constexpr estimateSpaceNeeded for string literals.

[folly.git] / folly / Conv.h

diff --git a/folly/Conv.h b/folly/Conv.h
index 72518d808f5ad895ad04c33eadb5a87a711f5cc9..ce30765c6f8d3bac9e8da6129d2ba6601eaeeed9 100644 (file)
--- a/folly/Conv.h
+++ b/folly/Conv.h
@@ -400,7 +400,7 @@ void toAppend(char value, Tgt * result) {
   *result += value;
 }
 
-template<class T>
+template <class T>
 constexpr typename std::enable_if<
   std::is_same<T, char>::value,
   size_t>::type
@@ -408,6 +408,11 @@ estimateSpaceNeeded(T) {
   return 1;
 }
 
+template <size_t N>
+constexpr size_t estimateSpaceNeeded(const char (&)[N]) {
+  return N;
+}
+
 /**
  * Everything implicitly convertible to const char* gets appended.
  */
@@ -435,7 +440,7 @@ typename std::enable_if<std::is_convertible<Src, const char*>::value, size_t>::
   return 0;
 }
 
-template<class Src>
+template <class Src>
 typename std::enable_if<
   (std::is_convertible<Src, folly::StringPiece>::value ||
   IsSomeString<Src>::value) &&
@@ -450,7 +455,7 @@ inline size_t estimateSpaceNeeded(std::nullptr_t /* value */) {
   return 0;
 }
 
-template<class Src>
+template <class Src>
 typename std::enable_if<
   std::is_pointer<Src>::value &&
   IsSomeString<std::remove_pointer<Src>>::value,
@@ -523,7 +528,7 @@ toAppend(unsigned __int128 value, Tgt * result) {
   result->append(buffer + p, buffer + sizeof(buffer));
 }
 
-template<class T>
+template <class T>
 constexpr typename std::enable_if<
   std::is_same<T, __int128>::value,
   size_t>::type
@@ -531,7 +536,7 @@ estimateSpaceNeeded(T) {
   return detail::digitsEnough<__int128>();
 }
 
-template<class T>
+template <class T>
 constexpr typename std::enable_if<
   std::is_same<T, unsigned __int128>::value,
   size_t>::type
@@ -656,7 +661,7 @@ estimateSpaceNeeded(Src value) {
 namespace detail {
 constexpr int kConvMaxDecimalInShortestLow = -6;
 constexpr int kConvMaxDecimalInShortestHigh = 21;
-} // folly::detail
+} // namespace detail
 
 /** Wrapper around DoubleToStringConverter **/
 template <class Tgt, class Src>
@@ -742,7 +747,7 @@ estimateSpaceNeeded(Src value) {
  * for estimateSpaceNeed for your type, so that we allocate
  * as much as you need instead of the default
  */
-template<class Src>
+template <class Src>
 struct HasLengthEstimator : std::false_type {};
 
 template <class Src>
@@ -776,12 +781,12 @@ size_t estimateSpaceToReserve(size_t sofar, const T& v, const Ts&... vs) {
   return estimateSpaceToReserve(sofar + estimateSpaceNeeded(v), vs...);
 }
 
-template<class...Ts>
+template <class... Ts>
 void reserveInTarget(const Ts&...vs) {
   getLastElement(vs...)->reserve(estimateSpaceToReserve(0, vs...));
 }
 
-template<class Delimiter, class...Ts>
+template <class Delimiter, class... Ts>
 void reserveInTargetDelim(const Delimiter& d, const Ts&...vs) {
   static_assert(sizeof...(vs) >= 2, "Needs at least 2 args");
   size_t fordelim = (sizeof...(vs) - 2) *
@@ -830,8 +835,7 @@ toAppendDelimStrImpl(const Delimiter& delim, const T& v, const Ts&... vs) {
   toAppend(delim, detail::getLastElement(vs...));
   toAppendDelimStrImpl(delim, vs...);
 }
-} // folly::detail
-
+} // namespace detail
 
 /**
  * Variadic conversion to string. Appends each element in turn.