private int PushChunkWrite(uint type, uint id, uint size)
{
ContextNode cn;
int err;
uint parentType;
Chunk chunk;
SmallChunk smallChunk;
bool firstChunk;
byte[] buffer;
if ((cn = GetCurrentContext()) != null)
{
parentType = cn.Type;
firstChunk = false;
}
else if (_newIO)
{
parentType = 0;
firstChunk = true;
_newIO = false;
/* first chunk must be FORM, CAT, or LIST */
if ((id != GenericChunkIds.ID_FORM) &&
(id != GenericChunkIds.ID_CAT) &&
(id != GenericChunkIds.ID_LIST))
{
return((int)ParserStatus.NotIFF);
}
}
else
{
return((int)ParserStatus.EndOfFile);
}
if (!IdUtility.IsGoodId(id))
{
return((int)ParserStatus.SyntaxError);
}
if (IdUtility.IsGenericId(id))
{
if (id == GenericChunkIds.ID_PROP)
{
/* the containing context for PROP must be a LIST */
if (cn.Id != GenericChunkIds.ID_LIST)
{
return((int)ParserStatus.SyntaxError);
}
}
/* Generic ID. Check the validity of its subtype. */
if (!IdUtility.IsGoodType(type))
{
return((int)ParserStatus.NotIFF);
}
}
else
{
/* Non-generic ID. Containing context must be PROP or FORM or container */
if ((cn.Id != GenericChunkIds.ID_FORM) &&
(cn.Id != GenericChunkIds.ID_PROP) &&
(!IsContainerId(cn.Id)))
{
return((int)ParserStatus.SyntaxError);
}
}
/* Write the chunk header: ID and size (if IFF_SIZE_UNKNOWN, it will
* be patched later by PopChunkW()).
*/
if ((size >= (uint)ChunkSize.Reserved) &&
(size != (uint)ChunkSize.Unknown32Bit))
{
chunk.Id = id;
chunk.Filler = (uint)ChunkSize.Known64Bit;
chunk.Size = size;
buffer = Marshal.StructToBytes(chunk);
if (firstChunk)
{
err = _streamOperations.Write(_ioContext, buffer, 0, buffer.Length);
}
else
{
/* Update parent's count of bytes written. */
err = WriteChunkInternal(cn, buffer, 0, buffer.Length);
}
}
else
{
smallChunk.Id = id;
smallChunk.Size = size;
buffer = Marshal.StructToBytes(smallChunk);
if (firstChunk)
{
err = _streamOperations.Write(_ioContext, buffer, 0, buffer.Length);
}
else
{
/* Update parent's count of bytes written. */
err = WriteChunkInternal(cn, buffer, 0, buffer.Length);
}
}
if (err < 0)
{
return(err);
}
/* Allocate and fill in a ContextNode for the new chunk */
cn = new ContextNode(id, 0);
cn.Size = size;
cn.Offset = 0;
cn.CurrentSize = 0;
_stack.AddHead(cn);
/* For generic chunks, write the type out now that
* the chunk context node is initialized.
*/
if (IdUtility.IsGenericId(id) || IsContainerId(id))
{
if (IdUtility.IsGenericId(id))
{
var bigEndianType = type;
Swap(ref bigEndianType);
buffer = BitConverter.GetBytes(bigEndianType);
err = WriteChunkInternal(cn, buffer, 0, buffer.Length);
cn.Type = type;
}
else
{
cn.Type = 0;
}
}
else
{
cn.Type = parentType;
}
return(err);
}
private int PushChunkRead(bool firstChunk)
{
Chunk chunk;
int err;
byte[] buffer;
var top = GetCurrentContext();
if (top == null && !firstChunk)
{
return((int)ParserStatus.EndOfFile);
}
var type = top != null ? top.Type : 0;
if (firstChunk)
{
buffer = new byte[Marshal.SizeOf <SmallChunk>()];
err = _streamOperations.Read(_ioContext, buffer, 0, buffer.Length);
if (err != Marshal.SizeOf <SmallChunk>())
{
if (err >= 0)
{
err = (int)ParserStatus.NotIFF;
}
return(err);
}
var smallChunk = Marshal.BytesToStruct <SmallChunk>(buffer);
chunk.Id = smallChunk.Id;
chunk.Size = smallChunk.Size;
if (chunk.Size == (ulong)ChunkSize.Known64Bit)
{
buffer = new byte[chunk.Size];
err = _streamOperations.Read(_ioContext, buffer, 0, buffer.Length);
if ((ulong)err != chunk.Size)
{
if (err >= 0)
{
err = (int)ParserStatus.NotIFF;
}
return(err);
}
chunk.Size = BitConverter.ToUInt32(buffer, 0);
}
else if (chunk.Size >= (ulong)ChunkSize.Reserved)
{
return((int)ParserStatus.Mangled);
}
}
else
{
/* Using ReadChunk() causes these bytes to go into the
* parent's scan count
*/
buffer = new byte[Marshal.SizeOf <SmallChunk>()];
err = ReadChunk(buffer, 0, buffer.Length);
if (err != Marshal.SizeOf <SmallChunk>())
{
if (err >= 0)
{
err = (int)ParserStatus.PrematureEndOfFile;
}
return(err);
}
var smallChunk = Marshal.BytesToStruct <SmallChunk>(buffer);
chunk.Id = smallChunk.Id;
chunk.Size = smallChunk.Size;
if (chunk.Size == (ulong)ChunkSize.Known64Bit)
{
buffer = new byte[chunk.Size];
err = _streamOperations.Read(_ioContext, buffer, 0, buffer.Length);
if ((ulong)err != chunk.Size)
{
if (err >= 0)
{
err = (int)ParserStatus.NotIFF;
}
return(err);
}
chunk.Size = BitConverter.ToUInt32(buffer, 0);
}
else if (chunk.Size >= (ulong)ChunkSize.Reserved)
{
return((int)ParserStatus.Mangled);
}
if (chunk.Size > (top.Size - top.Offset))
{
return((int)ParserStatus.Mangled);
}
}
if (IdUtility.IsGoodId(chunk.Id))
{
try {
var contextNode = new ContextNode(chunk.Id, type);
contextNode.Size = chunk.Size;
contextNode.Offset = 0;
contextNode.CurrentSize = chunk.Size;
_stack.AddHead(contextNode);
return(0);
} catch (OutOfMemoryException) {
return((int)ParserStatus.OutOfMemory);
}
}
if (this._newIO)
{
return((int)ParserStatus.NotIFF);
}
return((int)ParserStatus.SyntaxError);
}