Fixes for Win32 and vsnprintf.

1 files changed, 38 insertions, 21 deletions

diff --git a/xdelta3/xdelta3-main.h b/xdelta3/xdelta3-main.h
index 1e30e27..fc0d92b 100644
--- a/xdelta3/xdelta3-main.h
+++ b/xdelta3/xdelta3-main.h
@@ -1115,38 +1115,52 @@ main_set_secondary_flags (xd3_config *config)
 
 #if VCDIFF_TOOLS
 
-/* The following macros let VCDIFF printing something printf-like with
- * main_file_write(), e.g.,:
- *
- *   VC(UT "trying to be portable: %d\n", x)VE;
- */
-#define SNPRINTF_BUFSIZE 1024
-#define VC do { if (((ret = snprintf
-#define UT (char*)xfile->snprintf_buf, SNPRINTF_BUFSIZE,
-#define VE ) >= SNPRINTF_BUFSIZE                               \
-  && (ret = main_print_overflow(ret)) != 0)                    \
-  || (ret = main_file_write(xfile, xfile->snprintf_buf,        \
-                            ret, "print")) != 0)               \
-  { return ret; } } while (0)
-
-#ifdef WIN32
+#if defined(_WIN32) || defined(__DJGPP__)
 /* According to the internet, Windows vsnprintf() differs from most
  * Unix implementations regarding the terminating 0 when the boundary
  * condition is met. It doesn't matter here, we don't rely on the
- * trailing 0. */
+ * trailing 0.  Besides, both Windows and DJGPP vsnprintf return -1
+ * upon truncation, which isn't C99 compliant. To overcome this,
+ * recent MinGW runtimes provided their own vsnprintf (notice the
+ * absence of the '_' prefix) but they were initially buggy.  So,
+ * always use the native '_'-prefixed version with Win32. */
 #include <stdarg.h>
+#ifdef _WIN32
+#define vsnprintf_func _vsnprintf
+#else
+#define vsnprintf_func  vsnprintf
+#endif
+
 int
-snprintf (char *str, int n, char *fmt, ...)
+snprintf_func (char *str, int n, char *fmt, ...)
 {
   va_list a;
   int ret;
   va_start (a, fmt);
-  ret = vsnprintf (str, n, fmt, a);
+  ret = vsnprintf_func (str, n, fmt, a);
   va_end (a);
+  if (ret < 0)
+      ret = n;
   return ret;
 }
+#else
+#define snprintf_func snprintf
 #endif
 
+/* The following macros let VCDIFF printing something printf-like with
+ * main_file_write(), e.g.,:
+ *
+ *   VC(UT "trying to be portable: %d\n", x)VE;
+ */
+#define SNPRINTF_BUFSIZE 1024
+#define VC do { if (((ret = snprintf
+#define UT (char*)xfile->snprintf_buf, SNPRINTF_BUFSIZE,
+#define VE ) >= SNPRINTF_BUFSIZE                               \
+  && (ret = main_print_overflow(ret)) != 0)                    \
+  || (ret = main_file_write(xfile, xfile->snprintf_buf,        \
+                            ret, "print")) != 0)               \
+  { return ret; } } while (0)
+
 static int
 main_print_overflow (int x)
 {
@@ -3369,7 +3383,8 @@ main (int argc, char **argv)
           if (*my_optarg == 0)
             {
               /* Condition 4-5 */
-              int have_arg = my_optind < (argc - 1) && *argv[my_optind+1] != '-';
+              int have_arg = (my_optind < (argc - 1) &&
+                              *argv[my_optind+1] != '-');
 
               if (! have_arg)
                 {
@@ -3424,8 +3439,10 @@ main (int argc, char **argv)
 #endif
 #if VCDIFF_TOOLS
           else if (strcmp (my_optstr, "printhdr") == 0) { cmd = CMD_PRINTHDR; }
-          else if (strcmp (my_optstr, "printhdrs") == 0) { cmd = CMD_PRINTHDRS; }
-          else if (strcmp (my_optstr, "printdelta") == 0) { cmd = CMD_PRINTDELTA; }
+          else if (strcmp (my_optstr, "printhdrs") == 0)
+            { cmd = CMD_PRINTHDRS; }
+          else if (strcmp (my_optstr, "printdelta") == 0)
+            { cmd = CMD_PRINTDELTA; }
           else if (strcmp (my_optstr, "recode") == 0) { cmd = CMD_RECODE; }
 #endif