Support MSVC prior to 2015

5 files changed, 45 insertions, 5 deletions

diff --git a/upb/json/parser.rl b/upb/json/parser.rl
index fd3704c..f80ed18 100644
--- a/upb/json/parser.rl
+++ b/upb/json/parser.rl
@@ -947,7 +947,7 @@ static bool parse_number_from_buffer(upb_json_parser *p, const char *buf,
   upb_fieldtype_t type = upb_fielddef_type(p->top->f);
   double val;
   double dummy;
-  double inf = 1.0 / 0.0;  /* C89 does not have an INFINITY macro. */
+  double inf = UPB_INFINITY;
 
   errno = 0;
 
diff --git a/upb/json/printer.c b/upb/json/printer.c
index 90705a7..38f817d 100644
--- a/upb/json/printer.c
+++ b/upb/json/printer.c
@@ -181,11 +181,11 @@ const char neginf[] = "\"-Infinity\"";
 const char inf[] = "\"Infinity\"";
 
 static size_t fmt_double(double val, char* buf, size_t length) {
-  if (val == (1.0 / 0.0)) {
+  if (val == UPB_INFINITY) {
     CHKLENGTH(length >= strlen(inf));
     strcpy(buf, inf);
     return strlen(inf);
-  } else if (val == (-1.0 / 0.0)) {
+  } else if (val == -UPB_INFINITY) {
     CHKLENGTH(length >= strlen(neginf));
     strcpy(buf, neginf);
     return strlen(neginf);
diff --git a/upb/port.c b/upb/port.c
new file mode 100644
index 0000000..023f7dc
--- /dev/null
+++ b/upb/port.c
@@ -0,0 +1,27 @@
+
+#include "upb/upb.h"
+#include "upb/port_def.inc"
+
+#ifdef UPB_MSVC_VSNPRINTF
+/* Visual C++ earlier than 2015 doesn't have standard C99 snprintf and
+ * vsnprintf. To support them, missing functions are manually implemented
+ * using the existing secure functions. */
+int msvc_vsnprintf(char* s, size_t n, const char* format, va_list arg) {
+  if (!s) {
+    return _vscprintf(format, arg);
+  }
+  int ret = _vsnprintf_s(s, n, _TRUNCATE, format, arg);
+  if (ret < 0) {
+	ret = _vscprintf(format, arg);
+  }
+  return ret;
+}
+
+int msvc_snprintf(char* s, size_t n, const char* format, ...) {
+  va_list arg;
+  va_start(arg, format);
+  int ret = msvc_vsnprintf(s, n, format, arg);
+  va_end(arg);
+  return ret;
+}
+#endif
diff --git a/upb/port_def.inc b/upb/port_def.inc
index 05c4ebc..0650920 100644
--- a/upb/port_def.inc
+++ b/upb/port_def.inc
@@ -76,8 +76,11 @@
 #include <stdarg.h>
 #include <stdio.h>
 #if defined(_MSC_VER) && _MSC_VER < 1900
-#define _upb_snprintf _snprintf
-#define _upb_vsnprintf _vsnprintf
+int msvc_vsnprintf(char* s, size_t n, const char* format, va_list arg);
+int msvc_snprintf(char* s, size_t n, const char* format, ...);
+#define UPB_MSVC_VSNPRINTF
+#define _upb_snprintf msvc_snprintf
+#define _upb_vsnprintf msvc_vsnprintf
 #else
 #define _upb_snprintf snprintf
 #define _upb_vsnprintf vsnprintf
@@ -135,3 +138,11 @@
 #else
 #define UPB_UNREACHABLE() do { assert(0); } while(0)
 #endif
+
+/* UPB_INFINITY representing floating-point positive infinity. */
+#include <math.h>
+#ifdef INFINITY
+#define UPB_INFINITY INFINITY
+#else
+#define UPB_INFINITY (1.0 / 0.0)
+#endif
diff --git a/upb/port_undef.inc b/upb/port_undef.inc
index bfd2a08..103180b 100644
--- a/upb/port_undef.inc
+++ b/upb/port_undef.inc
@@ -14,6 +14,8 @@
 #undef UPB_ASSERT
 #undef UPB_ASSERT_DEBUGVAR
 #undef UPB_UNREACHABLE
+#undef UPB_INFINITY
+#undef UPB_MSVC_VSNPRINTF
 #undef _upb_snprintf
 #undef _upb_vsnprintf
 #undef _upb_va_copy