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/**
* @file json.h
* @author Radek Krejci <rkrejci@cesnet.cz>
* @brief Generic JSON format parser routines.
*
* Copyright (c) 2020 CESNET, z.s.p.o.
*
* This source code is licensed under BSD 3-Clause License (the "License").
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://opensource.org/licenses/BSD-3-Clause
*/
#ifndef LY_JSON_H_
#define LY_JSON_H_
#include <stddef.h>
#include <stdint.h>
#include "log.h"
#include "set.h"
struct ly_ctx;
struct ly_in;
/* Macro to test if character is whitespace */
#define is_jsonws(c) (c == 0x20 || c == 0x9 || c == 0xa || c == 0xd)
/* Macro to test if character is valid string character */
#define is_jsonstrchar(c) (c == 0x20 || c == 0x21 || (c >= 0x23 && c <= 0x5b) || (c >= 0x5d && c <= 0x10ffff))
/* Macro to push JSON parser status */
#define LYJSON_STATUS_PUSH_RET(CTX, STATUS) \
LY_CHECK_RET(ly_set_add(&CTX->status, (void *)(uintptr_t)(STATUS), 1, NULL))
/* Macro to pop JSON parser status */
#define LYJSON_STATUS_POP_RET(CTX) \
assert(CTX->status.count); CTX->status.count--;
/**
* @brief Status of the parser providing information what is expected next (which function is supposed to be called).
*/
enum LYJSON_PARSER_STATUS {
LYJSON_ERROR, /* JSON parser error - value is used as an error return code */
LYJSON_ROOT, /* JSON document root, used internally */
LYJSON_OBJECT, /* JSON object */
LYJSON_OBJECT_CLOSED, /* JSON object closed */
LYJSON_OBJECT_EMPTY, /* empty JSON object { } */
LYJSON_ARRAY, /* JSON array */
LYJSON_ARRAY_CLOSED, /* JSON array closed */
LYJSON_ARRAY_EMPTY, /* empty JSON array */
LYJSON_NUMBER, /* JSON number value */
LYJSON_STRING, /* JSON string value */
LYJSON_FALSE, /* JSON false value */
LYJSON_TRUE, /* JSON true value */
LYJSON_NULL, /* JSON null value */
LYJSON_END /* end of input data */
};
struct lyjson_ctx {
const struct ly_ctx *ctx;
struct ly_in *in; /* input structure */
struct ly_set status; /* stack of ::LYJSON_PARSER_STATUS values corresponding to the JSON items being processed */
const char *value; /* ::LYJSON_STRING, ::LYJSON_NUMBER, ::LYJSON_OBJECT */
size_t value_len; /* ::LYJSON_STRING, ::LYJSON_NUMBER, ::LYJSON_OBJECT */
ly_bool dynamic; /* ::LYJSON_STRING, ::LYJSON_NUMBER, ::LYJSON_OBJECT */
uint32_t depth; /* current number of nested blocks, see ::LY_MAX_BLOCK_DEPTH */
struct {
enum LYJSON_PARSER_STATUS status;
uint32_t status_count;
const char *value;
size_t value_len;
ly_bool dynamic;
uint32_t depth;
const char *input;
} backup;
};
/**
* @brief Create a new JSON parser context and start parsing.
*
* @param[in] ctx libyang context.
* @param[in] in JSON string data to parse.
* @param[in] subtree Whether this is a special case of parsing a subtree (starting with object name).
* @param[out] jsonctx New JSON context with status referring the parsed value.
* @return LY_ERR value.
*/
LY_ERR lyjson_ctx_new(const struct ly_ctx *ctx, struct ly_in *in, ly_bool subtree, struct lyjson_ctx **jsonctx);
/**
* @brief Get status of the parser as the last/previous parsed token
*
* @param[in] jsonctx JSON context to check.
* @param[in] index Index of the token, starting by 0 for the last token
* @return ::LYJSON_ERROR in case of invalid index, other ::LYJSON_PARSER_STATUS corresponding to the token.
*/
enum LYJSON_PARSER_STATUS lyjson_ctx_status(struct lyjson_ctx *jsonctx, uint32_t index);
/**
* @brief Get string representation of the JSON context status (token).
*
* @param[in] status Context status (aka JSON token)
* @return String representation of the @p status.
*/
const char *lyjson_token2str(enum LYJSON_PARSER_STATUS status);
/**
* @brief Move to the next JSON artifact and update parser status.
*
* @param[in] jsonctx XML context to move.
* @param[out] status Optional parameter to provide new parser status
* @return LY_ERR value.
*/
LY_ERR lyjson_ctx_next(struct lyjson_ctx *jsonctx, enum LYJSON_PARSER_STATUS *status);
/**
* @brief Backup the JSON parser context's state To restore the backup, use ::lyjson_ctx_restore().
* @param[in] jsonctx JSON parser context to backup.
*/
void lyjson_ctx_backup(struct lyjson_ctx *jsonctx);
/**
* @brief REstore the JSON parser context's state from the backup created by ::lyjson_ctx_backup().
* @param[in] jsonctx JSON parser context to restore.
*/
void lyjson_ctx_restore(struct lyjson_ctx *jsonctx);
/**
* @brief Remove the allocated working memory of the context.
*
* @param[in] jsonctx JSON context to clear.
*/
void lyjson_ctx_free(struct lyjson_ctx *jsonctx);
#endif /* LY_JSON_H_ */
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