picom/src/string_utils.c

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// SPDX-License-Identifier: MPL-2.0
// Copyright (c) Yuxuan Shui <yshuiv7@gmail.com>
#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;
}