src/common.[ch]: Add the ssnprintf_alloc() function.

[collectd.git] / src / common.c

diff --git a/src/common.c b/src/common.c
index 79e4c02..d963efa 100644 (file)
--- a/src/common.c
+++ b/src/common.c
@@ -86,6 +86,47 @@ int ssnprintf (char *dest, size_t n, const char *format, ...)
        return (ret);
 } /* int ssnprintf */
 
+char *ssnprintf_alloc (char const *format, ...) /* {{{ */
+{
+       char static_buffer[1024] = "";
+       char *alloc_buffer;
+       size_t alloc_buffer_size;
+       int status;
+       va_list ap;
+
+       /* Try printing into the static buffer. In many cases it will be
+        * sufficiently large and we can simply return a strdup() of this
+        * buffer. */
+       va_start (ap, format);
+       status = vsnprintf (static_buffer, sizeof (static_buffer), format, ap);
+       va_end (ap);
+       if (status < 0)
+               return (NULL);
+
+       /* "status" does not include the null byte. */
+       alloc_buffer_size = (size_t) (status + 1);
+       if (alloc_buffer_size <= sizeof (static_buffer))
+               return (strdup (static_buffer));
+
+       /* Allocate a buffer large enough to hold the string. */
+       alloc_buffer = malloc (alloc_buffer_size);
+       if (alloc_buffer == NULL)
+               return (NULL);
+       memset (alloc_buffer, 0, alloc_buffer_size);
+
+       /* Print again into this new buffer. */
+       va_start (ap, format);
+       status = vsnprintf (alloc_buffer, alloc_buffer_size, format, ap);
+       va_end (ap);
+       if (status < 0)
+       {
+               sfree (alloc_buffer);
+               return (NULL);
+       }
+
+       return (alloc_buffer);
+} /* }}} char *ssnprintf_alloc */
+
 char *sstrdup (const char *s)
 {
        char *r;