/** * @file lyb.h * @author Michal Vasko * @brief Header for LYB format printer & parser * * Copyright (c) 2020 - 2022 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_LYB_H_ #define LY_LYB_H_ #include #include #include "parser_internal.h" struct ly_ctx; struct lysc_node; /* * LYB format * * Unlike XML or JSON, it is binary format so most data are represented in similar way but in binary. * Some notable differences: * * - schema nodes are identified based on their hash instead of their string name. In case of collisions * an array of hashes is created with each next hash one bit shorter until a unique sequence of all these * hashes is found and then all of them are stored. * * - tree structure is represented as individual strictly bounded "siblings". Each "siblings" begins * with its metadata, which consist of 1) the whole "sibling" length in bytes and 2) number * of included metadata chunks of nested "siblings". * * - since length of a "sibling" is not known before it is printed, holes are first written and * after the "sibling" is printed, they are filled with actual valid metadata. As a consequence, * LYB data cannot be directly printed into streams! * * - data are preceded with information about all the used modules. It is needed because of * possible augments and deviations which must be known beforehand, otherwise schema hashes * could be matched to the wrong nodes. * * This is a short summary of the format: * @verbatim sb = siblings_start se = siblings_end siblings = zero-LYB_SIZE_BYTES | (sb instance+ se) instance = node_type model hash node model = 16bit_zero | (model_name_length model_name revision) node = opaq | leaflist | list | any | inner | leaf opaq = opaq_data siblings leaflist = sb leaf+ se list = sb (node_header siblings)+ se any = node_header anydata_data inner = node_header siblings leaf = node_header term_value node_header = metadata node_flags @endverbatim */ /** * @brief LYB data node type */ enum lylyb_node_type { LYB_NODE_TOP, /**< top-level node */ LYB_NODE_CHILD, /**< child node with a parent */ LYB_NODE_OPAQ, /**< opaque node */ LYB_NODE_EXT /**< nested extension data node */ }; /** * @brief LYB format parser context */ struct lylyb_ctx { const struct ly_ctx *ctx; uint64_t line; /* current line */ struct ly_in *in; /* input structure */ const struct lys_module **models; struct lyd_lyb_sibling { size_t written; size_t position; uint16_t inner_chunks; } *siblings; LY_ARRAY_COUNT_TYPE sibling_size; /* LYB printer only */ struct lyd_lyb_sib_ht { struct lysc_node *first_sibling; struct ly_ht *ht; } *sib_hts; }; /** * @brief Destructor for the lylyb_ctx structure */ void lyd_lyb_ctx_free(struct lyd_ctx *lydctx); /* just a shortcut */ #define LYB_LAST_SIBLING(lybctx) lybctx->siblings[LY_ARRAY_COUNT(lybctx->siblings) - 1] /* struct lyd_lyb_sibling allocation step */ #define LYB_SIBLING_STEP 4 /* current LYB format version */ #define LYB_VERSION_NUM 0x05 /* LYB format version mask of the header byte */ #define LYB_VERSION_MASK 0x0F /** * LYB schema hash constants * * Hash is divided to collision ID and hash itself. * * @anchor collisionid * * First bits are collision ID until 1 is found. The rest is truncated 32b hash. * 1xxx xxxx - collision ID 0 (no collisions) * 01xx xxxx - collision ID 1 (collision ID 0 hash collided) * 001x xxxx - collision ID 2 ... * * When finding a match for a unique schema (siblings) hash (sequence of hashes with increasing collision ID), the highest * collision ID can be read from the last hash (LYB parser). * * To learn what is the highest collision ID of a hash that must be included in a unique schema (siblings) hash, * collisions with all the preceding sibling schema hashes must be checked (LYB printer). */ /* Number of bits the whole hash will take (including hash collision ID) */ #define LYB_HASH_BITS 8 /* Masking 32b hash (collision ID 0) */ #define LYB_HASH_MASK 0x7f /* Type for storing the whole hash (used only internally, publicly defined directly) */ #define LYB_HASH uint8_t /* Need to move this first >> collision number (from 0) to get collision ID hash part */ #define LYB_HASH_COLLISION_ID 0x80 /* How many bytes are reserved for one data chunk SIZE (8B is maximum) */ #define LYB_SIZE_BYTES 2 /* Maximum size that will be written into LYB_SIZE_BYTES (must be large enough) */ #define LYB_SIZE_MAX UINT16_MAX /* How many bytes are reserved for one data chunk inner chunk count */ #define LYB_INCHUNK_BYTES 2 /* Maximum size that will be written into LYB_INCHUNK_BYTES (must be large enough) */ #define LYB_INCHUNK_MAX UINT16_MAX /* Just a helper macro */ #define LYB_META_BYTES (LYB_INCHUNK_BYTES + LYB_SIZE_BYTES) /* model revision as XXXX XXXX XXXX XXXX (2B) (year is offset from 2000) * YYYY YYYM MMMD DDDD */ #define LYB_REV_YEAR_OFFSET 2000 #define LYB_REV_YEAR_MASK 0xfe00U #define LYB_REV_YEAR_SHIFT 9 #define LYB_REV_MONTH_MASK 0x01E0U #define LYB_REV_MONTH_SHIFT 5 #define LYB_REV_DAY_MASK 0x001fU /** * @brief Get single hash for a schema node to be used for LYB data. Read from cache, if possible. * * @param[in] node Node to hash. * @param[in] collision_id Collision ID of the hash to generate, see @ref collisionid. * @return Generated hash. */ LYB_HASH lyb_get_hash(const struct lysc_node *node, uint8_t collision_id); /** * @brief Fill the hash cache of all the schema nodes of a module. * * @param[in] mod Module to process. */ void lyb_cache_module_hash(const struct lys_module *mod); /** * @brief Check whether a node's module is in a module array. * * @param[in] node Node to check. * @param[in] models Modules in a sized array. * @return Boolean value whether @p node's module was found in the given @p models array. */ ly_bool lyb_has_schema_model(const struct lysc_node *node, const struct lys_module **models); #endif /* LY_LYB_H_ */