#include "block_header.h"

/**
 * \brief Get the address of the block header of a memory block.
 *
 * \param ptr The data part of the memory block.
 */
static block_header_t * get_header(void *ptr);

static block_header_t * get_header(void *ptr) {
    return (block_header_t *) ((char *) ptr - HEADER_SIZE);
}

void * get_next(void *ptr) {
    return get_header(ptr)->next;
}

size_t get_size(void *ptr) {
    return get_header(ptr)->size >> 1;
}

size_t get_size_availability(void *ptr) {
    return get_header(ptr)->size;
}

void set_size(void *ptr, size_t size) {
    get_header(ptr)->size = size << 1;
}

void set_requested_size(void *ptr, size_t size) {
    get_header(ptr)->requested_size = size;
}

void set_next(void *ptr, void *next_block) {
    get_header(ptr)->next = next_block;
}

bool is_previous_free(void *ptr) {
    return (bool) (get_header(ptr)->previous_size & 1);
}

void set_previous_size(void *ptr, size_t previous_size) {
    get_header(ptr)->previous_size = previous_size;
}

size_t get_previous_size(void *ptr) {
    return get_header(ptr)->previous_size >> 1;
}

void * get_previous(void *ptr) {
    return (void *) ((char *) ptr - get_previous_size(ptr));
}

void remove_block(void *block, void *starting_node) {

    void *current_node, *previous_node;

    // Traverse a list starting from the starting node until block is found.
    for(current_node = starting_node; current_node != NULL; 
            current_node = get_next(current_node)) {
        if(current_node == block) {
            if(current_node == starting_node) {
                starting_node = get_next(block);
            } else {
                set_next(previous_node, get_next(block));
            }
            break;
        }
        previous_node = current_node;
    }
}