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Reactos
1/***
2*strspn.c - find length of initial substring of chars from a control string
3*
4* Copyright (c) Microsoft Corporation. All rights reserved.
5*
6*Purpose:
7* defines strspn() - finds the length of the initial substring of
8* a string consisting entirely of characters from a control string.
9*
10* defines strcspn()- finds the length of the initial substring of
11* a string consisting entirely of characters not in a control string.
12*
13* defines strpbrk()- finds the index of the first character in a string
14* that is not in a control string
15*
16*******************************************************************************/
17
18#include <string.h>
19
20#pragma warning(disable:__WARNING_POTENTIAL_BUFFER_OVERFLOW_NULLTERMINATED) // 26018 Prefast doesn't understand reading past buffer but staying on same page.
21#pragma warning(disable:__WARNING_RETURNING_BAD_RESULT) // 28196
22
23/* Determine which routine we're compiling for (default to STRSPN) */
24#define _STRSPN 1
25#define _STRCSPN 2
26#define _STRPBRK 3
27
28#if defined (SSTRCSPN)
29 #define ROUTINE _STRCSPN
30#elif defined (SSTRPBRK)
31 #define ROUTINE _STRPBRK
32#else
33 #define ROUTINE _STRSPN
34#endif
35
36/***
37*int strspn(string, control) - find init substring of control chars
38*
39*Purpose:
40* Finds the index of the first character in string that does belong
41* to the set of characters specified by control. This is
42* equivalent to the length of the initial substring of string that
43* consists entirely of characters from control. The '\0' character
44* that terminates control is not considered in the matching process.
45*
46*Entry:
47* char *string - string to search
48* char *control - string containing characters not to search for
49*
50*Exit:
51* returns index of first char in string not in control
52*
53*Exceptions:
54*
55*******************************************************************************/
56
57/***
58*int strcspn(string, control) - search for init substring w/o control chars
59*
60*Purpose:
61* returns the index of the first character in string that belongs
62* to the set of characters specified by control. This is equivalent
63* to the length of the length of the initial substring of string
64* composed entirely of characters not in control. Null chars not
65* considered.
66*
67*Entry:
68* char *string - string to search
69* char *control - set of characters not allowed in init substring
70*
71*Exit:
72* returns the index of the first char in string
73* that is in the set of characters specified by control.
74*
75*Exceptions:
76*
77*******************************************************************************/
78
79/***
80*char *strpbrk(string, control) - scans string for a character from control
81*
82*Purpose:
83* Finds the first occurence in string of any character from
84* the control string.
85*
86*Entry:
87* char *string - string to search in
88* char *control - string containing characters to search for
89*
90*Exit:
91* returns a pointer to the first character from control found
92* in string.
93* returns NULL if string and control have no characters in common.
94*
95*Exceptions:
96*
97*******************************************************************************/
98
99
100
101/* Routine prototype */
102#if ROUTINE == _STRSPN
103size_t __cdecl strspn (
104#elif ROUTINE == _STRCSPN
105size_t __cdecl strcspn (
106#else /* ROUTINE == _STRCSPN */
107char * __cdecl strpbrk (
108#endif /* ROUTINE == _STRCSPN */
109 const char * string,
110 const char * control
111 )
112{
113 const unsigned char *str = (unsigned char const*)string;
114 const unsigned char *ctrl = (unsigned char const*)control;
115
116 unsigned char map[32];
117 int count;
118
119 /* Clear out bit map */
120 for (count=0; count<32; count++)
121 map[count] = 0;
122
123 /* Set bits in control map */
124 while (*ctrl)
125 {
126 map[*ctrl >> 3] |= (1 << (*ctrl & 7));
127 ctrl++;
128 }
129
130#if ROUTINE == _STRSPN
131
132 /* 1st char NOT in control map stops search */
133 if (*str)
134 {
135 count=0;
136 while (map[*str >> 3] & (1 << (*str & 7)))
137 {
138 count++;
139 str++;
140 }
141 return(count);
142 }
143 return(0);
144
145#elif ROUTINE == _STRCSPN
146
147 /* 1st char in control map stops search */
148 count=0;
149 map[0] |= 1; /* null chars not considered */
150 while (!(map[*str >> 3] & (1 << (*str & 7))))
151 {
152 count++;
153 str++;
154 }
155 return(count);
156
157#else /* ROUTINE == _STRCSPN */
158
159 /* 1st char in control map stops search */
160 while (*str)
161 {
162 if (map[*str >> 3] & (1 << (*str & 7)))
163 return((char *)str);
164 str++;
165 }
166 return(NULL);
167
168#endif /* ROUTINE == _STRCSPN */
169
170}