src/core/common/appender.cpp

/*
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 *     derived from this software without specific prior written permission.
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/**
 * @file
 *   This file implements the `Appender` class.
 */

#include "appender.hpp"

namespace ot {

Appender::Appender(Message &aMessage)
    : mType(kMessage)
{
    mShared.mMessage.mMessage     = &aMessage;
    mShared.mMessage.mStartOffset = aMessage.GetLength();
}

Appender::Appender(uint8_t *aBuffer, uint16_t aSize)
    : mType(kBuffer)
{
    mShared.mBuffer.mStart = aBuffer;
    mShared.mBuffer.mCur   = aBuffer;
    mShared.mBuffer.mEnd   = aBuffer + aSize;
}

Error Appender::AppendBytes(const void *aBuffer, uint16_t aLength)
{
    Error error = kErrorNone;

    switch (mType)
    {
    case kMessage:
        error = mShared.mMessage.mMessage->AppendBytes(aBuffer, aLength);
        break;

    case kBuffer:
        VerifyOrExit(aLength <= static_cast<uint16_t>(mShared.mBuffer.mEnd - mShared.mBuffer.mCur),
                     error = kErrorNoBufs);
        memcpy(mShared.mBuffer.mCur, aBuffer, aLength);
        mShared.mBuffer.mCur += aLength;
        break;
    }

exit:
    return error;
}

uint16_t Appender::GetAppendedLength(void) const
{
    uint16_t length = 0;

    switch (mType)
    {
    case kMessage:
        length = mShared.mMessage.mMessage->GetLength() - mShared.mMessage.mStartOffset;
        break;

    case kBuffer:
        length = static_cast<uint16_t>(mShared.mBuffer.mCur - mShared.mBuffer.mStart);
        break;
    }

    return length;
}

void Appender::GetAsData(Data<kWithUint16Length> &aData)
{
    aData.Init(mShared.mBuffer.mStart, GetAppendedLength());
}

} // namespace ot