path: root/src/modules/json/JSONChildren.h

#ifndef JSONCHILDREN_H
#define JSONCHILDREN_H

#include "JSONMemory.h"
#include "JSONDebug.h"  //for JSON_ASSERT macro

#define json_foreach(children, iterator)\
    JSONNode ** iterator = children.begin();\
    for(JSONNode ** iterator##_end = children.end(); iterator != iterator##_end; ++iterator)

/*
 This class is essentially a vector that has been heavily optimized for the specific purpose
 of holding JSONNode children.  It acts the same way as a vector, it has a automatically
 expanding array.  On destruction, this container automatically destroys everything contained
 in it as well, so that you libJSON doesn't have to do that.
 
 T is JSONNode*, I can't define it that way directly because JSONNode uses this container, and because
 the container deletes the children automatically, forward declaration can't be used
 */

class JSONNode;  //forward declaration

class jsonChildren {
public:
    //starts completely empty and the array is not allocated
    jsonChildren(void) : array(0), mysize(0), mycapacity(0) { }
    
    //deletes the array and everything that is contained within it (using delete)
    ~jsonChildren(void){
	   if (array){  //the following function calls are safe, but take more time than a check here
		  deleteAll();
		  libjson_free<JSONNode*>(array);
	   }
    }
    
    //increase the size of the array
    void inc(json_index_t amount);
    void inc(void);
    
    //Adds something to the vector, doubling the array if necessary
    void push_back(JSONNode * item){
	   inc();
	   array[mysize++] = item;
    }
    
    //Adds something to the front of the vector, doubling the array if necessary
    void push_front(JSONNode * item){
	   inc();
	   memmove(array + 1, array, mysize++ * sizeof(JSONNode *));
	   array[0] = item;
    }
    
    //gets an item out of the vector by it's position
    inline JSONNode * operator[] (json_index_t position) const {
	   JSON_ASSERT(position < mysize, JSON_TEXT("Using [] out of bounds"));
	   JSON_ASSERT(position < mycapacity, JSON_TEXT("Using [] out of bounds"));
	   JSON_ASSERT(array, JSON_TEXT("Array is null"));
	   return array[position];
    }
    
    //returns the allocated capacity, but keep in mind that some might not be valid
    inline json_index_t capacity() const {
	   return mycapacity;
    }
    
    //returns the number of valid objects within the vector
    inline json_index_t size() const {
	   return mysize;
    }
    
    //tests whether or not the vector is empty
    inline bool empty() const {
	   return mysize == 0;
    }
    
    //clears (and deletes) everything from the vector and sets it's size to 0
    inline void clear() {
	   if (array){  //don't bother clearing anything if there is nothing in it
		  JSON_ASSERT(mycapacity != 0, JSON_TEXT("mycapacity is not zero, but array is null"));
		  deleteAll();
		  mysize = 0;
	   }
	   JSON_ASSERT(mysize == 0, JSON_TEXT("mysize is not zero after clear"));
    }
    
    //returns the beginning of the array
    inline JSONNode ** begin(void) const {
	   return array;
    }
    
    //returns the end of the array
    inline JSONNode ** end(void) const {
	   return array + mysize;
    }
    
    //makes sure that even after shirnking and expanding, the iterator is in same relative position
    struct iteratorKeeper {
    public:
	   #ifdef JSON_LIBRARY
		  iteratorKeeper(jsonChildren * pthis, JSONNode ** & position) : 
			 myRelativeOffset((json_index_t)(position - pthis -> array)),
	   #else
		  iteratorKeeper(jsonChildren * pthis, JSONNode ** & position, bool reverse = false) : 
			 myRelativeOffset(reverse ? (json_index_t)(pthis -> array + (size_t)pthis -> mysize - position) : (json_index_t)(position - pthis -> array)),
			 myReverse(reverse),
	   #endif
			 myChildren(pthis), 
			 myPos(position){}

	   ~iteratorKeeper(void){
		  #ifdef JSON_LIBRARY
			 myPos = myChildren -> array + myRelativeOffset;
		  #else
			 if (myReverse){
				myPos = myChildren -> array + myChildren -> mysize - myRelativeOffset;
			 } else {
				myPos = myChildren -> array + myRelativeOffset;
			 }
		  #endif
	   }
    private:
	   iteratorKeeper(const iteratorKeeper &);
	   iteratorKeeper & operator = (const iteratorKeeper &);
	   
	   jsonChildren * myChildren;
	   JSONNode ** & myPos;
	   json_index_t myRelativeOffset;
	   #ifndef JSON_LIBRARY
		  bool myReverse BITS(1);
	   #endif
    };
    
    //This function DOES NOT delete the item it points to
    inline void erase(JSONNode ** & position){
	   JSON_ASSERT(array, JSON_TEXT("erasing something from a null array 1"));
	   JSON_ASSERT(position >= array, JSON_TEXT("position is beneath the start of the array 1"));
	   JSON_ASSERT(position <= array + mysize, JSON_TEXT("erasing out of bounds 1"));
	   memmove(position, position + 1, (mysize-- - (position - array) - 1) * sizeof(JSONNode *));
	   iteratorKeeper ik(this, position);
	   shrink();
    }
    
    //This function DOES NOT delete the item it points to
    inline void erase(JSONNode ** & position, json_index_t number){
	   doerase(position, number);
	   iteratorKeeper ik(this, position);
	   shrink();
    }
    
    
    //This function DOES NOT delete the item it points to
    inline void erase(JSONNode ** position, json_index_t number, JSONNode ** & starter){
	   doerase(position, number);
	   iteratorKeeper ik(this, starter);
	   shrink();
    }
    
    #ifdef JSON_LIBRARY
	   void insert(JSONNode ** & position, JSONNode * item){
    #else
	   void insert(JSONNode ** & position, JSONNode * item, bool reverse = false){
    #endif
	   //position isnt relative to array because of realloc
	   JSON_ASSERT(position >= array, JSON_TEXT("position is beneath the start of the array insert 1"));
	   JSON_ASSERT(position <= array + mysize, JSON_TEXT("position is above the end of the array insert 1"));
	   {
		  #ifdef JSON_LIBRARY
			 iteratorKeeper ik(this, position);
		  #else
			 iteratorKeeper ik(this, position, reverse);
		  #endif
		  inc();
	   }
	   memmove(position + 1, position, (mysize++ - (position - array)) * sizeof(JSONNode *));
	   *position = item;
    }

    void insert(JSONNode ** & position, JSONNode ** items, json_index_t num){
	   JSON_ASSERT(position >= array, JSON_TEXT("position is beneath the start of the array insert 2"));
	   JSON_ASSERT(position <= array + mysize, JSON_TEXT("position is above the end of the array insert 2"));
	   {
		  iteratorKeeper ik(this, position);
		  inc(num);
	   }
	   const size_t ptrs = ((JSONNode **)(array + mysize)) - position;
	   memmove(position + num, position, ptrs * sizeof(JSONNode *));
	   memcpy(position, items, num * sizeof(JSONNode *));
	   mysize += num;
    }
    
    inline void reserve(json_index_t amount){
	   JSON_ASSERT(!array, JSON_TEXT("reserve is not meant to expand a preexisting array"));
	   JSON_ASSERT(!mycapacity, JSON_TEXT("reservec is not meant to expand a preexisting array"));
	   JSON_ASSERT(!mysize, JSON_TEXT("reserves is not meant to expand a preexisting array"));
	   array = json_malloc<JSONNode*>(mycapacity = amount);
    }

    inline void reserve2(json_index_t amount){
	   if (array){
		  if (mycapacity < amount) inc(amount - mycapacity);
	   } else {
		  reserve(amount);
	   }
    }
		  
    //shrinks the array to only as large as it needs to be to hold everything within it
    inline void shrink() {
	   if (mysize == 0){  //size is zero, we should completely free the array
		  libjson_free<JSONNode*>(array);  //free does checks for a null pointer, so don't bother checking
		  array = 0;
		  #ifdef JSON_LESS_MEMORY
			 } else {  //need to shrink it, using realloc
				JSON_ASSERT(array, JSON_TEXT("shrinking a null array that is not size 0"));
				array = json_realloc<JSONNode*>(array, mysize);
		  #endif  
	   }
	   mycapacity = mysize;
    }
JSON_PRIVATE
    //to make sure it's not copyable
    jsonChildren(const jsonChildren &);
    jsonChildren & operator = (const jsonChildren &);
    
    void deleteAll(void);  //implemented in JSONNode.cpp
    void doerase(JSONNode ** position, json_index_t number);
    
    JSONNode ** array;  //the expandable array

    json_index_t mysize;	     //the number of valid items
    json_index_t mycapacity;   //the number of possible items
};


#endif