src/xpath.c - github/CESNET/libyang - Gitiles

 /**
  * @file xpath.c
  * @author Michal Vasko <mvasko@cesnet.cz>
  * @brief YANG XPath evaluation functions
  *
  * Copyright (c) 2015 - 2017 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 "common.h"

 #include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
 #include <assert.h>
 #include <limits.h>
 #include <errno.h>
 #include <math.h>

 #include "xpath.h"
 #include "xml.h"

 /**
  * @brief Parse NCName.
  *
  * @param[in] ncname Name to parse.
  *
  * @return Length of \p ncname valid bytes.
  */
 static long int
 parse_ncname(const char *ncname)
 {
     unsigned int uc;
     size_t size;
     long int len = 0;

     LY_CHECK_RET(ly_getutf8(&ncname, &uc, &size), 0);
     if (!is_xmlqnamestartchar(uc) || (uc == ':')) {
         return len;
     }

     do {
         len += size;
         if (!*ncname) {
             break;
         }
         LY_CHECK_RET(ly_getutf8(&ncname, &uc, &size), -len);
     } while (is_xmlqnamechar(uc) && (uc != ':'));

     return len;
 }

 /**
  * @brief Add \p token into the expression \p exp.
  *
  * @param[in] ctx libyang context to log in.
  * @param[in] exp Expression to use.
  * @param[in] token Token to add.
  * @param[in] expr_pos Token position in the XPath expression.
  * @param[in] tok_len Token length in the XPath expression.
  * @return LY_ERR value
  */
 static LY_ERR
 exp_add_token(struct ly_ctx *ctx, struct lyxp_expr *exp, enum lyxp_token token, uint16_t expr_pos, uint16_t tok_len)
 {
     uint32_t prev;

     if (exp->used == exp->size) {
         prev = exp->size;
         exp->size += LYXP_EXPR_SIZE_STEP;
         if (prev > exp->size) {
             LOGINT(ctx);
             return LY_EINT;
         }

         exp->tokens = ly_realloc(exp->tokens, exp->size * sizeof *exp->tokens);
         LY_CHECK_ERR_RET(!exp->tokens, LOGMEM(ctx), LY_EMEM);
         exp->tok_pos = ly_realloc(exp->tok_pos, exp->size * sizeof *exp->tok_pos);
         LY_CHECK_ERR_RET(!exp->tok_pos, LOGMEM(ctx), LY_EMEM);
         exp->tok_len = ly_realloc(exp->tok_len, exp->size * sizeof *exp->tok_len);
         LY_CHECK_ERR_RET(!exp->tok_len, LOGMEM(ctx), LY_EMEM);
     }

     exp->tokens[exp->used] = token;
     exp->tok_pos[exp->used] = expr_pos;
     exp->tok_len[exp->used] = tok_len;
     ++exp->used;
     return LY_SUCCESS;
 }

 void
 lyxp_expr_free(struct ly_ctx *ctx, struct lyxp_expr *expr)
 {
     uint16_t i;

     if (!expr) {
         return;
     }

     lydict_remove(ctx, expr->expr);
     free(expr->tokens);
     free(expr->tok_pos);
     free(expr->tok_len);
     if (expr->repeat) {
         for (i = 0; i < expr->used; ++i) {
             free(expr->repeat[i]);
         }
     }
     free(expr->repeat);
     free(expr);
 }

 struct lyxp_expr *
 lyxp_expr_parse(struct ly_ctx *ctx, const char *expr)
 {
     struct lyxp_expr *ret;
     size_t parsed = 0, tok_len;
     long int ncname_len;
     enum lyxp_token tok_type;
     int prev_function_check = 0;

     if (strlen(expr) > UINT16_MAX) {
         LOGERR(ctx, LY_EINVAL, "XPath expression cannot be longer than %ud characters.", UINT16_MAX);
         return NULL;
     }

     /* init lyxp_expr structure */
     ret = calloc(1, sizeof *ret);
     LY_CHECK_ERR_GOTO(!ret, LOGMEM(ctx), error);
     ret->expr = lydict_insert(ctx, expr, strlen(expr));
     LY_CHECK_ERR_GOTO(!ret->expr, LOGMEM(ctx), error);
     ret->used = 0;
     ret->size = LYXP_EXPR_SIZE_START;
     ret->tokens = malloc(ret->size * sizeof *ret->tokens);
     LY_CHECK_ERR_GOTO(!ret->tokens, LOGMEM(ctx), error);

     ret->tok_pos = malloc(ret->size * sizeof *ret->tok_pos);
     LY_CHECK_ERR_GOTO(!ret->tok_pos, LOGMEM(ctx), error);

     ret->tok_len = malloc(ret->size * sizeof *ret->tok_len);
     LY_CHECK_ERR_GOTO(!ret->tok_len, LOGMEM(ctx), error);

     while (is_xmlws(expr[parsed])) {
         ++parsed;
     }

     do {
         if (expr[parsed] == '(') {

             /* '(' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_PAR1;

             if (prev_function_check && ret->used && (ret->tokens[ret->used - 1] == LYXP_TOKEN_NAMETEST)) {
                 /* it is a NodeType/FunctionName after all */
                 if (((ret->tok_len[ret->used - 1] == 4)
                         && (!strncmp(&expr[ret->tok_pos[ret->used - 1]], "node", 4)
                         || !strncmp(&expr[ret->tok_pos[ret->used - 1]], "text", 4))) ||
                         ((ret->tok_len[ret->used - 1] == 7)
                         && !strncmp(&expr[ret->tok_pos[ret->used - 1]], "comment", 7))) {
                     ret->tokens[ret->used - 1] = LYXP_TOKEN_NODETYPE;
                 } else {
                     ret->tokens[ret->used - 1] = LYXP_TOKEN_FUNCNAME;
                 }
                 prev_function_check = 0;
             }

         } else if (expr[parsed] == ')') {

             /* ')' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_PAR2;

         } else if (expr[parsed] == '[') {

             /* '[' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_BRACK1;

         } else if (expr[parsed] == ']') {

             /* ']' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_BRACK2;

         } else if (!strncmp(&expr[parsed], "..", 2)) {

             /* '..' */
             tok_len = 2;
             tok_type = LYXP_TOKEN_DDOT;

         } else if ((expr[parsed] == '.') && (!isdigit(expr[parsed + 1]))) {

             /* '.' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_DOT;

         } else if (expr[parsed] == '@') {

             /* '@' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_AT;

         } else if (expr[parsed] == ',') {

             /* ',' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_COMMA;

         } else if (expr[parsed] == '\'') {

             /* Literal with ' */
             for (tok_len = 1; (expr[parsed + tok_len] != '\0') && (expr[parsed + tok_len] != '\''); ++tok_len);
             LY_CHECK_ERR_GOTO(expr[parsed + tok_len] == '\0',
                               LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_EOE, expr[parsed], &expr[parsed]), error);
             ++tok_len;
             tok_type = LYXP_TOKEN_LITERAL;

         } else if (expr[parsed] == '\"') {

             /* Literal with " */
             for (tok_len = 1; (expr[parsed + tok_len] != '\0') && (expr[parsed + tok_len] != '\"'); ++tok_len);
             LY_CHECK_ERR_GOTO(expr[parsed + tok_len] == '\0',
                               LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_EOE, expr[parsed], &expr[parsed]), error);
             ++tok_len;
             tok_type = LYXP_TOKEN_LITERAL;

         } else if ((expr[parsed] == '.') || (isdigit(expr[parsed]))) {

             /* Number */
             for (tok_len = 0; isdigit(expr[parsed + tok_len]); ++tok_len);
             if (expr[parsed + tok_len] == '.') {
                 ++tok_len;
                 for (; isdigit(expr[parsed + tok_len]); ++tok_len);
             }
             tok_type = LYXP_TOKEN_NUMBER;

         } else if (expr[parsed] == '/') {

             /* Operator '/', '//' */
             if (!strncmp(&expr[parsed], "//", 2)) {
                 tok_len = 2;
             } else {
                 tok_len = 1;
             }
             tok_type = LYXP_TOKEN_OPERATOR_PATH;

         } else if  (!strncmp(&expr[parsed], "!=", 2) || !strncmp(&expr[parsed], "<=", 2)
                 || !strncmp(&expr[parsed], ">=", 2)) {

             /* Operator '!=', '<=', '>=' */
             tok_len = 2;
             tok_type = LYXP_TOKEN_OPERATOR_COMP;

         } else if (expr[parsed] == '|') {

             /* Operator '|' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_OPERATOR_UNI;

         } else if ((expr[parsed] == '+') || (expr[parsed] == '-')) {

             /* Operator '+', '-' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_OPERATOR_MATH;

         } else if ((expr[parsed] == '=') || (expr[parsed] == '<') || (expr[parsed] == '>')) {

             /* Operator '=', '<', '>' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_OPERATOR_COMP;

         } else if (ret->used && (ret->tokens[ret->used - 1] != LYXP_TOKEN_AT)
                 && (ret->tokens[ret->used - 1] != LYXP_TOKEN_PAR1)
                 && (ret->tokens[ret->used - 1] != LYXP_TOKEN_BRACK1)
                 && (ret->tokens[ret->used - 1] != LYXP_TOKEN_COMMA)
                 && (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_LOG)
                 && (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_COMP)
                 && (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_MATH)
                 && (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_UNI)
                 && (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_PATH)) {

             /* Operator '*', 'or', 'and', 'mod', or 'div' */
             if (expr[parsed] == '*') {
                 tok_len = 1;
                 tok_type = LYXP_TOKEN_OPERATOR_MATH;

             } else if (!strncmp(&expr[parsed], "or", 2)) {
                 tok_len = 2;
                 tok_type = LYXP_TOKEN_OPERATOR_LOG;

             } else if (!strncmp(&expr[parsed], "and", 3)) {
                 tok_len = 3;
                 tok_type = LYXP_TOKEN_OPERATOR_LOG;

             } else if (!strncmp(&expr[parsed], "mod", 3) || !strncmp(&expr[parsed], "div", 3)) {
                 tok_len = 3;
                 tok_type = LYXP_TOKEN_OPERATOR_MATH;

             } else if (prev_function_check) {
                 LOGVAL(ctx, LY_VLOG_NONE, NULL, LYVE_XPATH, "Invalid character 0x%x, perhaps \"%.*s\" is supposed to be a function call.",
                        expr[parsed], &expr[parsed], ret->tok_len[ret->used - 1], &ret->expr[ret->tok_pos[ret->used - 1]]);
                 goto error;
             } else {
                 LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_INEXPR, parsed + 1, expr);
                 goto error;
             }
         } else if (expr[parsed] == '*') {

             /* NameTest '*' */
             tok_len = 1;
             tok_type = LYXP_TOKEN_NAMETEST;

         } else {

             /* NameTest (NCName ':' '*' | QName) or NodeType/FunctionName */
             ncname_len = parse_ncname(&expr[parsed]);
             LY_CHECK_ERR_GOTO(ncname_len < 0, LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_INEXPR, parsed - ncname_len + 1, expr), error);
             tok_len = ncname_len;

             if (expr[parsed + tok_len] == ':') {
                 ++tok_len;
                 if (expr[parsed + tok_len] == '*') {
                     ++tok_len;
                 } else {
                     ncname_len = parse_ncname(&expr[parsed + tok_len]);
                     LY_CHECK_ERR_GOTO(ncname_len < 0, LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_INEXPR, parsed - ncname_len + 1, expr), error);
                     tok_len += ncname_len;
                 }
                 /* remove old flag to prevent ambiguities */
                 prev_function_check = 0;
                 tok_type = LYXP_TOKEN_NAMETEST;
             } else {
                 /* there is no prefix so it can still be NodeType/FunctionName, we can't finally decide now */
                 prev_function_check = 1;
                 tok_type = LYXP_TOKEN_NAMETEST;
             }
         }

         /* store the token, move on to the next one */
         LY_CHECK_GOTO(exp_add_token(ctx, ret, tok_type, parsed, tok_len), error);
         parsed += tok_len;
         while (is_xmlws(expr[parsed])) {
             ++parsed;
         }

     } while (expr[parsed]);

     /* prealloc repeat */
     ret->repeat = calloc(ret->size, sizeof *ret->repeat);
     LY_CHECK_ERR_GOTO(!ret->repeat, LOGMEM(ctx), error);

     return ret;

 error:
     lyxp_expr_free(ctx, ret);
     return NULL;
 }
	/**
	* @file xpath.c
	* @author Michal Vasko <mvasko@cesnet.cz>
	* @brief YANG XPath evaluation functions
	*
	* Copyright (c) 2015 - 2017 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 "common.h"

	#include <ctype.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <stdint.h>
	#include <string.h>
	#include <assert.h>
	#include <limits.h>
	#include <errno.h>
	#include <math.h>

	#include "xpath.h"
	#include "xml.h"

	/**
	* @brief Parse NCName.
	*
	* @param[in] ncname Name to parse.
	*
	* @return Length of \p ncname valid bytes.
	*/
	static long int
	parse_ncname(const char *ncname)
	{
	unsigned int uc;
	size_t size;
	long int len = 0;

	LY_CHECK_RET(ly_getutf8(&ncname, &uc, &size), 0);
	if (!is_xmlqnamestartchar(uc) \|\| (uc == ':')) {
	return len;
	}

	do {
	len += size;
	if (!*ncname) {
	break;
	}
	LY_CHECK_RET(ly_getutf8(&ncname, &uc, &size), -len);
	} while (is_xmlqnamechar(uc) && (uc != ':'));

	return len;
	}

	/**
	* @brief Add \p token into the expression \p exp.
	*
	* @param[in] ctx libyang context to log in.
	* @param[in] exp Expression to use.
	* @param[in] token Token to add.
	* @param[in] expr_pos Token position in the XPath expression.
	* @param[in] tok_len Token length in the XPath expression.
	* @return LY_ERR value
	*/
	static LY_ERR
	exp_add_token(struct ly_ctx ctx, struct lyxp_expr exp, enum lyxp_token token, uint16_t expr_pos, uint16_t tok_len)
	{
	uint32_t prev;

	if (exp->used == exp->size) {
	prev = exp->size;
	exp->size += LYXP_EXPR_SIZE_STEP;
	if (prev > exp->size) {
	LOGINT(ctx);
	return LY_EINT;
	}

	exp->tokens = ly_realloc(exp->tokens, exp->size * sizeof *exp->tokens);
	LY_CHECK_ERR_RET(!exp->tokens, LOGMEM(ctx), LY_EMEM);
	exp->tok_pos = ly_realloc(exp->tok_pos, exp->size * sizeof *exp->tok_pos);
	LY_CHECK_ERR_RET(!exp->tok_pos, LOGMEM(ctx), LY_EMEM);
	exp->tok_len = ly_realloc(exp->tok_len, exp->size * sizeof *exp->tok_len);
	LY_CHECK_ERR_RET(!exp->tok_len, LOGMEM(ctx), LY_EMEM);
	}

	exp->tokens[exp->used] = token;
	exp->tok_pos[exp->used] = expr_pos;
	exp->tok_len[exp->used] = tok_len;
	++exp->used;
	return LY_SUCCESS;
	}

	void
	lyxp_expr_free(struct ly_ctx ctx, struct lyxp_expr expr)
	{
	uint16_t i;

	if (!expr) {
	return;
	}

	lydict_remove(ctx, expr->expr);
	free(expr->tokens);
	free(expr->tok_pos);
	free(expr->tok_len);
	if (expr->repeat) {
	for (i = 0; i < expr->used; ++i) {
	free(expr->repeat[i]);
	}
	}
	free(expr->repeat);
	free(expr);
	}

	struct lyxp_expr *
	lyxp_expr_parse(struct ly_ctx ctx, const char expr)
	{
	struct lyxp_expr *ret;
	size_t parsed = 0, tok_len;
	long int ncname_len;
	enum lyxp_token tok_type;
	int prev_function_check = 0;

	if (strlen(expr) > UINT16_MAX) {
	LOGERR(ctx, LY_EINVAL, "XPath expression cannot be longer than %ud characters.", UINT16_MAX);
	return NULL;
	}

	/* init lyxp_expr structure */
	ret = calloc(1, sizeof *ret);
	LY_CHECK_ERR_GOTO(!ret, LOGMEM(ctx), error);
	ret->expr = lydict_insert(ctx, expr, strlen(expr));
	LY_CHECK_ERR_GOTO(!ret->expr, LOGMEM(ctx), error);
	ret->used = 0;
	ret->size = LYXP_EXPR_SIZE_START;
	ret->tokens = malloc(ret->size * sizeof *ret->tokens);
	LY_CHECK_ERR_GOTO(!ret->tokens, LOGMEM(ctx), error);

	ret->tok_pos = malloc(ret->size * sizeof *ret->tok_pos);
	LY_CHECK_ERR_GOTO(!ret->tok_pos, LOGMEM(ctx), error);

	ret->tok_len = malloc(ret->size * sizeof *ret->tok_len);
	LY_CHECK_ERR_GOTO(!ret->tok_len, LOGMEM(ctx), error);

	while (is_xmlws(expr[parsed])) {
	++parsed;
	}

	do {
	if (expr[parsed] == '(') {

	/* '(' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_PAR1;

	if (prev_function_check && ret->used && (ret->tokens[ret->used - 1] == LYXP_TOKEN_NAMETEST)) {
	/* it is a NodeType/FunctionName after all */
	if (((ret->tok_len[ret->used - 1] == 4)
	&& (!strncmp(&expr[ret->tok_pos[ret->used - 1]], "node", 4)
	\|\| !strncmp(&expr[ret->tok_pos[ret->used - 1]], "text", 4))) \|\|
	((ret->tok_len[ret->used - 1] == 7)
	&& !strncmp(&expr[ret->tok_pos[ret->used - 1]], "comment", 7))) {
	ret->tokens[ret->used - 1] = LYXP_TOKEN_NODETYPE;
	} else {
	ret->tokens[ret->used - 1] = LYXP_TOKEN_FUNCNAME;
	}
	prev_function_check = 0;
	}

	} else if (expr[parsed] == ')') {

	/* ')' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_PAR2;

	} else if (expr[parsed] == '[') {

	/* '[' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_BRACK1;

	} else if (expr[parsed] == ']') {

	/* ']' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_BRACK2;

	} else if (!strncmp(&expr[parsed], "..", 2)) {

	/* '..' */
	tok_len = 2;
	tok_type = LYXP_TOKEN_DDOT;

	} else if ((expr[parsed] == '.') && (!isdigit(expr[parsed + 1]))) {

	/* '.' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_DOT;

	} else if (expr[parsed] == '@') {

	/* '@' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_AT;

	} else if (expr[parsed] == ',') {

	/* ',' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_COMMA;

	} else if (expr[parsed] == '\'') {

	/* Literal with ' */
	for (tok_len = 1; (expr[parsed + tok_len] != '\0') && (expr[parsed + tok_len] != '\''); ++tok_len);
	LY_CHECK_ERR_GOTO(expr[parsed + tok_len] == '\0',
	LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_EOE, expr[parsed], &expr[parsed]), error);
	++tok_len;
	tok_type = LYXP_TOKEN_LITERAL;

	} else if (expr[parsed] == '\"') {

	/* Literal with " */
	for (tok_len = 1; (expr[parsed + tok_len] != '\0') && (expr[parsed + tok_len] != '\"'); ++tok_len);
	LY_CHECK_ERR_GOTO(expr[parsed + tok_len] == '\0',
	LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_EOE, expr[parsed], &expr[parsed]), error);
	++tok_len;
	tok_type = LYXP_TOKEN_LITERAL;

	} else if ((expr[parsed] == '.') \|\| (isdigit(expr[parsed]))) {

	/* Number */
	for (tok_len = 0; isdigit(expr[parsed + tok_len]); ++tok_len);
	if (expr[parsed + tok_len] == '.') {
	++tok_len;
	for (; isdigit(expr[parsed + tok_len]); ++tok_len);
	}
	tok_type = LYXP_TOKEN_NUMBER;

	} else if (expr[parsed] == '/') {

	/* Operator '/', '//' */
	if (!strncmp(&expr[parsed], "//", 2)) {
	tok_len = 2;
	} else {
	tok_len = 1;
	}
	tok_type = LYXP_TOKEN_OPERATOR_PATH;

	} else if (!strncmp(&expr[parsed], "!=", 2) \|\| !strncmp(&expr[parsed], "<=", 2)
	\|\| !strncmp(&expr[parsed], ">=", 2)) {

	/* Operator '!=', '<=', '>=' */
	tok_len = 2;
	tok_type = LYXP_TOKEN_OPERATOR_COMP;

	} else if (expr[parsed] == '\|') {

	/* Operator '\|' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_OPERATOR_UNI;

	} else if ((expr[parsed] == '+') \|\| (expr[parsed] == '-')) {

	/* Operator '+', '-' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_OPERATOR_MATH;

	} else if ((expr[parsed] == '=') \|\| (expr[parsed] == '<') \|\| (expr[parsed] == '>')) {

	/* Operator '=', '<', '>' */
	tok_len = 1;
	tok_type = LYXP_TOKEN_OPERATOR_COMP;

	} else if (ret->used && (ret->tokens[ret->used - 1] != LYXP_TOKEN_AT)
	&& (ret->tokens[ret->used - 1] != LYXP_TOKEN_PAR1)
	&& (ret->tokens[ret->used - 1] != LYXP_TOKEN_BRACK1)
	&& (ret->tokens[ret->used - 1] != LYXP_TOKEN_COMMA)
	&& (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_LOG)
	&& (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_COMP)
	&& (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_MATH)
	&& (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_UNI)
	&& (ret->tokens[ret->used - 1] != LYXP_TOKEN_OPERATOR_PATH)) {

	/* Operator '', 'or', 'and', 'mod', or 'div' /
	if (expr[parsed] == '*') {
	tok_len = 1;
	tok_type = LYXP_TOKEN_OPERATOR_MATH;

	} else if (!strncmp(&expr[parsed], "or", 2)) {
	tok_len = 2;
	tok_type = LYXP_TOKEN_OPERATOR_LOG;

	} else if (!strncmp(&expr[parsed], "and", 3)) {
	tok_len = 3;
	tok_type = LYXP_TOKEN_OPERATOR_LOG;

	} else if (!strncmp(&expr[parsed], "mod", 3) \|\| !strncmp(&expr[parsed], "div", 3)) {
	tok_len = 3;
	tok_type = LYXP_TOKEN_OPERATOR_MATH;

	} else if (prev_function_check) {
	LOGVAL(ctx, LY_VLOG_NONE, NULL, LYVE_XPATH, "Invalid character 0x%x, perhaps \"%.*s\" is supposed to be a function call.",
	expr[parsed], &expr[parsed], ret->tok_len[ret->used - 1], &ret->expr[ret->tok_pos[ret->used - 1]]);
	goto error;
	} else {
	LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_INEXPR, parsed + 1, expr);
	goto error;
	}
	} else if (expr[parsed] == '*') {

	/* NameTest '' /
	tok_len = 1;
	tok_type = LYXP_TOKEN_NAMETEST;

	} else {

	/* NameTest (NCName ':' '' \| QName) or NodeType/FunctionName /
	ncname_len = parse_ncname(&expr[parsed]);
	LY_CHECK_ERR_GOTO(ncname_len < 0, LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_INEXPR, parsed - ncname_len + 1, expr), error);
	tok_len = ncname_len;

	if (expr[parsed + tok_len] == ':') {
	++tok_len;
	if (expr[parsed + tok_len] == '*') {
	++tok_len;
	} else {
	ncname_len = parse_ncname(&expr[parsed + tok_len]);
	LY_CHECK_ERR_GOTO(ncname_len < 0, LOGVAL(ctx, LY_VLOG_NONE, NULL, LY_VCODE_XP_INEXPR, parsed - ncname_len + 1, expr), error);
	tok_len += ncname_len;
	}
	/* remove old flag to prevent ambiguities */
	prev_function_check = 0;
	tok_type = LYXP_TOKEN_NAMETEST;
	} else {
	/* there is no prefix so it can still be NodeType/FunctionName, we can't finally decide now */
	prev_function_check = 1;
	tok_type = LYXP_TOKEN_NAMETEST;
	}
	}

	/* store the token, move on to the next one */
	LY_CHECK_GOTO(exp_add_token(ctx, ret, tok_type, parsed, tok_len), error);
	parsed += tok_len;
	while (is_xmlws(expr[parsed])) {
	++parsed;
	}

	} while (expr[parsed]);

	/* prealloc repeat */
	ret->repeat = calloc(ret->size, sizeof *ret->repeat);
	LY_CHECK_ERR_GOTO(!ret->repeat, LOGMEM(ctx), error);

	return ret;

	error:
	lyxp_expr_free(ctx, ret);
	return NULL;
	}