From 3d5d02fc15197eac5a663f5c79db21ff88cae5a4 Mon Sep 17 00:00:00 2001
From: Steel Titanium <steeltitanium1@gmail.com>
Date: Sun, 3 Mar 2019 19:58:01 -0500
Subject: [PATCH] Error if the lump is a PNG lump

---
 src/w_wad.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/src/w_wad.c b/src/w_wad.c
index 88e89974..9ca4e0ff 100644
--- a/src/w_wad.c
+++ b/src/w_wad.c
@@ -1175,6 +1175,29 @@ void zerr(int ret)
 }
 #endif
 
+#define NO_PNG_LUMPS
+
+#ifdef NO_PNG_LUMPS
+static void ErrorIfPNG(void *d, size_t s, char *f, char *l)
+{
+    if (s < 67) // http://garethrees.org/2007/11/14/pngcrush/
+        return;
+#define sigcheck ((UINT8 *)d)
+    if (sigcheck[0] == 0x89
+        && sigcheck[1] == 0x50
+        && sigcheck[2] == 0x4e
+        && sigcheck[3] == 0x47
+        && sigcheck[4] == 0x0d
+        && sigcheck[5] == 0x0a
+        && sigcheck[6] == 0x1a
+        && sigcheck[7] == 0x0a)
+    {
+        I_Error("W_Wad: Lump \"%s\" in file \"%s\" is a .PNG - please convert to either Doom or Flat (raw) image format.", l, f);
+    }
+#undef sigcheck
+}
+#endif
+
 /** Reads bytes from the head of a lump.
   * Note: If the lump is compressed, the whole thing has to be read anyway.
   *
@@ -1214,7 +1237,15 @@ size_t W_ReadLumpHeaderPwad(UINT16 wad, UINT16 lump, void *dest, size_t size, si
 	switch(wadfiles[wad]->lumpinfo[lump].compression)
 	{
 	case CM_NOCOMPRESSION:		// If it's uncompressed, we directly write the data into our destination, and return the bytes read.
+#ifdef NO_PNG_LUMPS
+		{
+			size_t bytesread = fread(dest, 1, size, handle);
+			ErrorIfPNG(dest, bytesread, wadfiles[wad]->filename, l->name2);
+			return bytesread;
+		}
+#else
 		return fread(dest, 1, size, handle);
+#endif
 	case CM_LZF:		// Is it LZF compressed? Used by ZWADs.
 		{
 #ifdef ZWAD
@@ -1249,11 +1280,15 @@ size_t W_ReadLumpHeaderPwad(UINT16 wad, UINT16 lump, void *dest, size_t size, si
 			M_Memcpy(dest, decData + offset, size);
 			Z_Free(rawData);
 			Z_Free(decData);
+#ifdef NO_PNG_LUMPS
+			ErrorIfPNG(dest, size, wadfiles[wad]->filename, l->name2);
+#endif
 			return size;
 #else
 			//I_Error("ZWAD files not supported on this platform.");
 			return 0;
 #endif
+
 		}
 #ifdef HAVE_ZLIB
 	case CM_DEFLATE: // Is it compressed via DEFLATE? Very common in ZIPs/PK3s, also what most doom-related editors support.
@@ -1307,6 +1342,9 @@ size_t W_ReadLumpHeaderPwad(UINT16 wad, UINT16 lump, void *dest, size_t size, si
 			Z_Free(rawData);
 			Z_Free(decData);
 
+#ifdef NO_PNG_LUMPS
+			ErrorIfPNG(dest, size, wadfiles[wad]->filename, l->name2);
+#endif
 			return size;
 		}
 #endif