1 files changed, 28 insertions, 16 deletions

diff --git a/absl/strings/str_cat.h b/absl/strings/str_cat.h
index edda40ad..c2700475 100644
--- a/absl/strings/str_cat.h
+++ b/absl/strings/str_cat.h
@@ -5,7 +5,7 @@
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//      https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ -37,12 +37,12 @@
 // attempt to pass ':' instead of ":" might result in a 58 ending up in your
 // result.
 //
-// Bools convert to "0" or "1".
+// Bools convert to "0" or "1". Pointers to types other than `char *` are not
+// valid inputs. No output is generated for null `char *` pointers.
 //
 // Floating point numbers are formatted with six-digit precision, which is
 // the default for "std::cout <<" or printf "%g" (the same as "%.6g").
 //
-//
 // You can convert to hexadecimal output rather than decimal output using the
 // `Hex` type contained here. To do so, pass `Hex(my_int)` as a parameter to
 // `StrCat()` or `StrAppend()`. You may specify a minimum hex field width using
@@ -57,13 +57,14 @@
 #include <cstdint>
 #include <string>
 #include <type_traits>
+#include <vector>
 
 #include "absl/base/port.h"
 #include "absl/strings/numbers.h"
 #include "absl/strings/string_view.h"
 
 namespace absl {
-inline namespace lts_2018_12_18 {
+inline namespace lts_2019_08_08 {
 
 namespace strings_internal {
 // AlphaNumBuffer allows a way to pass a string to StrCat without having to do
@@ -79,8 +80,8 @@ struct AlphaNumBuffer {
 
 // Enum that specifies the number of significant digits to return in a `Hex` or
 // `Dec` conversion and fill character to use. A `kZeroPad2` value, for example,
-// would produce hexadecimal strings such as "0A","0F" and a 'kSpacePad5' value
-// would produce hexadecimal strings such as "    A","    F".
+// would produce hexadecimal strings such as "0a","0f" and a 'kSpacePad5' value
+// would produce hexadecimal strings such as "    a","    f".
 enum PadSpec : uint8_t {
   kNoPad = 1,
   kZeroPad2,
@@ -246,6 +247,7 @@ class AlphaNum {
 
   AlphaNum(const char* c_str) : piece_(c_str) {}  // NOLINT(runtime/explicit)
   AlphaNum(absl::string_view pc) : piece_(pc) {}  // NOLINT(runtime/explicit)
+
   template <typename Allocator>
   AlphaNum(  // NOLINT(runtime/explicit)
       const std::basic_string<char, std::char_traits<char>, Allocator>& str)
@@ -269,6 +271,17 @@ class AlphaNum {
   AlphaNum(T e)  // NOLINT(runtime/explicit)
       : AlphaNum(static_cast<typename std::underlying_type<T>::type>(e)) {}
 
+  // vector<bool>::reference and const_reference require special help to
+  // convert to `AlphaNum` because it requires two user defined conversions.
+  template <
+      typename T,
+      typename std::enable_if<
+          std::is_class<T>::value &&
+          (std::is_same<T, std::vector<bool>::reference>::value ||
+           std::is_same<T, std::vector<bool>::const_reference>::value)>::type* =
+          nullptr>
+  AlphaNum(T e) : AlphaNum(static_cast<bool>(e)) {}  // NOLINT(runtime/explicit)
+
  private:
   absl::string_view piece_;
   char digits_[numbers_internal::kFastToBufferSize];
@@ -318,16 +331,15 @@ ABSL_MUST_USE_RESULT inline std::string StrCat(const AlphaNum& a) {
 
 ABSL_MUST_USE_RESULT std::string StrCat(const AlphaNum& a, const AlphaNum& b);
 ABSL_MUST_USE_RESULT std::string StrCat(const AlphaNum& a, const AlphaNum& b,
-                                   const AlphaNum& c);
+                                        const AlphaNum& c);
 ABSL_MUST_USE_RESULT std::string StrCat(const AlphaNum& a, const AlphaNum& b,
-                                   const AlphaNum& c, const AlphaNum& d);
+                                        const AlphaNum& c, const AlphaNum& d);
 
 // Support 5 or more arguments
 template <typename... AV>
-ABSL_MUST_USE_RESULT inline std::string StrCat(const AlphaNum& a, const AlphaNum& b,
-                                          const AlphaNum& c, const AlphaNum& d,
-                                          const AlphaNum& e,
-                                          const AV&... args) {
+ABSL_MUST_USE_RESULT inline std::string StrCat(
+    const AlphaNum& a, const AlphaNum& b, const AlphaNum& c, const AlphaNum& d,
+    const AlphaNum& e, const AV&... args) {
   return strings_internal::CatPieces(
       {a.Piece(), b.Piece(), c.Piece(), d.Piece(), e.Piece(),
        static_cast<const AlphaNum&>(args).Piece()...});
@@ -345,18 +357,18 @@ ABSL_MUST_USE_RESULT inline std::string StrCat(const AlphaNum& a, const AlphaNum
 // not try to check each of its input arguments to be sure that they are not
 // a subset of the string being appended to. That is, while this will work:
 //
-//   string s = "foo";
+//   std::string s = "foo";
 //   s += s;
 //
 // This output is undefined:
 //
-//   string s = "foo";
+//   std::string s = "foo";
 //   StrAppend(&s, s);
 //
 // This output is undefined as well, since `absl::string_view` does not own its
 // data:
 //
-//   string s = "foobar";
+//   std::string s = "foobar";
 //   absl::string_view p = s;
 //   StrAppend(&s, p);
 
@@ -389,7 +401,7 @@ SixDigits(double d) {
   return result;
 }
 
-}  // inline namespace lts_2018_12_18
+}  // inline namespace lts_2019_08_08
 }  // namespace absl
 
 #endif  // ABSL_STRINGS_STR_CAT_H_