X-Git-Url: http://plrg.eecs.uci.edu/git/?p=folly.git;a=blobdiff_plain;f=folly%2FIPAddressV6.cpp;h=6f1eb5958996c5f12bb16204a6c2a3398ddf26de;hp=203d14a88489746e77195a6d7ebdedcab266aee1;hb=14d85244f8b72912c44ff43ccdd5e55c0b84c9e2;hpb=b41eb6f0aa3c97a31df39cfcacd6a1a46ed976b6

diff --git a/folly/IPAddressV6.cpp b/folly/IPAddressV6.cpp
index 203d14a8..6f1eb595 100644
--- a/folly/IPAddressV6.cpp
+++ b/folly/IPAddressV6.cpp
@@ -173,6 +173,34 @@ void IPAddressV6::setFromBinary(ByteRange bytes) {
   scope_ = 0;
 }
 
+// static
+IPAddressV6 IPAddressV6::fromInverseArpaName(const std::string& arpaname) {
+  auto piece = StringPiece(arpaname);
+  if (!piece.removeSuffix(".ip6.arpa")) {
+    throw IPAddressFormatException(sformat(
+        "Invalid input. Should end with 'ip6.arpa'. Got '{}'", arpaname));
+  }
+  std::vector<StringPiece> pieces;
+  split(".", piece, pieces);
+  if (pieces.size() != 32) {
+    throw IPAddressFormatException(sformat("Invalid input. Got '{}'", piece));
+  }
+  std::array<char, IPAddressV6::kToFullyQualifiedSize> ip;
+  size_t pos = 0;
+  int count = 0;
+  for (size_t i = 1; i <= pieces.size(); i++) {
+    ip[pos] = pieces[pieces.size() - i][0];
+    pos++;
+    count++;
+    // add ':' every 4 chars
+    if (count == 4 && pos < ip.size()) {
+      ip[pos++] = ':';
+      count = 0;
+    }
+  }
+  return IPAddressV6(folly::range(ip));
+}
+
 // public
 IPAddressV4 IPAddressV6::createIPv4() const {
   if (!isIPv4Mapped()) {