From 90f235342571364a574f701ed33ebc563142c0ec Mon Sep 17 00:00:00 2001
From: Christian Schneider <schnaader@gmx.de>
Date: Wed, 15 May 2019 07:59:05 +0200
Subject: [PATCH] Change order of allocation and image descriptor check in GIF
 code

- Fixes #100
- Improves speed when processing invalid GIF files or false positives
---
 precomp.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/precomp.cpp b/precomp.cpp
index ccaf8f7..a064d2c 100644
--- a/precomp.cpp
+++ b/precomp.cpp
@@ -6212,6 +6212,10 @@ bool decompress_gif(FILE* srcfile, FILE* dstfile, long long src_pos, int& gif_le
 
     switch (RecordType) {
       case IMAGE_DESC_RECORD_TYPE:
+        if (DGifGetImageDesc(myGifFile) == GIF_ERROR) {
+          return d_gif_error(ScreenBuff, myGifFile);
+        }
+
         if (ScreenBuff == NULL) {
           ScreenBuff = alloc_gif_screenbuf(myGifFile);
           if (!ScreenBuff) {
@@ -6220,10 +6224,6 @@ bool decompress_gif(FILE* srcfile, FILE* dstfile, long long src_pos, int& gif_le
           }
         }
 
-        if (DGifGetImageDesc(myGifFile) == GIF_ERROR) {
-          return d_gif_error(ScreenBuff, myGifFile);
-        }
-
         srcfile_pos = tell_64(srcfile);
         if (last_pos != srcfile_pos) {
           if (last_pos == -1) {