/// <summary>
/// Returns the number of free bytes in the given arena.
/// </summary>
/// <param name="inArena"></param>
/// <returns></returns>
static public int ArenaFreeBytes(ArenaHandle inArena)
{
ArenaHeader *header = (ArenaHeader *)inArena.HeaderStart;
if (header != null)
{
return((int)header->SizeRemaining);
}
return(0);
}
/// <summary>
/// Resets the given allocation arena.
/// </summary>
static public void ResetArena(ArenaHandle inArena)
{
ArenaHeader *header = (ArenaHeader *)inArena.HeaderStart;
if (header != null)
{
header->SizeRemaining = header->Size;
header->CurrentPtr = header->StartPtr;
}
}
/// <summary>
/// Returns the size of the given arena.
/// </summary>
static public int ArenaSize(ArenaHandle inArena)
{
ArenaHeader *header = (ArenaHeader *)inArena.HeaderStart;
if (header != null)
{
return((int)header->Size);
}
return(0);
}
/// <summary>
/// Creates a linear allocation arena.
/// </summary>
static public ArenaHandle CreateArena(int inSize, StringHash32 inName = default)
{
uint arenaSize = AlignUp32((uint)inSize);
int totalSize = (int)(ArenaHeader.HeaderSize + arenaSize);
void * block = Alloc(totalSize);
ArenaHeader *blockHeader = (ArenaHeader *)block;
byte * dataStart = (byte *)block + ArenaHeader.HeaderSize;
ArenaHeader header;
header.Name = inName;
header.StartPtr = header.CurrentPtr = dataStart;
header.Size = header.SizeRemaining = arenaSize;
*blockHeader = header;
return(new ArenaHandle(blockHeader));
}
/// <summary>
/// Allocates from the given arena.
/// </summary>
static public void *Alloc(ArenaHandle inArena, int inLength)
{
ArenaHeader *header = (ArenaHeader *)inArena.HeaderStart;
if (header == null)
{
return(null);
}
if (header->SizeRemaining < inLength)
{
Log.Warn("[Unsafe] Unable to allocate region of size {0} in arena {1} (size remaining {2})", inLength, header->Name, header->SizeRemaining);
return(null);
}
void *addr = header->CurrentPtr;
header->CurrentPtr += inLength;
header->SizeRemaining -= (uint)inLength;
return(addr);
}
/// <summary>
/// Allocates from the given arena with the given alignment.
/// </summary>
static public void *AllocAligned(ArenaHandle inArena, int inLength, uint inAlignment)
{
ArenaHeader *header = (ArenaHeader *)inArena.HeaderStart;
if (header == null)
{
return(null);
}
byte *aligned = (byte *)AlignUpN((ulong)header->CurrentPtr, inAlignment);
uint padding = (uint)(aligned - header->CurrentPtr);
if (header->SizeRemaining < padding + inLength)
{
Log.Warn("[Unsafe] Unable to allocate region of size {0} and alignment {1} in arena {2} (size remaining {3})", inLength, inAlignment, header->Name, header->SizeRemaining);
return(null);
}
header->CurrentPtr += inLength + padding;
header->SizeRemaining -= (uint)inLength + padding;
return(aligned);
}
internal ArenaHandle(ArenaHeader *inHeader)
{
HeaderStart = inHeader;
}
