alloc.c

#include "alloc.h"

#include <stdio.h>
#include <stdint.h>
#include <string.h>

void *m_malloc(uint32_t size){
  meta* temp;
  if(size%4 != 0)
    size += (4-size%4);

  if(head == NULL){
    temp = sbrk(size);
    temp -> next_memory = NULL;
    temp -> prev_memory = NULL;
    temp -> size = size;
    temp -> free = 0;
    strcpy(temp -> comment,tmp_comment);
    temp -> fit= fit;

    head = temp;
    first = temp;
  }
  else{
    meta* prev = NULL;
    meta* next = NULL;
    meta* tmp_head = head;
      while(1){
	if(tmp_head->next_memory == NULL){
	  if(prev == NULL){
	    prev = tmp_head;
	  }
	  break;
	}
	else if(tmp_head -> next_memory -> free == 1 && tmp_head -> next_memory -> size > size){
          if( prev == NULL){
	    prev = tmp_head;
	    if(fit == "F")
	      break;
	  }
	  else{
	    if(fit == "B")
	      prev = (prev -> size < tmp_head -> next_memory -> size) ? prev : tmp_head;
	    else if(fit == "W")
	      prev = (prev -> size > tmp_head -> next_memory -> size) ? prev : tmp_head;
	  }
	}
	tmp_head = tmp_head-> next_memory;
      }
    tmp_head = prev -> next_memory;
    next = tmp_head -> next_memory;
    if(tmp_head -> size == size){
      prev -> next_memory -> free = 0;
    }
    else{
      temp -> prev_memory = prev;
      temp -> next_memory = tmp_head;
      temp -> size = size;
      temp -> free = 0;
      strcpy(temp -> comment,tmp_comment);
      temp -> fit = fit;

      tmp_head -> size -= size; 
      tmp_head -> prev_memory = temp;

      prev -> next_memory = temp;
    }
  }
}

void m_realoc(void* p,uint32_t size){
  if(size%4 != 0)
    size += (4-size%4);

  int index = *(int *)p;
  int count = 0;
  meta* temp = head;

  while(1){
    if(count == index)
      break;
    
    temp = temp -> next_memory;
    if(temp -> free == 0)
      count++;
  }
  if(temp -> next_memory == NULL){
    temp -> size = size;
  }
  else if(size < (temp -> next_memory -> size) + temp -> size){
	temp -> next_memory -> size -= (size - temp->size);
	temp -> size = size;
  }
  else if(size = (temp -> next_memory -> size) + temp -> size){
  	temp -> size = size;
	temp -> next_memory = temp -> next_memory -> next_memory;
  }
  else
    m_malloc(size);
}

void m_free(void *ptr){
  int index = *(int *)ptr;
  int count = 0;
  meta* tmp_head;
  meta* temp = head;
  int size = head -> size;
  int break_point = 0;
   
    if(temp -> next_memory != NULL){
      if(temp -> next_memory -> free == 1){
        size += temp -> next_memory -> size;
        tmp_head -> next_memory = temp -> next_memory -> next_memory;
	temp -> next_memory -> next_memory -> prev_memory = tmp_head;
      }
    }
    else
      tmp_head -> next_memory = NULL;
      
    if(temp -> prev_memory != NULL){
      if(temp -> prev_memory -> free == 1){
        size += temp -> prev_memory -> size;
        tmp_head -> prev_memory = temp -> prev_memory -> prev_memory;
	temp -> prev_memory -> prev_memory -> next_memory = tmp_head;
      }
    }
    else
      tmp_head -> prev_memory = NULL;
    
  tmp_head -> free = 1;
  tmp_head -> size = size;
  strcpy(temp -> comment," ");
  if( index == 0)
    head == tmp_head -> next_memory;
}


void read(){
  meta* temp = first;
  
  while(1){
    if(temp -> next_memory == NULL)
      break;

    printf("%d %d %s\n", temp -> free, temp -> size, temp -> comment);
  }
}