Add wrbuf_cstr_null

diff --git a/include/yaz/wrbuf.h b/include/yaz/wrbuf.h
index e7629d0..1d4f83b 100644 (file)
--- a/include/yaz/wrbuf.h
+++ b/include/yaz/wrbuf.h
@@ -242,11 +242,20 @@ YAZ_EXPORT int wrbuf_grow(WRBUF b, size_t minsize);
 #define wrbuf_buf(b) ((b)->buf)
 
 /** \brief returns WRBUF content as C-string
-    \param b WRBUF
+    \param b WRBUF (may not be NULL)
     \returns C-string
 */
 YAZ_EXPORT const char *wrbuf_cstr(WRBUF b);
 
+/** \brief returns WRBUF content as C-string or NULL
+    \param b WRBUF
+    \returns C-string or NULL
+
+    This function returns NULL if either b is NULL or length of buffer is 0
+*/
+YAZ_EXPORT
+const char *wrbuf_cstr_null(WRBUF b);
+
 #define wrbuf_putc(b, c) \
     ((void) ((b)->pos >= (b)->size ? wrbuf_grow(b, 1) : 0),  \
     (b)->buf[(b)->pos++] = (c), 0)

diff --git a/src/wrbuf.c b/src/wrbuf.c
index 3c63170..e57aab7 100644 (file)
--- a/src/wrbuf.c
+++ b/src/wrbuf.c
@@ -270,6 +270,15 @@ const char *wrbuf_cstr(WRBUF b)
     return b->buf;
 }
 
+const char *wrbuf_cstr_null(WRBUF b)
+{
+    if (!b || b->pos == 0)
+        return 0;
+    assert(b->pos < b->size);
+    b->buf[b->pos] = '\0';
+    return b->buf;
+}
+
 void wrbuf_cut_right(WRBUF b, size_t no_to_remove)
 {
     if (no_to_remove > b->pos)