json.h

/* SPDX-License-Identifier: MIT
 * Source: https://ccodearchive.net/info/json.html
 * Copyright (C) 2011 Joseph A. Adams (joeyadams3.14159@gmail.com) */

#ifndef CCAN_JSON_H
#define CCAN_JSON_H

#include <lib/defines.h>
#include <stdbool.h>
#include <stddef.h>

typedef enum {
	JSON_NULL,
	JSON_BOOL,
	JSON_STRING,
	JSON_NUMBER,
	JSON_ARRAY,
	JSON_OBJECT,
} JsonTag;

typedef struct JsonNode JsonNode;

struct JsonNode
{
	/* only if parent is an object or array (NULL otherwise) */
	JsonNode *parent;
	JsonNode *prev, *next;
	
	/* only if parent is an object (NULL otherwise) */
	char *key; /* Must be valid UTF-8. */
	
	JsonTag tag;
	union {
		/* JSON_BOOL */
		bool bool_;
		
		/* JSON_STRING */
		char *string_; /* Must be valid UTF-8. */
		
		/* JSON_NUMBER */
		double number_;
		
		/* JSON_ARRAY */
		/* JSON_OBJECT */
		struct {
			JsonNode *head, *tail;
		} children;
	};
};

/*** Encoding, decoding, and validation ***/

KR_EXPORT JsonNode   *json_decode         (const char *json);
KR_EXPORT char       *json_encode         (const JsonNode *node);
KR_EXPORT char       *json_encode_string  (const char *str);
KR_EXPORT char       *json_stringify      (const JsonNode *node, const char *space);
KR_EXPORT void        json_delete         (JsonNode *node);

KR_EXPORT bool        json_validate       (const char *json);

/*** Lookup and traversal ***/

KR_EXPORT JsonNode   *json_find_element   (JsonNode *array, int index);
KR_EXPORT JsonNode   *json_find_member    (JsonNode *object, const char *key);

KR_EXPORT JsonNode   *json_first_child    (const JsonNode *node);

#define json_foreach(i, object_or_array)            \
	for ((i) = json_first_child(object_or_array);   \
		 (i) != NULL;                               \
		 (i) = (i)->next)

/*** Construction and manipulation ***/

KR_EXPORT JsonNode *json_mknull(void);
KR_EXPORT JsonNode *json_mkbool(bool b);
KR_EXPORT JsonNode *json_mkstring(const char *s);
KR_EXPORT JsonNode *json_mknumber(double n);
KR_EXPORT JsonNode *json_mkarray(void);
KR_EXPORT JsonNode *json_mkobject(void);

KR_EXPORT void json_append_element(JsonNode *array, JsonNode *element);
KR_EXPORT void json_prepend_element(JsonNode *array, JsonNode *element);
KR_EXPORT void json_append_member(JsonNode *object, const char *key, JsonNode *value);
KR_EXPORT void json_prepend_member(JsonNode *object, const char *key, JsonNode *value);

KR_EXPORT void json_remove_from_parent(JsonNode *node);

/*** Debugging ***/

/*
 * Look for structure and encoding problems in a JsonNode or its descendents.
 *
 * If a problem is detected, return false, writing a description of the problem
 * to errmsg (unless errmsg is NULL).
 */
KR_EXPORT bool json_check(const JsonNode *node, char errmsg[256]);

#endif