#include "mem.h"
#include <stdio.h>

#define BASE_HEAP_SIZE 2000
#define HEAP_EXPANSION_SIZE 1000

int memory_allocated = 0;
int heap_size = 0;
char *heap = 0;
int heap_offset;

void mem_error()
{
	if(heap != 0)
	{
		printf("Dumping Memory To File\n");
		mem_dump("lastrun.dump");
		printf("Freeing Heap\n");
		free(heap);
	}
	exit(1);
}

void mem_initialize()
{
	heap = malloc(BASE_HEAP_SIZE);
	memset(heap,0,BASE_HEAP_SIZE);
	heap_size = BASE_HEAP_SIZE;
}

void mem_dump(const char *file)
{
	FILE *f = fopen(file, "wb");
	if(!f) return;

	fwrite(heap,1,memory_allocated,f);

	fclose(f);
}

int mem_increaseHeapSize()
{

}

void *mem_alloc(int size)
{
	int remain = heap_size - memory_allocated;
	int position = 0;
	if(size > 127)
	{
		printf("Unable to allocate memory[%i]\
, max allocation size is 127",size);
		mem_error();
	}
	if(remain <= 0 || size > remain)
	{
		printf("Unable to allocate memory[%i]\
, heap is full\n",size);
		mem_error();
	}
	while(position < heap_size)
	{
		char ident = (char) *(heap + position);
		char iSize = ident & 127;
		char bAllocated = ident & 128;
		if(!bAllocated)
		{
			if(iSize == 0 || iSize == size)
			{
				*(heap + position) = (size & 127) | 128;
				memory_allocated += size;
				return (heap + position + 1);
			}
		}
		position += iSize + 1;
	}

	printf("Unable to allocate memory, end of heap\n");
	mem_error();

	return 0;
}

void *mem_put(void *o, int size)
{
	void *mem = mem_alloc(size);
	memcpy(mem,o,size);
	return mem;
}

void mem_free(void *mem)
{
	int addr = mem - (void *) heap;
	char ident = (char) *(heap + addr - 1);
	char iSize = ident & 127;
	char bAllocated = ident & 128;
	if(!bAllocated) return;

	printf("%i SIZE\n",iSize);

	memory_allocated -= iSize;
	*(heap + addr - 1) = ident & 127;
}

void mem_destroy()
{
	free(heap);
}

int total_allocated()
{
	return memory_allocated;
}