src/parser_yang.c

/**
 * @file parser_yang.c
 * @author Pavol Vican
 * @brief YANG parser for libyang
 *
 * Copyright (c) 2015 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
 */

#include <ctype.h>
#include <pcre.h>
#include "parser_yang.h"
#include "parser_yang_lex.h"
#include "parser.h"
#include "xpath.h"

static int 
yang_check_string(struct lys_module *module, const char **target, char *what, char *where, char *value)
{
    if (*target) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, what, where);
        free(value);
        return 1;
    } else {
        *target = lydict_insert_zc(module->ctx, value);
        return 0;
    }
}

int 
yang_read_common(struct lys_module *module, char *value, enum yytokentype type)
{
    int ret = 0;

    switch (type) {
    case MODULE_KEYWORD:
        module->name = lydict_insert_zc(module->ctx, value);
        break;
    case NAMESPACE_KEYWORD:
        ret = yang_check_string(module, &module->ns, "namespace", "module", value);
        break;
    case ORGANIZATION_KEYWORD:
        ret = yang_check_string(module, &module->org, "organization", "module", value);
        break;
    case CONTACT_KEYWORD:
        ret = yang_check_string(module, &module->contact, "contact", "module", value);
        break;
    default:
        free(value);
        LOGINT;
        ret = EXIT_FAILURE;
        break;
    }

    return ret;
}

int 
yang_read_prefix(struct lys_module *module, void *save, char *value, enum yytokentype type)
{
    int ret = 0;

    if (lyp_check_identifier(value, LY_IDENT_PREFIX, module, NULL)) {
        free(value);
        return EXIT_FAILURE;
    }
    switch (type){
    case MODULE_KEYWORD:
        ret = yang_check_string(module, &module->prefix, "prefix", "module", value);
        break;
    case IMPORT_KEYWORD:
        ((struct lys_import *)save)->prefix = lydict_insert_zc(module->ctx, value);
        break;
    default:
        free(value);
        LOGINT;
        ret = EXIT_FAILURE;
        break;
    }

    return ret;
}

int
yang_fill_import(struct lys_module *module, struct lys_import *imp, char *value)
{
    const char *exp;
    int rc, i;

    exp = lydict_insert_zc(module->ctx, value);
    rc = lyp_check_import(module, exp, imp);
    lydict_remove(module->ctx, exp);
    if (rc) {
        goto error;
    }

    /* check duplicities in imported modules */
    for (i = 0; i < module->imp_size; i++) {
        if (!strcmp(module->imp[i].module->name, module->imp[module->imp_size].module->name)) {
            LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, module->imp[i].module->name, "import");
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Importing module \"%s\" repeatedly.", module->imp[i].module->name);
            goto error;
        }
    }
    module->imp_size++;
    return EXIT_SUCCESS;

error:
    module->imp_size++;
    return EXIT_FAILURE;
}

int
yang_read_description(struct lys_module *module, void *node, char *value, char *where)
{
    int ret;
    char *dsc = "description";

    if (!node) {
        ret = yang_check_string(module, &module->dsc, dsc, "module", value);
    } else {
        if (!strcmp("revision", where)) {
            ret = yang_check_string(module, &((struct lys_revision *)node)->dsc, dsc, where, value);
        } else {
            ret = yang_check_string(module, &((struct lys_node *)node)->dsc, dsc, where, value);
        }
    }
    return ret;
}

int
yang_read_reference(struct lys_module *module, void *node, char *value, char *where)
{
    int ret;
    char *ref = "reference";

    if (!node) {
        ret = yang_check_string(module, &module->ref, "reference", "module", value);
    } else {
        if (!strcmp("revision", where)) {
            ret = yang_check_string(module, &((struct lys_revision *)node)->ref, ref, where, value);
        } else {
            ret = yang_check_string(module, &((struct lys_node *)node)->ref, ref, where, value);
        }
    }
    return ret;
}

void *
yang_read_revision(struct lys_module *module, char *value)
{
    struct lys_revision *retval;

    retval = &module->rev[module->rev_size];

    /* first member of array is last revision */
    if (module->rev_size && strcmp(module->rev[0].date, value) < 0) {
        memcpy(retval->date, module->rev[0].date, LY_REV_SIZE);
        memcpy(module->rev[0].date, value, LY_REV_SIZE);
        retval->dsc = module->rev[0].dsc;
        retval->ref = module->rev[0].ref;
        retval = module->rev;
        retval->dsc = NULL;
        retval->ref = NULL;
    } else {
        memcpy(retval->date, value, LY_REV_SIZE);
    }
    module->rev_size++;
    free(value);
    return retval;
}

int
yang_add_elem(struct lys_node_array **node, uint32_t *size)
{
    if (!(*size % LY_ARRAY_SIZE)) {
        if (!(*node = ly_realloc(*node, (*size + LY_ARRAY_SIZE) * sizeof **node))) {
            LOGMEM;
            return EXIT_FAILURE;
        } else {
            memset(*node + *size, 0, LY_ARRAY_SIZE * sizeof **node);
        }
    }
    (*size)++;
    return EXIT_SUCCESS;
}

void *
yang_read_feature(struct lys_module *module, char *value)
{
    struct lys_feature *retval;

    /* check uniqueness of feature's names */
    if (lyp_check_identifier(value, LY_IDENT_FEATURE, module, NULL)) {
        goto error;
    }
    retval = &module->features[module->features_size];
    retval->name = lydict_insert_zc(module->ctx, value);
    retval->module = module;
    module->features_size++;
    return retval;

error:
    free(value);
    return NULL;
}

int
yang_read_if_feature(struct lys_module *module, void *ptr, char *value, struct unres_schema *unres, enum yytokentype type)
{
    const char *exp;
    int ret;
    struct lys_feature *f;
    struct lys_node *n;

    if (!(exp = transform_schema2json(module, value))) {
        free(value);
        return EXIT_FAILURE;
    }
    free(value);

    /* hack - store pointer to the parent node for later status check */
    if (type == FEATURE_KEYWORD) {
        f = (struct lys_feature *) ptr;
        f->features[f->features_size] = f;
        ret = unres_schema_add_str(module, unres, &f->features[f->features_size], UNRES_IFFEAT, exp);
        f->features_size++;
    } else {
        n = (struct lys_node *) ptr;
        n->features[n->features_size] = (struct lys_feature *) n;
        ret = unres_schema_add_str(module, unres, &n->features[n->features_size], UNRES_IFFEAT, exp);
        n->features_size++;
    }

    lydict_remove(module->ctx, exp);
    if (ret == -1) {

        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}

int
yang_check_flags(uint8_t *flags, uint8_t mask, char *what, char *where, int value)
{
    if (*flags & mask) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, what, where);
        return EXIT_FAILURE;
    } else {
        *flags |= value;
        return EXIT_SUCCESS;
    }
}

void *
yang_read_identity(struct lys_module *module, char *value)
{
    struct lys_ident *ret;

    ret = &module->ident[module->ident_size];
    ret->name = lydict_insert_zc(module->ctx, value);
    ret->module = module;
    module->ident_size++;
    return ret;
}

int
yang_read_base(struct lys_module *module, struct lys_ident *ident, char *value, struct unres_schema *unres)
{
    const char *exp;

    if (!value) {
        /* base statement not found */
        return EXIT_SUCCESS;
    }
    exp = transform_schema2json(module, value);
    free(value);
    if (!exp) {
        return EXIT_FAILURE;
    }
    if (unres_schema_add_str(module, unres, ident, UNRES_IDENT, exp) == -1) {
        lydict_remove(module->ctx, exp);
        return EXIT_FAILURE;
    }

    lydict_remove(module->ctx, exp);
    return EXIT_SUCCESS;
}

void *
yang_read_must(struct lys_module *module, struct lys_node *node, char *value, enum yytokentype type)
{
    struct lys_restr *retval;

    switch (type) {
    case CONTAINER_KEYWORD:
        retval = &((struct lys_node_container *)node)->must[((struct lys_node_container *)node)->must_size++];
        break;
    case ANYXML_KEYWORD:
        retval = &((struct lys_node_anyxml *)node)->must[((struct lys_node_anyxml *)node)->must_size++];
        break;
    case LEAF_KEYWORD:
        retval = &((struct lys_node_leaf *)node)->must[((struct lys_node_leaf *)node)->must_size++];
        break;
    case LEAF_LIST_KEYWORD:
        retval = &((struct lys_node_leaflist *)node)->must[((struct lys_node_leaflist *)node)->must_size++];
        break;
    case LIST_KEYWORD:
        retval = &((struct lys_node_list *)node)->must[((struct lys_node_list *)node)->must_size++];
        break;
    case REFINE_KEYWORD:
        retval = &((struct lys_refine *)node)->must[((struct lys_refine *)node)->must_size++];
        break;
    case ADD_KEYWORD:
        retval = &(*((struct type_deviation *)node)->trg_must)[(*((struct type_deviation *)node)->trg_must_size)++];
        memset(retval, 0, sizeof *retval);
        break;
    case DELETE_KEYWORD:
        retval = &((struct type_deviation *)node)->deviate->must[((struct type_deviation *)node)->deviate->must_size++];
        break;
    default:
        goto error;
        break;
    }
    retval->expr = transform_schema2json(module, value);
    if (!retval->expr || lyxp_syntax_check(retval->expr)) {
        goto error;
    }
    free(value);
    return retval;

error:
    free(value);
    return NULL;
}

int
yang_read_message(struct lys_module *module,struct lys_restr *save,char *value, char *what, int message)
{
    int ret;

    if (message==ERROR_APP_TAG_KEYWORD) {
        ret = yang_check_string(module, &save->eapptag, "error_app_tag", what, value);
    } else {
        ret = yang_check_string(module, &save->emsg, "error_app_tag", what, value);
    }
    return ret;
}

int
yang_read_presence(struct lys_module *module, struct lys_node_container *cont, char *value)
{
    if (cont->presence) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, cont, "presence", "container");
        free(value);
        return EXIT_FAILURE;
    } else {
        cont->presence = lydict_insert_zc(module->ctx, value);
        return EXIT_SUCCESS;
    }
}

void *
yang_read_when(struct lys_module *module, struct lys_node *node, enum yytokentype type, char *value)
{
    struct lys_when *retval;

    retval = calloc(1, sizeof *retval);
    if (!retval) {
        LOGMEM;
        free(value);
        return NULL;
    }
    retval->cond = transform_schema2json(module, value);
    if (!retval->cond || lyxp_syntax_check(retval->cond)) {
        goto error;
    }
    switch (type) {
    case CONTAINER_KEYWORD:
        if (((struct lys_node_container *)node)->when) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, node, "when", "container");
            goto error;
        }
        ((struct lys_node_container *)node)->when = retval;
        break;
    case ANYXML_KEYWORD:
        if (((struct lys_node_anyxml *)node)->when) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, node, "when", "anyxml");
            goto error;
        }
        ((struct lys_node_anyxml *)node)->when = retval;
        break;
    case CHOICE_KEYWORD:
        if (((struct lys_node_choice *)node)->when) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, node, "when", "choice");
            goto error;
        }
        ((struct lys_node_choice *)node)->when = retval;
        break;
    case CASE_KEYWORD:
        if (((struct lys_node_case *)node)->when) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, node, "when", "case");
            goto error;
        }
        ((struct lys_node_case *)node)->when = retval;
        break;
    case LEAF_KEYWORD:
        if (((struct lys_node_leaf *)node)->when) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, node, "when", "leaf");
            goto error;
        }
        ((struct lys_node_leaf *)node)->when = retval;
        break;
    case LEAF_LIST_KEYWORD:
        if (((struct lys_node_leaflist *)node)->when) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, node, "when", "leaflist");
            goto error;
        }
        ((struct lys_node_leaflist *)node)->when = retval;
        break;
    case LIST_KEYWORD:
        if (((struct lys_node_list *)node)->when) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, node, "when", "list");
            goto error;
        }
        ((struct lys_node_list *)node)->when = retval;
        break;
    case USES_KEYWORD:
        if (((struct lys_node_uses *)node)->when) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, node, "when", "uses");
            goto error;
        }
        ((struct lys_node_uses *)node)->when = retval;
        break;
    case AUGMENT_KEYWORD:
        if (((struct lys_node_augment *)node)->when) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_LYS, node, "when", "augment");
            goto error;
        }
        ((struct lys_node_augment *)node)->when = retval;
        break;
    default:
        goto error;
        break;
    }
    free(value);
    return retval;

error:
    free(value);
    lys_when_free(module->ctx, retval);
    return NULL;
}

void *
yang_read_node(struct lys_module *module, struct lys_node *parent, char *value, int nodetype, int sizeof_struct)
{
    struct lys_node *node;

    node = calloc(1, sizeof_struct);
    if (!node) {
        free(value);
        LOGMEM;
        return NULL;
    }
    if (value) {
        node->name = lydict_insert_zc(module->ctx, value);
    }
    node->module = module;
    node->nodetype = nodetype;
    node->prev = node;

    /* insert the node into the schema tree */
    if (lys_node_addchild(parent, module->type ? ((struct lys_submodule *)module)->belongsto: module, node)) {
        if (value) {
            lydict_remove(module->ctx, node->name);
        }
        free(node);
        return NULL;
    }
    return node;
}

int
yang_read_default(struct lys_module *module, void *node, char *value, enum yytokentype type)
{
    int ret;

    switch (type) {
    case LEAF_KEYWORD:
        ret = yang_check_string(module, &((struct lys_node_leaf *) node)->dflt, "default", "leaf", value);
        break;
    case TYPEDEF_KEYWORD:
        ret = yang_check_string(module, &((struct lys_tpdf *) node)->dflt, "default", "typedef", value);
        break;
    default:
        free(value);
        LOGINT;
        ret = EXIT_FAILURE;
        break;
    }
    return ret;
}

int
yang_read_units(struct lys_module *module, void *node, char *value, enum yytokentype type)
{
    int ret;

    switch (type) {
    case LEAF_KEYWORD:
        ret = yang_check_string(module, &((struct lys_node_leaf *) node)->units, "units", "leaf", value);
        break;
    case LEAF_LIST_KEYWORD:
        ret = yang_check_string(module, &((struct lys_node_leaflist *) node)->units, "units", "leaflist", value);
        break;
    case TYPEDEF_KEYWORD:
        ret = yang_check_string(module, &((struct lys_tpdf *) node)->units, "units", "typedef", value);
        break;
    default:
        free(value);
        LOGINT;
        ret = EXIT_FAILURE;
        break;
    }
    return ret;
}

int
yang_read_key(struct lys_module *module, struct lys_node_list *list, struct unres_schema *unres)
{
    char *exp, *value;

    exp = value = (char *) list->keys;
    while ((value = strpbrk(value, " \t\n"))) {
        list->keys_size++;
        while (isspace(*value)) {
            value++;
        }
    }
    list->keys_size++;
    list->keys = calloc(list->keys_size, sizeof *list->keys);
    if (!list->keys) {
        LOGMEM;
        goto error;
    }
    if (unres_schema_add_str(module, unres, list, UNRES_LIST_KEYS, exp) == -1) {
        goto error;
    }
    free(exp);
    return EXIT_SUCCESS;

error:
    free(exp);
    return EXIT_FAILURE;
}

int
yang_fill_unique(struct lys_module *module, struct lys_node_list *list, struct lys_unique *unique, char *value, struct unres_schema *unres)
{
    int i, j;
    char *vaux;

    /* count the number of unique leafs in the value */
    vaux = value;
    while ((vaux = strpbrk(vaux, " \t\n"))) {
       unique->expr_size++;
        while (isspace(*vaux)) {
            vaux++;
        }
    }
    unique->expr_size++;
    unique->expr = calloc(unique->expr_size, sizeof *unique->expr);
    if (!unique->expr) {
        LOGMEM;
        goto error;
    }

    for (i = 0; i < unique->expr_size; i++) {
        vaux = strpbrk(value, " \t\n");
        if (!vaux) {
            /* the last token, lydict_insert() will count its size on its own */
            vaux = value;
        }

        /* store token into unique structure */
        unique->expr[i] = lydict_insert(module->ctx, value, vaux - value);

        /* check that the expression does not repeat */
        for (j = 0; j < i; j++) {
            if (ly_strequal(unique->expr[j], unique->expr[i], 1)) {
                LOGVAL(LYE_INARG, LY_VLOG_LYS, list, unique->expr[i], "unique");
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "The identifier is not unique");
                goto error;
            }
        }
        /* try to resolve leaf */
        if (unres) {
            unres_schema_add_str(module, unres, (struct lys_node *)list, UNRES_LIST_UNIQ, unique->expr[i]);
        } else {
            if (resolve_unique((struct lys_node *)list, unique->expr[i])) {
                goto error;
            }
        }

        /* move to next token */
        value = vaux;
        while(isspace(*value)) {
            value++;
        }
    }

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

int
yang_read_unique(struct lys_module *module, struct lys_node_list *list, struct unres_schema *unres)
{
    uint8_t k;
    char *str;

    for(k=0; k<list->unique_size; k++) {
        str = (char *)list->unique[k].expr;
        if (yang_fill_unique(module, list, &list->unique[k], str, unres)) {
            goto error;
        }
        free(str);
    }
    return EXIT_SUCCESS;

error:
    free(str);
    return EXIT_FAILURE;
}

static int
yang_read_identyref(struct lys_module *module, struct lys_type *type, struct unres_schema *unres)
{
    const char *value, *tmp;
    int rc, ret = EXIT_FAILURE;

    value = tmp = type->info.lref.path;
    /* store in the JSON format */
    value = transform_schema2json(module, value);
    if (!value) {
        goto end;
    }
    rc = unres_schema_add_str(module, unres, type, UNRES_TYPE_IDENTREF, value);
    lydict_remove(module->ctx, value);

    if (rc == -1) {
        goto end;
    }

    ret = EXIT_SUCCESS;

end:
    lydict_remove(module->ctx, tmp);
    return ret;
}

int
yang_check_type(struct lys_module *module, struct lys_node *parent, struct yang_type *typ, struct unres_schema *unres)
{
    int i, rc;
    int ret = -1;
    const char *name, *value;
    LY_DATA_TYPE base;

    base = typ->base;
    value = transform_schema2json(module, typ->name);
    if (!value) {
        goto error;
    }

    i = parse_identifier(value);
    if (i < 1) {
        LOGVAL(LYE_INCHAR, LY_VLOG_NONE, NULL, value[-i], &value[-i]);
        lydict_remove(module->ctx, value);
        goto error;
    }
    /* module name*/
    name = value;
    if (value[i]) {
        typ->type->module_name = lydict_insert(module->ctx, value, i);
        name += i;
        if ((name[0] != ':') || (parse_identifier(name + 1) < 1)) {
            LOGVAL(LYE_INCHAR, LY_VLOG_NONE, NULL, name[0], name);
            lydict_remove(module->ctx, value);
            goto error;
        }
        ++name;
    }

    rc = resolve_superior_type(name, typ->type->module_name, module, parent, &typ->type->der);
    lydict_remove(module->ctx, value);
    if (rc == -1) {
        LOGVAL(LYE_INMOD, LY_VLOG_NONE, NULL, typ->type->module_name);
        goto error;

    /* the type could not be resolved or it was resolved to an unresolved typedef*/
    } else if (rc == EXIT_FAILURE) {
        ret = EXIT_FAILURE;
        goto error;
    }
    typ->type->base = typ->type->der->type.base;
    if (base == 0) {
        base = typ->type->der->type.base;
    }
    switch (base) {
    case LY_TYPE_STRING:
        if (typ->type->base == LY_TYPE_BINARY) {
            if (typ->type->info.str.pat_count) {
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Binary type could not include pattern statement.");
                goto error;
            }
            typ->type->info.binary.length = typ->type->info.str.length;
            if (typ->type->info.binary.length && lyp_check_length_range(typ->type->info.binary.length->expr, typ->type)) {
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, typ->type->info.binary.length->expr, "length");
                goto error;
            }
        } else if (typ->type->base == LY_TYPE_STRING) {
            if (typ->type->info.str.length && lyp_check_length_range(typ->type->info.str.length->expr, typ->type)) {
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, typ->type->info.str.length->expr, "length");
                goto error;
            }
        } else {
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Invalid restriction in type \"%s\".", typ->type->parent->name);
            goto error;
        }
        break;
    case LY_TYPE_DEC64:
        if (typ->type->base == LY_TYPE_DEC64) {
            if (typ->type->info.dec64.range && lyp_check_length_range(typ->type->info.dec64.range->expr, typ->type)) {
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, typ->type->info.dec64.range->expr, "range");
                goto error;
            }
            /* mandatory sub-statement(s) check */
            if (!typ->type->info.dec64.dig && !typ->type->der->type.der) {
                /* decimal64 type directly derived from built-in type requires fraction-digits */
                LOGVAL(LYE_MISSCHILDSTMT, LY_VLOG_NONE, NULL, "fraction-digits", "type");
                goto error;
            }
            if (typ->type->info.dec64.dig && typ->type->der->type.der) {
                /* type is not directly derived from buit-in type and fraction-digits statement is prohibited */
                LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "fraction-digits");
                goto error;
            }
        } else if (typ->type->base >= LY_TYPE_INT8 && typ->type->base <=LY_TYPE_UINT64) {
            if (typ->type->info.dec64.dig) {
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Numerical type could not include fraction statement.");
                goto error;
            }
            typ->type->info.num.range = typ->type->info.dec64.range;
            if (typ->type->info.num.range && lyp_check_length_range(typ->type->info.num.range->expr, typ->type)) {
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, typ->type->info.num.range->expr, "range");
                goto error;
            }
        } else {
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Invalid restriction in type \"%s\".", typ->type->parent->name);
            goto error;
        }
        break;
    case LY_TYPE_ENUM:
        if (typ->type->base != LY_TYPE_ENUM) {
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Invalid restriction in type \"%s\".", typ->type->parent->name);
            goto error;
        }
        if (!typ->type->der->type.der && !typ->type->info.bits.count) {
            /* type is derived directly from buit-in enumeartion type and enum statement is required */
            LOGVAL(LYE_MISSCHILDSTMT, LY_VLOG_NONE, NULL, "enum", "type");
            goto error;
        }
        if (typ->type->der->type.der && typ->type->info.enums.count) {
            /* type is not directly derived from buit-in enumeration type and enum statement is prohibited */
            LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "enum");
            goto error;
        }
        break;
    case LY_TYPE_BITS:
        if (typ->type->base != LY_TYPE_BITS) {
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Invalid restriction in type \"%s\".", typ->type->parent->name);
            goto error;
        }
        if (!typ->type->der->type.der && !typ->type->info.bits.count) {
            /* type is derived directly from buit-in bits type and bit statement is required */
            LOGVAL(LYE_MISSCHILDSTMT, LY_VLOG_NONE, NULL, "bit", "type");
            goto error;
        }
        if (typ->type->der->type.der && typ->type->info.bits.count) {
            /* type is not directly derived from buit-in bits type and bit statement is prohibited */
            LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "bit");
            goto error;
        }
        break;
    case LY_TYPE_LEAFREF:
        if (typ->type->base == LY_TYPE_IDENT && (typ->flags & LYS_TYPE_BASE)) {
            if (yang_read_identyref(module, typ->type, unres)) {
                goto error;
            }
        } else if (typ->type->base == LY_TYPE_LEAFREF) {
            if (typ->type->info.lref.path) {
                value = typ->type->info.lref.path;
                /* store in the JSON format */
                typ->type->info.lref.path = transform_schema2json(module, value);
                lydict_remove(module->ctx, value);
                if (!typ->type->info.lref.path) {
                    goto error;
                }
                if (unres_schema_add_node(module, unres, typ->type, UNRES_TYPE_LEAFREF, parent) == -1) {
                    goto error;
                }
            } else if (!typ->type->der->type.der) {
                LOGVAL(LYE_MISSCHILDSTMT, LY_VLOG_NONE, NULL, "path", "type");
                goto error;
            }
        } else {
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Invalid restriction in type \"%s\".", typ->type->parent->name);
            goto error;
        }
        break;
    case LY_TYPE_IDENT:
        if (typ->type->der->type.der) {
            /* this is just a derived type with no base specified/required */
            break;
        } else {
            LOGVAL(LYE_MISSCHILDSTMT, LY_VLOG_NONE, NULL, "base", "type");
            goto error;
        }
        break;
    case LY_TYPE_UNION:
        if (typ->type->base != LY_TYPE_UNION) {
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Invalid restriction in type \"%s\".", typ->type->parent->name);
            goto error;
        }
        if (!typ->type->info.uni.types) {
            if (typ->type->der->type.der) {
                /* this is just a derived type with no additional type specified/required */
                break;
            }
            LOGVAL(LYE_MISSCHILDSTMT, LY_VLOG_NONE, NULL, "type", "(union) type");
            goto error;
        }
        for (i = 0; i < typ->type->info.uni.count; i++) {
            if (unres_schema_add_node(module, unres, &typ->type->info.uni.types[i], UNRES_TYPE_DER, parent)) {
                goto error;
            }
            if (typ->type->info.uni.types[i].base == LY_TYPE_EMPTY) {
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, "empty", typ->name);
                goto error;
            } else if (typ->type->info.uni.types[i].base == LY_TYPE_LEAFREF) {
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, "leafref", typ->name);
                goto error;
            }
        }
        break;

    default:
        if (base >= LY_TYPE_BINARY && base <= LY_TYPE_UINT64) {
            if (typ->type->base != base) {
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Invalid restriction in type \"%s\".", typ->type->parent->name);
                goto error;
            }
        } else {
            LOGINT;
            goto error;
        }
    }
    return EXIT_SUCCESS;

error:
    if (typ->type->module_name) {
        lydict_remove(module->ctx, typ->type->module_name);
        typ->type->module_name = NULL;
    }
    return ret;
}

void *
yang_read_type(struct lys_module *module, void *parent, char *value, enum yytokentype type)
{
    struct yang_type *typ;
    struct type_deviation *dev;
    struct lys_tpdf *tmp_parent;

    typ = calloc(1, sizeof *typ);
    if (!typ) {
        LOGMEM;
        return NULL;
    }

    typ->flags = LY_YANG_STRUCTURE_FLAG;
    switch (type) {
    case LEAF_KEYWORD:
        ((struct lys_node_leaf *)parent)->type.der = (struct lys_tpdf *)typ;
        ((struct lys_node_leaf *)parent)->type.parent = (struct lys_tpdf *)parent;
        typ->type = &((struct lys_node_leaf *)parent)->type;
        break;
    case LEAF_LIST_KEYWORD:
        ((struct lys_node_leaflist *)parent)->type.der = (struct lys_tpdf *)typ;
        ((struct lys_node_leaflist *)parent)->type.parent = (struct lys_tpdf *)parent;
        typ->type = &((struct lys_node_leaflist *)parent)->type;
        break;
    case UNION_KEYWORD:
        ((struct lys_type *)parent)->der = (struct lys_tpdf *)typ;
        typ->type = (struct lys_type *)parent;
        break;
    case TYPEDEF_KEYWORD:
        ((struct lys_tpdf *)parent)->type.der = (struct lys_tpdf *)typ;
        typ->type = &((struct lys_tpdf *)parent)->type;
        break;
    case REPLACE_KEYWORD:
        /* deviation replace type*/
        dev = (struct type_deviation *)parent;
        if (dev->deviate->type) {
            LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, "type", "deviation");
            goto error;
        }
        /* check target node type */
        if (dev->target->nodetype == LYS_LEAF) {
            typ->type = &((struct lys_node_leaf *)dev->target)->type;
        } else if (dev->target->nodetype == LYS_LEAFLIST) {
            typ->type = &((struct lys_node_leaflist *)dev->target)->type;
        } else {
            LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "type");
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Target node does not allow \"type\" property.");
            goto error;
        }

        /* remove type and initialize it */
        lys_type_free(module->ctx, typ->type);
        tmp_parent = typ->type->parent;
        memset(typ->type, 0, sizeof *typ->type);
        typ->type->parent = tmp_parent;

        /* replace it with the value specified in deviation */
        /* HACK for unres */
        typ->type->der = (struct lys_tpdf *)typ;
        dev->deviate->type = typ->type;
        break;
    default:
        goto error;
        break;
    }
    typ->name = lydict_insert_zc(module->ctx, value);
    return typ;

error:
    free(value);
    free(typ);
    return NULL;
}

void *
yang_read_length(struct lys_module *module, struct yang_type *typ, char *value)
{
    struct lys_restr **length;

    if (typ->base == 0 || typ->base == LY_TYPE_STRING) {
        length = &typ->type->info.str.length;
        typ->base = LY_TYPE_STRING;
    } else if (typ->base == LY_TYPE_BINARY) {
        length = &typ->type->info.binary.length;
    } else {
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Unexpected length statement.");
        goto error;
    }

    if (*length) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, "length", "type");
    }
    *length = calloc(1, sizeof **length);
    if (!*length) {
        LOGMEM;
        goto error;
    }
    (*length)->expr = lydict_insert_zc(module->ctx, value);
    return *length;

error:
    free(value);
    return NULL;

}

void *
yang_read_pattern(struct lys_module *module, struct yang_type *typ, char *value)
{
    pcre *precomp;
    int err_offset;
    const char *err_ptr;

    /* check that the regex is valid */
    precomp = pcre_compile(value, PCRE_NO_AUTO_CAPTURE, &err_ptr, &err_offset, NULL);
    if (!precomp) {
        LOGVAL(LYE_INREGEX, LY_VLOG_NONE, NULL, value, err_ptr);
        free(value);
        return NULL;
    }
    free(precomp);

    typ->type->info.str.patterns[typ->type->info.str.pat_count].expr = lydict_insert_zc(module->ctx, value);
    typ->type->info.str.pat_count++;
    return &typ->type->info.str.patterns[typ->type->info.str.pat_count-1];
}

void *
yang_read_range(struct  lys_module *module, struct yang_type *typ, char *value)
{
    if (typ->base != 0 && typ->base != LY_TYPE_DEC64) {
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Unexpected range statement.");
        goto error;
    }
    typ->base = LY_TYPE_DEC64;
    if (typ->type->info.dec64.range) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, "range", "type");
        goto error;
    }
    typ->type->info.dec64.range = calloc(1, sizeof *typ->type->info.dec64.range);
    if (!typ->type->info.dec64.range) {
        LOGMEM;
        goto error;
    }
    typ->type->info.dec64.range->expr = lydict_insert_zc(module->ctx, value);
    return typ->type->info.dec64.range;

error:
    free(value);
    return NULL;
}

int
yang_read_fraction(struct yang_type *typ, uint32_t value)
{
    if (typ->base == 0 || typ->base == LY_TYPE_DEC64) {
        typ->base = LY_TYPE_DEC64;
    } else {
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Unexpected fraction-digits statement.");
        goto error;
    }
    if (typ->type->info.dec64.dig) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, "fraction-digits", "type");
        goto error;
    }
    /* range check */
    if (value < 1 || value > 18) {
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Invalid value \"%d\" of \"%s\".", value, "fraction-digits");
        goto error;
    }
    typ->type->info.dec64.dig = value;
    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

void *
yang_read_enum(struct lys_module *module, struct yang_type *typ, char *value)
{
    struct lys_type_enum *enm;
    int i;

    enm = &typ->type->info.enums.enm[typ->type->info.enums.count];
    enm->name = lydict_insert_zc(module->ctx, value);

    /* the assigned name MUST NOT have any leading or trailing whitespace characters */
    if (isspace(enm->name[0]) || isspace(enm->name[strlen(enm->name) - 1])) {
        LOGVAL(LYE_ENUM_WS, LY_VLOG_NONE, NULL, enm->name);
        goto error;
    }

    /* check the name uniqueness */
    for (i = 0; i < typ->type->info.enums.count; i++) {
        if (!strcmp(typ->type->info.enums.enm[i].name, typ->type->info.enums.enm[typ->type->info.enums.count].name)) {
            LOGVAL(LYE_ENUM_DUPNAME, LY_VLOG_NONE, NULL, typ->type->info.enums.enm[i].name);
            goto error;
        }
    }

    typ->type->info.enums.count++;
    return enm;

error:
    typ->type->info.enums.count++;
    return NULL;
}

int
yang_check_enum(struct yang_type *typ, struct lys_type_enum *enm, int64_t *value, int assign)
{
    int i, j;

    if (!assign) {
        /* assign value automatically */
        if (*value > INT32_MAX) {
            LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, "2147483648", "enum/value");
            goto error;
        }
        enm->value = *value;
        enm->flags |= LYS_AUTOASSIGNED;
        (*value)++;
    }

    /* check that the value is unique */
    j = typ->type->info.enums.count-1;
    for (i = 0; i < j; i++) {
        if (typ->type->info.enums.enm[i].value == typ->type->info.enums.enm[j].value) {
            LOGVAL(LYE_ENUM_DUPVAL, LY_VLOG_NONE, NULL,
                   typ->type->info.enums.enm[j].value, typ->type->info.enums.enm[j].name);
            goto error;
        }
    }

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

void *
yang_read_bit(struct lys_module *module, struct yang_type *typ, char *value)
{
    int i;
    struct lys_type_bit *bit;

    bit = &typ->type->info.bits.bit[typ->type->info.bits.count];
    if (lyp_check_identifier(value, LY_IDENT_SIMPLE, NULL, NULL)) {
        free(value);
        goto error;
    }
    bit->name = lydict_insert_zc(module->ctx, value);

    /* check the name uniqueness */
    for (i = 0; i < typ->type->info.bits.count; i++) {
        if (!strcmp(typ->type->info.bits.bit[i].name, bit->name)) {
            LOGVAL(LYE_BITS_DUPNAME, LY_VLOG_NONE, NULL, bit->name);
            typ->type->info.bits.count++;
            goto error;
        }
    }
    typ->type->info.bits.count++;
    return bit;

error:
    return NULL;
}

int
yang_check_bit(struct yang_type *typ, struct lys_type_bit *bit, int64_t *value, int assign)
{
    int i,j;
    struct lys_type_bit bit_tmp;

    if (!assign) {
        /* assign value automatically */
        if (*value > UINT32_MAX) {
            LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, "4294967295", "bit/position");
            goto error;
        }
        bit->pos = (uint32_t)*value;
        bit->flags |= LYS_AUTOASSIGNED;
        (*value)++;
    }

    j = typ->type->info.bits.count - 1;
    /* check that the value is unique */
    for (i = 0; i < j; i++) {
        if (typ->type->info.bits.bit[i].pos == bit->pos) {
            LOGVAL(LYE_BITS_DUPVAL, LY_VLOG_NONE, NULL, bit->pos, bit->name);
            goto error;
        }
    }

    /* keep them ordered by position */
    while (j && typ->type->info.bits.bit[j - 1].pos > typ->type->info.bits.bit[j].pos) {
        /* switch them */
        memcpy(&bit_tmp, &typ->type->info.bits.bit[j], sizeof bit_tmp);
        memcpy(&typ->type->info.bits.bit[j], &typ->type->info.bits.bit[j - 1], sizeof bit_tmp);
        memcpy(&typ->type->info.bits.bit[j - 1], &bit_tmp, sizeof bit_tmp);
        j--;
    }

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

void *
yang_read_typedef(struct lys_module *module, struct lys_node *parent, char *value)
{
    struct lys_tpdf *ret;

    if (lyp_check_identifier(value, LY_IDENT_TYPE, module, parent)) {
        free(value);
        return NULL;
    }
    if (!parent) {
        ret = &module->tpdf[module->tpdf_size];
        module->tpdf_size++;
    } else {
        switch (parent->nodetype) {
        case LYS_GROUPING:
            ret = &((struct lys_node_grp *)parent)->tpdf[((struct lys_node_grp *)parent)->tpdf_size];
            ((struct lys_node_grp *)parent)->tpdf_size++;
            break;
        case LYS_CONTAINER:
            ret = &((struct lys_node_container *)parent)->tpdf[((struct lys_node_container *)parent)->tpdf_size];
            ((struct lys_node_container *)parent)->tpdf_size++;
            break;
        case LYS_LIST:
            ret = &((struct lys_node_list *)parent)->tpdf[((struct lys_node_list *)parent)->tpdf_size];
            ((struct lys_node_list *)parent)->tpdf_size++;
            break;
        case LYS_RPC:
            ret = &((struct lys_node_rpc *)parent)->tpdf[((struct lys_node_rpc *)parent)->tpdf_size];
            ((struct lys_node_rpc *)parent)->tpdf_size++;
            break;
        case LYS_INPUT:
        case LYS_OUTPUT:
            ret = &((struct lys_node_rpc_inout *)parent)->tpdf[((struct lys_node_rpc_inout *)parent)->tpdf_size];
            ((struct lys_node_rpc_inout *)parent)->tpdf_size++;
            break;
        case LYS_NOTIF:
            ret = &((struct lys_node_notif *)parent)->tpdf[((struct lys_node_notif *)parent)->tpdf_size];
            ((struct lys_node_notif *)parent)->tpdf_size++;
            break;
        default:
            /* another type of nodetype is error*/
            LOGINT;
            free(value);
            return NULL;
        }
    }

    ret->type.parent = ret;
    ret->name = lydict_insert_zc(module->ctx, value);
    ret->module = module;
    return ret;
}

void *
yang_read_refine(struct lys_module *module, struct lys_node_uses *uses, char *value)
{
    struct lys_refine *rfn;

    rfn = &uses->refine[uses->refine_size];
    uses->refine_size++;
    rfn->target_name = transform_schema2json(module, value);
    free(value);
    if (!rfn->target_name) {
        return NULL;
    }
    return rfn;
}

void *
yang_read_augment(struct lys_module *module, struct lys_node *parent, char *value)
{
    struct lys_node_augment *aug;

    if (parent) {
        aug = &((struct lys_node_uses *)parent)->augment[((struct lys_node_uses *)parent)->augment_size];
    } else {
        aug = &module->augment[module->augment_size];
    }
    aug->nodetype = LYS_AUGMENT;
    aug->target_name = transform_schema2json(module, value);
    free(value);
    if (!aug->target_name) {
        return NULL;
    }
    aug->parent = parent;
    aug->module = module;
    if (parent) {
        ((struct lys_node_uses *)parent)->augment_size++;
    } else {
        module->augment_size++;
    }
    return aug;
}

void *
yang_read_deviation(struct lys_module *module, char *value)
{
    struct lys_node *dev_target = NULL;
    struct lys_deviation *dev;
    struct type_deviation *deviation = NULL;
    int i, j, rc;

    dev = &module->deviation[module->deviation_size];
    dev->target_name = transform_schema2json(module, value);
    free(value);
    if (!dev->target_name) {
        goto error;
    }

    deviation = calloc(1, sizeof *deviation);
    if (!deviation) {
        LOGMEM;
        goto error;
    }

    /* resolve target node */
    rc = resolve_augment_schema_nodeid(dev->target_name, NULL, module, (const struct lys_node **)&dev_target);
    if (rc || !dev_target) {
        LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, dev->target_name, "deviations");
        goto error;
    }
    if (dev_target->module == lys_module(module)) {
        LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, dev->target_name, "deviation");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Deviating own module is not allowed.");
        goto error;
    }
    /*save pointer to the deviation and deviated target*/
    deviation->deviation = dev;
    deviation->target = dev_target;

    /* mark the target module as deviated */
    dev_target->module->deviated = 1;

    /* copy our imports to the deviated module (deviations may need them to work) */
    for (i = 0; i < module->imp_size; ++i) {
        for (j = 0; j < dev_target->module->imp_size; ++j) {
            if (module->imp[i].module == dev_target->module->imp[j].module) {
                break;
            }
        }

        if (j < dev_target->module->imp_size) {
            /* import is already there */
            continue;
        }

        /* copy the import, mark it as external */
        ++dev_target->module->imp_size;
        dev_target->module->imp = ly_realloc(dev_target->module->imp, dev_target->module->imp_size * sizeof *dev_target->module->imp);
        if (!dev_target->module->imp) {
            LOGMEM;
            goto error;
        }
        dev_target->module->imp[dev_target->module->imp_size - 1].module = module->imp[i].module;
        dev_target->module->imp[dev_target->module->imp_size - 1].prefix = lydict_insert(module->ctx, module->imp[i].prefix, 0);
        memcpy(dev_target->module->imp[dev_target->module->imp_size - 1].rev, module->imp[i].rev, LY_REV_SIZE);
        dev_target->module->imp[dev_target->module->imp_size - 1].external = 1;
    }

    /* copy ourselves to the deviated module as a special import (if we haven't yet, there could be more deviations of the same module) */
    for (i = 0; i < dev_target->module->imp_size; ++i) {
        if (dev_target->module->imp[i].module == module) {
            break;
        }
    }

    if (i == dev_target->module->imp_size) {
        ++dev_target->module->imp_size;
        dev_target->module->imp = ly_realloc(dev_target->module->imp, dev_target->module->imp_size * sizeof *dev_target->module->imp);
        if (!dev_target->module->imp) {
            LOGMEM;
            goto error;
        }
        dev_target->module->imp[dev_target->module->imp_size - 1].module = module;
        dev_target->module->imp[dev_target->module->imp_size - 1].prefix = lydict_insert(module->ctx, module->prefix, 0);
        if (module->rev_size) {
            memcpy(dev_target->module->imp[dev_target->module->imp_size - 1].rev, module->rev[0].date, LY_REV_SIZE);
        } else {
            memset(dev_target->module->imp[dev_target->module->imp_size - 1].rev, 0, LY_REV_SIZE);
        }
        dev_target->module->imp[dev_target->module->imp_size - 1].external = 2;
    } else {
        /* it could have been added by another deviating module that imported this deviating module */
        dev_target->module->imp[i].external = 2;
    }


    return deviation;

error:
    free(deviation);
    lydict_remove(module->ctx, dev->target_name);
    return NULL;
}

int
yang_read_deviate_unsupported(struct type_deviation *dev)
{
    int i;

    if (dev->deviation->deviate_size) {
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "\"not-supported\" deviation cannot be combined with any other deviation.");
        return EXIT_FAILURE;
    }
    dev->deviation->deviate[dev->deviation->deviate_size].mod = LY_DEVIATE_NO;

    /* you cannot remove a key leaf */
    if ((dev->target->nodetype == LYS_LEAF) && dev->target->parent && (dev->target->parent->nodetype == LYS_LIST)) {
        for (i = 0; i < ((struct lys_node_list *)dev->target->parent)->keys_size; ++i) {
            if (((struct lys_node_list *)dev->target->parent)->keys[i] == (struct lys_node_leaf *)dev->target) {
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, "not-supported", "deviation");
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "\"not-supported\" deviation cannot remove a list key.");
                return EXIT_FAILURE;
            }
        }
    }
 
    /* unlink and store the original node */
    dev->deviation->orig_node = dev->target;

    dev->deviation->deviate_size = 1;
    return EXIT_SUCCESS;
}

int
yang_read_deviate(struct type_deviation *dev, LYS_DEVIATE_TYPE mod)
{
    struct unres_schema tmp_unres;

    dev->deviation->deviate[dev->deviation->deviate_size].mod = mod;
    dev->deviate = &dev->deviation->deviate[dev->deviation->deviate_size];
    dev->deviation->deviate_size++;
    if (dev->deviation->deviate[0].mod == LY_DEVIATE_NO) {
        LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "not-supported");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "\"not-supported\" deviation cannot be combined with any other deviation.");
        return EXIT_FAILURE;
    }

    /* store a shallow copy of the original node */
    if (!dev->deviation->orig_node) {
        memset(&tmp_unres, 0, sizeof tmp_unres);
        dev->deviation->orig_node = lys_node_dup(dev->target->module, NULL, dev->target, 0, 0, &tmp_unres, 1);
        /* just to be safe */
        if (tmp_unres.count) {
            LOGINT;
            return EXIT_FAILURE;
        }
    }

    return EXIT_SUCCESS;
}

int
yang_read_deviate_units(struct ly_ctx *ctx, struct type_deviation *dev, char *value)
{
    const char **stritem;

    if (dev->deviate->units) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, "units", "deviate");
        free(value);
        goto error;
    }

    /* check target node type */
    if (dev->target->nodetype == LYS_LEAFLIST) {
        stritem = &((struct lys_node_leaflist *)dev->target)->units;
    } else if (dev->target->nodetype == LYS_LEAF) {
        stritem = &((struct lys_node_leaf *)dev->target)->units;
    } else {
        LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "units");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Target node does not allow \"units\" property.");
        free(value);
        goto error;
    }

    dev->deviate->units = lydict_insert_zc(ctx, value);

    if (dev->deviate->mod == LY_DEVIATE_DEL) {
        /* check values */
        if (*stritem != dev->deviate->units) {
            LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, dev->deviate->units, "units");
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Value differs from the target being deleted.");
            goto error;
        }
        /* remove current units value of the target */
        lydict_remove(ctx, *stritem);
    } else {
        if (dev->deviate->mod == LY_DEVIATE_ADD) {
            /* check that there is no current value */
            if (*stritem) {
                LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "units");
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Adding property that already exists.");
                goto error;
            }
        } else { /* replace */
            if (!*stritem) {
                LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "units");
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Replacing a property that does not exist.");
                goto error;
            }
        }
        /* remove current units value of the target ... */
        lydict_remove(ctx, *stritem);

        /* ... and replace it with the value specified in deviation */
        *stritem = lydict_insert(ctx, dev->deviate->units, 0);
    }

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

int
yang_read_deviate_must(struct type_deviation *dev, uint8_t c_must)
{
    /* check target node type */
    switch (dev->target->nodetype) {
    case LYS_LEAF:
        dev->trg_must = &((struct lys_node_leaf *)dev->target)->must;
        dev->trg_must_size = &((struct lys_node_leaf *)dev->target)->must_size;
        break;
    case LYS_CONTAINER:
        dev->trg_must = &((struct lys_node_container *)dev->target)->must;
        dev->trg_must_size = &((struct lys_node_container *)dev->target)->must_size;
        break;
    case LYS_LEAFLIST:
        dev->trg_must = &((struct lys_node_leaflist *)dev->target)->must;
        dev->trg_must_size = &((struct lys_node_leaflist *)dev->target)->must_size;
        break;
    case LYS_LIST:
        dev->trg_must = &((struct lys_node_list *)dev->target)->must;
        dev->trg_must_size = &((struct lys_node_list *)dev->target)->must_size;
        break;
    case LYS_ANYXML:
        dev->trg_must = &((struct lys_node_anyxml *)dev->target)->must;
        dev->trg_must_size = &((struct lys_node_anyxml *)dev->target)->must_size;
        break;
    default:
        LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "must");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Target node does not allow \"must\" property.");
        goto error;
    }

    if (dev->deviate->mod == LY_DEVIATE_ADD) {
        /* reallocate the must array of the target */
        dev->deviate->must = ly_realloc(*dev->trg_must, (c_must + *dev->trg_must_size) * sizeof *dev->deviate->must);
        if (!dev->deviate->must) {
            LOGMEM;
            goto error;
        }
        *dev->trg_must = dev->deviate->must;
        dev->deviate->must = &((*dev->trg_must)[*dev->trg_must_size]);
        dev->deviate->must_size = c_must;
    } else {
        /* LY_DEVIATE_DEL */
        dev->deviate->must = calloc(c_must, sizeof *dev->deviate->must);
        if (!dev->deviate->must) {
            LOGMEM;
            goto error;
        }
    }

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

int
yang_read_deviate_unique(struct type_deviation *dev, uint8_t c_uniq)
{
    struct lys_node_list *list;

    /* check target node type */
    if (dev->target->nodetype != LYS_LIST) {
        LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "unique");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Target node does not allow \"unique\" property.");
        goto error;
    }

    list = (struct lys_node_list *)dev->target;
    if (dev->deviate->mod == LY_DEVIATE_ADD) {
        /* reallocate the unique array of the target */
        dev->deviate->unique = ly_realloc(list->unique, (c_uniq + list->unique_size) * sizeof *dev->deviate->unique);
        if (!dev->deviate->unique) {
            LOGMEM;
            goto error;
        }
        list->unique = dev->deviate->unique;
        dev->deviate->unique = &list->unique[list->unique_size];
        dev->deviate->unique_size = c_uniq;
        memset(dev->deviate->unique, 0, c_uniq * sizeof *dev->deviate->unique);
    } else {
        /* LY_DEVIATE_DEL */
        dev->deviate->unique = calloc(c_uniq, sizeof *dev->deviate->unique);
        if (!dev->deviate->unique) {
            LOGMEM;
            goto error;
        }
    }

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

int
yang_read_deviate_default(struct ly_ctx *ctx, struct type_deviation *dev, char *value)
{
    int rc;
    struct lys_node_choice *choice;
    struct lys_node_leaf *leaf;
    struct lys_node *node;

    if (dev->deviate->dflt) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, "default", "deviate");
        free(value);
        goto error;
    }

    dev->deviate->dflt = lydict_insert_zc(ctx, value);

    if (dev->target->nodetype == LYS_CHOICE) {
        choice = (struct lys_node_choice *)dev->target;

        rc = resolve_choice_default_schema_nodeid(dev->deviate->dflt, choice->child, (const struct lys_node **)&node);
        if (rc || !node) {
            LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, dev->deviate->dflt, "default");
            goto error;
        }
        if (dev->deviate->mod == LY_DEVIATE_DEL) {
            if (!choice->dflt || (choice->dflt != node)) {
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, dev->deviate->dflt, "default");
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Value differs from the target being deleted.");
                goto error;
            }
            choice->dflt = NULL;
        } else {
            if (dev->deviate->mod == LY_DEVIATE_ADD) {
                /* check that there is no current value */
                if (choice->dflt) {
                    LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "default");
                    LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Adding property that already exists.");
                    goto error;
                } else if (choice->flags & LYS_MAND_TRUE) {
                    LOGVAL(LYE_INCHILDSTMT, LY_VLOG_NONE, NULL, "default", "choice");
                    LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "The \"default\" statement is forbidden on choices with \"mandatory\".");
                    goto error;
                }
            } else { /* replace*/
                if (!choice->dflt) {
                    LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "default");
                    LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Replacing a property that does not exist.");
                    goto error;
                }
            }

            choice->dflt = node;
            if (!choice->dflt) {
                /* default branch not found */
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, dev->deviate->dflt, "default");
                goto error;
            }
        }
    } else if (dev->target->nodetype == LYS_LEAF) {
        leaf = (struct lys_node_leaf *)dev->target;

        if (dev->deviate->mod == LY_DEVIATE_DEL) {
            if (!leaf->dflt || (leaf->dflt != dev->deviate->dflt)) {
                LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, dev->deviate->dflt, "default");
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Value differs from the target being deleted.");
                goto error;
            }
            /* remove value */
            lydict_remove(ctx, leaf->dflt);
            leaf->dflt = NULL;
        } else {
            if (dev->deviate->mod == LY_DEVIATE_ADD) {
                /* check that there is no current value */
                if (leaf->dflt) {
                    LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "default");
                    LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Adding property that already exists.");
                    goto error;
                } else if (leaf->flags & LYS_MAND_TRUE) {
                    /* RFC 6020, 7.6.4 - default statement must not with mandatory true */
                    LOGVAL(LYE_INCHILDSTMT, LY_VLOG_NONE, NULL, "default", "leaf");
                    LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "The \"default\" statement is forbidden on leaf with \"mandatory\".");
                    goto error;
                }
            } else { /* replace*/
                if (!leaf->dflt) {
                    LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "default");
                    LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Replacing a property that does not exist.");
                    goto error;
                }
            }
            /* remove value */
            lydict_remove(ctx, leaf->dflt);

            /* set new value */
            leaf->dflt = lydict_insert(ctx, dev->deviate->dflt, 0);
        }
    } else {
        /* invalid target for default value */
        LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "default");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Target node does not allow \"default\" property.");
        goto error;
    }

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

int
yang_read_deviate_config(struct type_deviation *dev, uint8_t value)
{
    if (dev->deviate->flags & LYS_CONFIG_MASK) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, "config", "deviate");
        goto error;
    }

    /* for we deviate from RFC 6020 and allow config property even it is/is not
     * specified in the target explicitly since config property inherits. So we expect
     * that config is specified in every node. But for delete, we check that the value
     * is the same as here in deviation
     */
    dev->deviate->flags |= value;

    /* add and replace are the same in this case */
    /* remove current config value of the target ... */
    dev->target->flags &= ~LYS_CONFIG_MASK;

    /* ... and replace it with the value specified in deviation */
    dev->target->flags |= dev->deviate->flags & LYS_CONFIG_MASK;

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

int
yang_read_deviate_mandatory(struct type_deviation *dev, uint8_t value)
{
    if (dev->deviate->flags & LYS_MAND_MASK) {
        LOGVAL(LYE_TOOMANY, LY_VLOG_NONE, NULL, "mandatory", "deviate");
        goto error;
    }

    /* check target node type */
    if (!(dev->target->nodetype & (LYS_LEAF | LYS_CHOICE | LYS_ANYXML))) {
        LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "mandatory");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Target node does not allow \"mandatory\" property.");
        goto error;
    }

    dev->deviate->flags |= value;

    if (dev->deviate->mod == LY_DEVIATE_ADD) {
        /* check that there is no current value */
        if (dev->target->flags & LYS_MAND_MASK) {
            LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "mandatory");
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Adding property that already exists.");
            goto error;
        } else {
            if (dev->target->nodetype == LYS_LEAF && ((struct lys_node_leaf *)dev->target)->dflt) {
                /* RFC 6020, 7.6.4 - default statement must not with mandatory true */
                LOGVAL(LYE_INCHILDSTMT, LY_VLOG_NONE, NULL, "mandatory", "leaf");
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "The \"mandatory\" statement is forbidden on leaf with \"default\".");
                goto error;
            } else if (dev->target->nodetype == LYS_CHOICE && ((struct lys_node_choice *)dev->target)->dflt) {
                LOGVAL(LYE_INCHILDSTMT, LY_VLOG_NONE, NULL, "mandatory", "choice");
                LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "The \"mandatory\" statement is forbidden on choices with \"default\".");
                goto error;
            }
        }
    } else { /* replace */
        if (!(dev->target->flags & LYS_MAND_MASK)) {
            LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, "mandatory");
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Replacing a property that does not exist.");
            goto error;
        }
    }

    /* remove current mandatory value of the target ... */
    dev->target->flags &= ~LYS_MAND_MASK;

    /* ... and replace it with the value specified in deviation */
    dev->target->flags |= dev->deviate->flags & LYS_MAND_MASK;

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

int
yang_read_deviate_minmax(struct type_deviation *dev, uint32_t value, int type)
{
    uint32_t *ui32val;

    /* check target node type */
    if (dev->target->nodetype == LYS_LEAFLIST) {
        if (type) {
            ui32val = &((struct lys_node_leaflist *)dev->target)->max;
        } else {
            ui32val = &((struct lys_node_leaflist *)dev->target)->min;
        }
    } else if (dev->target->nodetype == LYS_LIST) {
        if (type) {
            ui32val = &((struct lys_node_list *)dev->target)->max;
        } else {
            ui32val = &((struct lys_node_list *)dev->target)->min;
        }
    } else {
        LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, (type) ? "max-elements" : "min-elements");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Target node does not allow \"%s\" property.", (type) ? "max-elements" : "min-elements");
        goto error;
    }

    if (type) {
        dev->deviate->max = value;
        dev->deviate->max_set = 1;
    } else {
        dev->deviate->min = value;
        dev->deviate->min_set = 1;
    }

    if (dev->deviate->mod == LY_DEVIATE_ADD) {
        /* check that there is no current value */
        if (*ui32val) {
            LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, (type) ? "max-elements" : "min-elements");
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Adding property that already exists.");
            goto error;
        }
    } else if (dev->deviate->mod == LY_DEVIATE_RPL) {
        /* unfortunately, there is no way to check reliably that there
         * was a value before, it could have been the default */
    }

    /* add (already checked) and replace */
    /* set new value specified in deviation */
    *ui32val = value;

    return EXIT_SUCCESS;

error:
    return EXIT_FAILURE;
}

int
yang_check_deviate_must(struct ly_ctx *ctx, struct type_deviation *dev)
{
    int i;

    /* find must to delete, we are ok with just matching conditions */
    for (i = 0; i < *dev->trg_must_size; i++) {
        if (ly_strequal(dev->deviate->must[dev->deviate->must_size - 1].expr, (*dev->trg_must)[i].expr, 1)) {
            /* we have a match, free the must structure ... */
            lys_restr_free(ctx, &((*dev->trg_must)[i]));
            /* ... and maintain the array */
            (*dev->trg_must_size)--;
            if (i != *dev->trg_must_size) {
                (*dev->trg_must)[i].expr = (*dev->trg_must)[*dev->trg_must_size].expr;
                (*dev->trg_must)[i].dsc = (*dev->trg_must)[*dev->trg_must_size].dsc;
                (*dev->trg_must)[i].ref = (*dev->trg_must)[*dev->trg_must_size].ref;
                (*dev->trg_must)[i].eapptag = (*dev->trg_must)[*dev->trg_must_size].eapptag;
                (*dev->trg_must)[i].emsg = (*dev->trg_must)[*dev->trg_must_size].emsg;
            }
            if (!(*dev->trg_must_size)) {
                free(*dev->trg_must);
                *dev->trg_must = NULL;
            } else {
                (*dev->trg_must)[*dev->trg_must_size].expr = NULL;
                (*dev->trg_must)[*dev->trg_must_size].dsc = NULL;
                (*dev->trg_must)[*dev->trg_must_size].ref = NULL;
                (*dev->trg_must)[*dev->trg_must_size].eapptag = NULL;
                (*dev->trg_must)[*dev->trg_must_size].emsg = NULL;
            }

            i = -1; /* set match flag */
            break;
        }
    }
    if (i != -1) {
        /* no match found */
        LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, dev->deviate->must[dev->deviate->must_size - 1].expr, "must");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Value does not match any must from the target.");
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}

int
yang_check_deviate_unique(struct lys_module *module, struct type_deviation *dev, char *value)
{
    struct lys_node_list *list;
    int i, j;

    list = (struct lys_node_list *)dev->target;
    if (yang_fill_unique(module, list, &dev->deviate->unique[dev->deviate->unique_size], value, NULL)) {
        dev->deviate->unique_size++;
        goto error;
    }

    /* find unique structures to delete */
    for (i = 0; i < list->unique_size; i++) {
        if (list->unique[i].expr_size != dev->deviate->unique[dev->deviate->unique_size].expr_size) {
            continue;
        }

        for (j = 0; j < dev->deviate->unique[dev->deviate->unique_size].expr_size; j++) {
            if (!ly_strequal(list->unique[i].expr[j], dev->deviate->unique[dev->deviate->unique_size].expr[j], 1)) {
                break;
            }
        }

        if (j == dev->deviate->unique[dev->deviate->unique_size].expr_size) {
            /* we have a match, free the unique structure ... */
            for (j = 0; j < list->unique[i].expr_size; j++) {
                lydict_remove(module->ctx, list->unique[i].expr[j]);
            }
            free(list->unique[i].expr);
            /* ... and maintain the array */
            list->unique_size--;
            if (i != list->unique_size) {
                list->unique[i].expr_size = list->unique[list->unique_size].expr_size;
                list->unique[i].expr = list->unique[list->unique_size].expr;
            }

            if (!list->unique_size) {
                free(list->unique);
                list->unique = NULL;
            } else {
                list->unique[list->unique_size].expr_size = 0;
                list->unique[list->unique_size].expr = NULL;
            }

            i = -1; /* set match flag */
            break;
        }
    }
    dev->deviate->unique_size++;

    if (i != -1) {
        /* no match found */
        LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, value, "unique");
        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Value differs from the target being deleted.");
        goto error;
    }

    free(value);
    return EXIT_SUCCESS;

error:
    free(value);
    return EXIT_FAILURE;
}

int
yang_check_deviation(struct lys_module *module, struct type_deviation *dev, struct unres_schema *unres)
{
    int i, rc;

    if (dev->target->nodetype == LYS_LEAF) {
        for(i = 0; i < dev->deviation->deviate_size; ++i) {
            if (dev->deviation->deviate[i].mod != LY_DEVIATE_DEL) {
                if (dev->deviation->deviate[i].dflt || dev->deviation->deviate[i].type) {
                    rc = unres_schema_add_str(module, unres, &((struct lys_node_leaf *)dev->target)->type, UNRES_TYPE_DFLT, ((struct lys_node_leaf *)dev->target)->dflt);
                    if (rc == -1) {
                      return EXIT_FAILURE;
                    } else if (rc == EXIT_FAILURE) {
                        LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Leaf \"%s\" default value no longer matches its type.", dev->deviation->target_name);
                        return EXIT_FAILURE;
                    }
                    break;
                }
            }
        }
    }
    return EXIT_SUCCESS;
}

int
yang_fill_include(struct lys_module *module, struct lys_submodule *submodule, char *value,
                  char *rev, int inc_size, struct unres_schema *unres)
{
    struct lys_include inc;
    struct lys_module *trg;
    int i;
    const char *str;

    str = lydict_insert_zc(module->ctx, value);
    trg = (submodule) ? (struct lys_module *)submodule : module;
    inc.submodule = NULL;
    inc.external = 0;
    memcpy(inc.rev, rev, LY_REV_SIZE);
    if (lyp_check_include(module, submodule, str, &inc, unres)) {
        goto error;
    }
    memcpy(&trg->inc[inc_size], &inc, sizeof inc);

    /* check duplications in include submodules */
    for (i = 0; i < inc_size; ++i) {
        if (trg->inc[i].submodule && !strcmp(trg->inc[i].submodule->name, trg->inc[inc_size].submodule->name)) {
            LOGVAL(LYE_INARG, LY_VLOG_NONE, NULL, trg->inc[i].submodule->name, "include");
            LOGVAL(LYE_SPEC, LY_VLOG_NONE, NULL, "Including submodule \"%s\" repeatedly.", trg->inc[i].submodule->name);
            trg->inc[inc_size].submodule = NULL;
            goto error;
        }
    }
    lydict_remove(module->ctx, str);
    return EXIT_SUCCESS;

error:
    lydict_remove(module->ctx, str);
    return EXIT_FAILURE;
}

int
yang_use_extension(struct lys_module *module, struct lys_node *data_node, void *actual, char *value)
{
    char *prefix;
    char *identif;
    const char *ns = NULL;
    int i;

    /* check to the same pointer */
    if (data_node != actual) {
        return EXIT_SUCCESS;
    }

    prefix = strdup(value);
    if (!prefix) {
        LOGMEM;
        goto error;
    }
    /* find prefix anf identificator*/
    identif = strchr(prefix, ':');
    *identif = '\0';
    identif++;

    for(i = 0; i < module->imp_size; ++i) {
        if (!strcmp(module->imp[i].prefix, prefix)) {
            ns = module->imp[i].module->ns;
            break;
        }
    }
    if (!ns && !strcmp(module->prefix, prefix)) {
        ns = (module->type) ? ((struct lys_submodule *)module)->belongsto->ns : module->ns;
    }
    if (ns && !strcmp(ns, LY_NSNACM)) {
        if (!strcmp(identif, "default-deny-write")) {
            data_node->nacm |= LYS_NACM_DENYW;
        } else if (!strcmp(identif, "default-deny-all")) {
            data_node->nacm |= LYS_NACM_DENYA;
        } else {
            LOGVAL(LYE_INSTMT, LY_VLOG_NONE, NULL, identif);
            goto error;
        }
    }
    free(prefix);
    return EXIT_SUCCESS;

error:
    free(prefix);
    return EXIT_FAILURE;
}

void
nacm_inherit(struct lys_module *module)
{
    struct lys_node *next, *elem, *tmp_node, *tmp_child;

    LY_TREE_DFS_BEGIN(module->data, next, elem) {
        tmp_node = NULL;
        if (elem->parent) {
            switch (elem->nodetype) {
                case LYS_GROUPING:
                    /* extension nacm not inherited*/
                    break;
                case LYS_CHOICE:
                case LYS_ANYXML:
                case LYS_USES:
                    if (elem->parent->nodetype != LYS_GROUPING) {
                        elem->nacm |= elem->parent->nacm;
                    }
                    break;
                case LYS_CONTAINER:
                case LYS_LIST:
                case LYS_CASE:
                case LYS_NOTIF:
                case LYS_RPC:
                case LYS_INPUT:
                case LYS_OUTPUT:
                case LYS_AUGMENT:
                    elem->nacm |= elem->parent->nacm;
                    break;
                case LYS_LEAF:
                case LYS_LEAFLIST:
                    tmp_node = elem;
                    tmp_child = elem->child;
                    elem->child = NULL;
                default:
                    break;
            }
        }
        LY_TREE_DFS_END(module->data, next, elem);
        if (tmp_node) {
            tmp_node->child = tmp_child;
        }
    }
}

void
store_flags(struct lys_node *node, uint8_t flags, int config_inherit)
{
    node->flags |= flags;
    if (!(node->flags & LYS_CONFIG_MASK) && config_inherit) {
        /* get config flag from parent */
        if (node->parent) {
            node->flags |= node->parent->flags & LYS_CONFIG_MASK;
        } else {
            /* default config is true */
            node->flags |= LYS_CONFIG_W;
        }
    }
}

static int
yang_parse(struct lys_module *module, struct lys_submodule *submodule, struct unres_schema *unres, const char *data,
           unsigned int size, struct lys_array_size *size_arrays, int type_read)
{
    YY_BUFFER_STATE bp;
    yyscan_t scanner = NULL;
    int ret = EXIT_SUCCESS;

    yylex_init(&scanner);
    bp = yy_scan_buffer((char *)data, size, scanner);
    yy_switch_to_buffer(bp, scanner);
    if (yyparse(scanner, module, submodule, unres, size_arrays, type_read)) {
        ret = EXIT_FAILURE;
    }
    yy_delete_buffer(bp, scanner);
    yylex_destroy(scanner);
    return ret;
}

int
yang_parse_mem(struct lys_module *module, struct lys_submodule *submodule, struct unres_schema *unres, const char *data, unsigned int size_data)
{
    struct lys_array_size *size_arrays=NULL;
    unsigned int size;
    int ret;

    size_arrays = calloc(1, sizeof *size_arrays);
    if (!size_arrays) {
        LOGMEM;
        return EXIT_FAILURE;
    }
    size = (size_data) ? size_data : strlen(data) + 2;
    ret = yang_parse(module, submodule, unres, data, size, size_arrays, LY_READ_ONLY_SIZE);
    if (!ret) {
        ret = yang_parse(module, submodule, unres, data, size, size_arrays, LY_READ_ALL);
    }
    free(size_arrays->node);
    free(size_arrays);
    return ret;
}

struct lys_module *
yang_read_module(struct ly_ctx *ctx, const char* data, unsigned int size, const char *revision, int implement)
{

    struct lys_module *tmp_module, *module = NULL;
    struct unres_schema *unres = NULL;

    unres = calloc(1, sizeof *unres);
    if (!unres) {
        LOGMEM;
        goto error;
    }

    module = calloc(1, sizeof *module);
    if (!module) {
        LOGMEM;
        goto error;
    }

    /* initiale module */
    module->ctx=ctx;
    module->type = 0;
    module->implemented = (implement ? 1 : 0);

    if (yang_parse_mem(module, NULL, unres, data, size)) {
        goto error;
    }

    if (module && unres->count && resolve_unres_schema(module, unres)) {
        goto error;
    }

    if (revision) {
        /* check revision of the parsed model */
        if (!module->rev_size || strcmp(revision, module->rev[0].date)) {
            LOGVRB("Module \"%s\" parsed with the wrong revision (\"%s\" instead \"%s\").",
                   module->name, module->rev[0].date, revision);
            goto error;
        }
    }

    tmp_module = module;
    if (lyp_add_module(&module, implement)) {
        goto error;
    }

    if (module == tmp_module) {
        nacm_inherit(module);
    }

    unres_schema_free(NULL, &unres);
    LOGVRB("Module \"%s\" successfully parsed.", module->name);
    return module;

error:
    unres_schema_free(module, &unres);
    if (!module || !module->name) {
        free(module);
        LOGERR(ly_errno, "Module parsing failed.");
        return NULL;
    }

    LOGERR(ly_errno, "Module \"%s\" parsing failed.", module->name);
    lyp_fail_module(module);
    lys_free(module,NULL,1);
    return NULL;
}

struct lys_submodule *
yang_read_submodule(struct lys_module *module, const char *data, unsigned int size, struct unres_schema *unres)
{
    struct lys_submodule *submodule;

    submodule = calloc(1, sizeof *submodule);
    if (!submodule) {
        LOGMEM;
        goto error;
    }

    submodule->ctx = module->ctx;
    submodule->type = 1;
    submodule->belongsto = module;

    if (yang_parse_mem(module, submodule, unres, data, size)) {
        goto error;
    }

    /* cleanup */

    LOGVRB("Submodule \"%s\" successfully parsed.", submodule->name);

    return submodule;

error:
    /* cleanup */
    unres_schema_free((struct lys_module *)submodule, &unres);

    if (!submodule || !submodule->name) {
        free(submodule);
        LOGERR(ly_errno, "Submodule parsing failed.");
        return NULL;
    }

    LOGERR(ly_errno, "Submodule \"%s\" parsing failed.", submodule->name);

    lyp_fail_submodule(submodule);
    lys_submodule_free(submodule, NULL);

    return NULL;
}

static int
count_substring(const char *str, char c)
{
    const char *tmp = str;
    int count = 0;

    while ((tmp = strchr(tmp, c))) {
        tmp++;
        count++;
    }
    return count;
}

static int
read_indent(const char *input, int indent, int size, int in_index, int *out_index, char *output)
{
    int k = 0, j;

    while (in_index < size) {
        if (input[in_index] == ' ') {
            k++;
        } else if (input[in_index] == '\t') {
            /* RFC 6020 6.1.3 tab character is treated as 8 space characters */
            k += 8;
        } else {
            break;
        }
        ++in_index;
        if (k >= indent) {
            for (j = k - indent; j > 0; --j) {
                output[*out_index] = ' ';
                ++(*out_index);
            }
            break;
        }
    }
    return in_index;
}

char *
yang_read_string(const char *input, int size, int indent)
{
    int space, count;
    int in_index, out_index;
    char *value;
    char *retval = NULL;

    value = malloc(size + 1);
    if (!value) {
        LOGMEM;
        return NULL;
    }
    /* replace special character in escape sequence */
    in_index = out_index = 0;
    while (in_index < size) {
        if (input[in_index] == '\\') {
            if (input[in_index + 1] == 'n') {
                value[out_index] = '\n';
                ++in_index;
            } else if (input[in_index + 1] == 't') {
                value[out_index] = '\t';
                ++in_index;
            } else if (input[in_index + 1] == '\\') {
                value[out_index] = '\\';
                ++in_index;
            } else if ((in_index + 1) != size && input[in_index + 1] == '"') {
                value[out_index] = '"';
                ++in_index;
            } else {
                value[out_index] = input[in_index];
            }
        } else {
            value[out_index] = input[in_index];
        }
        ++in_index;
        ++out_index;
    }
    value[out_index] = '\0';
    size = out_index;
    count = count_substring(value, '\t');

    /* extend size of string due to replacing character '\t' with 8 spaces */
    retval = malloc(size + 1 + 7 * count);
    if (!retval) {
        LOGMEM;
        goto error;
    }
    in_index = out_index = space = 0;
    while (in_index < size) {
        if (value[in_index] == '\n') {
            out_index -= space;
            space = 0;
            retval[out_index] = '\n';
            ++out_index;
            ++in_index;
            in_index = read_indent(value, indent, size, in_index, &out_index, retval);
            continue;
        } else {
            space = (value[in_index] == ' ' || value[in_index] == '\t') ? space + 1 : 0;
            retval[out_index] = value[in_index];
            ++out_index;
        }
        ++in_index;
    }
    retval[out_index] = '\0';
    if (out_index != size) {
        retval = ly_realloc(retval, out_index + 1);
    }
    free(value);
    return retval;
error:
    free(value);
    return NULL;
}