From 5af570e75be1420dd4a58117f61ccebd4286acb7 Mon Sep 17 00:00:00 2001
From: Misa <infoteddy@infoteddy.info>
Date: Thu, 4 Mar 2021 14:37:21 -0800
Subject: [PATCH] Set length to 0 if PHYSFS_fileLength() is negative

PHYSFS_fileLength() returns -1 if the file size can't be determined. I'm
going to set it to 0 instead, because it seems like that's more
well-behaved with consumers.

Take lodepng_decode24() or lodepng_decode32(), for example - from a
quick glance at the source, it only takes in a size_t (an unsigned
integer) for the filesize, and one of the first things it does is malloc
with the given filesize. If the -1 turns into SIZE_MAX and LodePNG
attempts to allocate that many bytes... well, I don't know of any
systems that have 18 exabytes of memory. So that seems pretty bad.
---
 desktop_version/src/FileSystemUtils.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/desktop_version/src/FileSystemUtils.cpp b/desktop_version/src/FileSystemUtils.cpp
index dd0724c8..cda6924c 100644
--- a/desktop_version/src/FileSystemUtils.cpp
+++ b/desktop_version/src/FileSystemUtils.cpp
@@ -363,6 +363,10 @@ void FILESYSTEM_loadFileToMemory(
 	PHYSFS_sint64 length = PHYSFS_fileLength(handle);
 	if (len != NULL)
 	{
+		if (length < 0)
+		{
+			length = 0;
+		}
 		*len = length;
 	}
 	if (addnull)