Improve early return in CGifLZWDecoder::Decode

core/fxcodec/lgif/fx_gif.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fxcodec/lgif/fx_gif.h"
 
 #include "core/fxcodec/lbmp/fx_bmp.h"
 
@@ skipping 100 matching lines @@
       avail_in--;
       bits_left += 8;
     }
     while (bits_left >= code_size_cur) {
       code = (uint16_t)code_store & ((1 << code_size_cur) - 1);
       code_store >>= code_size_cur;
       bits_left -= code_size_cur;
       if (code == code_clear) {
         ClearTable();
         continue;
-      } else if (code == code_end) {
+      } else if (code >= code_end) {
         des_size = i;
         return 1;
       } else {
         if (code_old != (uint16_t)-1) {
           if (code_next < GIF_MAX_LZW_CODE) {
             if (code == code_next) {
               AddCode(code_old, code_first);
               DecodeString(code);
             } else if (code > code_next) {
               if (err_msg_ptr) {
@@ skipping 1102 matching lines @@
     gif_ptr->cur_offset = cur_offset;
     res = false;
   }
   dst_len = gif_ptr->cur_offset;
   dst_buf[dst_len - 1] = GIF_SIG_TRAILER;
   if (res) {
     gif_ptr->frames++;
   }
   return res;
 }