blobmsg: add support for double

This adds support for double floating point type to make it more JSON
compatible. For type checking it also adds a stub BLOB_ATTR_DOUBLE type.
If necessary, the accessor functions for blob can be added later

Signed-off-by: André Gaul <andre@gaul.io>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

blob.c

@@ -192,6 +192,7 @@ static const int blob_type_minlen[BLOB_ATTR_LAST] = {
 	[BLOB_ATTR_INT16] = sizeof(uint16_t),
 	[BLOB_ATTR_INT32] = sizeof(uint32_t),
 	[BLOB_ATTR_INT64] = sizeof(uint64_t),
+	[BLOB_ATTR_DOUBLE] = sizeof(double),
 };
 
 bool

blob.h

@@ -39,6 +39,7 @@ enum {
 	BLOB_ATTR_INT16,
 	BLOB_ATTR_INT32,
 	BLOB_ATTR_INT64,
+	BLOB_ATTR_DOUBLE,
 	BLOB_ATTR_LAST
 };
 

blobmsg.c

@@ -20,6 +20,7 @@ static const int blob_type[__BLOBMSG_TYPE_LAST] = {
 	[BLOBMSG_TYPE_INT16] = BLOB_ATTR_INT16,
 	[BLOBMSG_TYPE_INT32] = BLOB_ATTR_INT32,
 	[BLOBMSG_TYPE_INT64] = BLOB_ATTR_INT64,
+	[BLOBMSG_TYPE_DOUBLE] = BLOB_ATTR_DOUBLE,
 	[BLOBMSG_TYPE_STRING] = BLOB_ATTR_STRING,
 	[BLOBMSG_TYPE_UNSPEC] = BLOB_ATTR_BINARY,
 };

blobmsg.h

@@ -31,6 +31,7 @@ enum blobmsg_type {
 	BLOBMSG_TYPE_INT32,
 	BLOBMSG_TYPE_INT16,
 	BLOBMSG_TYPE_INT8,
+	BLOBMSG_TYPE_DOUBLE,
 	__BLOBMSG_TYPE_LAST,
 	BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,
 	BLOBMSG_TYPE_BOOL = BLOBMSG_TYPE_INT8,
@@ -113,6 +114,18 @@ int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
 int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
                       const void *data, unsigned int len);
 
+static inline int
+blobmsg_add_double(struct blob_buf *buf, const char *name, double val)
+{
+	union {
+		double d;
+		uint64_t u64;
+	} v;
+	v.d = val;
+	v.u64 = cpu_to_be64(v.u64);
+	return blobmsg_add_field(buf, BLOBMSG_TYPE_DOUBLE, name, &v.u64, 8);
+}
+
 static inline int
 blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
 {
@@ -212,6 +225,16 @@ static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
 	return tmp;
 }
 
+static inline double blobmsg_get_double(struct blob_attr *attr)
+{
+	union {
+		double d;
+		uint64_t u64;
+	} v;
+	v.u64 = blobmsg_get_u64(attr);
+	return v.d;
+}
+
 static inline char *blobmsg_get_string(struct blob_attr *attr)
 {
 	if (!attr)

blobmsg_json.c

@@ -69,6 +69,9 @@ bool blobmsg_add_json_element(struct blob_buf *b, const char *name, json_object
 	case json_type_int:
 		blobmsg_add_u32(b, name, json_object_get_int(obj));
 		break;
+	case json_type_double:
+		blobmsg_add_double(b, name, json_object_get_double(obj));
+		break;
 	case json_type_null:
 		blobmsg_add_field(b, BLOBMSG_TYPE_UNSPEC, name, NULL, 0);
 		break;
@@ -255,6 +258,9 @@ static void blobmsg_format_element(struct strbuf *s, struct blob_attr *attr, boo
 	case BLOBMSG_TYPE_INT64:
 		sprintf(buf, "%" PRId64, (int64_t) be64_to_cpu(*(uint64_t *)data));
 		break;
+	case BLOBMSG_TYPE_DOUBLE:
+		sprintf(buf, "%lf", blobmsg_get_double(attr));
+		break;
 	case BLOBMSG_TYPE_STRING:
 		blobmsg_format_string(s, data);
 		return;

examples/blobmsg-example.c

@@ -49,6 +49,9 @@ static void dump_attr_data(struct blob_attr *data, int indent, int next_indent)
 	case BLOBMSG_TYPE_INT64:
 		indent_printf(indent, "%"PRIu64"\n", blobmsg_get_u64(data));
 		break;
+	case BLOBMSG_TYPE_DOUBLE:
+		indent_printf(indent, "%lf\n", blobmsg_get_double(data));
+		break;
 	case BLOBMSG_TYPE_TABLE:
 	case BLOBMSG_TYPE_ARRAY:
 		if (!indent)
@@ -113,6 +116,7 @@ fill_message(struct blob_buf *buf)
 	blobmsg_add_string(buf, "message", "Hello, world!");
 
 	tbl = blobmsg_open_table(buf, "testdata");
+	blobmsg_add_double(buf, "double", 1.337e2);
 	blobmsg_add_u32(buf, "hello", 1);
 	blobmsg_add_string(buf, "world", "2");
 	blobmsg_close_table(buf, tbl);
@@ -121,6 +125,7 @@ fill_message(struct blob_buf *buf)
 	blobmsg_add_u32(buf, NULL, 0);
 	blobmsg_add_u32(buf, NULL, 1);
 	blobmsg_add_u32(buf, NULL, 2);
+	blobmsg_add_double(buf, "double", 1.337e2);
 	blobmsg_close_table(buf, tbl);
 }