libubox/blobmsg.h

/*
 * blobmsg - library for generating/parsing structured blob messages
 *
 * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#ifndef __BLOBMSG_H
#define __BLOBMSG_H

#include "blob.h"

#define BLOBMSG_ALIGN	2
#define BLOBMSG_PADDING(len) (((len) + (1 << BLOBMSG_ALIGN) - 1) & ~((1 << BLOBMSG_ALIGN) - 1))

enum blobmsg_type {
	BLOBMSG_TYPE_UNSPEC,
	BLOBMSG_TYPE_ARRAY,
	BLOBMSG_TYPE_TABLE,
	BLOBMSG_TYPE_STRING,
	BLOBMSG_TYPE_INT64,
	BLOBMSG_TYPE_INT32,
	BLOBMSG_TYPE_INT16,
	BLOBMSG_TYPE_INT8,
	__BLOBMSG_TYPE_LAST,
	BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1
};

struct blobmsg_hdr {
	uint16_t namelen;
	uint8_t name[];
} __packed;

struct blobmsg_policy {
	const char *name;
	enum blobmsg_type type;
};

static inline int blobmsg_hdrlen(int namelen)
{
	return BLOBMSG_PADDING(sizeof(struct blobmsg_hdr) + namelen + 1);
}

static inline void *blobmsg_name(struct blob_attr *attr)
{
	struct blobmsg_hdr *hdr = blob_data(attr);
	return &hdr->name;
}

static inline void *blobmsg_data(struct blob_attr *attr)
{
	struct blobmsg_hdr *hdr = blob_data(attr);
	return (char *) hdr + blobmsg_hdrlen(hdr->namelen);
}

static inline int blobmsg_data_len(struct blob_attr *attr)
{
	uint8_t *start, *end;

	start = blob_data(attr);
	end = blobmsg_data(attr);

	return blob_len(attr) - (end - start);
}

bool blobmsg_check_attr(const struct blob_attr *attr, bool name);
int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
                  struct blob_attr **tb, void *data, int len);

int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
                      const void *data, int len);

static inline int
blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
{
	return blobmsg_add_field(buf, BLOBMSG_TYPE_INT8, name, &val, 1);
}

static inline int
blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)
{
	return blobmsg_add_field(buf, BLOBMSG_TYPE_INT16, name, &val, 2);
}

static inline int
blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)
{
	return blobmsg_add_field(buf, BLOBMSG_TYPE_INT32, name, &val, 4);
}

static inline int
blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)
{
	return blobmsg_add_field(buf, BLOBMSG_TYPE_INT64, name, &val, 8);
}

static inline int
blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)
{
	return blobmsg_add_field(buf, BLOBMSG_TYPE_STRING, name, string, strlen(string) + 1);
}

void *blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array);

static inline void *
blobmsg_open_array(struct blob_buf *buf, const char *name)
{
	return blobmsg_open_nested(buf, name, true);
}

static inline void *
blobmsg_open_table(struct blob_buf *buf, const char *name)
{
	return blobmsg_open_nested(buf, name, false);
}

static inline void
blobmsg_close_array(struct blob_buf *buf, void *cookie)
{
	blob_nest_end(buf, cookie);
}

static inline void
blobmsg_close_table(struct blob_buf *buf, void *cookie)
{
	blob_nest_end(buf, cookie);
}

static inline int blobmsg_buf_init(struct blob_buf *buf)
{
	return blob_buf_init(buf, BLOBMSG_TYPE_TABLE);
}

char *blobmsg_format_json(struct blob_attr *attr);

#define blobmsg_for_each_attr(pos, attr, rem) \
	for (rem = blobmsg_data_len(attr), pos = blobmsg_data(attr); \
		 (blob_pad_len(pos) <= rem) && \
		 (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
		 rem -= blob_pad_len(pos), pos = blob_next(pos))

#endif