C#: Re-implemented the RLE decompression in the new format. The new format file has not been added to the project file, as I can only work in VS2010 where I am at the moment (and manually editing the file seems to break the autorun every time I try it).

2025-02-21 13:47:14 +01:00 · 2011-03-22 14:24:22 +00:00 · 2011-03-22 14:24:22 +00:00 · 0e5fe616c3
commit 0e5fe616c3
parent 1bd750c76d
1 changed files with 124 additions and 0 deletions
--- a/CSharp/DSDecmp/Formats/Nitro/RLE.cs
+++ b/CSharp/DSDecmp/Formats/Nitro/RLE.cs
@ -0,0 +1,124 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.IO;
+
+namespace DSDecmp.Formats.Nitro
+{
+    public class RLE : NitroCFormat
+    {
+        public RLE() : base(0x30) { }
+
+        public override void Decompress(Stream instream, long inLength, Stream outstream)
+        {
+            /*      
+                Data header (32bit)
+                    Bit 0-3   Reserved
+                    Bit 4-7   Compressed type (must be 3 for run-length)
+                    Bit 8-31  Size of decompressed data
+                Repeat below. Each Flag Byte followed by one or more Data Bytes.
+                Flag data (8bit)
+                    Bit 0-6   Expanded Data Length (uncompressed N-1, compressed N-3)
+                    Bit 7     Flag (0=uncompressed, 1=compressed)
+                Data Byte(s) - N uncompressed bytes, or 1 byte repeated N times
+             */
+
+            long readBytes = 0;
+
+            byte type = (byte)instream.ReadByte();
+            if (type != base.magicByte)
+                throw new InvalidDataException("The provided stream is not a valid LZ-0x11 "
+                            + "compressed stream (invalid type 0x" + type.ToString("X") + ")");
+            byte[] sizeBytes = new byte[3];
+            instream.Read(sizeBytes, 0, 3);
+            int decompressedSize = base.Bytes2Size(sizeBytes);
+            readBytes += 4;
+            if (decompressedSize == 0)
+            {
+                sizeBytes = new byte[4];
+                instream.Read(sizeBytes, 0, 4);
+                decompressedSize = base.Bytes2Size(sizeBytes);
+                readBytes += 4;
+            }
+
+
+            int currentOutSize = 0;
+            while (currentOutSize < decompressedSize)
+            {
+                #region (try to) get the flag byte with the length data and compressed flag
+
+                if (readBytes >= inLength)
+                    throw new NotEnoughDataException(currentOutSize, decompressedSize);
+                int flag = instream.ReadByte(); readBytes++;
+                if (flag < 0)
+                    throw new StreamTooShortException();
+
+                bool compressed = (flag & 0x80) > 0;
+                int length = flag & 0x7F;
+
+                if (compressed)
+                    length += 3;
+                else
+                    length += 1;
+
+                #endregion
+
+                if (compressed)
+                {
+                    #region compressed: write the next byte (length) times.
+
+                    if (readBytes >= inLength)
+                        throw new NotEnoughDataException(currentOutSize, decompressedSize);
+                    int data = instream.ReadByte(); readBytes++;
+                    if (data < 0)
+                        throw new StreamTooShortException();
+
+                    if (currentOutSize + length > decompressedSize)
+                        throw new InvalidDataException("The given stream is not a valid RLE stream; the "
+                            + "output length does not match the provided plaintext length.");
+                    byte bdata = (byte)data;
+                    for (int i = 0; i < length; i++)
+                    {
+                        // Stream.Write(byte[], offset, len) may also work, but only if it is a circular buffer
+                        outstream.WriteByte(bdata);
+                        currentOutSize++;
+                    }
+
+                    #endregion
+                }
+                else
+                {
+                    #region uncompressed: copy the next (length) bytes.
+
+                    int tryReadLength = length;
+                    // limit the amount of bytes read by the indicated number of bytes available
+                    if (readBytes + length > inLength)
+                        tryReadLength = (int)(inLength - readBytes);
+                    
+                    byte[] data = new byte[length];
+                    int readLength = instream.Read(data, 0, (int)tryReadLength);
+                    readBytes += readLength;
+                    outstream.Write(data, 0, readLength);
+                    currentOutSize += readLength;
+
+                    // if the attempted number of bytes read is less than the desired number, the given input
+                    // length is too small (or there is not enough data in the stream)
+                    if (tryReadLength < length)
+                        throw new NotEnoughDataException(currentOutSize, decompressedSize);
+                    // if the actual number of read bytes is even less, it means that the end of the stream has
+                    // bee reached, thus the given input length is larger than the actual length of the input
+                    if (readLength < length)
+                        throw new StreamTooShortException();
+
+                    #endregion
+                }
+            }
+        }
+
+        public override void Compress(Stream instream, long inLength, Stream outstream)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}