1 files changed, 4 insertions, 9 deletions
diff --git a/Swiften/IDN/ICUConverter.cpp b/Swiften/IDN/ICUConverter.cpp
index d6b0827..37ce708 100644
--- a/Swiften/IDN/ICUConverter.cpp
+++ b/Swiften/IDN/ICUConverter.cpp
@@ -1,11 +1,11 @@
 /*
- * Copyright (c) 2012-2016 Isode Limited.
+ * Copyright (c) 2012-2018 Isode Limited.
  * All rights reserved.
  * See the COPYING file for more information.
  */
 
 #include <Swiften/IDN/ICUConverter.h>
 
 #pragma GCC diagnostic ignored "-Wold-style-cast"
 #pragma clang diagnostic ignored "-Wheader-hygiene"
 #include <unicode/uidna.h>
@@ -13,18 +13,20 @@
 #include <unicode/ucnv.h>
 #include <unicode/ustring.h>
 
  #include <boost/numeric/conversion/cast.hpp>
 
 using namespace Swift;
 using boost::numeric_cast;
 
 namespace {
+    static constexpr auto maxStringPrepLength = 1023;
+
     typedef std::vector<UChar, SafeAllocator<UChar> > ICUString;
 
     const char* toConstCharArray(const std::string& input) {
         return input.c_str();
     }
 
     const char* toConstCharArray(const std::vector<unsigned char, SafeAllocator<unsigned char> >& input) {
         return reinterpret_cast<const char*>(vecptr(input));
     }
@@ -87,27 +89,20 @@ namespace {
     std::vector<char, SafeAllocator<char> > getStringPreparedDetail(const StringType& s, IDNConverter::StringPrepProfile profile) {
         UErrorCode status = U_ZERO_ERROR;
 
         std::shared_ptr<UStringPrepProfile> icuProfile(usprep_openByType(getICUProfileType(profile), &status), usprep_close);
         assert(U_SUCCESS(status));
 
         ICUString icuInput = convertToICUString(s);
         ICUString icuResult;
         UParseError parseError;
-        icuResult.resize(icuInput.size());
+        icuResult.resize(maxStringPrepLength);
         int32_t icuResultLength = usprep_prepare(icuProfile.get(), vecptr(icuInput), numeric_cast<int32_t>(icuInput.size()), vecptr(icuResult), numeric_cast<int32_t>(icuResult.size()), USPREP_ALLOW_UNASSIGNED, &parseError, &status);
-        icuResult.resize(numeric_cast<size_t>(icuResultLength));
-        if (status == U_BUFFER_OVERFLOW_ERROR) {
-            status = U_ZERO_ERROR;
-            icuResult.resize(numeric_cast<size_t>(icuResultLength));
-            icuResultLength = usprep_prepare(icuProfile.get(), vecptr(icuInput), numeric_cast<int32_t>(icuInput.size()), vecptr(icuResult), numeric_cast<int32_t>(icuResult.size()), USPREP_ALLOW_UNASSIGNED, &parseError, &status);
-            icuResult.resize(numeric_cast<size_t>(icuResultLength));
-        }
         if (U_FAILURE(status)) {
             return std::vector<char, SafeAllocator<char> >();
         }
         icuResult.resize(numeric_cast<size_t>(icuResultLength));
 
         return convertToArray(icuResult);
     }
 }