string_utils: add trim_both

trim_both removes whitespaces from both side of a string.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/string_utils.c

@@ -127,3 +127,31 @@ TEST_CASE(strtod_simple) {
 	TEST_EQUAL(result, 0.5);
 	TEST_EQUAL(*end, '\0');
 }
+
+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;
+}
+
+TEST_CASE(trim_both) {
+	size_t length;
+	const char *str = trim_both("  \t\n\r\f", &length);
+	TEST_EQUAL(length, 0);
+	TEST_EQUAL(*str, '\0');
+
+	str = trim_both(" asdfas  ", &length);
+	TEST_EQUAL(length, 6);
+	TEST_STRNEQUAL(str, "asdfas", length);
+
+	str = trim_both("  asdf asdf   ", &length);
+	TEST_EQUAL(length, 9);
+	TEST_STRNEQUAL(str, "asdf asdf", length);
+}

src/string_utils.h

@@ -11,6 +11,7 @@
 char *mstrjoin(const char *src1, const char *src2);
 char *mstrjoin3(const char *src1, const char *src2, const char *src3);
 void mstrextend(char **psrc1, const char *src2);
+const char *trim_both(const char *src, size_t *length);
 
 /// Parse a floating point number of form (+|-)?[0-9]*(\.[0-9]*)
 double strtod_simple(const char *, const char **);

subprojects/test.h/test.h

@@ -84,7 +84,7 @@ struct test_file_metadata __attribute__((weak)) * test_file_head;
 			const char *part2 = " != " #b;                                   \
 			size_t len2 = len + strlen(part2) + 3;                           \
 			char *buf = malloc(len2);                                        \
-			snprintf(buf, len2, "\"%.*s\"%s", len, a, part2);                \
+			snprintf(buf, len2, "\"%.*s\"%s", (int)len, a, part2);           \
 			SET_FAILURE(buf, true);                                          \
 			return;                                                          \
 		}                                                                        \