Fixing IPAddress::fromString for '1.1.1.' as well as '...'

Author: aentinger

api/IPAddress.cpp

@@ -49,15 +49,15 @@ bool IPAddress::fromString(const char *address)
 {
     // TODO: add support for "a", "a.b", "a.b.c" formats
 
-    uint16_t acc = 0; // Accumulator
+    int16_t acc = -1; // Accumulator
     uint8_t dots = 0;
 
     while (*address)
     {
         char c = *address++;
         if (c >= '0' && c <= '9')
         {
-            acc = acc * 10 + (c - '0');
+            acc = (acc < 0) ? (c - '0') : acc * 10 + (c - '0');
             if (acc > 255) {
                 // Value out of [0..255] range
                 return false;
@@ -69,8 +69,12 @@ bool IPAddress::fromString(const char *address)
                 // Too much dots (there must be 3 dots)
                 return false;
             }
+            if (acc < 0) {
+                /* No value between dots, e.g. '1..' */
+                return false;
+            }
             _address.bytes[dots++] = acc;
-            acc = 0;
+            acc = -1;
         }
         else
         {
@@ -83,6 +87,10 @@ bool IPAddress::fromString(const char *address)
         // Too few dots (there must be 3 dots)
         return false;
     }
+    if (acc < 0) {
+        /* No value between dots, e.g. '1..' */
+        return false;
+    }
     _address.bytes[3] = acc;
     return true;
 }

test/src/IPAddress/test_fromString.cpp

@@ -41,7 +41,6 @@ TEST_CASE ("Extract valid IP address 'fromString(const String &)'", "[IPAddress-
   REQUIRE(ip[3] == 2);
 }
 
-
 TEST_CASE ("Extract invalid IP address 'fromString(const char *)'", "[IPAddress-fromString-03]")
 {
   arduino::IPAddress ip;
@@ -53,6 +52,7 @@ TEST_CASE ("Extract invalid IP address 'fromString(const char *)'", "[IPAddress-
   REQUIRE(ip.fromString("1.1.")      == false);
   REQUIRE(ip.fromString("1.1.1")     == false);
   REQUIRE(ip.fromString("1.1.1.")    == false);
+  REQUIRE(ip.fromString("...")       == false);
   REQUIRE(ip.fromString("256.1.1.1") == false);
   REQUIRE(ip.fromString("a.1.1.1")   == false);
   REQUIRE(ip.fromString("-.1.1.1")   == false);