- Added a compatibility lump because I think it's a shame that Void doesn't

work properly on new ZDooms after all the collaboration I had with Cyb on
  that map. (Works with other maps, too.)


SVN r1402 (trunk)

docs/rh-log.txt

@@ -1,3 +1,8 @@
+February 4, 2009
+- Added a compatibility lump because I think it's a shame that Void doesn't
+  work properly on new ZDooms after all the collaboration I had with Cyb on
+  that map. (Works with other maps, too.)
+
 February 5, 2009  (Changes by Graf Zahl)
 - Made improvements so that the FOptionalMapinfoData class is easier to use.
 

src/compatibility.cpp

@@ -0,0 +1,246 @@
+/*
+** compatibility.cpp
+** Handles compatibility flags for maps that are unlikely to be updated.
+**
+**---------------------------------------------------------------------------
+** Copyright 2009 Randy Heit
+** All rights reserved.
+**
+** Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions
+** are met:
+**
+** 1. Redistributions of source code must retain the above copyright
+**    notice, this list of conditions and the following disclaimer.
+** 2. Redistributions in binary form must reproduce the above copyright
+**    notice, this list of conditions and the following disclaimer in the
+**    documentation and/or other materials provided with the distribution.
+** 3. The name of the author may not be used to endorse or promote products
+**    derived from this software without specific prior written permission.
+**
+** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+**---------------------------------------------------------------------------
+**
+** This file is for maps that have been rendered broken by bug fixes or other
+** changes that seemed minor at the time, and it is unlikely that the maps
+** will be changed. If you are making a map and you know it needs a
+** compatibility option to play properly, you are advised to specify so with
+** a MAPINFO.
+*/
+
+// HEADER FILES ------------------------------------------------------------
+
+#include "compatibility.h"
+#include "sc_man.h"
+#include "cmdlib.h"
+#include "doomdef.h"
+#include "doomstat.h"
+#include "c_dispatch.h"
+
+// MACROS ------------------------------------------------------------------
+
+// TYPES -------------------------------------------------------------------
+
+struct FCompatOption
+{
+	const char *Name;
+	int CompatFlags;
+	int BCompatFlags;
+};
+
+// EXTERNAL FUNCTION PROTOTYPES --------------------------------------------
+
+// PUBLIC FUNCTION PROTOTYPES ----------------------------------------------
+
+// PRIVATE FUNCTION PROTOTYPES ---------------------------------------------
+
+// EXTERNAL DATA DECLARATIONS ----------------------------------------------
+
+// PUBLIC DATA DEFINITIONS -------------------------------------------------
+
+TMap<FMD5Holder, FCompatValues, FMD5HashTraits> BCompatMap;
+
+// PRIVATE DATA DEFINITIONS ------------------------------------------------
+
+static FCompatOption Options[] =
+{
+	{ "setslopeoverflow",		0, BCOMPATF_SETSLOPEOVERFLOW },
+	{ "resetplayerspeed",		0, BCOMPATF_RESETPLAYERSPEED },
+
+	// list copied from g_mapinfo.cpp
+	{ "shorttex",				COMPATF_SHORTTEX, 0 },
+	{ "stairs",					COMPATF_STAIRINDEX, 0 },
+	{ "limitpain",				COMPATF_LIMITPAIN, 0 },
+	{ "nopassover",				COMPATF_NO_PASSMOBJ, 0 },
+	{ "notossdrops",			COMPATF_NOTOSSDROPS, 0 },
+	{ "useblocking", 			COMPATF_USEBLOCKING, 0 },
+	{ "nodoorlight",			COMPATF_NODOORLIGHT, 0 },
+	{ "ravenscroll",			COMPATF_RAVENSCROLL, 0 },
+	{ "soundtarget",			COMPATF_SOUNDTARGET, 0 },
+	{ "dehhealth",				COMPATF_DEHHEALTH, 0 },
+	{ "trace",					COMPATF_TRACE, 0 },
+	{ "dropoff",				COMPATF_DROPOFF, 0 },
+	{ "boomscroll",				COMPATF_BOOMSCROLL, 0 },
+	{ "invisibility",			COMPATF_INVISIBILITY, 0 },
+	{ "silentinstantfloors",	COMPATF_SILENT_INSTANT_FLOORS, 0 },
+	{ "sectorsounds",			COMPATF_SECTORSOUNDS, 0 },
+	{ "missileclip",			COMPATF_MISSILECLIP, 0 },
+	{ "crossdropoff",			COMPATF_CROSSDROPOFF, 0 },
+	{ NULL, 0, 0 }
+};
+
+// CODE --------------------------------------------------------------------
+
+//==========================================================================
+//
+// ParseCompatibility
+//
+//==========================================================================
+
+void ParseCompatibility()
+{
+	TArray<FMD5Holder> md5array;
+	FMD5Holder md5;
+	FCompatValues flags;
+	int i, x;
+	unsigned int j;
+
+	// The contents of this file are not cumulative, as it should not
+	// be present in user-distributed maps.
+	FScanner sc(Wads.GetNumForFullName("compatibility.txt"));
+
+	while (sc.GetString())	// Get MD5 signature
+	{
+		do
+		{
+			if (strlen(sc.String) != 32)
+			{
+				sc.ScriptError("MD5 signature must be exactly 32 characters long");
+			}
+			for (i = 0; i < 32; ++i)
+			{
+				if (sc.String[i] >= '0' && sc.String[i] <= '9')
+				{
+					x = sc.String[i] - '0';
+				}
+				else
+				{
+					sc.String[i] |= 'a' ^ 'A';
+					if (sc.String[i] >= 'a' && sc.String[i] <= 'f')
+					{
+						x = sc.String[i] - 'a' + 10;
+					}
+					else
+					{
+						sc.ScriptError("MD5 signature must be a hexadecimal value");
+					}
+				}
+				if (!(i & 1))
+				{
+					md5.Bytes[i / 2] = x << 4;
+				}
+				else
+				{
+					md5.Bytes[i / 2] |= x;
+				}
+			}
+			md5array.Push(md5);
+			sc.MustGetString();
+		} while (!sc.Compare("{"));
+		flags.CompatFlags = 0;
+		flags.BCompatFlags = 0;
+		while (sc.MustGetString(), (i = sc.MatchString(&Options[0].Name, sizeof(*Options))) >= 0)
+		{
+			flags.CompatFlags |= Options[i].CompatFlags;
+			flags.BCompatFlags |= Options[i].BCompatFlags;
+		}
+		sc.UnGet();
+		sc.MustGetStringName("}");
+		for (j = 0; j < md5array.Size(); ++j)
+		{
+			BCompatMap[md5array[j]] = flags;
+		}
+	}
+}
+
+//==========================================================================
+//
+// CheckCompatibility
+//
+//==========================================================================
+
+void CheckCompatibility(MapData *map)
+{
+	FMD5Holder md5;
+	FCompatValues *flags;
+
+	map->GetChecksum(md5.Bytes);
+	flags = BCompatMap.CheckKey(md5);
+	if (flags != NULL)
+	{
+		ii_compatflags = flags->CompatFlags;
+		ib_compatflags = flags->BCompatFlags;
+	}
+	else
+	{
+		ii_compatflags = 0;
+		ib_compatflags = 0;
+	}
+	// Reset i_compatflags
+	compatflags = compatflags;
+}
+
+//==========================================================================
+//
+// CCMD mapchecksum
+//
+//==========================================================================
+
+CCMD (mapchecksum)
+{
+	MapData *map;
+	BYTE cksum[16];
+
+	if (argv.argc() < 2)
+	{
+		Printf("Usage: mapchecksum <map> ...\n");
+	}
+	for (unsigned int i = 1; i < argv.argc(); ++i)
+	{
+		map = P_OpenMapData(argv[i]);
+		if (map == NULL)
+		{
+			Printf("Cannot load %s as a map\n", argv[i]);
+		}
+		else
+		{
+			map->GetChecksum(cksum);
+			delete map;
+			for (int j = 0; j < sizeof(cksum); ++j)
+			{
+				Printf("%02X", cksum[j]);
+			}
+			Printf(" // %s\n", argv[i]);
+		}
+	}
+}
+
+//==========================================================================
+//
+// CCMD hiddencompatflags
+//
+//==========================================================================
+
+CCMD (hiddencompatflags)
+{
+	Printf("%08x %08x\n", ii_compatflags, ib_compatflags);
+}

src/compatibility.h

@@ -0,0 +1,40 @@
+#ifndef COMPATIBILITY_H
+#define COMPATIBILITY_H
+
+#include "doomtype.h"
+#include "tarray.h"
+#include "p_setup.h"
+
+union FMD5Holder
+{
+	BYTE Bytes[16];
+	DWORD DWords[4];
+};
+
+struct FCompatValues
+{
+	int CompatFlags;
+	int BCompatFlags;
+};
+
+struct FMD5HashTraits
+{
+	hash_t Hash(const FMD5Holder key)
+	{
+		return *(hash_t *)key.Bytes;
+	}
+	int Compare(const FMD5Holder left, const FMD5Holder right)
+	{
+		return left.DWords[0] != right.DWords[0] ||
+			   left.DWords[1] != right.DWords[1] ||
+			   left.DWords[2] != right.DWords[2] ||
+			   left.DWords[3] != right.DWords[3];
+	}
+};
+
+extern TMap<FMD5Holder, FCompatValues, FMD5HashTraits> BCompatMap;
+
+void ParseCompatibility();
+void CheckCompatibility(MapData *map);
+
+#endif

src/d_main.cpp

@@ -100,6 +100,7 @@
 #include "d_netinf.h"
 #include "v_palette.h"
 #include "m_cheat.h"
+#include "compatibility.h"
 
 EXTERN_CVAR(Bool, hud_althud)
 void DrawHUD();
@@ -509,6 +510,7 @@ CVAR (Flag, sv_noautoaim,			dmflags2, DF2_NOAUTOAIM);
 //==========================================================================
 
 int i_compatflags;	// internal compatflags composed from the compatflags CVAR and MAPINFO settings
+int ii_compatflags, ib_compatflags;
 
 EXTERN_CVAR(Int, compatmode)
 
@@ -520,7 +522,7 @@ static int GetCompatibility(int mask)
 
 CUSTOM_CVAR (Int, compatflags, 0, CVAR_ARCHIVE|CVAR_SERVERINFO)
 {
-	i_compatflags = GetCompatibility(self);
+	i_compatflags = GetCompatibility(self) | ii_compatflags;
 }
 
 CUSTOM_CVAR(Int, compatmode, 0, CVAR_ARCHIVE|CVAR_SERVERINFO|CVAR_NOINITCALL)
@@ -2366,6 +2368,8 @@ void D_DoomMain (void)
 	Printf ("ST_Init: Init startup screen.\n");
 	StartScreen = FStartupScreen::CreateInstance (R_GuesstimateNumTextures() + 5);
 
+	ParseCompatibility();
+
 	Printf ("P_Init: Checking cmd-line parameters...\n");
 	flags = dmflags;
 	if (Args->CheckParm ("-nomonsters"))	flags |= DF_NO_MONSTERS;

src/doomdef.h

@@ -282,6 +282,14 @@ enum
 	COMPATF_CROSSDROPOFF	= 1 << 20,	// monsters can't be pushed over dropoffs
 };
 
+// Emulate old bugs for select maps. These are not exposed by a cvar
+// or mapinfo because we do not want new maps to use these bugs.
+enum
+{
+	BCOMPATF_SETSLOPEOVERFLOW	= 1 << 0,	// SetSlope things can overflow
+	BCOMPATF_RESETPLAYERSPEED	= 1 << 1,	// Set player speed to 1.0 when changing maps
+};
+
 // phares 3/20/98:
 //
 // Player friction is variable, based on controlling

src/doomstat.h

@@ -249,6 +249,6 @@ EXTERN_CVAR (Int, dmflags);
 EXTERN_CVAR (Int, dmflags2);	// [BC]
 
 EXTERN_CVAR (Int, compatflags);
-extern int i_compatflags;
+extern int i_compatflags, ii_compatflags, ib_compatflags;
 
 #endif

src/g_level.cpp

@@ -1185,6 +1185,10 @@ void G_FinishTravel ()
 				inv->LinkToWorld ();
 				inv->Travelled ();
 			}
+			if (ib_compatflags & BCOMPATF_RESETPLAYERSPEED)
+			{
+				pawn->Speed = pawn->GetDefault()->Speed;
+			}
 			if (level.FromSnapshot)
 			{
 				FBehavior::StaticStartTypedScripts (SCRIPT_Return, pawn, true);

src/md5.cpp

@@ -0,0 +1,294 @@
+/*
+ * This code implements the MD5 message-digest algorithm.
+ * The algorithm is due to Ron Rivest.  This code was
+ * written by Colin Plumb in 1993, no copyright is claimed.
+ * This code is in the public domain; do with it what you wish.
+ *
+ * Equivalent code is available from RSA Data Security, Inc.
+ * This code has been tested against that, and is equivalent,
+ * except that you don't need to include two pages of legalese
+ * with every copy.
+ *
+ * To compute the message digest of a chunk of bytes, declare an
+ * MD5Context structure, pass it to MD5Init, call MD5Update as
+ * needed on buffers full of bytes, and then call MD5Final, which
+ * will fill a supplied 16-byte array with the digest.
+ */
+
+#include <string.h>		/* for memcpy() */
+
+#include "doomtype.h"
+#include "md5.h"
+#include "templates.h"
+
+#ifdef WORDS_BIGENDIAN
+void byteSwap(DWORD *buf, unsigned words)
+{
+	BYTE *p = (BYTE *)buf;
+
+	do {
+		*buf++ = (DWORD)((unsigned)p[3] << 8 | p[2]) << 16 |
+			((unsigned)p[1] << 8 | p[0]);
+		p += 4;
+	} while (--words);
+}
+#else
+#define byteSwap(buf,words)
+#endif
+
+/*
+ * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
+ * initialization constants.
+ */
+void MD5Context::Init()
+{
+	buf[0] = 0x67452301;
+	buf[1] = 0xefcdab89;
+	buf[2] = 0x98badcfe;
+	buf[3] = 0x10325476;
+
+	bytes[0] = 0;
+	bytes[1] = 0;
+}
+
+/*
+ * Update context to reflect the concatenation of another buffer full
+ * of bytes.
+ */
+void MD5Context::Update(const BYTE *buf, unsigned len)
+{
+	DWORD t;
+
+	/* Update byte count */
+
+	t = bytes[0];
+	if ((bytes[0] = t + len) < t)
+		bytes[1]++;	/* Carry from low to high */
+
+	t = 64 - (t & 0x3f);	/* Space available in ctx->in (at least 1) */
+	if (t > len) {
+		memcpy((BYTE *)in + 64 - t, buf, len);
+		return;
+	}
+	/* First chunk is an odd size */
+	if (t < 64)
+	{
+		memcpy((BYTE *)in + 64 - t, buf, t);
+		byteSwap(in, 16);
+		MD5Transform(this->buf, in);
+		buf += t;
+		len -= t;
+	}
+
+	/* Process data in 64-byte chunks */
+	while (len >= 64)
+	{
+		memcpy(in, buf, 64);
+		byteSwap(in, 16);
+		MD5Transform(this->buf, in);
+		buf += 64;
+		len -= 64;
+	}
+
+	/* Handle any remaining bytes of data. */
+	memcpy(in, buf, len);
+}
+
+void MD5Context::Update(FileReader *file, unsigned len)
+{
+	BYTE readbuf[8192];
+	long t;
+
+	while (len != 0)
+	{
+		t = MIN(len, sizeof(readbuf));
+		len -= t;
+		t = file->Read(readbuf, t);
+		Update(readbuf, t);
+	}
+}
+
+/*
+ * Final wrapup - pad to 64-byte boundary with the bit pattern 
+ * 1 0* (64-bit count of bits processed, MSB-first)
+ */
+void MD5Context::Final(BYTE digest[16])
+{
+	int count = bytes[0] & 0x3f;	/* Number of bytes in ctx->in */
+	BYTE *p = (BYTE *)in + count;
+
+	/* Set the first char of padding to 0x80.  There is always room. */
+	*p++ = 0x80;
+
+	/* Bytes of padding needed to make 56 bytes (-8..55) */
+	count = 56 - 1 - count;
+
+	if (count < 0)		/* Padding forces an extra block */
+	{
+		memset(p, 0, count + 8);
+		byteSwap(in, 16);
+		MD5Transform(buf, in);
+		p = (BYTE *)in;
+		count = 56;
+	}
+	memset(p, 0, count);
+	byteSwap(in, 14);
+
+	/* Append length in bits and transform */
+	in[14] = bytes[0] << 3;
+	in[15] = (bytes[1] << 3) | (bytes[0] >> 29);
+	MD5Transform(buf, in);
+
+	byteSwap(buf, 4);
+	memcpy(digest, buf, 16);
+	memset(this, 0, sizeof(*this));	/* In case it's sensitive */
+}
+
+#ifndef ASM_MD5
+
+/* The four core functions - F1 is optimized somewhat */
+
+/* #define F1(x, y, z) (x & y | ~x & z) */
+#define F1(x, y, z) (z ^ (x & (y ^ z)))
+#define F2(x, y, z) F1(z, x, y)
+#define F3(x, y, z) (x ^ y ^ z)
+#define F4(x, y, z) (y ^ (x | ~z))
+
+/* This is the central step in the MD5 algorithm. */
+#define MD5STEP(f,w,x,y,z,in,s) \
+	 (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
+
+/*
+ * The core of the MD5 algorithm, this alters an existing MD5 hash to
+ * reflect the addition of 16 longwords of new data.  MD5Update blocks
+ * the data and converts bytes into longwords for this routine.
+ */
+void
+MD5Transform(DWORD buf[4], const DWORD in[16])
+{
+	register DWORD a, b, c, d;
+
+	a = buf[0];
+	b = buf[1];
+	c = buf[2];
+	d = buf[3];
+
+	MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
+	MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
+	MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
+	MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
+	MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
+	MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
+	MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
+	MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
+	MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
+	MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
+	MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
+	MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
+	MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
+	MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
+	MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
+	MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
+
+	MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
+	MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
+	MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
+	MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
+	MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
+	MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
+	MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
+	MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
+	MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
+	MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
+	MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
+	MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
+	MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
+	MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
+	MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
+	MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
+
+	MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
+	MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
+	MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
+	MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
+	MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
+	MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
+	MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
+	MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
+	MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
+	MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
+	MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
+	MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
+	MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
+	MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
+	MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
+	MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
+
+	MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
+	MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
+	MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
+	MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
+	MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
+	MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
+	MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
+	MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
+	MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
+	MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
+	MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
+	MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
+	MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
+	MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
+	MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
+	MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
+
+	buf[0] += a;
+	buf[1] += b;
+	buf[2] += c;
+	buf[3] += d;
+}
+
+#endif
+
+#include "c_dispatch.h"
+
+//==========================================================================
+//
+// CCMD md5sum
+//
+// Like the command-line tool, because I wanted to make sure I had it right.
+//
+//==========================================================================
+
+CCMD (md5sum)
+{
+	if (argv.argc() < 2)
+	{
+		Printf("Usage: md5sum <file> ...\n");
+	}
+	for (int i = 1; i < argv.argc(); ++i)
+	{
+		FILE *file = fopen(argv[i], "rb");
+		if (file == NULL)
+		{
+			Printf("%s: %s\n", argv[i], strerror(errno));
+		}
+		else
+		{
+			MD5Context md5;
+			BYTE readbuf[8192];
+			size_t len;
+
+			while ((len = fread(readbuf, 1, sizeof(readbuf), file)) > 0)
+			{
+				md5.Update(readbuf, (unsigned int)len);
+			}
+			md5.Final(readbuf);
+			for(int j = 0; j < 16; ++j)
+			{
+				Printf("%02x", readbuf[j]);
+			}
+			Printf(" *%s\n", argv[i]);
+			fclose (file);
+		}
+	}
+}

src/md5.h

@@ -0,0 +1,41 @@
+/*
+ * This is the header file for the MD5 message-digest algorithm.
+ * The algorithm is due to Ron Rivest.  This code was
+ * written by Colin Plumb in 1993, no copyright is claimed.
+ * This code is in the public domain; do with it what you wish.
+ *
+ * Equivalent code is available from RSA Data Security, Inc.
+ * This code has been tested against that, and is equivalent,
+ * except that you don't need to include two pages of legalese
+ * with every copy.
+ *
+ * To compute the message digest of a chunk of bytes, declare an
+ * MD5Context structure, pass it to MD5Init, call MD5Update as
+ * needed on buffers full of bytes, and then call MD5Final, which
+ * will fill a supplied 16-byte array with the digest.
+ */
+
+#ifndef MD5_H
+#define MD5_H
+
+#include "files.h"
+
+struct MD5Context
+{
+	MD5Context() { Init(); }
+
+	void Init();
+	void Update(const BYTE *buf, unsigned len);
+	void Update(FileReader *file, unsigned len);
+	void Final(BYTE digest[16]);
+
+private:
+	DWORD buf[4];
+	DWORD bytes[2];
+	DWORD in[16];
+
+};
+
+void MD5Transform(DWORD buf[4], DWORD const in[16]);
+
+#endif /* !MD5_H */

src/p_mobj.cpp

@@ -3762,7 +3762,6 @@ APlayerPawn *P_SpawnPlayer (FMapThing *mthing, bool tempplayer)
 				if (sectors[i].SoundTarget == oldactor) sectors[i].SoundTarget = NULL;
 			}
 
-
 			DObject::StaticPointerSubstitution (oldactor, p->mo);
 			// PointerSubstitution() will also affect the bodyque, so undo that now.
 			for (int ii=0; ii < BODYQUESIZE; ++ii)

src/p_setup.cpp

@@ -63,6 +63,8 @@
 #include "r_sky.h"
 #include "cmdlib.h"
 #include "g_level.h"
+#include "md5.h"
+#include "compatibility.h"
 
 void P_SpawnSlopeMakers (FMapThing *firstmt, FMapThing *lastmt);
 void P_SetSlopes ();
@@ -510,6 +512,51 @@ bool P_CheckMapData(const char *mapname)
 	return true;
 }
 
+//===========================================================================
+//
+// MapData :: GetChecksum
+//
+// Hashes a map based on its header, THINGS, LINEDEFS, SIDEDEFS, SECTORS,
+// and BEHAVIOR lumps. Node-builder generated lumps are not included.
+//
+//===========================================================================
+
+void MapData::GetChecksum(BYTE cksum[16])
+{
+	MD5Context md5;
+
+	if (file != NULL)
+	{
+		if (isText)
+		{
+			file->Seek(MapLumps[ML_TEXTMAP].FilePos, SEEK_SET);
+			md5.Update(file, MapLumps[ML_TEXTMAP].Size);
+		}
+		else
+		{
+			if (MapLumps[ML_LABEL].Size != 0)
+			{
+				file->Seek(MapLumps[ML_LABEL].FilePos, SEEK_SET);
+				md5.Update(file, MapLumps[ML_LABEL].Size);
+			}
+			file->Seek(MapLumps[ML_THINGS].FilePos, SEEK_SET);
+			md5.Update(file, MapLumps[ML_THINGS].Size);
+			file->Seek(MapLumps[ML_LINEDEFS].FilePos, SEEK_SET);
+			md5.Update(file, MapLumps[ML_LINEDEFS].Size);
+			file->Seek(MapLumps[ML_SIDEDEFS].FilePos, SEEK_SET);
+			md5.Update(file, MapLumps[ML_SIDEDEFS].Size);
+			file->Seek(MapLumps[ML_SECTORS].FilePos, SEEK_SET);
+			md5.Update(file, MapLumps[ML_SECTORS].Size);
+		}
+		if (HasBehavior)
+		{
+			file->Seek(MapLumps[ML_BEHAVIOR].FilePos, SEEK_SET);
+			md5.Update(file, MapLumps[ML_BEHAVIOR].Size);
+		}
+	}
+	md5.Final(cksum);
+}
+
 //===========================================================================
 //
 // [RH] Figure out blends for deep water sectors
@@ -3301,6 +3348,9 @@ void P_SetupLevel (char *lumpname, int position)
 	{
 		// note: most of this ordering is important 
 		ForceNodeBuild = gennodes;
+
+		CheckCompatibility(map);
+
 		// [RH] Load in the BEHAVIOR lump
 		FBehavior::StaticUnloadModules ();
 		if (map->HasBehavior)

src/p_setup.h

@@ -80,6 +80,8 @@ struct MapData
 		}
 		return 0;
 	}
+
+	void GetChecksum(BYTE cksum[16]);
 };
 
 MapData * P_OpenMapData(const char * mapname);

src/p_slopes.cpp

@@ -178,8 +178,16 @@ void P_SetSlope (secplane_t *plane, bool setCeil, int xyangi, int zangi,
 
 	FVector3 norm;
 
-	norm[0] = float(finecosine[zang]) * float(finecosine[xyang]);
+	if (ib_compatflags & BCOMPATF_SETSLOPEOVERFLOW)
-	norm[1] = float(finecosine[zang]) * float(finesine[xyang]);
+	{
+		norm[0] = float(finecosine[zang] * finecosine[xyang]);
+		norm[1] = float(finecosine[zang] * finesine[xyang]);
+	}
+	else
+	{
+		norm[0] = float(finecosine[zang]) * float(finecosine[xyang]);
+		norm[1] = float(finecosine[zang]) * float(finesine[xyang]);
+	}
 	norm[2] = float(finesine[zang]) * 65536.f;
 	norm.MakeUnit();
 	plane->a = (int)(norm[0] * 65536.f);

src/tarray.h

@@ -398,7 +398,7 @@ template<class KT> struct THashTraits
 
 template<class VT> struct TValueTraits
 {
-	// Initializes a value for TMap. If a regular consructor isn't
+	// Initializes a value for TMap. If a regular constructor isn't
 	// good enough, you can override it.
 	void Init(VT &value)
 	{

wadsrc/static/compatibility.txt

@@ -0,0 +1,32 @@
+6DC9F6CCEAE7A91AEC48EBE506F22BC4 // void.wad MAP01
+{
+	setslopeoverflow
+}
+
+B2D8DA03489D1C67F60DC87FBC4EA338 // map01 - Massmouth 2
+801304DA3784308D333951B5E0CF8E9E // map02
+6EA4D5CAEA16857B2A882467E1633BC2 // map03
+A4E01929938958BB9DA9EF3066802184 // map04
+54F4B897BAA50F070CECA25555031C15 // map05
+BB93EA15CA068FBC7E0381E4E959207C // map06
+960397183E44D26212E8876681D2801D // map07
+E4D05765BDB5BF9D22F0548E2807BAE9 // map08
+696203E7A2C8A14C00F8824F74BD3D53 // map09
+EEFB83ABB26A473382FAA063CF120501 // map10
+FD031167E57BD1EEB65279F5895300F2 // map11
+9C69328D5B82392DEA1C0552CF283F38 // map12
+16569BB1F80D52304319DDD0C2DE4B5A // map13
+1760E2F04B4E2C5CDD235855FCAB8327 // map14
+A80E7EE40E0D0C76A6FBD242BE29FE27 // map15
+2F1F8E27FBB5EF21AFBE1F3B13C03037 // map16
+1CE294781A2455DE72C197E0B3DF6212 // map31
+{
+	resetplayerspeed
+}
+
+10E1E2B36302D31AC4AE68C84B5DC457 // Eternal Doom MAP28
+{
+	// What's really sad is that I got a separate bug report for this map
+	// years ago, but nobody made mention of this problem back then.
+	trace
+}