commit 89fc8d89919ef71fd2d6030e9cf931630bcd4529
Author:     Simon Howard <fraggle@soulsphere.org>
AuthorDate: Wed Nov 23 00:38:01 2016 -0500
Commit:     Simon Howard <fraggle@soulsphere.org>
CommitDate: Wed Nov 23 00:38:01 2016 -0500

    heretic: Forbid vvHeretic options in WAD files.

    As with the Doom v1.91 format, parsing of vvHeretic extension bits is
    a convenience for demo playback purposes and not intended as an
    editing feature. If a demo with such bits set is found inside a WAD
    file, we ignore them as Vanilla Heretic would do.

    Part of #817.
---
 src/heretic/g_game.c | 40 +++++++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 7 deletions(-)

diff --git a/src/heretic/g_game.c b/src/heretic/g_game.c
index 73382f58..16ee4e5d 100644
--- a/src/heretic/g_game.c
+++ b/src/heretic/g_game.c
@@ -1873,23 +1873,49 @@ void G_DeferedPlayDemo(char *name)
     gameaction = ga_playdemo;
 }

+// Returns true if the given lump number corresponds to data from a .lmp
+// file, as opposed to a WAD.
+static boolean IsDemoFile(int lumpnum)
+{
+    char *lower;
+    boolean result;
+
+    lower = M_StringDuplicate(lumpinfo[lumpnum]->wad_file->path);
+    M_ForceLowercase(lower);
+    result = M_StringEndsWith(lower, ".lmp");
+    free(lower);
+
+    return result;
+}
+
 void G_DoPlayDemo(void)
 {
     skill_t skill;
-    int i, episode, map;
+    int i, lumpnum, episode, map;

     gameaction = ga_nothing;
-    demobuffer = demo_p = W_CacheLumpName(defdemoname, PU_STATIC);
+    lumpnum = W_GetNumForName(defdemoname);
+    demobuffer = W_CacheLumpNum(lumpnum, PU_STATIC);
+    demo_p = demobuffer;
     skill = *demo_p++;
     episode = *demo_p++;
     map = *demo_p++;

-    // Read special parameter bits: see G_RecordDemo() for details.
-    longtics = (*demo_p & DEMOHEADER_LONGTICS) != 0;
+    // vvHeretic allows extra options to be stored in the upper bits of
+    // the player 1 present byte. However, only recognize these bits if
+    // they are in a demo file being played manually by the user; we
+    // ignore them (as is Vanilla behavior) if they are inside a WAD file.
+    // These extra bits are a convenience feature for demo playback, not
+    // an editing extension for WAD authors.
+    if (IsDemoFile(lumpnum))
+    {
+        // Read special parameter bits: see G_RecordDemo() for details.
+        longtics = (*demo_p & DEMOHEADER_LONGTICS) != 0;

-    // don't overwrite arguments from the command line
-    respawnparm |= (*demo_p & DEMOHEADER_RESPAWN) != 0;
-    nomonsters  |= (*demo_p & DEMOHEADER_NOMONSTERS) != 0;
+        // don't overwrite arguments from the command line
+        respawnparm |= (*demo_p & DEMOHEADER_RESPAWN) != 0;
+        nomonsters |= (*demo_p & DEMOHEADER_NOMONSTERS) != 0;
+    }

     for (i = 0; i < MAXPLAYERS; i++)
         playeringame[i] = (*demo_p++) != 0;