From 1ce58af28e46872d003f3a38213815595f387a39 Mon Sep 17 00:00:00 2001
From: Snappy Team <no-reply@google.com>
Date: Mon, 2 Nov 2020 17:46:36 +0000
Subject: [PATCH] Fix the use of op + len when op is nullptr and len is
 non-zero. See https://reviews.llvm.org/D67122 for some discussion of why this
 can matter. I don't think this should have any noticeable effect on
 performance.

PiperOrigin-RevId: 340255083
---
 snappy.cc | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/snappy.cc b/snappy.cc
index 605e0f5..29e1e8e 100644
--- a/snappy.cc
+++ b/snappy.cc
@@ -1569,15 +1569,14 @@ class SnappyScatteredWriter {
                             static_cast<size_t>(op - op_base_) < offset ||
                             op >= op_limit_min_slop_ || offset < len)) {
       if (offset == 0) return false;
-      char* const op_end = op + len;
       if (SNAPPY_PREDICT_FALSE(static_cast<size_t>(op - op_base_) < offset ||
-                              op_end > op_limit_)) {
+                              op + len > op_limit_)) {
         op_ptr_ = op;
         bool res = SlowAppendFromSelf(offset, len);
         *op_p = op_ptr_;
         return res;
       }
-      *op_p = IncrementalCopy(op - offset, op, op_end, op_limit_);
+      *op_p = IncrementalCopy(op - offset, op, op + len, op_limit_);
       return true;
     }
     // Fast path