contrib.c: Added vasprintf/asprintf for windows.

core/contrib.c

@@ -5,6 +5,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include "config.h"
 
 //
 // wonderful utf-8 counting trickery
@@ -81,3 +82,32 @@ int potion_munmap(void *mem, size_t len)
 }
 
 #endif
+
+#if POTION_WIN32
+// vasprintf from nokogiri
+// http://github.com/tenderlove/nokogiri
+// (written by Geoffroy Couprie)
+int vasprintf (char **strp, const char *fmt, va_list ap)
+{
+  int len = vsnprintf (NULL, 0, fmt, ap) + 1;
+  char *res = (char *)malloc((unsigned int)len);
+  if (res == NULL)
+      return -1;
+  *strp = res;
+  return vsnprintf(res, (unsigned int)len, fmt, ap);
+}
+
+// asprintf from glibc
+int
+asprintf (char **string_ptr, const char *format, ...)
+{
+  va_list arg;
+  int done;
+
+  va_start (arg, format);
+  done = vasprintf (string_ptr, format, arg);
+  va_end (arg);
+
+  return done;
+}
+#endif