Use Windows CRT string functions in some places.

Copy wsutil/wsprintf.h from change 16537. Update it to use functions
appropriate to Visual C++ >= 2015, < 2015, and everything else. Add
notes about specific API issues.

Update epan/expert.c to use ws_snprintf, since the VS profiler shows it
as a minor hot spot. This reduces load time for a large-ish capture from
~14s to ~12s here.

Migrate a previous column-utils change.

Change-Id: Id4064b7c06c35fd447b63c73f731afee181df4f9
Reviewed-on: https://code.wireshark.org/review/16483
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: João Valverde <j@v6e.pt>

4 files changed, 109 insertions, 20 deletions

diff --git a/epan/column-utils.c b/epan/column-utils.c
index a3bfe87ecc..a4a9cf9a24 100644
--- a/epan/column-utils.c
+++ b/epan/column-utils.c
@@ -25,10 +25,6 @@
 #include <string.h>
 #include <time.h>
 
-#ifdef _WIN32
-#include <strsafe.h>
-#endif
-
 #include "column-utils.h"
 #include "timestamp.h"
 #include "to_str.h"
@@ -45,7 +41,9 @@
 #include <epan/strutil.h>
 #include <epan/epan.h>
 #include <epan/dfilter/dfilter.h>
+
 #include <wsutil/utf8_entities.h>
+#include <wsutil/ws_printf.h>
 
 #ifdef HAVE_LUA
 #include <epan/wslua/wslua.h>
@@ -445,21 +443,9 @@ col_snprint_port(gchar *buf, gulong buf_siz, port_type typ, guint16 val)
 
   if (gbl_resolv_flags.transport_name &&
         (str = try_serv_name_lookup(typ, val)) != NULL) {
-/*
- * I'm not sure what GLib is doing on Windows, but according to the VS 2013
- * profiler StringCchPrintf does it in 100x fewer samples.
- */
-#ifdef _WIN32
-    StringCchPrintfA(buf, buf_siz, "%s(%hu)", str, val);
-#else
-    g_snprintf(buf, buf_siz, "%s(%"G_GUINT16_FORMAT")", str, val);
-#endif
+    ws_snprintf(buf, buf_siz, "%s(%"G_GUINT16_FORMAT")", str, val);
   } else {
-#ifdef _WIN32
-    StringCchPrintfA(buf, buf_siz, "%hu", val);
-#else
-    g_snprintf(buf, buf_siz, "%"G_GUINT16_FORMAT, val);
-#endif
+    ws_snprintf(buf, buf_siz, "%"G_GUINT16_FORMAT, val);
   }
 }
 
diff --git a/epan/expert.c b/epan/expert.c
index b45541da2e..75e5981978 100644
--- a/epan/expert.c
+++ b/epan/expert.c
@@ -27,6 +27,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include <wsutil/ws_printf.h>
+
 #include "packet.h"
 #include "expert.h"
 #include "uat.h"
@@ -539,7 +541,7 @@ expert_set_info_vformat(packet_info *pinfo, proto_item *pi, int group, int sever
 	}
 
 	if (use_vaformat) {
-		g_vsnprintf(formatted, ITEM_LABEL_LENGTH, format, ap);
+		ws_vsnprintf(formatted, ITEM_LABEL_LENGTH, format, ap);
 	} else {
 		g_strlcpy(formatted, format, ITEM_LABEL_LENGTH);
 	}
diff --git a/wsutil/Makefile.am b/wsutil/Makefile.am
index 95c57d2582..2cedf9ddbb 100644
--- a/wsutil/Makefile.am
+++ b/wsutil/Makefile.am
@@ -89,7 +89,8 @@ libwsutil_nonrepl_INCLUDES = \
 	utf8_entities.h		\
 	ws_cpuid.h		\
 	ws_mempbrk.h		\
-	ws_mempbrk_int.h
+	ws_mempbrk_int.h	\
+	ws_printf.h
 
 # Header files for functions in libwsutil's ABI on this platform.
 libwsutil_abi_INCLUDES = \
diff --git a/wsutil/ws_printf.h b/wsutil/ws_printf.h
new file mode 100644
index 0000000000..1ee3bf69e6
--- /dev/null
+++ b/wsutil/ws_printf.h
@@ -0,0 +1,100 @@
+/*
+ * Wrappers for printf like functions.
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 2007 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef __WS_PRINTF_H__
+#define __WS_PRINTF_H__
+
+/*
+ * GLib's string utility routines are slow on windows, likely due to calling
+ * g_printf_string_upper_bound. Using ws_snprintf and ws_vsnprintf in hot
+ * code paths can speed up program execution. Otherwise you're probably safe
+ * sticking with g_snprintf and g_vsnprintf.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+#ifdef _WIN32
+#include <strsafe.h>
+
+#if _MSC_VER < 1900
+#include <stdarg.h>
+
+/*
+ * vsnprintf_s's return value isn't compatible with C99 vsnprintf. We don't
+ * return anything in order to avoid confusion.
+ */
+
+static __inline void
+ws_vsnprintf(char *buffer, size_t size_of_buffer, const char *format, va_list argptr) {
+    /* We could alternatively use StringCchVPrintfA */
+    vsnprintf_s(buffer, size_of_buffer, _TRUNCATE, format, argptr);
+}
+
+#else /* _MSC_VER uses UCRT */
+
+/* The UCRT versions of snprintf and vsnprintf conform to C99 */
+
+static __inline void
+ws_vsnprintf(char *buffer, size_t size_of_buffer, const char *format, va_list argptr)
+{
+    vsnprintf(buffer, size_of_buffer, format, argptr);
+}
+
+#endif /* _MSC_VER */
+
+#else /* _WIN32 */
+
+#include <glib.h>
+
+/*
+ * Use g_vsnprintf. On Linux and macOS these should be a thin wrapper around
+ * vsprintf.
+ */
+
+static inline void
+ws_vsnprintf(char *buffer, size_t size_of_buffer, const char *format, va_list argptr)
+{
+    g_vsnprintf(buffer, (gulong) size_of_buffer, format, argptr);
+}
+
+#endif /* _WIN32 */
+
+#ifdef _WIN32
+static __inline void
+#else
+static inline void
+#endif
+ws_snprintf(char *buffer, size_t size_of_buffer, const char * format, ...) {
+    va_list argptr;
+
+    va_start(argptr, format);
+    ws_vsnprintf(buffer, size_of_buffer, format, argptr);
+    va_end(argptr);
+}
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* __WS_PRINTF_H__ */