commit f25df35e1492f621bb0c3b3fd67593e324578c04
author Niels Möller <nisse@webrtc.org> Fri May 24 09:14:13 2019 +0200
committer Commit Bot <commit-bot@chromium.org> Fri May 24 09:33:06 2019 +0000
tree 237affaebc033fa1603e575bdac6c7c04a302d98
parent ce723234bacfd0eac80a31d2a7540e9e33371175

Reland "Delete STACK_ARRAY macro, and use of alloca"

This is a reland of 74b373f04a69b279e45b0792d86c594cb33d22c1

Original change's description:
> Delete STACK_ARRAY macro, and use of alloca
> 
> Refactor the few uses of STACK_ARRAY to avoid an extra copy
> on the stack.
> 
> Bug: webrtc:6424
> Change-Id: I5c8f3c0381523db0ead31207d949df9a286c76ba
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/137806
> Commit-Queue: Niels Moller <nisse@webrtc.org>
> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#28038}

Bug: webrtc:6424
Change-Id: Id635ccdfae12157cbb3ab9089c5e4a9f77f742ce
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/138211
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28052}

rtc_base/string_utils.h

diff --git a/rtc_base/string_utils.h b/rtc_base/string_utils.h
index bc33284..f8ad126 100644
--- a/rtc_base/string_utils.h
+++ b/rtc_base/string_utils.h
@@ -21,31 +21,15 @@
 #include <wchar.h>
 #include <windows.h>
 
-#define alloca _alloca
 #endif  // WEBRTC_WIN
 
 #if defined(WEBRTC_POSIX)
-#ifdef BSD
 #include <stdlib.h>
-#else  // BSD
-#include <alloca.h>
-#endif  // !BSD
 #include <strings.h>
 #endif  // WEBRTC_POSIX
 
 #include <string>
 
-///////////////////////////////////////////////////////////////////////////////
-// Generic string/memory utilities
-///////////////////////////////////////////////////////////////////////////////
-
-#define STACK_ARRAY(TYPE, LEN) \
-  static_cast<TYPE*>(::alloca((LEN) * sizeof(TYPE)))
-
-///////////////////////////////////////////////////////////////////////////////
-// Traits simplifies porting string functions to be CTYPE-agnostic
-///////////////////////////////////////////////////////////////////////////////
-
 namespace rtc {
 
 const size_t SIZE_UNKNOWN = static_cast<size_t>(-1);
@@ -65,9 +49,10 @@
 inline std::wstring ToUtf16(const char* utf8, size_t len) {
   int len16 = ::MultiByteToWideChar(CP_UTF8, 0, utf8, static_cast<int>(len),
                                     nullptr, 0);
-  wchar_t* ws = STACK_ARRAY(wchar_t, len16);
-  ::MultiByteToWideChar(CP_UTF8, 0, utf8, static_cast<int>(len), ws, len16);
-  return std::wstring(ws, len16);
+  std::wstring ws(len16, 0);
+  ::MultiByteToWideChar(CP_UTF8, 0, utf8, static_cast<int>(len), &*ws.begin(),
+                        len16);
+  return ws;
 }
 
 inline std::wstring ToUtf16(const std::string& str) {
@@ -77,10 +62,10 @@
 inline std::string ToUtf8(const wchar_t* wide, size_t len) {
   int len8 = ::WideCharToMultiByte(CP_UTF8, 0, wide, static_cast<int>(len),
                                    nullptr, 0, nullptr, nullptr);
-  char* ns = STACK_ARRAY(char, len8);
-  ::WideCharToMultiByte(CP_UTF8, 0, wide, static_cast<int>(len), ns, len8,
-                        nullptr, nullptr);
-  return std::string(ns, len8);
+  std::string ns(len8, 0);
+  ::WideCharToMultiByte(CP_UTF8, 0, wide, static_cast<int>(len), &*ns.begin(),
+                        len8, nullptr, nullptr);
+  return ns;
 }
 
 inline std::string ToUtf8(const wchar_t* wide) {