/// <summary>
/// Writes the chunk.
/// </summary>
/// <returns>The chunk.</returns>
/// <param name="buffer">Buffer.</param>
/// <param name="offset">Offset.</param>
/// <param name="count">Count.</param>
public int WriteChunk(byte[] buffer, int offset, int count)
{
var top = GetCurrentContext();
if (top == null)
{
return((int)ParserStatus.EndOfFile);
}
if (IdUtility.IsGenericId(top.Id))
{
return((int)ParserStatus.NotIFF);
}
return(WriteChunkInternal(top, buffer, offset, count));
}
/// <summary>
///Test current state and advance to the next state. State is one of:
/// - Start of file if iff_NewIO is TRUE.
/// Push initial chunk, get its info and return.
///
/// - Poised at end of chunk if iff_Paused is TRUE.
/// PopChunk() the current context. The top context will then be a generic
/// or end of file. Return EOF if the latter. If this chunk is exhausted,
/// pause again and return, otherwise push new chunk and return.
///
/// - Inside a generic chunk.
/// Push a new context and return.
///
/// - Inside a non-generic chunk.
/// Pause and return.
/// </summary>
/// <returns>The state.</returns>
private int NextState()
{
ContextNode top;
int err;
uint topId;
/* deal with the case of the first chunk */
if (_newIO)
{
err = PushChunkRead(true);
_newIO = false;
_paused = false;
if (err < 0)
{
return(err);
}
top = GetCurrentContext();
if ((top.Id != GenericChunkIds.ID_FORM) &&
(top.Id != GenericChunkIds.ID_CAT) &&
(top.Id != GenericChunkIds.ID_LIST) &&
(!IsContainerId(top.Id)))
{
return((int)ParserStatus.NotIFF);
}
if ((top.Size & 1) == 1)
{
/* containers must inherently be word-aligned */
return((int)ParserStatus.Mangled);
}
return(ReadGenericType());
}
/* In the PAUSE state, do the deferred PopChunk() */
if (_paused)
{
err = PopChunk();
if (err < 0)
{
return(err);
}
_paused = false;
}
/* If no top context node then the file is exhausted. */
if ((top = GetCurrentContext()) == null)
{
return((int)ParserStatus.EndOfFile);
}
topId = top.Id;
if (IdUtility.IsGenericId(topId) || IsContainerId(topId))
{
/* If inside a generic chunk, and not exhausted, push a subchunk. */
if (top.Offset < top.Size)
{
err = PushChunkRead(false);
if (err < 0)
{
return(err);
}
top = GetCurrentContext();
/* If non-generic, we're done, but if the containing chunk is not
* FORM or PROP, it's an IFF syntax error.
*/
if (!IdUtility.IsGenericId(top.Id))
{
if ((topId != GenericChunkIds.ID_FORM) &&
(topId != GenericChunkIds.ID_PROP) &&
(!IsContainerId(topId)))
{
return((int)ParserStatus.SyntaxError);
}
return(0);
}
/* If this new chunk is generic, and is a PROP, test to see if it's
* in the right place -- containing chunk should be a LIST.
*/
if ((top.Id == GenericChunkIds.ID_PROP) &&
(topId != GenericChunkIds.ID_LIST))
{
return((int)ParserStatus.SyntaxError);
}
/* since it's an ok generic, get its type and return */
return(ReadGenericType());
}
else if (top.Offset != top.Size)
{
/* If not exhaused, this is a junky IFF file */
return((int)ParserStatus.Mangled);
}
}
/* If the generic is exhausted, or this is a non-generic chunk,
* enter the pause state and return flag.
*/
_paused = true;
return((int)ParserStatus.EndOfContext);
}
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);
}
