From 216e03ce9e1b891cbbfaea942c4cd607d29b67f7 Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Sat, 25 Dec 2021 18:40:40 +0100
Subject: Minor refactoring

---
 include/unicode.h | 32 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/include/unicode.h b/include/unicode.h
index c2d727a..c9f2331 100644
--- a/include/unicode.h
+++ b/include/unicode.h
@@ -93,6 +93,8 @@ namespace unicode::detail {
   template<size_t n>
   inline static bool is_byte0_of(value_type b) noexcept
   {
+   static_assert(n >= 2 && n <= 4);
+
    return (b & static_cast<value_type>(0xFF << (7 - n))) == static_cast<value_type>(0xFF << (8 - n));
   }
 
@@ -548,19 +550,15 @@ namespace unicode {
   return it2 - it1;
  }
 
+ // Optimizations following:
+ static const size_t accu_size {sizeof(size_t)};
+
  template<int value_size>
  struct ConvertInputOptimizer {};
 
  template<> struct ConvertInputOptimizer<1>
  {
   static const uint32_t ascii_mask { 0x80808080 };
-  // 00112233
-  // 00112222
-  // 00111122
-  // 00111111
-  // 00001122
-  // 00001111
-  // 00000011
  };
  
  template<> struct ConvertInputOptimizer<2>
@@ -572,7 +570,7 @@ namespace unicode {
  {
   static const uint32_t ascii_mask { 0xFFFFFF80 };
  };
- 
+
  template<int AccuSize, class ConvertInputOptimizer>
  struct ArchitectureOptimizer {};
 
@@ -581,7 +579,6 @@ namespace unicode {
  {
   typedef ConvertInputOptimizer input_optimizer;
   typedef uint32_t accu_type;
-  static const size_t accu_size {4};
   static const accu_type addr_mask {accu_size - 1};
   static const accu_type ascii_mask { (accu_type)input_optimizer::ascii_mask };
   static const accu_type ascii_value { 0ULL };
@@ -610,7 +607,6 @@ namespace unicode {
  {
   typedef ConvertInputOptimizer input_optimizer;
   typedef uint64_t accu_type;
-  static const size_t accu_size {8};
   static const accu_type addr_mask {accu_size - 1};
   static const accu_type ascii_mask { ((accu_type)input_optimizer::ascii_mask) << 32 | (accu_type)input_optimizer::ascii_mask };
   static const accu_type ascii_value { 0ULL };
@@ -647,21 +643,21 @@ namespace unicode {
  {
   typename To::string_type result;
 
-  if constexpr(sizeof(size_t) == 4 || sizeof(size_t) == 8) {
-   typedef ConvertInputOptimizer<sizeof(typename From::string_type::value_type)> input_optimizer;
-   typedef ArchitectureOptimizer<sizeof(size_t), input_optimizer> arch_optimizer;
+  if constexpr(accu_size == 4 || accu_size == 8) {
+   typedef ConvertInputOptimizer<sizeof(typename From::value_type)> input_optimizer;
+   typedef ArchitectureOptimizer<accu_size, input_optimizer> arch_optimizer;
 
    auto begin{From::begin(s)};
    auto end{From::end(s)};
    auto back_inserter{To::back_inserter(result)};
    auto addr{reinterpret_cast<const typename arch_optimizer::accu_type*>(&s.data()[s.size() - input_distance(begin, end)])};
-   while (input_distance(begin, end) >= arch_optimizer::accu_size) {
+   while (input_distance(begin, end) >= accu_size) {
     if (((uintptr_t)(void*)addr & arch_optimizer::addr_mask) == 0) {
-     while (input_distance(begin, end) >= arch_optimizer::accu_size) {
+     while (input_distance(begin, end) >= accu_size) {
       typename arch_optimizer::accu_type data{*addr};
       if ((data & arch_optimizer::ascii_mask) == arch_optimizer::ascii_value) {
-       arch_optimizer::template append<typename From::string_type::value_type, typename To::string_type>(reinterpret_cast<const typename From::string_type::value_type*>(addr), result);
-       begin += arch_optimizer::accu_size / sizeof(typename From::string_type::value_type);
+       arch_optimizer::template append<typename From::value_type, typename To::string_type>(reinterpret_cast<const typename From::value_type*>(addr), result);
+       begin += accu_size / sizeof(typename From::value_type);
        ++addr;
       } else {
        // just advance one code unit for now
@@ -673,7 +669,7 @@ namespace unicode {
     }
 
     // keep up after unaligned Non-ASCII code points
-    while (begin!= end && (uintptr_t)(void*)(addr = reinterpret_cast<const typename arch_optimizer::accu_type*>(&s.data()[s.size() - input_distance(begin, end)])) & arch_optimizer::addr_mask) {
+    while (begin != end && (uintptr_t)(void*)(addr = reinterpret_cast<const typename arch_optimizer::accu_type*>(&s.data()[s.size() - input_distance(begin, end)])) & arch_optimizer::addr_mask) {
      back_inserter = *begin;
      ++begin;
     }
-- 
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