lib: add `%pFB` extension to print struct fbuf *

Useful to insert output from another bprintfrr() call.

Signed-off-by: David Lamparter <equinox@diac24.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/lib/printf/glue.c b/lib/printf/glue.c
index 2c97dd639e..1147901236 100644
--- a/lib/printf/glue.c
+++ b/lib/printf/glue.c
@@ -256,6 +256,28 @@ ssize_t printfrr_exti(struct fbuf *buf, struct printfrr_eargs *ea,
 	return -1;
 }
 
+printfrr_ext_autoreg_p("FB", printfrr_fb)
+static ssize_t printfrr_fb(struct fbuf *out, struct printfrr_eargs *ea,
+			   const void *ptr)
+{
+	const struct fbuf *in = ptr;
+	ptrdiff_t copy_len;
+
+	if (!in)
+		return bputs(out, "NULL");
+
+	if (out) {
+		copy_len = MIN(in->pos - in->buf,
+			       out->buf + out->len - out->pos);
+		if (copy_len > 0) {
+			memcpy(out->pos, in->buf, copy_len);
+			out->pos += copy_len;
+		}
+	}
+
+	return in->pos - in->buf;
+}
+
 printfrr_ext_autoreg_p("VA", printfrr_va)
 static ssize_t printfrr_va(struct fbuf *buf, struct printfrr_eargs *ea,
 			   const void *ptr)