Make fbstring libgcc-safe

[folly.git] / folly / String-inl.h

diff --git a/folly/String-inl.h b/folly/String-inl.h
index 8ae2d20af86a37a9172e1f9c7796c934f01b465a..52b665c75e6e662d464fa65ba42dfb18999f9078 100644 (file)
--- a/folly/String-inl.h
+++ b/folly/String-inl.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 Facebook, Inc.
+ * Copyright 2014 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -300,7 +300,7 @@ template<> struct OutputConverter<StringPiece> {
 template<class OutStringT, class DelimT, class OutputIterator>
 void internalSplit(DelimT delim, StringPiece sp, OutputIterator out,
     bool ignoreEmpty) {
-  assert(sp.start() != nullptr);
+  assert(sp.empty() || sp.start() != nullptr);
 
   const char* s = sp.start();
   const size_t strSize = sp.size();
@@ -347,6 +347,50 @@ template<class String> StringPiece prepareDelim(const String& s) {
 }
 inline char prepareDelim(char c) { return c; }
 
+template <class Dst>
+struct convertTo {
+  template <class Src>
+  static Dst from(const Src& src) { return folly::to<Dst>(src); }
+  static Dst from(const Dst& src) { return src; }
+};
+
+template<bool exact,
+         class Delim,
+         class OutputType>
+typename std::enable_if<IsSplitTargetType<OutputType>::value, bool>::type
+splitFixed(const Delim& delimiter,
+           StringPiece input,
+           OutputType& out) {
+  if (exact && UNLIKELY(std::string::npos != input.find(delimiter))) {
+    return false;
+  }
+  out = convertTo<OutputType>::from(input);
+  return true;
+}
+
+template<bool exact,
+         class Delim,
+         class OutputType,
+         class... OutputTypes>
+typename std::enable_if<IsSplitTargetType<OutputType>::value, bool>::type
+splitFixed(const Delim& delimiter,
+           StringPiece input,
+           OutputType& outHead,
+           OutputTypes&... outTail) {
+  size_t cut = input.find(delimiter);
+  if (UNLIKELY(cut == std::string::npos)) {
+    return false;
+  }
+  StringPiece head(input.begin(), input.begin() + cut);
+  StringPiece tail(input.begin() + cut + detail::delimSize(delimiter),
+                   input.end());
+  if (LIKELY(splitFixed<exact>(delimiter, tail, outTail...))) {
+    outHead = convertTo<OutputType>::from(head);
+    return true;
+  }
+  return false;
+}
+
 }
 
 //////////////////////////////////////////////////////////////////////
@@ -388,11 +432,38 @@ void splitTo(const Delim& delimiter,
     ignoreEmpty);
 }
 
+template<bool exact,
+         class Delim,
+         class OutputType,
+         class... OutputTypes>
+typename std::enable_if<IsSplitTargetType<OutputType>::value, bool>::type
+split(const Delim& delimiter,
+      StringPiece input,
+      OutputType& outHead,
+      OutputTypes&... outTail) {
+  return detail::splitFixed<exact>(
+    detail::prepareDelim(delimiter),
+    input,
+    outHead,
+    outTail...);
+}
+
 namespace detail {
 
+/*
+ * If a type can have its string size determined cheaply, we can more
+ * efficiently append it in a loop (see internalJoinAppend). Note that the
+ * struct need not conform to the std::string api completely (ex. does not need
+ * to implement append()).
+ */
+template <class T> struct IsSizableString {
+  enum { value = IsSomeString<T>::value
+         || std::is_same<T, StringPiece>::value };
+};
+
 template <class Iterator>
-struct IsStringContainerIterator :
-  IsSomeString<typename std::iterator_traits<Iterator>::value_type> {
+struct IsSizableStringContainerIterator :
+  IsSizableString<typename std::iterator_traits<Iterator>::value_type> {
 };
 
 template <class Delim, class Iterator, class String>
@@ -413,7 +484,7 @@ void internalJoinAppend(Delim delimiter,
 }
 
 template <class Delim, class Iterator, class String>
-typename std::enable_if<IsStringContainerIterator<Iterator>::value>::type
+typename std::enable_if<IsSizableStringContainerIterator<Iterator>::value>::type
 internalJoin(Delim delimiter,
              Iterator begin,
              Iterator end,
@@ -433,7 +504,8 @@ internalJoin(Delim delimiter,
 }
 
 template <class Delim, class Iterator, class String>
-typename std::enable_if<!IsStringContainerIterator<Iterator>::value>::type
+typename
+std::enable_if<!IsSizableStringContainerIterator<Iterator>::value>::type
 internalJoin(Delim delimiter,
              Iterator begin,
              Iterator end,
@@ -601,4 +673,3 @@ void hexDump(const void* ptr, size_t size, OutIt out) {
 }  // namespace folly
 
 #endif /* FOLLY_STRING_INL_H_ */
-