/***ここからマージソート***/
void m_sort(int first, int last){
if(first < last){
m_sort(first, (first + last)/2);
m_sort(((first + last)/2) + 1, last);
merge_two(first, (first + last)/2, ((first + last)/2) + 1, last);
}
}
Node * merge_two(Node * head)
{//merge the last two nodes in the list into one tree node
if (head -> next -> next == NULL)
{//we are at the left child to merge, head -> next is the right child
Node * newParent = create_node(0);
newParent -> left = head;
newParent -> right = head -> next;
newParent -> left -> next = NULL;
return (newParent);
}
//head -> next becomes the new parent
head -> next = merge_two(head -> next);
return (head);
}
Node * read_header(FILE * fporig)
{//reads the header from the beginning of the .huff file and builds the huffman tree
int donecheck = 0;
int count;
unsigned char readchar;
Node * root = NULL;
Node * newNode = NULL;
Node * head = NULL;
while (!donecheck)
{//while were not done, keep reading header
read_bit(fporig);
if (bit)
{//found a leaf in the header, read in the 8-bit unsigned char
readchar = 0;
read_bit(fporig);
readchar |= bit; //put in first bit
for (count = 0; count < 7; ++count)
{//loop 7 times to save the next 7 bits
readchar <<= 1;
read_bit(fporig);
readchar |= bit;
}
//create a list of nodes where the last two are the lowest in the tree
newNode = create_node(readchar);
head = add_list(head, newNode);
} else
{//we are at a non-leaf node
if (head == NULL)
{
fprintf(stderr, "\nERROR! FIRST BIT IN HEADER SHOULD NOT BE 0. WILL SEGFAULT.\n\n");
}
if (head -> next == NULL)
{//the list has become the tree
root = head;
donecheck = 1;
} else
{//have atleast 2 nodes in the list, merge the 2 furthest to the right
head = merge_two(head);
}
}
}
//done reading the header, root points to our tree, last 0 bits are padding
return (root);
}
