/** Write bytes to the buffer
* @param data pointer to the data to be written
* @param bytes number of bytes to be written
* @return true if was successful, otherwise false
*/
bool CircularBuffer::Write(const void * data, size_t bytes)
{
// If buffer B exists, write to it.
if( m_regionBPointer != NULL )
{
if( GetBFreeSpace() < bytes )
return false;
memcpy(&m_regionBPointer[m_regionBSize], data, bytes);
m_regionBSize += bytes;
return true;
}
// Otherwise, write to buffer A, or initialize buffer B depending on which has more space.
if( GetAFreeSpace() < GetSpaceBeforeA() )
{
AllocateB();
if( GetBFreeSpace() < bytes )
return false;
memcpy(&m_regionBPointer[m_regionBSize], data, bytes);
m_regionBSize += bytes;
return true;
}
else
{
if( !m_regionAPointer || GetAFreeSpace() < bytes )
return false;
memcpy(&m_regionAPointer[m_regionASize], data, bytes);
m_regionASize += bytes;
return true;
}
}
/** Returns the number of available bytes left.
*/
size_t CircularBuffer::GetSpace()
{
if( m_regionBPointer != NULL )
return GetBFreeSpace();
else
{
// would allocating buffer B get us more data?
if( GetAFreeSpace() < GetSpaceBeforeA() )
{
AllocateB();
return GetBFreeSpace();
}
// or not?
return GetAFreeSpace();
}
}
bool CircularBuffer::Write(const char* data, size_t bytes)
{
assert(mBuffer != nullptr);
/// Read와 반대로 B가 있다면 B영역에 먼저 쓴다
if (mBRegionPointer != nullptr)
{
if (GetBFreeSpace() < bytes)
return false;
memcpy(mBRegionPointer + mBRegionSize, data, bytes);
mBRegionSize += bytes;
return true;
}
/// A영역보다 다른 영역의 용량이 더 클 경우 그 영역을 B로 설정하고 기록
if (GetAFreeSpace() < GetSpaceBeforeA())
{
AllocateB();
if (GetBFreeSpace() < bytes)
return false;
memcpy(mBRegionPointer + mBRegionSize, data, bytes);
mBRegionSize += bytes;
return true;
}
/// A영역이 더 크면 당연히 A에 쓰기
else
{
if (GetAFreeSpace() < bytes)
return false;
memcpy(mARegionPointer + mARegionSize, data, bytes);
mARegionSize += bytes;
return true;
}
}