redAcore/ItemBufferCore.cpp

/*
 * BufferCore.h
 *
 *  Created on: 22 July 2017
 *      Author: wentzelc
 */

// Standard C/C++ Libraries
#include <stdlib.h>
#include <string.h>

// redA Libraries
#include "ItemBufferCore.h"

//---------------------------------------------------------------------------

//***** Function Prototypes *****//

CItemBufferCore::CItemBufferCore( bool pCopyEntries )
{
    // Parameters
    CopyEntries = pCopyEntries;

    // Clear Event list
    FirstItem   = NULL;
    LastItem    = &FirstItem;
}
//---------------------------------------------------------------------------

CItemBufferCore::~ CItemBufferCore()
{
    // Free Event List
    DeleteAll();
}
//---------------------------------------------------------------------------

TBufferItem *  CItemBufferCore::CreateItem( void * Entry, int Size )
{
    TBufferItem    * BufferItem;

    // Create structure
    if (!(BufferItem = (TBufferItem *)calloc( sizeof(TBufferItem), 1 )))
        return NULL;

    // Create Entry
    BufferItem->Size = Size;
    if (CopyEntries)
    {
        // Create copy
        if ((BufferItem->Entry = (void *)malloc( sizeof(char)*Size ))) {
            // Copy Value
            memcpy( BufferItem->Entry, Entry, Size );
        }
        else {
            // Fail
            free( BufferItem );
            return NULL;
        }
    }
    else
    {
        // Use pointer as is
        BufferItem->Entry = Entry;
    }

    // Return empty structure
    return BufferItem;
}
//---------------------------------------------------------------------------

bool CItemBufferCore::DestroyItem( TBufferItem ** BufferItem )
{
    // Check if valid pointer
    if (!BufferItem || !*BufferItem)
        return false;

    // Destroy pointers
    if (CopyEntries && (*BufferItem)->Entry)
        DestroyEntry( &((*BufferItem)->Entry) );

    // Destroy structure
    free( *BufferItem );
    *BufferItem = NULL;

    return true;
}
//---------------------------------------------------------------------------

bool  CItemBufferCore::DestroyEntry( void ** Entry )
{
    // Verify pointer
    if (!Entry || !*Entry)
        return false;

    // free & clear memory
    free( *Entry );
    *Entry = NULL;

    return true;
}
//---------------------------------------------------------------------------

bool  CItemBufferCore::Push( void * Entry, int Size )
{
    // Verify pointer
    if (!Entry || !Size)
        return false;

    // Try to create an add item to list
    if (!(*LastItem = CreateItem( Entry, Size )))
        return false;

    // Move Next entry reference
    LastItem = &((*LastItem)->NextItem);
    return true;
}
//---------------------------------------------------------------------------

void *  CItemBufferCore::Pop( int * Size )
{
    void          * Entry;

    // Return entry
    if ((Entry = Peek( Size ))) {
        Delete();
    }

    // return event
    return Entry;
}
//---------------------------------------------------------------------------

void *  CItemBufferCore::Peek( int * Size )
{
    void          * Entry;

    // Check if any events available
    if (!FirstItem) {
        if (Size)  *Size = 0;
        return NULL;
    }

    // Get entry and size
    Entry = FirstItem->Entry;
    if (Size)  *Size = FirstItem->Size;

    // return event
    return Entry;
}
//---------------------------------------------------------------------------

bool  CItemBufferCore::Delete()
{
    TBufferItem     * BufferItem;

    // check if buffer empty
    if (!FirstItem)
        return false;

    // Delete event from list
    BufferItem = FirstItem;
    FirstItem = FirstItem->NextItem;

    // Check if last event pointer still correct
    if (!FirstItem)
        LastItem = &FirstItem;

    // Destroy entry and holder
    if (CopyEntries)
        DestroyEntry( &(BufferItem->Entry) );
    free( BufferItem );

    return true;
}
//---------------------------------------------------------------------------

void  CItemBufferCore::DeleteAll()
{
    TBufferItem     * NextItem;

    while (FirstItem)
    {
        NextItem = FirstItem->NextItem;
        DestroyItem( &FirstItem );
        FirstItem = NextItem;
    }
}
//---------------------------------------------------------------------------