r25164: Add talloc_asprintf_append_buffer() and the docs for it.

[jelmer/samba4-debian.git] / source / lib / talloc / talloc.c

diff --git a/source/lib/talloc/talloc.c b/source/lib/talloc/talloc.c
index c3e5d2c076b87b58f32cce4ec0865db6e87b2951..7920a66d6460353265168938683c01b183906586 100644 (file)
--- a/source/lib/talloc/talloc.c
+++ b/source/lib/talloc/talloc.c
@@ -1223,7 +1223,8 @@ char *talloc_asprintf(const void *t, const char *fmt, ...)
 /**
  * Realloc @p s to append the formatted result of @p fmt and @p ap,
  * and return @p s, which may have moved.  Good for gradually
- * accumulating output into a string buffer.
+ * accumulating output into a string buffer. Appends at the end
+ * of the string.
  **/
 char *talloc_vasprintf_append(char *s, const char *fmt, va_list ap)
 {
@@ -1245,7 +1246,52 @@ char *talloc_vasprintf_append(char *s, const char *fmt, va_list ap)
                /* Either the vsnprintf failed or the format resulted in
                 * no characters being formatted. In the former case, we
                 * ought to return NULL, in the latter we ought to return
-                * the original string. Most current callers of this 
+                * the original string. Most current callers of this
+                * function expect it to never return NULL.
+                */
+               return s;
+       }
+
+       s = talloc_realloc(NULL, s, char, s_len + len+1);
+       if (!s) return NULL;
+
+       va_copy(ap2, ap);
+       vsnprintf(s+s_len, len+1, fmt, ap2);
+       va_end(ap2);
+       _talloc_set_name_const(s, s);
+
+       return s;
+}
+
+/**
+ * Realloc @p s to append the formatted result of @p fmt and @p ap,
+ * and return @p s, which may have moved. Always appends at the
+ * end of the talloc'ed buffer, not the end of the string.
+ **/
+char *talloc_vasprintf_append_buffer(char *s, const char *fmt, va_list ap)
+{
+       struct talloc_chunk *tc;
+       int len, s_len;
+       va_list ap2;
+       char c;
+
+       if (s == NULL) {
+               return talloc_vasprintf(NULL, fmt, ap);
+       }
+
+       tc = talloc_chunk_from_ptr(s);
+
+       s_len = tc->size - 1;
+
+       va_copy(ap2, ap);
+       len = vsnprintf(&c, 1, fmt, ap2);
+       va_end(ap2);
+
+       if (len <= 0) {
+               /* Either the vsnprintf failed or the format resulted in
+                * no characters being formatted. In the former case, we
+                * ought to return NULL, in the latter we ought to return
+                * the original string. Most current callers of this
                 * function expect it to never return NULL.
                 */
                return s;
@@ -1277,6 +1323,21 @@ char *talloc_asprintf_append(char *s, const char *fmt, ...)
        return s;
 }
 
+/*
+  Realloc @p s to append the formatted result of @p fmt and return @p
+  s, which may have moved.  Good for gradually accumulating output
+  into a buffer.
+ */
+char *talloc_asprintf_append_buffer(char *s, const char *fmt, ...)
+{
+       va_list ap;
+
+       va_start(ap, fmt);
+       s = talloc_vasprintf_append_buffer(s, fmt, ap);
+       va_end(ap);
+       return s;
+}
+
 /*
   alloc an array, checking for integer overflow in the array size
 */