lib/base: Support colons in from_hex()

src/lib/base/String.cpp

@@ -234,20 +234,27 @@ std::string to_hex(const std::vector<std::uint8_t>& subject, int width, const ch
 
 std::vector<std::uint8_t> from_hex(const std::string& data)
 {
-    if ((data.size() % 2) != 0) {
-        return {};
-    }
-
     std::vector<std::uint8_t> result;
     result.reserve(data.size() / 2);
 
-    for (std::size_t i = 0; i < data.size(); i += 2) {
+    std::size_t i = 0;
+    while (i < data.size()) {
+        if (data[i] == ':') {
+            i++;
+            continue;
+        }
+
+        if (i + 2 > data.size()) {
+            return {}; // uneven character count follows, it's unclear how to interpret it
+        }
+
         auto high = hex_to_number(data[i]);
         auto low = hex_to_number(data[i + 1]);
         if (high < 0 || low < 0) {
             return {};
         }
         result.push_back(high * 16 + low);
+        i += 2;
     }
     return result;
 }

src/test/unittests/base/StringTests.cpp

@@ -69,6 +69,13 @@ TEST(StringTests, fromhex_plaintext_string)
     EXPECT_EQ(result, std::vector<std::uint8_t>(expected.begin(), expected.end()));
 }
 
+TEST(StringTests, fromhex_plaintext_string_colons)
+{
+    auto result = string::from_hex("66:6f:6f:62:61:72");
+    std::string expected = "foobar";
+    EXPECT_EQ(result, std::vector<std::uint8_t>(expected.begin(), expected.end()));
+}
+
 TEST(StringTests, fromhex_binary_string)
 {
     auto result = string::from_hex("01020304050600fff9");
@@ -76,6 +83,13 @@ TEST(StringTests, fromhex_binary_string)
     EXPECT_EQ(result, expected);
 }
 
+TEST(StringTests, fromhex_invalid_string)
+{
+    EXPECT_TRUE(string::from_hex("66:6").empty());
+    EXPECT_TRUE(string::from_hex("66:612").empty());
+    EXPECT_TRUE(string::from_hex("66:WW").empty());
+}
+
 TEST(StringTests, uppercase_lowercaseInput_uppercaseOutput)
 {
     String subject = "12foo3BaR";