strutil: Fix sr_parse_rational for integral parts between -0 and -1

[libsigrok.git] / src / strutil.c

diff --git a/src/strutil.c b/src/strutil.c
index fd9a438e647a6210e63091050b78c7790ffe97be..68a9004e609339de53560dc7fb29c0605e51c465 100644 (file)
--- a/src/strutil.c
+++ b/src/strutil.c
@@ -233,13 +233,19 @@ SR_API int sr_parse_rational(const char *str, struct sr_rational *ret)
        int64_t denominator = 1;
        int32_t fractional_len = 0;
        int32_t exponent = 0;
+       int is_negative = 0;
 
        errno = 0;
        integral = g_ascii_strtoll(str, &endptr, 10);
 
-       if (errno)
+       if (str == endptr && (str[0] == '-' || str[0] == '+') && str[1] == '.')
+               endptr += 1;
+       else if (errno)
                return SR_ERR;
 
+       if (integral < 0 || str[0] == '-')
+               is_negative = 1;
+
        if (*endptr == '.') {
                const char* start = endptr + 1;
                fractional = g_ascii_strtoll(start, &endptr, 10);
@@ -261,7 +267,7 @@ SR_API int sr_parse_rational(const char *str, struct sr_rational *ret)
                integral *= 10;
        exponent -= fractional_len;
 
-       if (integral >= 0)
+       if (!is_negative)
                integral += fractional;
        else
                integral -= fractional;