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}
diff --git a/rtc_base/string_encode.cc b/rtc_base/string_encode.cc
index 7b2eda7..da31ac0 100644
--- a/rtc_base/string_encode.cc
+++ b/rtc_base/string_encode.cc
@@ -14,7 +14,6 @@
#include "rtc_base/arraysize.h"
#include "rtc_base/checks.h"
-#include "rtc_base/string_utils.h"
namespace rtc {
@@ -45,25 +44,22 @@
return true;
}
-// hex_encode, but separate each byte representation with a delimiter.
-// |delimiter| == 0 means no delimiter
-// If the buffer is too short, we return 0
-size_t hex_encode_with_delimiter(char* buffer,
- size_t buflen,
- const char* csource,
- size_t srclen,
- char delimiter) {
- RTC_DCHECK(buffer); // TODO(kwiberg): estimate output size
- if (buflen == 0)
- return 0;
+size_t hex_encode_output_length(size_t srclen, char delimiter) {
+ return delimiter && srclen > 0 ? (srclen * 3 - 1) : (srclen * 2);
+}
+
+// hex_encode shows the hex representation of binary data in ascii, with
+// |delimiter| between bytes, or none if |delimiter| == 0.
+void hex_encode_with_delimiter(char* buffer,
+ const char* csource,
+ size_t srclen,
+ char delimiter) {
+ RTC_DCHECK(buffer);
// Init and check bounds.
const unsigned char* bsource =
reinterpret_cast<const unsigned char*>(csource);
size_t srcpos = 0, bufpos = 0;
- size_t needed = delimiter ? (srclen * 3) : (srclen * 2 + 1);
- if (buflen < needed)
- return 0;
while (srcpos < srclen) {
unsigned char ch = bsource[srcpos++];
@@ -77,10 +73,6 @@
++bufpos;
}
}
-
- // Null terminate.
- buffer[bufpos] = '\0';
- return bufpos;
}
} // namespace
@@ -96,12 +88,11 @@
std::string hex_encode_with_delimiter(const char* source,
size_t srclen,
char delimiter) {
- const size_t kBufferSize = srclen * 3;
- char* buffer = STACK_ARRAY(char, kBufferSize);
- size_t length =
- hex_encode_with_delimiter(buffer, kBufferSize, source, srclen, delimiter);
- RTC_DCHECK(srclen == 0 || length > 0);
- return std::string(buffer, length);
+ std::string s(hex_encode_output_length(srclen, delimiter), 0);
+ // TODO(nisse): When we can use C++17, switch the below hack with begin to
+ // just s.data().
+ hex_encode_with_delimiter(&*s.begin(), source, srclen, delimiter);
+ return s;
}
size_t hex_decode(char* cbuffer,
diff --git a/rtc_base/string_utils.h b/rtc_base/string_utils.h
index bc33284..5b5d33c 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(),
+ ws.size());
+ 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(),
+ ns.size(), nullptr, nullptr);
+ return ns;
}
inline std::string ToUtf8(const wchar_t* wide) {
