CCArrayList.h

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/*
 * Copyright 2015 Brendan Bruner
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * bbruner@ualberta.ca
 * July 3, 2016
 */
#ifndef UTIL_CIARRAYLIST_H_
#define UTIL_CIARRAYLIST_H_

#include "CIList.h"
#include <CError.h>


/* There is one bit for every element in the list do indicate full/empty status.
 * To get the number of bytes required for a one to one
 * map of element indices to bits: divide the max size of the list by the
 * number of bits in a byte, then add one to ensure
 * a round up. 
 */
#define CCARRAY_LIST_MASK_SIZE( list_size ) (((list_size) >> 3) + 1)

/* Macro which resolves to the number of bytes that must be
 * allocated for a list of length 'list_length' with elements of size
 * 'element_length'.
 */
#define CCARRAY_LIST_SIZE( element_length, list_length )                \
    (((list_length) * (element_length)) + CCARRAY_LIST_MASK_SIZE(list_length))


/************************************************************************/
/* Class and vtable decalre.                        */
/************************************************************************/
struct CCArrayList
{
    /* Super class must always be first member */
    /* of a C class struct. */
    struct CObject cobject;

    /* Implementing the CIList interface. */
    struct CIList cilist;

    /* Private member variables. */
    struct
    {
        /* Base address of memory used for the lsit
         */
        char* list_base;

        /* Defines a bit mask to indicate the empty/full
         * status of all list elements. For example, bit 3
         * indicates if the element at index 3 is empty/full.
         */
        unsigned char* list_mask;
        
        size_t max_size;
        size_t current_size;
        size_t element_size;

        /* Holds the last known empty index within the list.
         * This is a cache to speed up the CIList_Add( ) 
         * implementation.
         */
        size_t add_index;

        /* Used in destructor.
         */
        CBool is_static;
    } _;
};

struct CCArrayList_VTable
{
    /* Space for a copy of the super class' virtual table must  */
    /* be the first member of a class virtual table declaration. */
    struct CObject_VTable  cobject_override;

    /* Since we are overriding the destructor, we need to keep */
    /* keep a reference to the super class' implementation of */
    /* the destructor. */
    const struct CObject_VTable* cobject;

    /* Space for a copy of the implemented interface's virtual table */
    struct CIList_VTable cilist_override;
};

const struct CCArrayList_VTable* CCArrayList_GetVTable( );


/************************************************************************/
/* Constructor                              */
/************************************************************************/
CError CCArrayList( struct CCArrayList* self, size_t element_size, size_t max_size );

CError CCArrayListStatic
(
    struct CCArrayList* self,
    size_t element_size,
    size_t max_size,
    void* memory
);

#endif /* UTIL_CIARRAYLIST_H_ */