Add util function to parse a list of integers

This will help parsing arguments like '1234:5678' into a list of
integers.

app/tests/test_strutil.c

@@ -187,6 +187,55 @@ static void test_parse_integer(void) {
     assert(!ok); // out-of-range
 }
 
+static void test_parse_integers(void) {
+    long values[5];
+
+    size_t count = parse_integers("1234", ':', 5, values);
+    assert(count == 1);
+    assert(values[0] == 1234);
+
+    count = parse_integers("1234:5678", ':', 5, values);
+    assert(count == 2);
+    assert(values[0] == 1234);
+    assert(values[1] == 5678);
+
+    count = parse_integers("1234:5678", ':', 2, values);
+    assert(count == 2);
+    assert(values[0] == 1234);
+    assert(values[1] == 5678);
+
+    count = parse_integers("1234:-5678", ':', 2, values);
+    assert(count == 2);
+    assert(values[0] == 1234);
+    assert(values[1] == -5678);
+
+    count = parse_integers("1:2:3:4:5", ':', 5, values);
+    assert(count == 5);
+    assert(values[0] == 1);
+    assert(values[1] == 2);
+    assert(values[2] == 3);
+    assert(values[3] == 4);
+    assert(values[4] == 5);
+
+    count = parse_integers("1234:5678", ':', 1, values);
+    assert(count == 0); // max_items == 1
+
+    count = parse_integers("1:2:3:4:5", ':', 3, values);
+    assert(count == 0); // max_items == 3
+
+    count = parse_integers(":1234", ':', 5, values);
+    assert(count == 0); // invalid
+
+    count = parse_integers("1234:", ':', 5, values);
+    assert(count == 0); // invalid
+
+    count = parse_integers("1234:", ':', 1, values);
+    assert(count == 0); // invalid, even when max_items == 1
+
+    count = parse_integers("1234::5678", ':', 5, values);
+    assert(count == 0); // invalid
+}
+
 static void test_parse_integer_with_suffix(void) {
     long value;
     bool ok = parse_integer_with_suffix("1234", &value);
@@ -249,6 +298,7 @@ int main(void) {
     test_strquote();
     test_utf8_truncate();
     test_parse_integer();
+    test_parse_integers();
     test_parse_integer_with_suffix();
     return 0;
 }