/// <summary>
/// Searches for a top-level chunk with a given id inside of the given container chunk.
/// This method assumes that starting with the offset given, there is nothing in the container chunk besides
/// chunks written one after another. Any stray data between chunks is unexpected.
/// </summary>
/// <param name="container">The chunk to search within.</param>
/// <param name="id">The id of the chunk to look for.</param>
/// <param name="start">The starting offset from the beginning of the container chunk data to apply.</param>
/// <returns>The header of the chunk found, or a header with an offset of -1 if none is found.</returns>
public MDFChunkHeader findNextChunk(MDFChunkHeader container, UInt32 id, long start)
{
long origPos = reader.BaseStream.Position;
long curPos = start + container.offset + sizeof(UInt32) + sizeof(UInt32);
MDFChunkHeader temp;
while (curPos < container.offset + container.size)
{
reader.BaseStream.Seek(curPos, SeekOrigin.Begin);
if ((temp = peekChunkHeader()).id == id)
{
reader.BaseStream.Seek(origPos, SeekOrigin.Begin);
return(temp);
}
else
{
curPos = temp.offset + temp.size;
}
}
reader.BaseStream.Seek(origPos, SeekOrigin.Begin);
temp.offset = -1;
temp.id = 0;
temp.size = 0;
return(temp);
}
/// <summary>
/// Writes the chunk header and returns a new header with an offset field marking the place where the header was written.
/// </summary>
/// <param name="header"></param>
public MDFChunkHeader writeChunkHeader(MDFChunkHeader header)
{
header.offset = writer.BaseStream.Position;
writer.Write(header.id);
writer.Write(header.size);
return(header);
}
/// <summary>
/// Calculates the size of the chunk from the current file position back to the start of the chunk header and writes that size into the chunk header.
/// The size is corrected straight into the file, and the file position is reset back to the end of the chunk.
/// </summary>
/// <param name="header">The chunk header of this chunk.</param>
/// <returns>The updated chunk header structure, with the new corrected size field (just in case anyone needs it).</returns>
public MDFChunkHeader writeCalculatedChunkSize(MDFChunkHeader header)
{
long curPos = writer.BaseStream.Position;
header.size = (UInt32)(curPos - header.offset);
writer.BaseStream.Seek(header.offset, SeekOrigin.Begin);
header = writeChunkHeader(header);
writer.BaseStream.Seek(curPos, SeekOrigin.Begin);
return(header);
}
/// <summary>
/// Returns true if the given chunk is empty.
/// </summary>
/// <param name="header">The header of the chunk to test.</param>
/// <returns>true if the given chunk is completely empty (in which the size field only accounts for the header), false otherwise.</returns>
public bool isEmpty(MDFChunkHeader header)
{
if (header.size == sizeof(UInt32) + sizeof(UInt32))
{
return(true);
}
else
{
return(false);
}
}
/// <summary>
/// Skips the current chunk by seeking past its size.
/// </summary>
/// <param name="chunk">The header of the chunk to skip over.</param>
public void skipChunk(MDFChunkHeader chunk)
{
reader.BaseStream.Seek(chunk.offset + chunk.size, SeekOrigin.Begin);
}
/// <summary>
/// Skips over the given chunk header, positioning the file position at the beginning of the chunk's data.
/// </summary>
/// <param name="header">The chunk header of the chunk to enter.</param>
public void enterChunk(MDFChunkHeader header)
{
reader.BaseStream.Seek(header.offset + sizeof(UInt32) + sizeof(UInt32), SeekOrigin.Begin);
}
/// <summary>
/// Searches for a top-level chunk with a given id inside of the given container chunk.
/// This method assumes that starting with the offset given, there is nothing in the container chunk besides
/// chunks written one after another. Any stray data between chunks is unexpected.
/// </summary>
/// <param name="container">The chunk to search within.</param>
/// <param name="id">The id of the chunk to look for.</param>
/// <param name="start">The starting offset from the beginning of the container chunk data to apply.</param>
/// <returns>The header of the chunk found, or a header with an offset of -1 if none is found.</returns>
public MDFChunkHeader findNextChunk(MDFChunkHeader container, UInt32 id, long start)
{
long origPos = reader.BaseStream.Position;
long curPos = start + container.offset + sizeof(UInt32) + sizeof(UInt32);
MDFChunkHeader temp;
while (curPos < container.offset + container.size)
{
reader.BaseStream.Seek(curPos, SeekOrigin.Begin);
if ((temp = peekChunkHeader()).id == id)
{
reader.BaseStream.Seek(origPos, SeekOrigin.Begin);
return temp;
}
else
{
curPos = temp.offset + temp.size;
}
}
reader.BaseStream.Seek(origPos, SeekOrigin.Begin);
temp.offset = -1;
temp.id = 0;
temp.size = 0;
return temp;
}
/// <summary>
/// Calculates the size of the chunk from the current file position back to the start of the chunk header and writes that size into the chunk header.
/// The size is corrected straight into the file, and the file position is reset back to the end of the chunk.
/// </summary>
/// <param name="header">The chunk header of this chunk.</param>
/// <returns>The updated chunk header structure, with the new corrected size field (just in case anyone needs it).</returns>
public MDFChunkHeader writeCalculatedChunkSize(MDFChunkHeader header)
{
long curPos = writer.BaseStream.Position;
header.size = (UInt32)(curPos - header.offset);
writer.BaseStream.Seek(header.offset, SeekOrigin.Begin);
header = writeChunkHeader(header);
writer.BaseStream.Seek(curPos, SeekOrigin.Begin);
return header;
}
/// <summary>
/// Writes the chunk header and returns a new header with an offset field marking the place where the header was written.
/// </summary>
/// <param name="header"></param>
public MDFChunkHeader writeChunkHeader(MDFChunkHeader header)
{
header.offset = writer.BaseStream.Position;
writer.Write(header.id);
writer.Write(header.size);
return header;
}
/// <summary>
/// Skips the current chunk by seeking past its size.
/// </summary>
/// <param name="chunk">The header of the chunk to skip over.</param>
public void skipChunk(MDFChunkHeader chunk)
{
reader.BaseStream.Seek(chunk.offset + chunk.size, SeekOrigin.Begin);
}
/// <summary>
/// Skips over the given chunk header, positioning the file position at the beginning of the chunk's data.
/// </summary>
/// <param name="header">The chunk header of the chunk to enter.</param>
public void enterChunk(MDFChunkHeader header)
{
reader.BaseStream.Seek(header.offset + sizeof(UInt32) + sizeof(UInt32), SeekOrigin.Begin);
}
/// <summary>
/// Returns true if the given chunk is empty.
/// </summary>
/// <param name="header">The header of the chunk to test.</param>
/// <returns>true if the given chunk is completely empty (in which the size field only accounts for the header), false otherwise.</returns>
public bool isEmpty(MDFChunkHeader header)
{
if (header.size == sizeof(UInt32) + sizeof(UInt32))
return true;
else
return false;
}
