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//usr/include/yaz/json.h

/* This file is part of the YAZ toolkit.
 * Copyright (C) Index Data.
 * All rights reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Index Data nor the names of its contributors
 *       may be used to endorse or promote products derived from this
 *       software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** \file json.h
    \brief Header for JSON functions
*/

#ifndef YAZ_JSON_H
#define YAZ_JSON_H
#include <yaz/wrbuf.h>

YAZ_BEGIN_CDECL

/** \brief JSON node type for json_node */
enum json_node_type {
    json_node_object, /**< JSON object, u.link[0] is object content */
    json_node_array,  /**< JSON array, u.link[0] is array content */
    json_node_list,   /**< JSON elements or JSON members,
                         u.link[0] is value, u.link[1] is next elemen in list */
    json_node_pair,   /**< JSON pair, u.link[0] is name, u.link[1] is value */
    json_node_string, /**< JSON string, u.string is content */
    json_node_number, /**< JSON number (floating point), u.number is content */
    json_node_true,   /**< JSON true */
    json_node_false,  /**< JSON false */
    json_node_null    /**< JSON null */
};

/** \brief JSON node */
struct json_node {
    enum json_node_type type;
    union {
        char *string;
        double number;
        struct json_node *link[2];
    } u;
};

/** \brief JSON parser (opaque) */
typedef struct json_parser_s *json_parser_t;

/** \brief create JSON parser
    \returns JSON parser handle
*/
YAZ_EXPORT
json_parser_t json_parser_create(void);

/** \brief destroys JSON parser
    \param p JSON parser handle
*/
YAZ_EXPORT
void json_parser_destroy(json_parser_t p);

/** \brief parses JSON string
    \param p JSON parser handle
    \param json_str JSON string
    \returns JSON tree or NULL if parse error occurred.

The resulting tree should be removed with a call to json_remove_node.
*/
YAZ_EXPORT
struct json_node *json_parser_parse(json_parser_t p, const char *json_str);

/** \brief returns parser error
    \param p JSON parser handle
    \returns parse error msg

This function should be called if json_parser_parse returns NULL .
*/
YAZ_EXPORT
const char *json_parser_get_errmsg(json_parser_t p);

/** \brief returns parser position
    \param p JSON parser handle
    \returns number of bytes read from parser

This function should be called if json_parser_parse returns NULL .
*/
YAZ_EXPORT
size_t json_parser_get_position(json_parser_t p);

/** \brief parses JSON string
    \param json_str JSON string
    \param errmsg pointer to error message string
    \returns JSON tree or NULL if parse error occurred.

The resulting tree should be removed with a call to json_remove_node.
    The errmsg may be NULL in which case the error message is not returned.
*/
YAZ_EXPORT
struct json_node *json_parse(const char *json_str, const char **errmsg);

/** \brief parses JSON string
    \param json_str JSON string
    \param errmsg pointer to error message string
    \param pos position of parser stop (probably error)
    \returns JSON tree or NULL if parse error occurred.

/** \brief destroys JSON tree node and its children
    \param n JSON node
*/
YAZ_EXPORT
void json_remove_node(struct json_node *n);

/** \brief gets object pair value for some name
    \param n JSON node (presumably object node)
    \param name name to match
    \returns node or NULL if not found
*/
YAZ_EXPORT
struct json_node *json_get_object(struct json_node *n, const char *name);

/** \brief gets object value and detaches from existing tree
    \param n JSON node (presumably object node)
    \param name name to match
    \returns node or NULL if not found
*/
YAZ_EXPORT
struct json_node *json_detach_object(struct json_node *n, const char *name);

/** \brief gets array element
    \param n JSON node (presumably array node)
    \param idx (0=first, 1=second, ..)
    \returns node or NULL if not found
*/
YAZ_EXPORT
struct json_node *json_get_elem(struct json_node *n, int idx);

/** \brief returns number of children (array or object)
    \param n JSON node (presumably array node or object node)
    \returns number of children
*/
YAZ_EXPORT
int json_count_children(struct json_node *n);

/** \brief appends array to another
    \param dst original array and resulting array
    \param src array to be appended to dst
    \retval -1 not arrays
    \retval 0 array appended OK
*/
YAZ_EXPORT
int json_append_array(struct json_node *dst, struct json_node *src);

/** \brief configure subst rule
    \param p JSON parser
    \param idx (%id)
    \param n node to be substituted for idx (%idx)
*/
YAZ_EXPORT
void json_parser_subst(json_parser_t p, int idx, struct json_node *n);

/** \brief converts JSON tree to JSON string
    \param node JSON tree
    \param result resulting JSON string buffer
*/
YAZ_EXPORT
void json_write_wrbuf(struct json_node *node, WRBUF result);

/** \brief writes JSON tree with indentation (pretty print)
    \param node JSON tree
    \param result resulting JSON string buffer
*/
YAZ_EXPORT
void json_write_wrbuf_pretty(struct json_node *node, WRBUF result);

YAZ_END_CDECL

#endif

/*
 * Local variables:
 * c-basic-offset: 4
 * c-file-style: "Stroustrup"
 * indent-tabs-mode: nil
 * End:
 * vim: shiftwidth=4 tabstop=8 expandtab
 */