summaryrefslogtreecommitdiff
path: root/util.c
blob: 59ece0444cc71486f4db8ca385b2d99b807dd415 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
static u32 util_popcount(u64 x) {
#ifdef __GNUC__
	return (u32)__builtin_popcountll(x);
#else
	u32 count = 0;
	while (x) {
		x &= x-1;
		++count;
	}
	return count;
#endif
}

static bool util_is_power_of_2(u64 x) {
	return util_popcount(x) == 1;
}

// for finding a character in a char32 string
static char32_t *util_mem32chr(char32_t *s, char32_t c, size_t n) {
	for (size_t i = 0; i < n; ++i) {
		if (s[i] == c) {
			return &s[i];
		}
	}
	return NULL;
}

static char32_t const *util_mem32chr_const(char32_t const *s, char32_t c, size_t n) {
	for (size_t i = 0; i < n; ++i) {
		if (s[i] == c) {
			return &s[i];
		}
	}
	return NULL;
}

static bool str_is_prefix(char const *str, char const *prefix) {
	return strncmp(str, prefix, strlen(prefix)) == 0;
}

static bool streq(char const *a, char const *b) {
	return strcmp(a, b) == 0;
}

// duplicates a null-terminated string. the returned string should be passed to free()
static char *str_dup(char const *src) {
	size_t len = strlen(src);
	char *ret = malloc(len + 1);
	if (ret)
		memcpy(ret, src, len + 1);
	return ret;
}

// like snprintf, but not screwed up on windows
#define str_printf(str, size, ...) (str)[(size) - 1] = '\0', snprintf((str), (size) - 1, __VA_ARGS__)
// like snprintf, but the size is taken to be the length of the array str.
//                              first, check that str is actually an array
#define strbuf_printf(str, ...) assert(sizeof str != 4 && sizeof str != 8), \
	str_printf(str, sizeof str, __VA_ARGS__)

// on 16-bit systems, this is 16383. on 32/64-bit systems, this is 1073741823
// it is unusual to have a string that long.
#define STRLEN_SAFE_MAX (UINT_MAX >> 2)

// safer version of strncat. dst_sz includes a null terminator.
static void strn_cat(char *dst, size_t dst_sz, char const *src, size_t src_len) {
	size_t dst_len = strlen(dst);

	// make sure dst_len + src_len + 1 doesn't overflow
	if (dst_len > STRLEN_SAFE_MAX || src_len > STRLEN_SAFE_MAX) {
		assert(0);
		return;
	}

	if (dst_len >= dst_sz) {
		// dst doesn't actually contain a null-terminated string!
		assert(0);
		return;
	}

	if (dst_len + src_len + 1 > dst_sz) {
		// number of bytes left in dst, not including null terminator
		size_t n = dst_sz - dst_len - 1;
		memcpy(dst + dst_len, src, n);
		dst[dst_sz - 1] = 0; // dst_len + n == dst_sz - 1
	} else {
		memcpy(dst + dst_len, src, src_len);
		dst[dst_len + src_len] = 0;
	}
}

// safer version of strcat. dst_sz includes a null terminator.
static void str_cat(char *dst, size_t dst_sz, char const *src) {
	strn_cat(dst, dst_sz, src, strlen(src));
}

// safer version of strncpy. dst_sz includes a null terminator.
static void str_cpy(char *dst, size_t dst_sz, char const *src) {
	size_t srclen = strlen(src);
	size_t n = srclen; // number of bytes to copy
	
	if (dst_sz == 0) {
		assert(0);
		return;
	}

	if (dst_sz-1 < n)
		n = dst_sz-1;
	memcpy(dst, src, n);
	dst[n] = 0;
}

#define strbuf_cpy(dst, src) str_cpy(dst, sizeof dst, src)

// advances str to the start of the next UTF8 character
static void utf8_next_char_const(char const **str) {
	if (**str) {
		do {
			++*str;
		} while (((u8)(**str) & 0xC0) == 0x80); // while we are on a continuation byte
	}
}

/* 
returns the first instance of needle in haystack, where both are UTF-8 strings, ignoring the case of the characters,
or NULL if the haystack does not contain needle
WARNING: O(strlen(haystack) * strlen(needle))
*/
static char *stristr(char const *haystack, char const *needle) {
	size_t needle_bytes = strlen(needle), haystack_bytes = strlen(haystack);

	if (needle_bytes > haystack_bytes) return NULL;
	
	char const *haystack_end = haystack + haystack_bytes;
	char const *needle_end = needle + needle_bytes;

	for (char const *haystack_start = haystack; haystack_start + needle_bytes <= haystack_end; utf8_next_char_const(&haystack_start)) {
		char const *p = haystack_start, *q = needle;
		bool match = true;

		// check if p matches q
		while (q < needle_end) {
			char32_t pchar = 0, qchar = 0;
			size_t bytes_p = unicode_utf8_to_utf32(&pchar, p, (size_t)(haystack_end - p));
			size_t bytes_q = unicode_utf8_to_utf32(&qchar, q, (size_t)(needle_end - q));
			if (bytes_p == (size_t)-1 || bytes_q == (size_t)-1) return NULL; // invalid UTF-8
			bool same = pchar == qchar;
			if (pchar < WINT_MAX && qchar < WINT_MAX) // on Windows, there is no way of finding the lower-case version of a codepoint outside the BMP. ):
				same = towlower((wint_t)pchar) == towlower((wint_t)qchar);
			if (!same) match = false;
			p += bytes_p;
			q += bytes_q;
		}
		if (match)
			return (char *)haystack_start;
	}
	return NULL;
}

static void print_bytes(u8 *bytes, size_t n) {
	u8 *b, *end;
	for (b = bytes, end = bytes + n; b != end; ++b)
		printf("%x ", *b);
	printf("\n");
}

/*
does this predicate hold for all the characters of s. predicate is int (*)(int) instead
of bool (*)(char) so that you can pass isprint, etc. to it.
*/
static bool str_satisfies(char const *s, int (*predicate)(int)) {
	char const *p;
	for (p = s; *p; ++p)
		if (!predicate(*p))
			return false;
	return true;
}


static int strcmp_case_insensitive(char const *a, char const *b) {
#if _WIN32
	return _stricmp(a, b);
#else
	return strcasecmp(a, b);
#endif
}

// function to be passed into qsort for case insensitive sorting
static int str_qsort_case_insensitive_cmp(const void *av, const void *bv) {
	char const *const *a = av, *const *b = bv;
	return strcmp_case_insensitive(*a, *b);
}

static void *qsort_ctx_arg;
static int (*qsort_ctx_cmp)(void *, const void *, const void *);
static int qsort_with_context_cmp(const void *a, const void *b) {
	return qsort_ctx_cmp(qsort_ctx_arg, a, b);
}

static void qsort_with_context(void *base, size_t nmemb, size_t size, int (*compar)(void *, const void *, const void *), void *arg) {
	// @TODO(eventually): write this yourself
	// just use global variables. hopefully we don't try to run this in something multithreaded!
	qsort_ctx_arg = arg;
	qsort_ctx_cmp = compar;
	qsort(base, nmemb, size, qsort_with_context_cmp);
}

// the actual file name part of the path; get rid of the containing directory.
// NOTE: the returned string is part of path, so you don't need to free it or anything.
static char const *path_filename(char const *path) {
	char const *last_path_sep = strrchr(path, PATH_SEPARATOR);
	if (last_path_sep)
		return last_path_sep + 1;
	// (a relative path with no path separators)
	return path;
}