diff --git a/chrono/timespan.cpp b/chrono/timespan.cpp
index fc949cd..7499baa 100644
--- a/chrono/timespan.cpp
+++ b/chrono/timespan.cpp
@@ -41,26 +41,26 @@ TimeSpan TimeSpan::fromString(const char *str, char separator)
         return TimeSpan();
     }
 
-    vector<double> parts;
-    size_t partsSize = 1;
-    for (const char *i = str; *i; ++i) {
-        *i == separator && ++partsSize;
-    }
-    parts.reserve(partsSize);
-
-    for (const char *i = str;;) {
+    auto parts = std::array<double, 4>();
+    auto partsPresent = std::size_t();
+    for (const char *i = str;; ++i) {
+        if (*i != separator && *i != '\0') {
+            continue;
+        }
+        if (partsPresent >= 4) {
+            throw ConversionException("the time span specifications contains too many separators");
+        }
+        const auto part = std::string_view(str, i - str);
+        parts[partsPresent++] = part.empty() ? 0.0 : stringToNumber<double>(part);
         if (*i == separator) {
-            parts.emplace_back(stringToNumber<double>(string(str, i)));
-            str = ++i;
-        } else if (*i == '\0') {
-            parts.emplace_back(stringToNumber<double>(string(str, i)));
+            str = i + 1;
+        }
+        if (*i == '\0') {
             break;
-        } else {
-            ++i;
         }
     }
 
-    switch (parts.size()) {
+    switch (partsPresent) {
     case 1:
         return TimeSpan::fromSeconds(parts.front());
     case 2:
diff --git a/tests/chronotests.cpp b/tests/chronotests.cpp
index 38c6e12..0afd4d8 100644
--- a/tests/chronotests.cpp
+++ b/tests/chronotests.cpp
@@ -317,13 +317,17 @@ void ChronoTests::testDateTimeExpression()
  */
 void ChronoTests::testTimeSpan()
 {
-    // test fromString(...), this should also test all other from...() methods and + operator
+    // test various usages of fromString(...), all other from...() functions and the plus operator
     CPPUNIT_ASSERT_EQUAL(TimeSpan(), TimeSpan::fromString(string()));
     CPPUNIT_ASSERT_EQUAL(TimeSpan::fromSeconds(5.0), TimeSpan::fromString("5.0"));
     CPPUNIT_ASSERT_EQUAL(TimeSpan::fromMinutes(5.5), TimeSpan::fromString("5:30"));
     CPPUNIT_ASSERT_EQUAL(TimeSpan::fromHours(7.0) + TimeSpan::fromMinutes(5.5), TimeSpan::fromString("7:5:30"));
+    CPPUNIT_ASSERT_EQUAL(TimeSpan::fromDays(14.0), TimeSpan::fromString("14:::"));
+    CPPUNIT_ASSERT_THROW(TimeSpan::fromString("2:34a:53:32.5"), ConversionException);
+    CPPUNIT_ASSERT_THROW(TimeSpan::fromString("1:2:3:4:5"), ConversionException);
+
+    // test fromString(...) again and days(), hours(), ...
     const auto test1 = TimeSpan::fromString("2:34:53:2.5");
-    // test days(), hours(), ...
     CPPUNIT_ASSERT_EQUAL(3, test1.days());
     CPPUNIT_ASSERT_EQUAL(10, test1.hours());
     CPPUNIT_ASSERT_EQUAL(53, test1.minutes());
@@ -332,12 +336,14 @@ void ChronoTests::testTimeSpan()
     CPPUNIT_ASSERT(test1.totalDays() > 3.0 && test1.totalDays() < 4.0);
     CPPUNIT_ASSERT(test1.totalHours() > (2 * 24 + 34) && test1.totalHours() < (2 * 24 + 35));
     CPPUNIT_ASSERT(test1.totalMinutes() > (2 * 24 * 60 + 34 * 60 + 53) && test1.totalHours() < (2 * 24 * 60 + 34 * 60 + 54));
+
     // test toString(...)
     CPPUNIT_ASSERT_EQUAL("3 d 10 h 53 min 2 s 500 ms"s, test1.toString(TimeSpanOutputFormat::WithMeasures, false));
     CPPUNIT_ASSERT_EQUAL("07:05:30"s, (TimeSpan::fromHours(7.0) + TimeSpan::fromMinutes(5.5)).toString());
     CPPUNIT_ASSERT_EQUAL("-5 s"s, TimeSpan::fromSeconds(-5.0).toString(TimeSpanOutputFormat::WithMeasures, false));
     CPPUNIT_ASSERT_EQUAL("0 s"s, TimeSpan().toString(TimeSpanOutputFormat::WithMeasures, false));
     CPPUNIT_ASSERT_EQUAL("5e+02 µs"s, TimeSpan::fromMilliseconds(0.5).toString(TimeSpanOutputFormat::WithMeasures, false));
+
     // test accuracy (of 100 nanoseconds)
     const auto test2 = TimeSpan::fromString("15.985077682");
     CPPUNIT_ASSERT_EQUAL(15.9850776, test2.totalSeconds());
@@ -348,9 +354,6 @@ void ChronoTests::testTimeSpan()
     CPPUNIT_ASSERT_EQUAL("00:00:15.9850776"s, test2.toString());
     CPPUNIT_ASSERT_EQUAL("15 s 985 ms 77 µs 600 ns"s, test2.toString(TimeSpanOutputFormat::WithMeasures));
     CPPUNIT_ASSERT_EQUAL("15.9850776"s, test2.toString(TimeSpanOutputFormat::TotalSeconds));
-
-    // test whether ConversionException() is thrown when invalid values are specified
-    CPPUNIT_ASSERT_THROW(TimeSpan::fromString("2:34a:53:32.5"), ConversionException);
 }
 
 /*!