/// <summary>Creates a shallow copy of a huffnode.</summary>
/// <param name="other">Another huffnode to copy.</param>
public huffnode(huffnode other)
: this(other._pointer.Buffer, other._pointer.BaseIndex)
{
}
/// <summary>Creates a new huffnode for the nth element in an array of huffnodes.</summary>
/// <param name="array">The huffnode that is the first element in the array.</param>
/// <param name="elementIndex">The element index.</param>
public huffnode(huffnode array, int elementIndex)
: this(array._pointer.Buffer, array._pointer.BaseIndex + SizeOf * elementIndex)
{
}
public static void HuffExpand(memptr source, memptr dest, int length, huffnode hufftable)
{
HuffExpand(source.Buffer, source.BaseIndex, dest.Buffer, dest.BaseIndex, length, hufftable);
}
/*
======================
=
= HuffExpand
=
======================
*/
public static void HuffExpand(byte[] sourceBuffer, int sourceIndex, byte[] destBuffer, int destIndex, int length, huffnode hufftable)
{
memptr source = new memptr(sourceBuffer, sourceIndex);
memptr dest = new memptr(destBuffer, destIndex);
ushort bit, _byte, code;
huffnode nodeon, headptr;
headptr = new huffnode(hufftable, 254); // head node is allways node 254
// as: The disabled C code that was in this function appears to be the C version of the asm code
// this came in handy during the conversion
nodeon = new huffnode(headptr);
// as: bugfix - refactored to prevent the out of bounds read that can occur occasionally with the final byte
bit = 256;
_byte = 0;
while(length != 0)
{
if(bit == 256)
{
bit = 1;
_byte = source.GetUInt8(0);
source.Offset(1);
}
if((_byte & bit) != 0)
code = nodeon.bit1;
else
code = nodeon.bit0;
bit <<= 1;
if(code < 256)
{
dest.SetUInt8(0, (byte) code);
dest.Offset(1);
nodeon = headptr;
length--;
}
else
{
nodeon = new huffnode(hufftable, code - 256);
}
}
}
/*
============================================================================
COMPRESSION routines, see JHUFF.C for more
============================================================================
*/
/*
===============
=
= OptimizeNodes
=
= Goes through a huffman table and changes the 256-511 node numbers to the
= actular address of the node. Must be called before HuffExpand
=
===============
*/
private void OptimizeNodes(huffnode table)
{
// as: Leave nodes as they are, HuffExpand has been modified to handle this
}
//==========================================================================
/////////////////////////////////////////////////////////
//
// InitGrFile
//
/////////////////////////////////////////////////////////
private void InitGrFile()
{
//
// calculate some offsets in the header
//
grhuffman = new huffnode(grhead);
grstarts = new memptr(grhead.Buffer, grhead.dataoffsets);
OptimizeNodes(grhuffman);
//
// Open the graphics file, leaving it open until the game is finished
//
grhandle = _sys.open("EGAGRAPH." + EXTENSION);
if(grhandle.IsNull)
Quit("Cannot open EGAGRAPH." + EXTENSION + "!");
memptr buffer = new memptr();
//
// load the pic and sprite headers into the data segment
//
needgr[STRUCTPIC] = 1; // make sure this chunk never reloads
grsegs[STRUCTPIC] = new memptr(null, 0xffff);
GetChunkLength(STRUCTPIC); // position file pointer
MMGetPtr(ref buffer, chunkcomplen);
SegRead(ref grhandle, buffer, chunkcomplen);
// as: Added temp pointer
memptr temp = new memptr(new byte[pictable.Length * pictype.SizeOf], 0);
HuffExpand(buffer.Buffer, buffer.BaseIndex, temp.Buffer, 0, temp.Buffer.Length, grhuffman);
// as: Initialise pictypes
for(int i = 0; i < pictable.Length; i++)
{
pictable[i] = new pictype(temp);
temp.Offset(pictype.SizeOf);
}
MMFreePtr(ref buffer);
}