Add support for parsing NaN, INF, and -INF

2 files changed, 24 insertions, 4 deletions

diff --git a/src/string.c b/src/string.c
index 1e7e9348..9a6b4ff6 100644
--- a/src/string.c
+++ b/src/string.c
@@ -113,6 +113,19 @@ serd_strtod(const char* str, size_t* end)
 {
 	double result = 0.0;
 
+#define SET_END(index) do { if (end) { *end = index; } } while (0)
+
+	if (!strcmp(str, "NaN")) {
+		SET_END(3);
+		return NAN;
+	} else if (!strcmp(str, "-INF")) {
+		SET_END(4);
+		return -INFINITY;
+	} else if (!strcmp(str, "INF")) {
+		SET_END(3);
+		return INFINITY;
+	}
+
 	// Point s at the first non-whitespace character
 	const char* s = str;
 	while (is_space(*s)) { ++s; }
@@ -145,9 +158,6 @@ serd_strtod(const char* str, size_t* end)
 		result *= pow(10, expt * expt_sign);
 	}
 
-	if (end) {
-		*end = s - str;
-	}
-
+	SET_END(s - str);
 	return result * sign;
 }
diff --git a/tests/serd_test.c b/tests/serd_test.c
index a8853969..7f4c291b 100644
--- a/tests/serd_test.c
+++ b/tests/serd_test.c
@@ -209,6 +209,16 @@ test_read_string(void)
 static void
 test_string_to_double(void)
 {
+	size_t end = 0;
+	assert(isnan(serd_strtod("NaN", &end)));
+	assert(end == 3);
+
+	assert(isinf(serd_strtod("INF", &end)) == 1);
+	assert(end == 3);
+
+	assert(isinf(serd_strtod("-INF", &end)) == -1);
+	assert(end == 4);
+
 	const double expt_test_nums[] = {
 		2.0E18, -5e19, +8e20, 2e+24, -5e-5, 8e0, 9e-0, 2e+0
 	};