builtins/history.h

#ifndef HISTORY
#define HISTORY

/*
 * ================ *
 * === Includes === *
 * ================ *
 */

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

/*
 * =================== *
 * === Definitions === *
 * =================== *
 */

#define BLOCKS 64
#define BLOCK_SIZE 8

/*
 * ==============
 * === Macros ===
 * ==============
 */

// Shortcut for the number of commands in history
#define h_len() h_meta_len

/*
 * ===============
 * === Typedef ===
 * ===============
 */

// A struct to represent the meta blocks of this command history management
// module
typedef struct h_metablock_str
{
    // Contains a pointer to the next block
    struct h_metablock_str* next;

    // Contains the length of the command
    int length;

    // Contains the indices of the data in the bitmap and data structure
    int dataindex[15];
} h_metablock;

/*
 * =============== *
 * === Globals === *
 * =============== *
 */

short h_bitmap[BLOCKS]; // This is the bitmap
char h_data[BLOCKS][BLOCK_SIZE]; // This is the block of data

// h_meta is the pointer to the first meta-block
h_metablock* h_meta = NULL;
int h_meta_len = 0;

/*
 * ================= *
 * === Functions === *
 * ================= *
 */

/*
 * Add the input params to input history
 */
void h_add(char** param);

/*
 * Allocate space in the data blocks for the input amount of blocks
 */
int* h_allocate(int blocks);

/*
 * Remove the oldest command in history
 */
void h_removeoldest();

/*
 * Reconstructs and returns the string for the input meta block
 */
char* h_meta_getcmd(h_metablock* metablock);

/*
 * Calls h_meta_getcmd on the nth newest command in history and returns the
 * result
 */
char* h_cmd_index(int index);

/*
 * Free all resources allocated by the history module
 */
void h_free();

#endif