val: fully implement unpacking

Until now, val_unpack was just a stub that always returned -ENOTSUP.  With
the recent addition of the cbor unpacking API, we can finally wire it up.

Signed-off-by: Josef 'Jeff' Sipek <[email protected]>

Author: jeffpc

val_impl_packing.h

@@ -30,10 +30,12 @@
 
 struct valops {
 	int (*pack)(struct buffer *buffer, struct val *val);
+	struct val *(*unpack)(struct buffer *buffer);
 };
 
 static const struct valops valops_cbor = {
 	.pack = cbor_pack_val,
+	.unpack = cbor_unpack_val,
 };
 
 static const struct valops valops_json = {

val_unpack.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2018 Josef 'Jeff' Sipek <[email protected]>
+ * Copyright (c) 2017-2019 Josef 'Jeff' Sipek <[email protected]>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -28,13 +28,13 @@
 struct val *val_unpack(const void *ptr, size_t len, enum val_format format)
 {
 	const struct valops *ops;
-	int ret;
+	struct buffer buffer;
 
 	ops = select_ops(format);
-	if (!ops)
+	if (!ops || !ops->unpack)
 		return ERR_PTR(-ENOTSUP);
 
-	ret = -ENOTSUP; /* FIXME */
+	buffer_init_static(&buffer, ptr, len, false);
 
-	return ERR_PTR(ret);
+	return ops->unpack(&buffer);
 }