    }
+
+    void reserve(unsigned newsize) {
+      newsize = bit::round(newsize);  //round to nearest power of two (for amortized growth)
+
+      for(unsigned i = newsize; i < objectsize; i++) {
+        if(pool[i]) { delete pool[i]; pool[i] = 0; }
+      }
+
+      pool = (T**)realloc(pool, newsize * sizeof(T*));
+      for(unsigned i = poolsize; i < newsize; i++) pool[i] = 0;
+      poolsize = newsize;
+      objectsize = min(objectsize, newsize);
+    }
+
+    void resize(unsigned newsize) {
+      if(newsize > poolsize) reserve(newsize);
+
+      for(unsigned i = newsize; i < objectsize; i++) {
+        if(pool[i]) { delete pool[i]; pool[i] = 0; }
+      }
+
+      objectsize = newsize;
+    }
+
+    void add(const T data) {
+      if(objectsize + 1 > poolsize) reserve(objectsize + 1);
+      pool[objectsize++] = new T(data);
+    }
+
+    inline T& operator[](unsigned index) {
+      if(index >= objectsize) resize(index + 1);
+      if(!pool[index]) pool[index] = new T;
+      return *pool[index];
+    }
+
+    inline const T& operator[](unsigned index) const {
+      if(index >= objectsize || !pool[index]) throw "vector[] out of bounds";
+      return *pool[index];
+    }
+
+    pointer_vector() : pool(0), poolsize(0), objectsize(0) {}
+    ~pointer_vector() { reset(); }
+  };
+
+  //default vector type
+  template<typename T> class vector : public linear_vector<T> {};
+}
+
+#endif