1 /* CC0 (Public domain) - see LICENSE file for details */
2 #ifndef CCAN_STR_H
3 #define CCAN_STR_H
4 #include "config.h"
5 #include <string.h>
6 #include <stdbool.h>
7 #include <limits.h>
8 #include <ctype.h>
9
10 /**
11 * streq - Are two strings equal?
12 * @a: first string
13 * @b: first string
14 *
15 * This macro is arguably more readable than "!strcmp(a, b)".
16 *
17 * Example:
18 * if (streq(somestring, ""))
19 * printf("String is empty!\n");
20 */
21 #define streq(a,b) (strcmp((a),(b)) == 0)
22
23 /**
24 * strstarts - Does this string start with this prefix?
25 * @str: string to test
26 * @prefix: prefix to look for at start of str
27 *
28 * Example:
29 * if (strstarts(somestring, "foo"))
30 * printf("String %s begins with 'foo'!\n", somestring);
31 */
32 #define strstarts(str,prefix) (strncmp((str),(prefix),strlen(prefix)) == 0)
33
34 /**
35 * strends - Does this string end with this postfix?
36 * @str: string to test
37 * @postfix: postfix to look for at end of str
38 *
39 * Example:
40 * if (strends(somestring, "foo"))
41 * printf("String %s end with 'foo'!\n", somestring);
42 */
strends(const char * str,const char * postfix)43 static inline bool strends(const char *str, const char *postfix)
44 {
45 if (strlen(str) < strlen(postfix))
46 return false;
47
48 return streq(str + strlen(str) - strlen(postfix), postfix);
49 }
50
51 /**
52 * stringify - Turn expression into a string literal
53 * @expr: any C expression
54 *
55 * Example:
56 * #define PRINT_COND_IF_FALSE(cond) \
57 * ((cond) || printf("%s is false!", stringify(cond)))
58 */
59 #define stringify(expr) stringify_1(expr)
60 /* Double-indirection required to stringify expansions */
61 #define stringify_1(expr) #expr
62
63 /**
64 * strcount - Count number of (non-overlapping) occurrences of a substring.
65 * @haystack: a C string
66 * @needle: a substring
67 *
68 * Example:
69 * assert(strcount("aaa aaa", "a") == 6);
70 * assert(strcount("aaa aaa", "ab") == 0);
71 * assert(strcount("aaa aaa", "aa") == 2);
72 */
73 size_t strcount(const char *haystack, const char *needle);
74
75 /**
76 * STR_MAX_CHARS - Maximum possible size of numeric string for this type.
77 * @type_or_expr: a pointer or integer type or expression.
78 *
79 * This provides enough space for a nul-terminated string which represents the
80 * largest possible value for the type or expression.
81 *
82 * Note: The implementation adds extra space so hex values or negative
83 * values will fit (eg. sprintf(... "%p"). )
84 *
85 * Example:
86 * char str[STR_MAX_CHARS(int)];
87 *
88 * sprintf(str, "%i", 7);
89 */
90 #define STR_MAX_CHARS(type_or_expr) \
91 ((sizeof(type_or_expr) * CHAR_BIT + 8) / 9 * 3 + 2 \
92 + STR_MAX_CHARS_TCHECK_(type_or_expr))
93
94 #if HAVE_TYPEOF
95 /* Only a simple type can have 0 assigned, so test that. */
96 #define STR_MAX_CHARS_TCHECK_(type_or_expr) \
97 ({ typeof(type_or_expr) x = 0; (void)x; 0; })
98 #else
99 #define STR_MAX_CHARS_TCHECK_(type_or_expr) 0
100 #endif
101
102 /* These checks force things out of line, hence they are under DEBUG. */
103 #ifdef CCAN_STR_DEBUG
104 #if HAVE_TYPEOF
105 /* With GNU magic, we can make const-respecting standard string functions. */
106 #undef strstr
107 #undef strchr
108 #undef strrchr
109
110 /* + 0 is needed to decay array into pointer. */
111 #define strstr(haystack, needle) \
112 ((typeof((haystack) + 0))str_strstr((haystack), (needle)))
113 #define strchr(haystack, c) \
114 ((typeof((haystack) + 0))str_strchr((haystack), (c)))
115 #define strrchr(haystack, c) \
116 ((typeof((haystack) + 0))str_strrchr((haystack), (c)))
117 #endif
118 #endif /* CCAN_STR_DEBUG */
119
120 #endif /* CCAN_STR_H */
121