Adding upstream version 3.1.0+dfsg.upstream/3.1.0+dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1826 insertions, 0 deletions

diff --git a/src/tree_data_common.c b/src/tree_data_common.c
new file mode 100644
index 0000000..05cab2a
--- /dev/null
+++ b/src/tree_data_common.c
@@ -0,0 +1,1826 @@
+/**
+ * @file tree_data_common.c
+ * @author Radek Krejci <rkrejci@cesnet.cz>
+ * @author Michal Vasko <mvasko@cesnet.cz>
+ * @brief Parsing and validation common functions for data trees
+ *
+ * Copyright (c) 2015 - 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
+ */
+
+#define _GNU_SOURCE /* asprintf, strdup */
+
+#include <assert.h>
+#include <ctype.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "compat.h"
+#include "context.h"
+#include "dict.h"
+#include "hash_table.h"
+#include "log.h"
+#include "ly_common.h"
+#include "lyb.h"
+#include "metadata.h"
+#include "parser_data.h"
+#include "plugins_exts.h"
+#include "printer_data.h"
+#include "set.h"
+#include "tree.h"
+#include "tree_data.h"
+#include "tree_data_internal.h"
+#include "tree_edit.h"
+#include "tree_schema.h"
+#include "tree_schema_internal.h"
+#include "validation.h"
+#include "xml.h"
+#include "xpath.h"
+
+/**
+ * @brief Callback for checking first instance hash table values equivalence.
+ *
+ * @param[in] val1_p If not @p mod, pointer to the first instance.
+ * @param[in] val2_p If not @p mod, pointer to the found dup inst item.
+ */
+static ly_bool
+lyht_dup_inst_ht_equal_cb(void *val1_p, void *val2_p, ly_bool mod, void *UNUSED(cb_data))
+{
+    if (mod) {
+        struct lyd_dup_inst **item1 = val1_p, **item2 = val2_p;
+
+        /* equal on 2 dup inst items */
+        return *item1 == *item2 ? 1 : 0;
+    } else {
+        struct lyd_node **first_inst = val1_p;
+        struct lyd_dup_inst **item = val2_p;
+
+        /* equal on dup inst item and a first instance */
+        return (*item)->set->dnodes[0] == *first_inst ? 1 : 0;
+    }
+}
+
+/**
+ * @brief Find an entry in duplicate instance cache for an instance. Create it if it does not exist.
+ *
+ * @param[in] first_inst First instance of the cache entry.
+ * @param[in] dup_inst_ht Duplicate instance cache hash table.
+ * @return Instance cache entry.
+ */
+static struct lyd_dup_inst *
+lyd_dup_inst_get(const struct lyd_node *first_inst, struct ly_ht **dup_inst_ht)
+{
+    struct lyd_dup_inst **item_p, *item;
+
+    if (*dup_inst_ht) {
+        /* find the item of the first instance */
+        if (!lyht_find(*dup_inst_ht, &first_inst, first_inst->hash, (void **)&item_p)) {
+            return *item_p;
+        }
+    } else {
+        /* create the hash table */
+        *dup_inst_ht = lyht_new(2, sizeof item, lyht_dup_inst_ht_equal_cb, NULL, 1);
+        LY_CHECK_RET(!*dup_inst_ht, NULL);
+    }
+
+    /* first instance has no dup inst item, create it */
+    item = calloc(1, sizeof *item);
+    LY_CHECK_RET(!item, NULL);
+
+    /* add into the hash table */
+    if (lyht_insert(*dup_inst_ht, &item, first_inst->hash, NULL)) {
+        return NULL;
+    }
+
+    return item;
+}
+
+LY_ERR
+lyd_dup_inst_next(struct lyd_node **inst, const struct lyd_node *siblings, struct ly_ht **dup_inst_ht)
+{
+    struct lyd_dup_inst *dup_inst;
+
+    if (!*inst) {
+        /* no match, inst is unchanged */
+        return LY_SUCCESS;
+    }
+
+    /* there can be more exact same instances (even if not allowed in invalid data) and we must make sure we do not
+     * match a single node more times */
+    dup_inst = lyd_dup_inst_get(*inst, dup_inst_ht);
+    LY_CHECK_ERR_RET(!dup_inst, LOGMEM(LYD_CTX(siblings)), LY_EMEM);
+
+    if (!dup_inst->used) {
+        /* we did not cache these instances yet, do so */
+        lyd_find_sibling_dup_inst_set(siblings, *inst, &dup_inst->set);
+        assert(dup_inst->set->count && (dup_inst->set->dnodes[0] == *inst));
+    }
+
+    if (dup_inst->used == dup_inst->set->count) {
+        if (lysc_is_dup_inst_list((*inst)->schema)) {
+            /* we have used all the instances */
+            *inst = NULL;
+        } /* else just keep using the last (ideally only) instance */
+    } else {
+        assert(dup_inst->used < dup_inst->set->count);
+
+        /* use another instance */
+        *inst = dup_inst->set->dnodes[dup_inst->used];
+        ++dup_inst->used;
+    }
+
+    return LY_SUCCESS;
+}
+
+/**
+ * @brief Callback for freeing first instance hash table values.
+ */
+static void
+lyht_dup_inst_ht_free_cb(void *val_p)
+{
+    struct lyd_dup_inst **item = val_p;
+
+    ly_set_free((*item)->set, NULL);
+    free(*item);
+}
+
+void
+lyd_dup_inst_free(struct ly_ht *dup_inst_ht)
+{
+    lyht_free(dup_inst_ht, lyht_dup_inst_ht_free_cb);
+}
+
+struct lyd_node *
+lys_getnext_data(const struct lyd_node *last, const struct lyd_node *sibling, const struct lysc_node **slast,
+        const struct lysc_node *parent, const struct lysc_module *module)
+{
+    const struct lysc_node *siter = NULL;
+    struct lyd_node *match = NULL;
+
+    assert(parent || module);
+    assert(!last || (slast && *slast));
+
+    if (slast) {
+        siter = *slast;
+    }
+
+    if (last && last->next && (last->next->schema == siter)) {
+        /* return next data instance */
+        return last->next;
+    }
+
+    /* find next schema node data instance */
+    while ((siter = lys_getnext(siter, parent, module, 0))) {
+        if (!lyd_find_sibling_val(sibling, siter, NULL, 0, &match)) {
+            break;
+        }
+    }
+
+    if (slast) {
+        *slast = siter;
+    }
+    return match;
+}
+
+struct lyd_node **
+lyd_node_child_p(struct lyd_node *node)
+{
+    assert(node);
+
+    if (!node->schema) {
+        return &((struct lyd_node_opaq *)node)->child;
+    } else {
+        switch (node->schema->nodetype) {
+        case LYS_CONTAINER:
+        case LYS_LIST:
+        case LYS_RPC:
+        case LYS_ACTION:
+        case LYS_NOTIF:
+            return &((struct lyd_node_inner *)node)->child;
+        default:
+            return NULL;
+        }
+    }
+}
+
+LIBYANG_API_DEF LY_ERR
+lyxp_vars_set(struct lyxp_var **vars, const char *name, const char *value)
+{
+    LY_ERR ret = LY_SUCCESS;
+    char *var_name = NULL, *var_value = NULL;
+    struct lyxp_var *item;
+
+    if (!vars || !name || !value) {
+        return LY_EINVAL;
+    }
+
+    /* if variable is already defined then change its value */
+    if (*vars && !lyxp_vars_find(NULL, *vars, name, 0, &item)) {
+        var_value = strdup(value);
+        LY_CHECK_RET(!var_value, LY_EMEM);
+
+        /* update value */
+        free(item->value);
+        item->value = var_value;
+    } else {
+        var_name = strdup(name);
+        var_value = strdup(value);
+        LY_CHECK_ERR_GOTO(!var_name || !var_value, ret = LY_EMEM, error);
+
+        /* add new variable */
+        LY_ARRAY_NEW_GOTO(NULL, *vars, item, ret, error);
+        item->name = var_name;
+        item->value = var_value;
+    }
+
+    return LY_SUCCESS;
+
+error:
+    free(var_name);
+    free(var_value);
+    return ret;
+}
+
+LIBYANG_API_DEF void
+lyxp_vars_free(struct lyxp_var *vars)
+{
+    LY_ARRAY_COUNT_TYPE u;
+
+    if (!vars) {
+        return;
+    }
+
+    LY_ARRAY_FOR(vars, u) {
+        free(vars[u].name);
+        free(vars[u].value);
+    }
+
+    LY_ARRAY_FREE(vars);
+}
+
+LIBYANG_API_DEF struct lyd_node *
+lyd_child_no_keys(const struct lyd_node *node)
+{
+    struct lyd_node **children;
+
+    if (!node) {
+        return NULL;
+    }
+
+    if (!node->schema) {
+        /* opaq node */
+        return ((struct lyd_node_opaq *)node)->child;
+    }
+
+    children = lyd_node_child_p((struct lyd_node *)node);
+    if (children) {
+        struct lyd_node *child = *children;
+
+        while (child && child->schema && (child->schema->flags & LYS_KEY)) {
+            child = child->next;
+        }
+        return child;
+    } else {
+        return NULL;
+    }
+}
+
+LIBYANG_API_DEF const struct lys_module *
+lyd_owner_module(const struct lyd_node *node)
+{
+    const struct lyd_node_opaq *opaq;
+
+    if (!node) {
+        return NULL;
+    }
+
+    while (!node->schema && node->parent) {
+        node = lyd_parent(node);
+    }
+
+    if (!node->schema) {
+        /* top-level opaque node */
+        opaq = (struct lyd_node_opaq *)node;
+        switch (opaq->format) {
+        case LY_VALUE_XML:
+            if (opaq->name.module_ns) {
+                return ly_ctx_get_module_implemented_ns(LYD_CTX(node), opaq->name.module_ns);
+            }
+            break;
+        case LY_VALUE_JSON:
+            if (opaq->name.module_name) {
+                return ly_ctx_get_module_implemented(LYD_CTX(node), opaq->name.module_name);
+            }
+            break;
+        default:
+            return NULL;
+        }
+
+        return NULL;
+    }
+
+    return lysc_owner_module(node->schema);
+}
+
+LIBYANG_API_DEF const struct lys_module *
+lyd_node_module(const struct lyd_node *node)
+{
+    const struct lyd_node_opaq *opaq;
+
+    while (node) {
+        /* data node */
+        if (node->schema) {
+            return node->schema->module;
+        }
+
+        /* opaque node */
+        opaq = (struct lyd_node_opaq *)node;
+        switch (opaq->format) {
+        case LY_VALUE_XML:
+            if (opaq->name.module_ns) {
+                return ly_ctx_get_module_implemented_ns(LYD_CTX(node), opaq->name.module_ns);
+            }
+            break;
+        case LY_VALUE_JSON:
+            if (opaq->name.module_name) {
+                return ly_ctx_get_module_implemented(LYD_CTX(node), opaq->name.module_name);
+            }
+            break;
+        default:
+            break;
+        }
+
+        node = lyd_parent(node);
+    }
+
+    return NULL;
+}
+
+void
+lyd_first_module_sibling(struct lyd_node **node, const struct lys_module *mod)
+{
+    int cmp;
+    struct lyd_node *first;
+    const struct lys_module *own_mod;
+
+    assert(node && mod);
+
+    if (!*node) {
+        return;
+    }
+
+    first = *node;
+    own_mod = lyd_owner_module(first);
+    cmp = own_mod ? strcmp(own_mod->name, mod->name) : 1;
+    if (cmp > 0) {
+        /* there may be some preceding data */
+        while (first->prev->next) {
+            first = first->prev;
+            if (lyd_owner_module(first) == mod) {
+                cmp = 0;
+                break;
+            }
+        }
+    }
+
+    if (cmp == 0) {
+        /* there may be some preceding data belonging to this module */
+        while (first->prev->next) {
+            if (lyd_owner_module(first->prev) != mod) {
+                break;
+            }
+            first = first->prev;
+        }
+    }
+
+    if (cmp < 0) {
+        /* there may be some following data */
+        LY_LIST_FOR(first, first) {
+            if (lyd_owner_module(first) == mod) {
+                cmp = 0;
+                break;
+            }
+        }
+    }
+
+    if (cmp == 0) {
+        /* we have found the first module data node */
+        *node = first;
+    }
+}
+
+const struct lys_module *
+lyd_mod_next_module(struct lyd_node *tree, const struct lys_module *module, const struct ly_ctx *ctx, uint32_t *i,
+        struct lyd_node **first)
+{
+    struct lyd_node *iter;
+    const struct lys_module *mod;
+
+    /* get the next module */
+    if (module) {
+        if (*i) {
+            mod = NULL;
+        } else {
+            mod = module;
+            ++(*i);
+        }
+    } else {
+        do {
+            mod = ly_ctx_get_module_iter(ctx, i);
+        } while (mod && !mod->implemented);
+    }
+
+    /* find its data */
+    *first = NULL;
+    if (mod) {
+        LY_LIST_FOR(tree, iter) {
+            if (lyd_owner_module(iter) == mod) {
+                *first = iter;
+                break;
+            }
+        }
+    }
+
+    return mod;
+}
+
+const struct lys_module *
+lyd_data_next_module(struct lyd_node **next, struct lyd_node **first)
+{
+    const struct lys_module *mod;
+
+    if (!*next) {
+        /* all data traversed */
+        *first = NULL;
+        return NULL;
+    }
+
+    *first = *next;
+
+    /* prepare next */
+    mod = lyd_owner_module(*next);
+    LY_LIST_FOR(*next, *next) {
+        if (lyd_owner_module(*next) != mod) {
+            break;
+        }
+    }
+
+    return mod;
+}
+
+/**
+ * @brief Log generated error item and use log location information if not in the error item.
+ *
+ * @param[in] ctx Context to use.
+ * @param[in] node Optional data node to log.
+ * @param[in] scnode Optional schema node to log.
+ * @param[in] eitem Error item to log.
+ */
+static void
+ly_err_print_build_path(const struct ly_ctx *ctx, const struct lyd_node *node, const struct lysc_node *scnode,
+        struct ly_err_item *eitem)
+{
+    if (eitem->data_path || eitem->schema_path || eitem->line) {
+        ly_err_print(ctx, eitem);
+    } else {
+        if (node) {
+            LOG_LOCSET(NULL, node);
+        } else if (scnode) {
+            LOG_LOCSET(scnode, NULL);
+        }
+        ly_vlog(ctx, eitem->apptag, eitem->err == LY_EVALID ? eitem->vecode : LYVE_DATA, "%s", eitem->msg);
+        if (node) {
+            LOG_LOCBACK(0, 1);
+        } else if (scnode) {
+            LOG_LOCBACK(1, 0);
+        }
+    }
+}
+
+LY_ERR
+lyd_value_store(const struct ly_ctx *ctx, struct lyd_value *val, const struct lysc_type *type, const void *value,
+        size_t value_len, ly_bool is_utf8, ly_bool store_only, ly_bool *dynamic, LY_VALUE_FORMAT format, void *prefix_data,
+        uint32_t hints, const struct lysc_node *ctx_node, ly_bool *incomplete)
+{
+    LY_ERR ret;
+    struct ly_err_item *err = NULL;
+    uint32_t options = 0;
+
+    if (!value) {
+        value = "";
+    }
+    if (incomplete) {
+        *incomplete = 0;
+    }
+
+    if (dynamic && *dynamic) {
+        options |= LYPLG_TYPE_STORE_DYNAMIC;
+    }
+    if (is_utf8) {
+        options |= LYPLG_TYPE_STORE_IS_UTF8;
+    }
+    if (store_only) {
+        options |= LYPLG_TYPE_STORE_ONLY;
+    }
+
+    ret = type->plugin->store(ctx, type, value, value_len, options, format, prefix_data, hints, ctx_node, val, NULL, &err);
+    if (dynamic) {
+        *dynamic = 0;
+    }
+
+    if (ret == LY_EINCOMPLETE) {
+        if (incomplete) {
+            *incomplete = 1;
+        }
+    } else if (ret) {
+        if (err) {
+            ly_err_print_build_path(ctx, NULL, ctx_node, err);
+            ly_err_free(err);
+        } else {
+            LOGVAL(ctx, LYVE_OTHER, "Storing value failed.");
+        }
+        return ret;
+    }
+
+    return LY_SUCCESS;
+}
+
+LY_ERR
+lyd_value_validate_incomplete(const struct ly_ctx *ctx, const struct lysc_type *type, struct lyd_value *val,
+        const struct lyd_node *ctx_node, const struct lyd_node *tree)
+{
+    LY_ERR ret;
+    struct ly_err_item *err = NULL;
+
+    assert(type->plugin->validate);
+
+    ret = type->plugin->validate(ctx, type, ctx_node, tree, val, &err);
+    if (ret) {
+        if (err) {
+            ly_err_print_build_path(ctx, ctx_node, NULL, err);
+            ly_err_free(err);
+        } else {
+            LOGVAL(ctx, LYVE_OTHER, "Resolving value \"%s\" failed.",
+                    (char *)type->plugin->print(ctx, val, LY_VALUE_CANON, NULL, NULL, NULL));
+        }
+        return ret;
+    }
+
+    return LY_SUCCESS;
+}
+
+LY_ERR
+ly_value_validate(const struct ly_ctx *ctx, const struct lysc_node *node, const char *value, size_t value_len,
+        LY_VALUE_FORMAT format, void *prefix_data, uint32_t hints)
+{
+    LY_ERR rc = LY_SUCCESS;
+    struct ly_err_item *err = NULL;
+    struct lyd_value storage;
+    struct lysc_type *type;
+
+    LY_CHECK_ARG_RET(ctx, node, LY_EINVAL);
+
+    if (!(node->nodetype & (LYS_LEAF | LYS_LEAFLIST))) {
+        LOGARG(ctx, node);
+        return LY_EINVAL;
+    }
+
+    type = ((struct lysc_node_leaf *)node)->type;
+    rc = type->plugin->store(ctx ? ctx : node->module->ctx, type, value, value_len, 0, format, prefix_data, hints, node,
+            &storage, NULL, &err);
+    if (rc == LY_EINCOMPLETE) {
+        /* actually success since we do not provide the context tree and call validation with
+         * LY_TYPE_OPTS_INCOMPLETE_DATA */
+        rc = LY_SUCCESS;
+    } else if (rc && err) {
+        if (ctx) {
+            /* log only in case the ctx was provided as input parameter */
+            ly_err_print_build_path(ctx, NULL, node, err);
+        }
+        ly_err_free(err);
+    }
+
+    if (!rc) {
+        type->plugin->free(ctx ? ctx : node->module->ctx, &storage);
+    }
+    return rc;
+}
+
+LIBYANG_API_DEF LY_ERR
+lyd_value_validate(const struct ly_ctx *ctx, const struct lysc_node *schema, const char *value, size_t value_len,
+        const struct lyd_node *ctx_node, const struct lysc_type **realtype, const char **canonical)
+{
+    LY_ERR rc;
+    struct ly_err_item *err = NULL;
+    struct lysc_type *type;
+    struct lyd_value val = {0};
+    ly_bool stored = 0, log = 1;
+
+    LY_CHECK_ARG_RET(ctx, schema, !value_len || value, LY_EINVAL);
+
+    if (!ctx) {
+        ctx = schema->module->ctx;
+        log = 0;
+    }
+    if (!value_len) {
+        value = "";
+    }
+    type = ((struct lysc_node_leaf *)schema)->type;
+
+    /* store */
+    rc = type->plugin->store(ctx, type, value, value_len, 0, LY_VALUE_JSON, NULL,
+            LYD_HINT_DATA, schema, &val, NULL, &err);
+    if (!rc || (rc == LY_EINCOMPLETE)) {
+        stored = 1;
+    }
+
+    if (ctx_node && (rc == LY_EINCOMPLETE)) {
+        /* resolve */
+        rc = type->plugin->validate(ctx, type, ctx_node, ctx_node, &val, &err);
+    }
+
+    if (rc && (rc != LY_EINCOMPLETE) && err) {
+        if (log) {
+            /* log error */
+            ly_err_print_build_path(ctx, ctx_node, schema, err);
+        }
+        ly_err_free(err);
+    }
+
+    if (!rc || (rc == LY_EINCOMPLETE)) {
+        if (realtype) {
+            /* return realtype */
+            if (val.realtype->basetype == LY_TYPE_UNION) {
+                *realtype = val.subvalue->value.realtype;
+            } else {
+                *realtype = val.realtype;
+            }
+        }
+
+        if (canonical) {
+            /* return canonical value */
+            lydict_insert(ctx, val.realtype->plugin->print(ctx, &val, LY_VALUE_CANON, NULL, NULL, NULL), 0, canonical);
+        }
+    }
+
+    if (stored) {
+        /* free value */
+        type->plugin->free(ctx ? ctx : schema->module->ctx, &val);
+    }
+    return rc;
+}
+
+LIBYANG_API_DEF LY_ERR
+lyd_value_compare(const struct lyd_node_term *node, const char *value, size_t value_len)
+{
+    LY_ERR ret = LY_SUCCESS;
+    struct ly_ctx *ctx;
+    struct lysc_type *type;
+    struct lyd_value val = {0};
+
+    LY_CHECK_ARG_RET(node ? node->schema->module->ctx : NULL, node, value, LY_EINVAL);
+
+    ctx = node->schema->module->ctx;
+    type = ((struct lysc_node_leaf *)node->schema)->type;
+
+    /* store the value */
+    LOG_LOCSET(NULL, &node->node);
+    ret = lyd_value_store(ctx, &val, type, value, value_len, 0, 0, NULL, LY_VALUE_JSON, NULL, LYD_HINT_DATA, node->schema, NULL);
+    LOG_LOCBACK(0, 1);
+    LY_CHECK_RET(ret);
+
+    /* compare values */
+    ret = type->plugin->compare(ctx, &node->value, &val);
+
+    type->plugin->free(ctx, &val);
+    return ret;
+}
+
+LIBYANG_API_DEF ly_bool
+lyd_is_default(const struct lyd_node *node)
+{
+    const struct lysc_node_leaf *leaf;
+    const struct lysc_node_leaflist *llist;
+    const struct lyd_node_term *term;
+    LY_ARRAY_COUNT_TYPE u;
+
+    if (!(node->schema->nodetype & LYD_NODE_TERM)) {
+        return 0;
+    }
+
+    term = (const struct lyd_node_term *)node;
+
+    if (node->schema->nodetype == LYS_LEAF) {
+        leaf = (const struct lysc_node_leaf *)node->schema;
+        if (!leaf->dflt) {
+            return 0;
+        }
+
+        /* compare with the default value */
+        if (!leaf->type->plugin->compare(LYD_CTX(node), &term->value, leaf->dflt)) {
+            return 1;
+        }
+    } else {
+        llist = (const struct lysc_node_leaflist *)node->schema;
+        if (!llist->dflts) {
+            return 0;
+        }
+
+        LY_ARRAY_FOR(llist->dflts, u) {
+            /* compare with each possible default value */
+            if (!llist->type->plugin->compare(LYD_CTX(node), &term->value, llist->dflts[u])) {
+                return 1;
+            }
+        }
+    }
+
+    return 0;
+}
+
+LIBYANG_API_DEF uint32_t
+lyd_list_pos(const struct lyd_node *instance)
+{
+    const struct lyd_node *iter = NULL;
+    uint32_t pos = 0;
+
+    if (!instance || !(instance->schema->nodetype & (LYS_LIST | LYS_LEAFLIST))) {
+        return 0;
+    }
+
+    /* data instances are ordered, so we can stop when we found instance of other schema node */
+    for (iter = instance; iter->schema == instance->schema; iter = iter->prev) {
+        if (pos && (iter->next == NULL)) {
+            /* overrun to the end of the siblings list */
+            break;
+        }
+        ++pos;
+    }
+
+    return pos;
+}
+
+LIBYANG_API_DEF struct lyd_node *
+lyd_first_sibling(const struct lyd_node *node)
+{
+    struct lyd_node *start;
+
+    if (!node) {
+        return NULL;
+    }
+
+    /* get the first sibling */
+    if (node->parent) {
+        return node->parent->child;
+    } else if (!node->prev->next) {
+        return (struct lyd_node *)node;
+    }
+
+    for (start = (struct lyd_node *)node->prev; start->prev->next; start = start->prev) {
+        assert(start != node);
+    }
+
+    return start;
+}
+
+/**
+ * @brief Check list node parsed into an opaque node for the reason.
+ *
+ * @param[in] node Opaque node.
+ * @param[in] snode Schema node of @p opaq.
+ * @return LY_SUCCESS if the node is valid;
+ * @return LY_ERR on error.
+ */
+static LY_ERR
+lyd_parse_opaq_list_error(const struct lyd_node *node, const struct lysc_node *snode)
+{
+    LY_ERR ret = LY_SUCCESS;
+    struct ly_set key_set = {0};
+    const struct lysc_node *key = NULL;
+    const struct lyd_node *child;
+    const struct lyd_node_opaq *opaq_k;
+    uint32_t i;
+
+    assert(!node->schema);
+
+    /* get all keys into a set */
+    while ((key = lys_getnext(key, snode, NULL, 0)) && (key->flags & LYS_KEY)) {
+        LY_CHECK_GOTO(ret = ly_set_add(&key_set, (void *)key, 1, NULL), cleanup);
+    }
+
+    LY_LIST_FOR(lyd_child(node), child) {
+        /* find the key schema node */
+        for (i = 0; i < key_set.count; ++i) {
+            key = key_set.snodes[i];
+            if (!strcmp(key->name, LYD_NAME(child))) {
+                break;
+            }
+        }
+        if (i == key_set.count) {
+            /* some other node, skip */
+            continue;
+        }
+
+        /* key found */
+        ly_set_rm_index(&key_set, i, NULL);
+
+        if (child->schema) {
+            /* valid key */
+            continue;
+        }
+
+        /* check value */
+        opaq_k = (struct lyd_node_opaq *)child;
+        ret = ly_value_validate(LYD_CTX(node), key, opaq_k->value, strlen(opaq_k->value), opaq_k->format,
+                opaq_k->val_prefix_data, opaq_k->hints);
+        LY_CHECK_GOTO(ret, cleanup);
+    }
+
+    if (key_set.count) {
+        /* missing keys */
+        LOGVAL(LYD_CTX(node), LY_VCODE_NOKEY, key_set.snodes[0]->name);
+        ret = LY_EVALID;
+        goto cleanup;
+    }
+
+cleanup:
+    ly_set_erase(&key_set, NULL);
+    return ret;
+}
+
+LIBYANG_API_DEF LY_ERR
+lyd_parse_opaq_error(const struct lyd_node *node)
+{
+    LY_ERR rc = LY_SUCCESS;
+    const struct ly_ctx *ctx;
+    const struct lyd_node_opaq *opaq;
+    const struct lyd_node *parent;
+    const struct lys_module *mod;
+    const struct lysc_node *sparent, *snode;
+    uint32_t loc_scnode = 0, loc_dnode = 0;
+
+    LY_CHECK_ARG_RET(LYD_CTX(node), node, !node->schema, LY_EINVAL);
+
+    ctx = LYD_CTX(node);
+    opaq = (struct lyd_node_opaq *)node;
+    parent = lyd_parent(node);
+    sparent = lyd_node_schema(parent);
+
+    /* if parent is NULL, it is still added as root */
+    LOG_LOCSET(NULL, parent);
+    loc_dnode = 1;
+
+    if (!opaq->name.module_ns) {
+        LOGVAL(ctx, LYVE_REFERENCE, "Unknown module of node \"%s\".", opaq->name.name);
+        rc = LY_EVALID;
+        goto cleanup;
+    }
+
+    /* module */
+    switch (opaq->format) {
+    case LY_VALUE_XML:
+        if (!sparent || strcmp(opaq->name.module_ns, sparent->module->ns)) {
+            mod = ly_ctx_get_module_implemented_ns(ctx, opaq->name.module_ns);
+            if (!mod) {
+                LOGVAL(ctx, LYVE_REFERENCE, "No (implemented) module with namespace \"%s\" of node \"%s\" in the context.",
+                        opaq->name.module_ns, opaq->name.name);
+                rc = LY_EVALID;
+                goto cleanup;
+            }
+        } else {
+            /* inherit */
+            mod = sparent->module;
+        }
+        break;
+    case LY_VALUE_JSON:
+    case LY_VALUE_LYB:
+        if (!sparent || strcmp(opaq->name.module_name, sparent->module->name)) {
+            mod = ly_ctx_get_module_implemented(ctx, opaq->name.module_name);
+            if (!mod) {
+                LOGVAL(ctx, LYVE_REFERENCE, "No (implemented) module named \"%s\" of node \"%s\" in the context.",
+                        opaq->name.module_name, opaq->name.name);
+                rc = LY_EVALID;
+                goto cleanup;
+            }
+        } else {
+            /* inherit */
+            mod = sparent->module;
+        }
+        break;
+    default:
+        LOGERR(ctx, LY_EINVAL, "Unsupported value format.");
+        rc = LY_EINVAL;
+        goto cleanup;
+    }
+
+    /* schema */
+    snode = lys_find_child(sparent, mod, opaq->name.name, 0, 0, 0);
+    if (!snode && sparent && (sparent->nodetype & (LYS_RPC | LYS_ACTION))) {
+        /* maybe output node */
+        snode = lys_find_child(sparent, mod, opaq->name.name, 0, 0, LYS_GETNEXT_OUTPUT);
+    }
+    if (!snode) {
+        if (sparent) {
+            LOGVAL(ctx, LYVE_REFERENCE, "Node \"%s\" not found as a child of \"%s\" node.", opaq->name.name,
+                    sparent->name);
+        } else {
+            LOGVAL(ctx, LYVE_REFERENCE, "Node \"%s\" not found in the \"%s\" module.", opaq->name.name, mod->name);
+        }
+        rc = LY_EVALID;
+        goto cleanup;
+    }
+
+    /* schema node exists */
+    LOG_LOCBACK(0, 1);
+    loc_dnode = 0;
+    LOG_LOCSET(snode, NULL);
+    loc_scnode = 1;
+
+    if (snode->nodetype & LYD_NODE_TERM) {
+        /* leaf / leaf-list */
+        rc = ly_value_validate(ctx, snode, opaq->value, strlen(opaq->value), opaq->format, opaq->val_prefix_data, opaq->hints);
+        LY_CHECK_GOTO(rc, cleanup);
+    } else if (snode->nodetype == LYS_LIST) {
+        /* list */
+        rc = lyd_parse_opaq_list_error(node, snode);
+        LY_CHECK_GOTO(rc, cleanup);
+    } else if (snode->nodetype & LYD_NODE_INNER) {
+        /* inner node */
+        if (opaq->value) {
+            LOGVAL(ctx, LYVE_DATA, "Invalid value \"%s\" for %s \"%s\".", opaq->value,
+                    lys_nodetype2str(snode->nodetype), snode->name);
+            rc = LY_EVALID;
+            goto cleanup;
+        }
+    } else {
+        LOGERR(ctx, LY_EINVAL, "Unexpected opaque schema node %s \"%s\".", lys_nodetype2str(snode->nodetype), snode->name);
+        rc = LY_EINVAL;
+        goto cleanup;
+    }
+
+    LOGERR(ctx, LY_EINVAL, "Unexpected valid opaque node %s \"%s\".", lys_nodetype2str(snode->nodetype), snode->name);
+    rc = LY_EINVAL;
+
+cleanup:
+    LOG_LOCBACK(loc_scnode, loc_dnode);
+    return rc;
+}
+
+LIBYANG_API_DEF const char *
+lyd_value_get_canonical(const struct ly_ctx *ctx, const struct lyd_value *value)
+{
+    LY_CHECK_ARG_RET(ctx, ctx, value, NULL);
+
+    return value->_canonical ? value->_canonical :
+           (const char *)value->realtype->plugin->print(ctx, value, LY_VALUE_CANON, NULL, NULL, NULL);
+}
+
+LIBYANG_API_DEF LY_ERR
+lyd_any_value_str(const struct lyd_node *any, char **value_str)
+{
+    const struct lyd_node_any *a;
+    struct lyd_node *tree = NULL;
+    const char *str = NULL;
+    ly_bool dynamic = 0;
+    LY_ERR ret = LY_SUCCESS;
+
+    LY_CHECK_ARG_RET(NULL, any, value_str, LY_EINVAL);
+    LY_CHECK_ARG_RET(NULL, any->schema, any->schema->nodetype & LYS_ANYDATA, LY_EINVAL);
+
+    a = (struct lyd_node_any *)any;
+    *value_str = NULL;
+
+    if (!a->value.str) {
+        /* there is no value in the union */
+        return LY_SUCCESS;
+    }
+
+    switch (a->value_type) {
+    case LYD_ANYDATA_LYB:
+        /* parse into a data tree */
+        ret = lyd_parse_data_mem(LYD_CTX(any), a->value.mem, LYD_LYB, LYD_PARSE_ONLY, 0, &tree);
+        LY_CHECK_GOTO(ret, cleanup);
+        dynamic = 1;
+        break;
+    case LYD_ANYDATA_DATATREE:
+        tree = a->value.tree;
+        break;
+    case LYD_ANYDATA_STRING:
+    case LYD_ANYDATA_XML:
+    case LYD_ANYDATA_JSON:
+        /* simply use the string */
+        str = a->value.str;
+        break;
+    }
+
+    if (tree) {
+        /* print into a string */
+        ret = lyd_print_mem(value_str, tree, LYD_XML, LYD_PRINT_WITHSIBLINGS);
+        LY_CHECK_GOTO(ret, cleanup);
+    } else {
+        assert(str);
+        *value_str = strdup(str);
+        LY_CHECK_ERR_GOTO(!*value_str, LOGMEM(LYD_CTX(any)), cleanup);
+    }
+
+    /* success */
+
+cleanup:
+    if (dynamic) {
+        lyd_free_all(tree);
+    }
+    return ret;
+}
+
+LIBYANG_API_DEF LY_ERR
+lyd_any_copy_value(struct lyd_node *trg, const union lyd_any_value *value, LYD_ANYDATA_VALUETYPE value_type)
+{
+    struct lyd_node_any *t;
+
+    LY_CHECK_ARG_RET(NULL, trg, LY_EINVAL);
+    LY_CHECK_ARG_RET(NULL, trg->schema, trg->schema->nodetype & LYS_ANYDATA, LY_EINVAL);
+
+    t = (struct lyd_node_any *)trg;
+
+    /* free trg */
+    switch (t->value_type) {
+    case LYD_ANYDATA_DATATREE:
+        lyd_free_all(t->value.tree);
+        break;
+    case LYD_ANYDATA_STRING:
+    case LYD_ANYDATA_XML:
+    case LYD_ANYDATA_JSON:
+        lydict_remove(LYD_CTX(trg), t->value.str);
+        break;
+    case LYD_ANYDATA_LYB:
+        free(t->value.mem);
+        break;
+    }
+    t->value.str = NULL;
+
+    if (!value) {
+        /* only free value in this case */
+        return LY_SUCCESS;
+    }
+
+    /* copy src */
+    t->value_type = value_type;
+    switch (value_type) {
+    case LYD_ANYDATA_DATATREE:
+        if (value->tree) {
+            LY_CHECK_RET(lyd_dup_siblings(value->tree, NULL, LYD_DUP_RECURSIVE, &t->value.tree));
+        }
+        break;
+    case LYD_ANYDATA_STRING:
+    case LYD_ANYDATA_XML:
+    case LYD_ANYDATA_JSON:
+        if (value->str) {
+            LY_CHECK_RET(lydict_insert(LYD_CTX(trg), value->str, 0, &t->value.str));
+        }
+        break;
+    case LYD_ANYDATA_LYB:
+        if (value->mem) {
+            int len = lyd_lyb_data_length(value->mem);
+
+            LY_CHECK_RET(len == -1, LY_EINVAL);
+            t->value.mem = malloc(len);
+            LY_CHECK_ERR_RET(!t->value.mem, LOGMEM(LYD_CTX(trg)), LY_EMEM);
+            memcpy(t->value.mem, value->mem, len);
+        }
+        break;
+    }
+
+    return LY_SUCCESS;
+}
+
+LIBYANG_API_DEF const struct lysc_node *
+lyd_node_schema(const struct lyd_node *node)
+{
+    const struct lysc_node *schema = NULL;
+    const struct lyd_node *prev_iter = NULL, *iter;
+    const struct lys_module *mod;
+
+    if (!node) {
+        return NULL;
+    } else if (node->schema) {
+        return node->schema;
+    }
+
+    /* find the first schema node in the parents */
+    for (iter = lyd_parent(node); iter && !iter->schema; iter = lyd_parent(iter)) {}
+    if (iter) {
+        prev_iter = iter;
+        schema = prev_iter->schema;
+    }
+
+    /* get schema node of an opaque node */
+    do {
+        /* get next data node */
+        for (iter = node; lyd_parent(iter) != prev_iter; iter = lyd_parent(iter)) {}
+
+        /* get module */
+        mod = lyd_node_module(iter);
+        if (!mod) {
+            /* unknown module, no schema node */
+            schema = NULL;
+            break;
+        }
+
+        /* get schema node */
+        schema = lys_find_child(schema, mod, LYD_NAME(iter), 0, 0, 0);
+
+        /* move to the descendant */
+        prev_iter = iter;
+    } while (schema && (iter != node));
+
+    return schema;
+}
+
+LIBYANG_API_DEF ly_bool
+lyd_meta_is_internal(const struct lyd_meta *meta)
+{
+    const char *arg;
+
+    assert(meta->annotation);
+
+    arg = meta->annotation->argument;
+    if (!strcmp(meta->annotation->module->name, "yang") && !strcmp(arg, "lyds_tree")) {
+        return 1;
+    }
+
+    return 0;
+}
+
+void
+lyd_cont_set_dflt(struct lyd_node *node)
+{
+    const struct lyd_node *child;
+
+    while (node) {
+        if (!node->schema || (node->flags & LYD_DEFAULT) || !lysc_is_np_cont(node->schema)) {
+            /* not a non-dflt NP container */
+            break;
+        }
+
+        LY_LIST_FOR(lyd_child(node), child) {
+            if (!(child->flags & LYD_DEFAULT)) {
+                break;
+            }
+        }
+        if (child) {
+            /* explicit child, no dflt change */
+            break;
+        }
+
+        /* set the dflt flag */
+        node->flags |= LYD_DEFAULT;
+
+        /* check all parent containers */
+        node = lyd_parent(node);
+    }
+}
+
+/**
+ * @brief Comparison callback to match schema node with a schema of a data node.
+ *
+ * @param[in] val1_p Pointer to the schema node
+ * @param[in] val2_p Pointer to the data node
+ * Implementation of ::lyht_value_equal_cb.
+ */
+static ly_bool
+lyd_hash_table_schema_val_equal(void *val1_p, void *val2_p, ly_bool UNUSED(mod), void *UNUSED(cb_data))
+{
+    struct lysc_node *val1;
+    struct lyd_node *val2;
+
+    val1 = *((struct lysc_node **)val1_p);
+    val2 = *((struct lyd_node **)val2_p);
+
+    if (val1 == val2->schema) {
+        /* schema match is enough */
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+LY_ERR
+lyd_find_sibling_schema(const struct lyd_node *siblings, const struct lysc_node *schema, struct lyd_node **match)
+{
+    struct lyd_node **match_p;
+    struct lyd_node_inner *parent;
+    uint32_t hash;
+
+    assert(schema);
+    if (!siblings) {
+        /* no data */
+        if (match) {
+            *match = NULL;
+        }
+        return LY_ENOTFOUND;
+    }
+
+    parent = siblings->parent;
+    if (parent && parent->schema && parent->children_ht) {
+        /* calculate our hash */
+        hash = lyht_hash_multi(0, schema->module->name, strlen(schema->module->name));
+        hash = lyht_hash_multi(hash, schema->name, strlen(schema->name));
+        hash = lyht_hash_multi(hash, NULL, 0);
+
+        /* find by hash but use special hash table function (and stay thread-safe) */
+        if (!lyht_find_with_val_cb(parent->children_ht, &schema, hash, lyd_hash_table_schema_val_equal, (void **)&match_p)) {
+            siblings = *match_p;
+        } else {
+            /* not found */
+            siblings = NULL;
+        }
+    } else {
+        /* find first sibling */
+        if (siblings->parent) {
+            siblings = siblings->parent->child;
+        } else {
+            while (siblings->prev->next) {
+                siblings = siblings->prev;
+            }
+        }
+
+        /* search manually without hashes and ignore opaque nodes (cannot be found by hashes) */
+        for ( ; siblings && siblings->schema; siblings = siblings->next) {
+            /* schema match is enough */
+            if (LYD_CTX(siblings) == schema->module->ctx) {
+                if (siblings->schema == schema) {
+                    break;
+                }
+            } else {
+                if (!strcmp(LYD_NAME(siblings), schema->name) && !strcmp(siblings->schema->module->name, schema->module->name)) {
+                    break;
+                }
+            }
+        }
+        if (siblings && !siblings->schema) {
+            siblings = NULL;
+        }
+    }
+
+    if (!siblings) {
+        if (match) {
+            *match = NULL;
+        }
+        return LY_ENOTFOUND;
+    }
+
+    if (match) {
+        *match = (struct lyd_node *)siblings;
+    }
+    return LY_SUCCESS;
+}
+
+void
+lyd_del_move_root(struct lyd_node **root, const struct lyd_node *to_del, const struct lys_module *mod)
+{
+    if (*root && (lyd_owner_module(*root) != mod)) {
+        /* there are no data of mod so this is simply the first top-level sibling */
+        mod = NULL;
+    }
+
+    if ((*root != to_del) || (*root)->parent) {
+        return;
+    }
+
+    if (mod && (*root)->prev->next && (!(*root)->next || (lyd_owner_module(to_del) != lyd_owner_module((*root)->next)))) {
+        /* there are no more nodes from mod, simply get the first top-level sibling */
+        *root = lyd_first_sibling(*root);
+    } else {
+        *root = (*root)->next;
+    }
+}
+
+LY_ERR
+ly_nested_ext_schema(const struct lyd_node *parent, const struct lysc_node *sparent, const char *prefix,
+        size_t prefix_len, LY_VALUE_FORMAT format, void *prefix_data, const char *name, size_t name_len,
+        const struct lysc_node **snode, struct lysc_ext_instance **ext)
+{
+    LY_ERR r;
+    LY_ARRAY_COUNT_TYPE u;
+    struct lysc_ext_instance *nested_exts = NULL;
+    lyplg_ext_data_snode_clb ext_snode_cb;
+
+    /* check if there are any nested extension instances */
+    if (parent && parent->schema) {
+        nested_exts = parent->schema->exts;
+    } else if (sparent) {
+        nested_exts = sparent->exts;
+    }
+    LY_ARRAY_FOR(nested_exts, u) {
+        if (!nested_exts[u].def->plugin) {
+            /* no plugin */
+            continue;
+        }
+
+        ext_snode_cb = nested_exts[u].def->plugin->snode;
+        if (!ext_snode_cb) {
+            /* not an extension with nested data */
+            continue;
+        }
+
+        /* try to get the schema node */
+        r = ext_snode_cb(&nested_exts[u], parent, sparent, prefix, prefix_len, format, prefix_data, name, name_len, snode);
+        if (!r) {
+            if (ext) {
+                /* data successfully created, remember the ext instance */
+                *ext = &nested_exts[u];
+            }
+            return LY_SUCCESS;
+        } else if (r != LY_ENOT) {
+            /* fatal error */
+            return r;
+        }
+        /* data was not from this module, continue */
+    }
+
+    /* no extensions or none matched */
+    return LY_ENOT;
+}
+
+void
+ly_free_prefix_data(LY_VALUE_FORMAT format, void *prefix_data)
+{
+    struct ly_set *ns_list;
+    struct lysc_prefix *prefixes;
+    uint32_t i;
+    LY_ARRAY_COUNT_TYPE u;
+
+    if (!prefix_data) {
+        return;
+    }
+
+    switch (format) {
+    case LY_VALUE_XML:
+    case LY_VALUE_STR_NS:
+        ns_list = prefix_data;
+        for (i = 0; i < ns_list->count; ++i) {
+            free(((struct lyxml_ns *)ns_list->objs[i])->prefix);
+            free(((struct lyxml_ns *)ns_list->objs[i])->uri);
+        }
+        ly_set_free(ns_list, free);
+        break;
+    case LY_VALUE_SCHEMA_RESOLVED:
+        prefixes = prefix_data;
+        LY_ARRAY_FOR(prefixes, u) {
+            free(prefixes[u].prefix);
+        }
+        LY_ARRAY_FREE(prefixes);
+        break;
+    case LY_VALUE_CANON:
+    case LY_VALUE_SCHEMA:
+    case LY_VALUE_JSON:
+    case LY_VALUE_LYB:
+        break;
+    }
+}
+
+LY_ERR
+ly_dup_prefix_data(const struct ly_ctx *ctx, LY_VALUE_FORMAT format, const void *prefix_data,
+        void **prefix_data_p)
+{
+    LY_ERR ret = LY_SUCCESS;
+    struct lyxml_ns *ns;
+    struct lysc_prefix *prefixes = NULL, *orig_pref;
+    struct ly_set *ns_list, *orig_ns;
+    uint32_t i;
+    LY_ARRAY_COUNT_TYPE u;
+
+    assert(!*prefix_data_p);
+
+    switch (format) {
+    case LY_VALUE_SCHEMA:
+        *prefix_data_p = (void *)prefix_data;
+        break;
+    case LY_VALUE_SCHEMA_RESOLVED:
+        /* copy all the value prefixes */
+        orig_pref = (struct lysc_prefix *)prefix_data;
+        LY_ARRAY_CREATE_GOTO(ctx, prefixes, LY_ARRAY_COUNT(orig_pref), ret, cleanup);
+        *prefix_data_p = prefixes;
+
+        LY_ARRAY_FOR(orig_pref, u) {
+            if (orig_pref[u].prefix) {
+                prefixes[u].prefix = strdup(orig_pref[u].prefix);
+                LY_CHECK_ERR_GOTO(!prefixes[u].prefix, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+            }
+            prefixes[u].mod = orig_pref[u].mod;
+            LY_ARRAY_INCREMENT(prefixes);
+        }
+        break;
+    case LY_VALUE_XML:
+    case LY_VALUE_STR_NS:
+        /* copy all the namespaces */
+        LY_CHECK_GOTO(ret = ly_set_new(&ns_list), cleanup);
+        *prefix_data_p = ns_list;
+
+        orig_ns = (struct ly_set *)prefix_data;
+        for (i = 0; i < orig_ns->count; ++i) {
+            ns = calloc(1, sizeof *ns);
+            LY_CHECK_ERR_GOTO(!ns, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+            LY_CHECK_GOTO(ret = ly_set_add(ns_list, ns, 1, NULL), cleanup);
+
+            if (((struct lyxml_ns *)orig_ns->objs[i])->prefix) {
+                ns->prefix = strdup(((struct lyxml_ns *)orig_ns->objs[i])->prefix);
+                LY_CHECK_ERR_GOTO(!ns->prefix, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+            }
+            ns->uri = strdup(((struct lyxml_ns *)orig_ns->objs[i])->uri);
+            LY_CHECK_ERR_GOTO(!ns->uri, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+        }
+        break;
+    case LY_VALUE_CANON:
+    case LY_VALUE_JSON:
+    case LY_VALUE_LYB:
+        assert(!prefix_data);
+        *prefix_data_p = NULL;
+        break;
+    }
+
+cleanup:
+    if (ret) {
+        ly_free_prefix_data(format, *prefix_data_p);
+        *prefix_data_p = NULL;
+    }
+    return ret;
+}
+
+LY_ERR
+ly_store_prefix_data(const struct ly_ctx *ctx, const void *value, size_t value_len, LY_VALUE_FORMAT format,
+        const void *prefix_data, LY_VALUE_FORMAT *format_p, void **prefix_data_p)
+{
+    LY_ERR ret = LY_SUCCESS;
+    const struct lys_module *mod;
+    const struct lyxml_ns *ns;
+    struct lyxml_ns *new_ns;
+    struct ly_set *ns_list;
+    struct lysc_prefix *prefixes = NULL, *val_pref;
+    const char *value_iter, *value_next, *value_end;
+    uint32_t substr_len;
+    ly_bool is_prefix;
+
+    switch (format) {
+    case LY_VALUE_SCHEMA:
+        /* copy all referenced modules as prefix - module pairs */
+        if (!*prefix_data_p) {
+            /* new prefix data */
+            LY_ARRAY_CREATE_GOTO(ctx, prefixes, 0, ret, cleanup);
+            *format_p = LY_VALUE_SCHEMA_RESOLVED;
+            *prefix_data_p = prefixes;
+        } else {
+            /* reuse prefix data */
+            assert(*format_p == LY_VALUE_SCHEMA_RESOLVED);
+            prefixes = *prefix_data_p;
+        }
+
+        /* add current module for unprefixed values */
+        LY_ARRAY_NEW_GOTO(ctx, prefixes, val_pref, ret, cleanup);
+        *prefix_data_p = prefixes;
+
+        val_pref->prefix = NULL;
+        val_pref->mod = ((const struct lysp_module *)prefix_data)->mod;
+
+        /* add all used prefixes */
+        value_end = (char *)value + value_len;
+        for (value_iter = value; value_iter; value_iter = value_next) {
+            LY_CHECK_GOTO(ret = ly_value_prefix_next(value_iter, value_end, &substr_len, &is_prefix, &value_next), cleanup);
+            if (is_prefix) {
+                /* we have a possible prefix. Do we already have the prefix? */
+                mod = ly_resolve_prefix(ctx, value_iter, substr_len, *format_p, *prefix_data_p);
+                if (!mod) {
+                    mod = ly_resolve_prefix(ctx, value_iter, substr_len, format, prefix_data);
+                    if (mod) {
+                        assert(*format_p == LY_VALUE_SCHEMA_RESOLVED);
+                        /* store a new prefix - module pair */
+                        LY_ARRAY_NEW_GOTO(ctx, prefixes, val_pref, ret, cleanup);
+                        *prefix_data_p = prefixes;
+
+                        val_pref->prefix = strndup(value_iter, substr_len);
+                        LY_CHECK_ERR_GOTO(!val_pref->prefix, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+                        val_pref->mod = mod;
+                    } /* else it is not even defined */
+                } /* else the prefix is already present */
+            }
+        }
+        break;
+    case LY_VALUE_XML:
+    case LY_VALUE_STR_NS:
+        /* copy all referenced namespaces as prefix - namespace pairs */
+        if (!*prefix_data_p) {
+            /* new prefix data */
+            LY_CHECK_GOTO(ret = ly_set_new(&ns_list), cleanup);
+            *format_p = format;
+            *prefix_data_p = ns_list;
+        } else {
+            /* reuse prefix data */
+            assert(*format_p == format);
+            ns_list = *prefix_data_p;
+        }
+
+        /* store default namespace */
+        ns = lyxml_ns_get(prefix_data, NULL, 0);
+        if (ns) {
+            new_ns = calloc(1, sizeof *new_ns);
+            LY_CHECK_ERR_GOTO(!new_ns, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+            LY_CHECK_GOTO(ret = ly_set_add(ns_list, new_ns, 1, NULL), cleanup);
+
+            new_ns->prefix = NULL;
+            new_ns->uri = strdup(ns->uri);
+            LY_CHECK_ERR_GOTO(!new_ns->uri, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+        }
+
+        /* add all used prefixes */
+        value_end = (char *)value + value_len;
+        for (value_iter = value; value_iter; value_iter = value_next) {
+            LY_CHECK_GOTO(ret = ly_value_prefix_next(value_iter, value_end, &substr_len, &is_prefix, &value_next), cleanup);
+            if (is_prefix) {
+                /* we have a possible prefix. Do we already have the prefix? */
+                ns = lyxml_ns_get(ns_list, value_iter, substr_len);
+                if (!ns) {
+                    ns = lyxml_ns_get(prefix_data, value_iter, substr_len);
+                    if (ns) {
+                        /* store a new prefix - namespace pair */
+                        new_ns = calloc(1, sizeof *new_ns);
+                        LY_CHECK_ERR_GOTO(!new_ns, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+                        LY_CHECK_GOTO(ret = ly_set_add(ns_list, new_ns, 1, NULL), cleanup);
+
+                        new_ns->prefix = strndup(value_iter, substr_len);
+                        LY_CHECK_ERR_GOTO(!new_ns->prefix, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+                        new_ns->uri = strdup(ns->uri);
+                        LY_CHECK_ERR_GOTO(!new_ns->uri, LOGMEM(ctx); ret = LY_EMEM, cleanup);
+                    } /* else it is not even defined */
+                } /* else the prefix is already present */
+            }
+        }
+        break;
+    case LY_VALUE_CANON:
+    case LY_VALUE_SCHEMA_RESOLVED:
+    case LY_VALUE_JSON:
+    case LY_VALUE_LYB:
+        if (!*prefix_data_p) {
+            /* new prefix data - simply copy all the prefix data */
+            *format_p = format;
+            LY_CHECK_GOTO(ret = ly_dup_prefix_data(ctx, format, prefix_data, prefix_data_p), cleanup);
+        } /* else reuse prefix data - the prefix data are always the same, nothing to do */
+        break;
+    }
+
+cleanup:
+    if (ret) {
+        ly_free_prefix_data(*format_p, *prefix_data_p);
+        *prefix_data_p = NULL;
+    }
+    return ret;
+}
+
+const char *
+ly_format2str(LY_VALUE_FORMAT format)
+{
+    switch (format) {
+    case LY_VALUE_CANON:
+        return "canonical";
+    case LY_VALUE_SCHEMA:
+        return "schema imports";
+    case LY_VALUE_SCHEMA_RESOLVED:
+        return "schema stored mapping";
+    case LY_VALUE_XML:
+        return "XML prefixes";
+    case LY_VALUE_JSON:
+        return "JSON module names";
+    case LY_VALUE_LYB:
+        return "LYB prefixes";
+    default:
+        break;
+    }
+
+    return NULL;
+}
+
+LIBYANG_API_DEF int
+ly_time_tz_offset(void)
+{
+    return ly_time_tz_offset_at(time(NULL));
+}
+
+LIBYANG_API_DEF int
+ly_time_tz_offset_at(time_t time)
+{
+    struct tm tm_local, tm_utc;
+    int result = 0;
+
+    /* init timezone */
+    tzset();
+
+    /* get local and UTC time */
+    localtime_r(&time, &tm_local);
+    gmtime_r(&time, &tm_utc);
+
+    /* account for year/month/day change by adding/subtracting from the hours, the change cannot be more than 1 day */
+    if (tm_local.tm_year < tm_utc.tm_year) {
+        tm_utc.tm_hour += 24;
+    } else if (tm_local.tm_year > tm_utc.tm_year) {
+        tm_local.tm_hour += 24;
+    } else if (tm_local.tm_mon < tm_utc.tm_mon) {
+        tm_utc.tm_hour += 24;
+    } else if (tm_local.tm_mon > tm_utc.tm_mon) {
+        tm_local.tm_hour += 24;
+    } else if (tm_local.tm_mday < tm_utc.tm_mday) {
+        tm_utc.tm_hour += 24;
+    } else if (tm_local.tm_mday > tm_utc.tm_mday) {
+        tm_local.tm_hour += 24;
+    }
+
+    /* hours shift in seconds */
+    result += (tm_local.tm_hour - tm_utc.tm_hour) * 3600;
+
+    /* minutes shift in seconds */
+    result += (tm_local.tm_min - tm_utc.tm_min) * 60;
+
+    /* seconds shift */
+    result += tm_local.tm_sec - tm_utc.tm_sec;
+
+    return result;
+}
+
+LIBYANG_API_DEF LY_ERR
+ly_time_str2time(const char *value, time_t *time, char **fractions_s)
+{
+    struct tm tm = {0};
+    uint32_t i, frac_len;
+    const char *frac;
+    int64_t shift, shift_m;
+    time_t t;
+
+    LY_CHECK_ARG_RET(NULL, value, time, LY_EINVAL);
+
+    tm.tm_year = atoi(&value[0]) - 1900;
+    tm.tm_mon = atoi(&value[5]) - 1;
+    tm.tm_mday = atoi(&value[8]);
+    tm.tm_hour = atoi(&value[11]);
+    tm.tm_min = atoi(&value[14]);
+    tm.tm_sec = atoi(&value[17]);
+
+    /* explicit checks for some gross errors */
+    if (tm.tm_mon > 11) {
+        LOGERR(NULL, LY_EINVAL, "Invalid date-and-time month \"%d\".", tm.tm_mon);
+        return LY_EINVAL;
+    }
+    if ((tm.tm_mday < 1) || (tm.tm_mday > 31)) {
+        LOGERR(NULL, LY_EINVAL, "Invalid date-and-time day of month \"%d\".", tm.tm_mday);
+        return LY_EINVAL;
+    }
+    if (tm.tm_hour > 23) {
+        LOGERR(NULL, LY_EINVAL, "Invalid date-and-time hours \"%d\".", tm.tm_hour);
+        return LY_EINVAL;
+    }
+    if (tm.tm_min > 59) {
+        LOGERR(NULL, LY_EINVAL, "Invalid date-and-time minutes \"%d\".", tm.tm_min);
+        return LY_EINVAL;
+    }
+    if (tm.tm_sec > 60) {
+        LOGERR(NULL, LY_EINVAL, "Invalid date-and-time seconds \"%d\".", tm.tm_sec);
+        return LY_EINVAL;
+    }
+
+    t = timegm(&tm);
+    i = 19;
+
+    /* fractions of a second */
+    if (value[i] == '.') {
+        ++i;
+        frac = &value[i];
+        for (frac_len = 0; isdigit(frac[frac_len]); ++frac_len) {}
+
+        i += frac_len;
+    } else {
+        frac = NULL;
+    }
+
+    /* apply offset */
+    if ((value[i] == 'Z') || (value[i] == 'z')) {
+        /* zero shift */
+        shift = 0;
+    } else {
+        shift = strtol(&value[i], NULL, 10);
+        if (shift > 23) {
+            LOGERR(NULL, LY_EINVAL, "Invalid date-and-time timezone hour \"%" PRIi64 "\".", shift);
+            return LY_EINVAL;
+        }
+        shift = shift * 60 * 60; /* convert from hours to seconds */
+
+        shift_m = strtol(&value[i + 4], NULL, 10);
+        if (shift_m > 59) {
+            LOGERR(NULL, LY_EINVAL, "Invalid date-and-time timezone minutes \"%" PRIi64 "\".", shift_m);
+            return LY_EINVAL;
+        }
+        shift_m *= 60; /* convert from minutes to seconds */
+
+        /* correct sign */
+        if (shift < 0) {
+            shift_m *= -1;
+        }
+
+        /* connect hours and minutes of the shift */
+        shift = shift + shift_m;
+    }
+
+    /* we have to shift to the opposite way to correct the time */
+    t -= shift;
+
+    *time = t;
+    if (fractions_s) {
+        if (frac) {
+            *fractions_s = strndup(frac, frac_len);
+            LY_CHECK_RET(!*fractions_s, LY_EMEM);
+        } else {
+            *fractions_s = NULL;
+        }
+    }
+    return LY_SUCCESS;
+}
+
+LIBYANG_API_DEF LY_ERR
+ly_time_time2str(time_t time, const char *fractions_s, char **str)
+{
+    struct tm tm;
+    char zoneshift[12];
+    int zonediff_s, zonediff_h, zonediff_m;
+
+    LY_CHECK_ARG_RET(NULL, str, LY_EINVAL);
+
+    /* init timezone */
+    tzset();
+
+    /* convert */
+    if (!localtime_r(&time, &tm)) {
+        return LY_ESYS;
+    }
+
+    /* get timezone offset (do not use tm_gmtoff to avoid portability problems),
+     * zonediff_h may be negative, zonediff_m MUST NOT */
+    zonediff_s = ly_time_tz_offset_at(time);
+    zonediff_h = zonediff_s / 60 / 60;
+    zonediff_m = zonediff_s / 60 % 60;
+    sprintf(zoneshift, "%+03d:%02d", zonediff_h, zonediff_m < 0 ? -zonediff_m : zonediff_m);
+
+    /* print */
+    if (asprintf(str, "%04d-%02d-%02dT%02d:%02d:%02d%s%s%s",
+            tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec,
+            fractions_s ? "." : "", fractions_s ? fractions_s : "", zoneshift) == -1) {
+        return LY_EMEM;
+    }
+
+    return LY_SUCCESS;
+}
+
+LIBYANG_API_DEF LY_ERR
+ly_time_str2ts(const char *value, struct timespec *ts)
+{
+    LY_ERR rc;
+    char *fractions_s, frac_buf[10];
+    int frac_len;
+
+    LY_CHECK_ARG_RET(NULL, value, ts, LY_EINVAL);
+
+    rc = ly_time_str2time(value, &ts->tv_sec, &fractions_s);
+    LY_CHECK_RET(rc);
+
+    /* convert fractions of a second to nanoseconds */
+    if (fractions_s) {
+        /* init frac_buf with zeroes */
+        memset(frac_buf, '0', 9);
+        frac_buf[9] = '\0';
+
+        frac_len = strlen(fractions_s);
+        memcpy(frac_buf, fractions_s, frac_len > 9 ? 9 : frac_len);
+        ts->tv_nsec = atol(frac_buf);
+        free(fractions_s);
+    } else {
+        ts->tv_nsec = 0;
+    }
+
+    return LY_SUCCESS;
+}
+
+LIBYANG_API_DEF LY_ERR
+ly_time_ts2str(const struct timespec *ts, char **str)
+{
+    char frac_buf[10];
+
+    LY_CHECK_ARG_RET(NULL, ts, str, ((ts->tv_nsec <= 999999999) && (ts->tv_nsec >= 0)), LY_EINVAL);
+
+    /* convert nanoseconds to fractions of a second */
+    if (ts->tv_nsec) {
+        sprintf(frac_buf, "%09ld", ts->tv_nsec);
+    }
+
+    return ly_time_time2str(ts->tv_sec, ts->tv_nsec ? frac_buf : NULL, str);
+}