1/*
2 * Copyright (c) Huawei Technologies Co., Ltd. 2014-2021. All rights reserved.
3 * Licensed under Mulan PSL v2.
4 * You can use this software according to the terms and conditions of the Mulan PSL v2.
5 * You may obtain a copy of Mulan PSL v2 at:
6 *          http://license.coscl.org.cn/MulanPSL2
7 * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
8 * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
9 * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
10 * See the Mulan PSL v2 for more details.
11 * Description: strtok_s  function
12 * Create: 2014-02-25
13 */
14
15#include "securecutil.h"
16
17SECUREC_INLINE int SecIsInDelimit(char ch, const char *strDelimit)
18{
19    const char *ctl = strDelimit;
20    while (*ctl != '\0' && *ctl != ch) {
21        ++ctl;
22    }
23    return (int)(*ctl != '\0');
24}
25
26/*
27 * Find beginning of token (skip over leading delimiters).
28 * Note that there is no token if this loop sets string to point to the terminal null.
29 */
30SECUREC_INLINE char *SecFindBegin(char *strToken, const char *strDelimit)
31{
32    char *token = strToken;
33    while (*token != '\0') {
34        if (SecIsInDelimit(*token, strDelimit) != 0) {
35            ++token;
36            continue;
37        }
38        /* Don't find any delimiter in string header, break the loop */
39        break;
40    }
41    return token;
42}
43
44/*
45 * Find rest of token
46 */
47SECUREC_INLINE char *SecFindRest(char *strToken, const char *strDelimit)
48{
49    /* Find the rest of the token. If it is not the end of the string, put a null there */
50    char *token = strToken;
51    while (*token != '\0') {
52        if (SecIsInDelimit(*token, strDelimit) != 0) {
53            /* Find a delimiter, set string terminator */
54            *token = '\0';
55            ++token;
56            break;
57        }
58        ++token;
59    }
60    return token;
61}
62
63/*
64 * Find the final position pointer
65 */
66SECUREC_INLINE char *SecUpdateToken(char *strToken, const char *strDelimit, char **context)
67{
68    /* Point to updated position. Record string position for next search in the context */
69    *context = SecFindRest(strToken, strDelimit);
70    /* Determine if a token has been found. */
71    if (*context == strToken) {
72        return NULL;
73    }
74    return strToken;
75}
76
77/*
78 * <FUNCTION DESCRIPTION>
79 *    The strtok_s function parses a string into a sequence of strToken,
80 *    replace all characters in strToken string that match to strDelimit set with 0.
81 *    On the first call to strtok_s the string to be parsed should be specified in strToken.
82 *    In each subsequent call that should parse the same string, strToken should be NULL
83 * <INPUT PARAMETERS>
84 *    strToken            String containing token or tokens.
85 *    strDelimit          Set of delimiter characters.
86 *    context             Used to store position information between calls
87 *                             to strtok_s
88 * <OUTPUT PARAMETERS>
89 *   context               is updated
90 * <RETURN VALUE>
91 *   On the first call returns the address of the first non \0 character, otherwise NULL is returned.
92 *   In subsequent calls, the strtoken is set to NULL, and the context set is the same as the previous call,
93 *   return NULL if the *context string length is equal 0, otherwise return *context.
94 */
95char *strtok_s(char *strToken, const char *strDelimit, char **context)
96{
97    char *orgToken = strToken;
98    /* Validate delimiter and string context */
99    if (context == NULL || strDelimit == NULL) {
100        return NULL;
101    }
102    /* Valid input string and string pointer from where to search */
103    if (orgToken == NULL && *context == NULL) {
104        return NULL;
105    }
106    /* If string is null, continue searching from previous string position stored in context */
107    if (orgToken == NULL) {
108        orgToken = *context;
109    }
110    orgToken = SecFindBegin(orgToken, strDelimit);
111    return SecUpdateToken(orgToken, strDelimit, context);
112}
113#if SECUREC_EXPORT_KERNEL_SYMBOL
114EXPORT_SYMBOL(strtok_s);
115#endif
116
117