asprintf: new asprintf module.

[ccan] / ccan / asprintf / asprintf.c

diff --git a/ccan/asprintf/asprintf.c b/ccan/asprintf/asprintf.c
new file mode 100644 (file)
index 0000000..b6ccce6
--- /dev/null
+++ b/ccan/asprintf/asprintf.c
@@ -0,0 +1,55 @@
+#include <ccan/asprintf/asprintf.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+char *PRINTF_FMT(1, 2) afmt(const char *fmt, ...)
+{
+       va_list ap;
+       char *ptr;
+
+       va_start(ap, fmt);
+       /* The BSD version apparently sets ptr to NULL on fail.  GNU loses. */
+       if (vasprintf(&ptr, fmt, ap) < 0)
+               ptr = NULL;
+       va_end(ap);
+       return ptr;
+}
+
+#if !HAVE_ASPRINTF
+#include <stdarg.h>
+#include <stdlib.h>
+
+int vasprintf(char **strp, const char *fmt, va_list ap)
+{
+       int len;
+       va_list ap_copy;
+
+       /* We need to make a copy of ap, since it's a use-once. */
+       va_copy(ap_copy, ap);
+       len = vsnprintf(NULL, 0, fmt, ap_copy);
+       va_end(ap_copy);
+
+       /* Until version 2.0.6 glibc would return -1 on truncated output.
+        * OTOH, they had asprintf. */
+       if (len < 0)
+               return -1;
+
+       *strp = malloc(len+1);
+       if (!*strp)
+               return -1;
+
+       return vsprintf(*strp, fmt, ap);
+}
+
+int asprintf(char **strp, const char *fmt, ...)
+{
+       va_list ap;
+       int len;
+
+       va_start(ap, fmt);
+       len = vasprintf(strp, fmt, ap);
+       va_end(ap);
+
+       return len;
+}
+#endif /* !HAVE_ASPRINTF */