From 0bd6009a0c368e7ddd1b96284b11d1e8f5312f6a Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Fri, 21 Jan 2022 10:59:13 -0500
Subject: cm_utf8: Fail on empty input range

Issue: #23132
---
 Source/cm_utf8.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Source/cm_utf8.c b/Source/cm_utf8.c
index 62e7e8c..b046aef 100644
--- a/Source/cm_utf8.c
+++ b/Source/cm_utf8.c
@@ -42,6 +42,11 @@ static unsigned int const cm_utf8_min[7] = {
 const char* cm_utf8_decode_character(const char* first, const char* last,
                                      unsigned int* pc)
 {
+  /* We need at least one byte.  */
+  if (first == last) {
+    return 0;
+  }
+
   /* Count leading ones in the first byte.  */
   unsigned char c = (unsigned char)*first++;
   unsigned char const ones = cm_utf8_ones[c];
-- 
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