From: Miod Vallat <miod.vallat@powerdns.com>
Date: Thu, 26 Jun 2025 06:51:30 +0000 (+0200)
Subject: Use pdns_ilexicographical_compare_three_way() in DNSName::canonCompare()...
X-Git-Tag: rec-5.3.0-alpha2~40^2~7
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=52444a0b0e6d86f4ba497302f98853843ed2d42e;p=thirdparty%2Fpdns.git

Use pdns_ilexicographical_compare_three_way() in DNSName::canonCompare()...

...rather than two std::lexicographical_compare() calls.

Signed-off-by: Miod Vallat <miod.vallat@powerdns.com>
---

diff --git a/pdns/dnsname.cc b/pdns/dnsname.cc
index 04ba589c7e..f09f2b1e5f 100644
--- a/pdns/dnsname.cc
+++ b/pdns/dnsname.cc
@@ -498,25 +498,16 @@ bool DNSName::canonCompare(const DNSName& rhs) const
     ourcount--;
     rhscount--;
 
-    bool res=std::lexicographical_compare(
-					  d_storage.c_str() + ourpos[ourcount] + 1,
-					  d_storage.c_str() + ourpos[ourcount] + 1 + *(d_storage.c_str() + ourpos[ourcount]),
-					  rhs.d_storage.c_str() + rhspos[rhscount] + 1,
-					  rhs.d_storage.c_str() + rhspos[rhscount] + 1 + *(rhs.d_storage.c_str() + rhspos[rhscount]),
-					  DNSNameCompare());
-
-    //    cout<<"Forward: "<<res<<endl;
-    if(res)
-      return true;
-
-    res=std::lexicographical_compare(	  rhs.d_storage.c_str() + rhspos[rhscount] + 1,
-					  rhs.d_storage.c_str() + rhspos[rhscount] + 1 + *(rhs.d_storage.c_str() + rhspos[rhscount]),
-					  d_storage.c_str() + ourpos[ourcount] + 1,
-					  d_storage.c_str() + ourpos[ourcount] + 1 + *(d_storage.c_str() + ourpos[ourcount]),
-					  DNSNameCompare());
-    //    cout<<"Reverse: "<<res<<endl;
-    if(res)
-      return false;
+    int res = pdns_ilexicographical_compare_three_way(
+      std::string_view(
+        d_storage.c_str() + ourpos[ourcount] + 1,
+        *(d_storage.c_str() + ourpos[ourcount])),
+      std::string_view(
+        rhs.d_storage.c_str() + rhspos[rhscount] + 1,
+        *(rhs.d_storage.c_str() + rhspos[rhscount])));
+    if (res != 0) {
+      return res < 0;
+    }
   }
   return false;
 }
diff --git a/pdns/dnsname.hh b/pdns/dnsname.hh
index 3c44a6c8db..934a757296 100644
--- a/pdns/dnsname.hh
+++ b/pdns/dnsname.hh
@@ -62,14 +62,6 @@ inline unsigned char dns_tolower(unsigned char chr)
 #include "burtle.hh"
 #include "views.hh"
 
-struct DNSNameCompare
-{
-  bool operator()(const unsigned char& lhs, const unsigned char& rhs) const
-  {
-    return dns_tolower(lhs) < dns_tolower(rhs);
-  }
-};
-
 /* Quest in life:
      accept escaped ascii presentations of DNS names and store them "natively"
      accept a DNS packet with an offset, and extract a DNS name from it
@@ -183,10 +175,17 @@ public:
 
   bool operator<(const DNSName& rhs)  const // this delivers _some_ kind of ordering, but not one useful in a DNS context. Really fast though.
   {
+    struct DNSNameCompare
+    {
+      bool operator()(const unsigned char& lhs, const unsigned char& rhs) const
+      {
+        return dns_tolower(lhs) < dns_tolower(rhs);
+      }
+    };
+
     // note that this is case insensitive, including on the label lengths
     return std::lexicographical_compare(d_storage.rbegin(), d_storage.rend(),
-				 rhs.d_storage.rbegin(), rhs.d_storage.rend(),
-				 DNSNameCompare());
+             rhs.d_storage.rbegin(), rhs.d_storage.rend(), DNSNameCompare());
   }
 
   bool canonCompare(const DNSName& rhs) const;