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| -rw-r--r-- | src/json.h | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/src/json.h b/src/json.h new file mode 100644 index 0000000..53efe2a --- /dev/null +++ b/src/json.h @@ -0,0 +1,139 @@ +/** + * @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_ */ |