Use [[likely]] and [[unlikely]]

2 files changed, 27 insertions, 4 deletions

diff --git a/include/unicode/predicate.h b/include/unicode/predicate.h
index 5f8c6a4..e326529 100644
--- a/include/unicode/predicate.h
+++ b/include/unicode/predicate.h
@@ -1,3 +1,7 @@
+//
+// Unicode library - predicates for Unicode characters
+//
+
 #pragma once
 
 namespace unicode {
diff --git a/include/unicode/utf.h b/include/unicode/utf.h
index 046d9c6..6d7c2f7 100644
--- a/include/unicode/utf.h
+++ b/include/unicode/utf.h
@@ -58,9 +58,11 @@ namespace unicode::detail {
     if ((((s[i] & 7) << 2) | ((s[i + 1] >> 4) & 3)) >= 0x11)
      return false; // Unicode too big above 0x10FFFF
     i += 4;
-   } else {
+   } else
+#if __cplusplus >= 202002L
+   [[unlikely]]
+#endif
     return false;
-   }
   }
   return true;
  }
@@ -91,9 +93,11 @@ namespace unicode::detail {
     i++;
    } else if ((i < size - 1) && is_utf16_sequence(s[i], s[i + 1])) {
     i += 2;
-   } else {
+   } else
+#if __cplusplus >= 202002L
+    [[unlikely]]
+#endif
     return false;
-   }
   }
   return true;
  }
@@ -185,6 +189,9 @@ namespace unicode::detail {
 
    if constexpr(sequence_length > 1) {
     if (remaining_code_units() < sequence_length)
+#if __cplusplus >= 202002L
+     [[unlikely]]
+#endif
      throw std::invalid_argument("Bad input: Not enough bytes left for decoding UTF-8 sequence");
    }
 
@@ -192,6 +199,9 @@ namespace unicode::detail {
     std::advance(iterator, sequence_length);
     internal_type result{decode_utf8_sequence(bytes...)};
     if (!unicode::is_valid_unicode<sequence_length * 6>(result))
+#if __cplusplus >= 202002L
+     [[unlikely]]
+#endif
      throw std::invalid_argument("Invalid Unicode character: "s + std::to_string(static_cast<uint32_t>(result)));
     return result;
    } else {
@@ -218,10 +228,16 @@ namespace unicode::detail {
     return unit0;
    } else {
     if (remaining_code_units() < 2)
+#if __cplusplus >= 202002L
+     [[unlikely]]
+#endif
      throw std::invalid_argument("Bad input: Continuation of first UTF-16 unit missing");
 
     char16_t unit1 {static_cast<char16_t>(get_code_unit<1>())};
     if ((unit0 & 0xFC00) != 0xD800 || (unit1 & 0xFC00) != 0xDC00)
+#if __cplusplus >= 202002L
+     [[unlikely]]
+#endif
      throw std::invalid_argument("Bad input: 2 malformed UTF-16 surrogates");
 
     std::advance(iterator, 2);
@@ -235,6 +251,9 @@ namespace unicode::detail {
    internal_type result {static_cast<internal_type>(get_code_unit<0>())};
 
    if (!unicode::is_valid_unicode(result))
+#if __cplusplus >= 202002L
+    [[unlikely]]
+#endif
     throw std::invalid_argument("Invalid Unicode character: "s + std::to_string(static_cast<uint32_t>(result)));
 
    std::advance(iterator, 1);