From 8129939c312e4b5060042fdb93bd071b7b133381 Mon Sep 17 00:00:00 2001
From: Dimitri van Heesch <doxygen@gmail.com>
Date: Thu, 5 Jan 2023 11:16:24 +0100
Subject: [PATCH] issue #9319: Doc build fails with cairo 1.17.6

- Improve detection of "flate" encoded streams
---
 TinyDeflate/gunzip.hh |  2 +-
 src/dotrunner.cpp     | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/TinyDeflate/gunzip.hh b/TinyDeflate/gunzip.hh
index a631815a255..652058ab823 100644
--- a/TinyDeflate/gunzip.hh
+++ b/TinyDeflate/gunzip.hh
@@ -430,7 +430,7 @@ namespace gunzip_ns
         static_assert((T)false, "result_of<CallableType> is invalid; use "
             "result_of<CallableType(zero or more argument types)> instead.");
     };
-    #if __cplusplus > 201703UL
+    #if __cplusplus > 202000UL
     template <typename F, typename... Args>
     struct result_of<F(Args...)> : std::invoke_result<F, Args...> {};
     #else
diff --git a/src/dotrunner.cpp b/src/dotrunner.cpp
index 9246029cb61..2e87a0d4a37 100644
--- a/src/dotrunner.cpp
+++ b/src/dotrunner.cpp
@@ -20,6 +20,7 @@
 #pragma warning( push )
 #pragma warning( disable : 4242 )
 #pragma warning( disable : 4244 )
+#pragma warning( disable : 4996 )
 #endif
 #include <gunzip.hh>
 #ifdef _MSC_VER
@@ -156,11 +157,28 @@ bool DotRunner::readBoundingBox(const QCString &fileName,int *width,int *height,
   const std::string streamStart = "stream\n";
   const std::string streamEnd = "\nendstream";
 
+  auto detectDeflateStreamStart = [&streamStart](const char *s)
+  {
+    size_t len = streamStart.length();
+    bool streamOK = strncmp(s,streamStart.c_str(),len)==0;
+    if (streamOK) // ASCII marker matches, check stream header bytes as well
+    {
+      unsigned short header1 = static_cast<unsigned char>(s[len])<<8; // CMF byte
+      if (header1) // not end of string
+      {
+        unsigned short header = (static_cast<unsigned char>(s[len+1])) | header1; // FLG byte
+        // check for correct header (see https://www.rfc-editor.org/rfc/rfc1950)
+        return ((header&0x8F20)==0x0800) && (header%31)==0;
+      }
+    }
+    return false;
+  };
+
   const size_t l = contents.length();
   size_t i=0;
   while (i<l)
   {
-    if (!isEps && contents[i]=='s' && strncmp(&contents[i],streamStart.c_str(),streamStart.length())==0)
+    if (!isEps && contents[i]=='s' && detectDeflateStreamStart(&contents[i]))
     { // compressed stream start
       int col=17;
       i+=streamStart.length();