aboutsummaryrefslogtreecommitdiff
path: root/src/string_utils.c
blob: 871f29ab883a4961b06ef4441933a06da3aaf681 (plain) (blame)
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
// SPDX-License-Identifier: MPL-2.0
// Copyright (c) Yuxuan Shui <[email protected]>

#include <string.h>

#include "compiler.h"
#include "string_utils.h"
#include "utils.h"

#pragma GCC diagnostic push

// gcc warns about legitimate strncpy in mstrjoin and mstrextend
// strncpy(str, src1, len1) intentional truncates the null byte from src1.
// strncpy(str+len1, src2, len2) uses bound depends on the source argument,
// but str is allocated with len1+len2+1, so this strncpy can't overflow
#pragma GCC diagnostic ignored "-Wpragmas"
#pragma GCC diagnostic ignored "-Wstringop-truncation"
#pragma GCC diagnostic ignored "-Wstringop-overflow"

/**
 * Allocate the space and join two strings.
 */
char *mstrjoin(const char *src1, const char *src2) {
	auto len1 = strlen(src1);
	auto len2 = strlen(src2);
	auto len = len1 + len2 + 1;
	auto str = ccalloc(len, char);

	strncpy(str, src1, len1);
	strncpy(str + len1, src2, len2);
	str[len - 1] = '\0';

	return str;
}

/**
 * Concatenate a string on heap with another string.
 */
void mstrextend(char **psrc1, const char *src2) {
	if (!*psrc1) {
		*psrc1 = strdup(src2);
		return;
	}

	auto len1 = strlen(*psrc1);
	auto len2 = strlen(src2);
	auto len = len1 + len2 + 1;
	*psrc1 = crealloc(*psrc1, len);

	strncpy(*psrc1 + len1, src2, len2);
	(*psrc1)[len - 1] = '\0';
}

#pragma GCC diagnostic pop

/// Parse a floating point number of form (+|-)?[0-9]*(\.[0-9]*)
double strtod_simple(const char *src, const char **end) {
	double neg = 1;
	if (*src == '-') {
		neg = -1;
		src++;
	} else if (*src == '+') {
		src++;
	}

	double ret = 0;
	while (*src >= '0' && *src <= '9') {
		ret = ret * 10 + (*src - '0');
		src++;
	}

	if (*src == '.') {
		double frac = 0, mult = 0.1;
		src++;
		while (*src >= '0' && *src <= '9') {
			frac += mult * (*src - '0');
			mult *= 0.1;
			src++;
		}
		ret += frac;
	}

	*end = src;
	return ret * neg;
}

const char *trim_both(const char *src, size_t *length) {
	size_t i = 0;
	while (isspace(src[i])) {
		i++;
	}
	size_t j = strlen(src) - 1;
	while (j > i && isspace(src[j])) {
		j--;
	}
	*length = j - i + 1;
	return src + i;
}