/*
 * Copyright 2005, Ingo Weinhold <bonefish@cs.tu-berlin.de>.
 * All rights reserved. Distributed under the terms of the MIT License.
 */

#include <boot/net/ChainBuffer.h>

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

#include <util/kernel_cpp.h>

// constructor
ChainBuffer::ChainBuffer(void *data, uint32 size, ChainBuffer *next,
        bool freeData)
{
        _Init(data, size, next,
                CHAIN_BUFFER_ON_STACK | (freeData ? CHAIN_BUFFER_FREE_DATA : 0));
}

// destructor
ChainBuffer::~ChainBuffer()
{
        _Destroy();
}

// DetachNext
ChainBuffer *
ChainBuffer::DetachNext()
{
        if (!fNext)
                return NULL;

        ChainBuffer *next = fNext;

        fNext = NULL;
        next->fFlags |= CHAIN_BUFFER_HEAD;
        fTotalSize = fSize;

        return next;
}

// Append
void
ChainBuffer::Append(ChainBuffer *next)
{
        if (!next)
                return;

        if (fNext)
                fNext->Append(next);
        else
                fNext = next;

        fTotalSize = fSize + fNext->fTotalSize;
}

// Flatten
void
ChainBuffer::Flatten(void *_buffer) const
{
        if (uint8 *buffer = (uint8*)_buffer) {
                if (fData && fSize > 0) {
                        memcpy(buffer, fData, fSize);
                        buffer += fSize;
                }

                if (fNext)
                        fNext->Flatten(buffer);
        }
}

// _Init
void
ChainBuffer::_Init(void *data, uint32 size, ChainBuffer *next, uint32 flags)
{
        fFlags = flags | CHAIN_BUFFER_HEAD;
        fSize = size;
        fTotalSize = fSize;
        fData = data;
        fNext = NULL;
        Append(next);
}

// _Destroy
void
ChainBuffer::_Destroy()
{
        ChainBuffer *next = fNext;
        fNext = NULL;
        if ((fFlags & CHAIN_BUFFER_FREE_DATA) && fData) {
                free(fData);
                fData = NULL;
        }

        if (!(fFlags & CHAIN_BUFFER_EMBEDDED_DATA))
                fSize = 0;
        fTotalSize = fSize;

        if (next) {
                if (next->fFlags & CHAIN_BUFFER_ON_STACK)
                        next->_Destroy();
                else
                        delete next;
        }
}