From d234c1ca09af512e9a13579a6fff8d5834d7b36c Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Mon, 3 Jan 2022 16:08:38 +0100
Subject: Separated out remaining functions from unicode.h, documentation

---
 include/unicode.h | 402 +-----------------------------------------------------
 1 file changed, 5 insertions(+), 397 deletions(-)

(limited to 'include/unicode.h')

diff --git a/include/unicode.h b/include/unicode.h
index d033f63..6102a21 100644
--- a/include/unicode.h
+++ b/include/unicode.h
@@ -1,5 +1,7 @@
 // libunicode
 //
+// Reichwein.IT Unicode Library
+//
 // Author: Roland Reichwein <mail@reichwein.it>
 //
 // Available under the conditions of CC0 1.0 Universal
@@ -10,407 +12,13 @@
 
 #pragma once
 
+#include "unicode/conversion.h"
 #include "unicode/endian.h"
 #include "unicode/iso.h"
+#include "unicode/optimization.h"
 #include "unicode/predicate.h"
 #include "unicode/types.h"
 #include "unicode/type_traits.h"
 #include "unicode/utf.h"
-
-#include <algorithm>
-#include <array>
-#include <cstdint>
-#include <iterator>
-#include <memory>
-#include <stdexcept>
-#include <string>
-#include <type_traits>
-#include <utility>
-
-namespace unicode {
-
- // Helper function: Item distance of specified iterators
- // std::distance doesn't work here: it is based on "output" distance of iterators
- template<class Iterator>
- inline size_t input_distance(const Iterator& it1, const Iterator& it2)
- {
-  return it2 - it1;
- }
- 
- template<class Iterator>
- inline size_t input_distance_bytes(const Iterator& it1, const Iterator& it2)
- {
-  return input_distance(it1, it2) * sizeof(typename Iterator::value_type);
- }
-
- // 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 };
- };
- 
- template<> struct ConvertInputOptimizer<2>
- {
-  static const uint32_t ascii_mask { 0xFF80FF80 };
- };
- 
- template<> struct ConvertInputOptimizer<4>
- {
-  static const uint32_t ascii_mask { 0xFFFFFF80 };
- };
-
- template<int AccuSize, class ConvertInputOptimizer>
- struct ArchitectureOptimizer {};
-
- template<class ConvertInputOptimizer>
- struct ArchitectureOptimizer<4, ConvertInputOptimizer>
- {
-  typedef ConvertInputOptimizer input_optimizer;
-  typedef uint32_t accu_type;
-  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 };
-  
-  template<typename input_value_type, class output_string_type>
-  inline static void append(const input_value_type* addr, output_string_type& s)
-  {
-   if constexpr(sizeof(input_value_type) == sizeof(typename output_string_type::value_type)) {
-    s.append(reinterpret_cast<const typename output_string_type::value_type*>(addr), accu_size / sizeof(input_value_type));
-   } else if constexpr(is_utf_8_v<input_value_type>) {
-    s.append({static_cast<typename output_string_type::value_type>(addr[0]),
-              static_cast<typename output_string_type::value_type>(addr[1]),
-              static_cast<typename output_string_type::value_type>(addr[2]),
-              static_cast<typename output_string_type::value_type>(addr[3])});
-   } else if constexpr(is_utf_16_v<input_value_type>) {
-    s.append({static_cast<typename output_string_type::value_type>(addr[0]),
-              static_cast<typename output_string_type::value_type>(addr[1])});
-   } else if constexpr(is_utf_32_v<input_value_type>) {
-    s.append({static_cast<typename output_string_type::value_type>(addr[0])});
-   }
-  }
- };
-
- template<class ConvertInputOptimizer>
- struct ArchitectureOptimizer<8, ConvertInputOptimizer>
- {
-  typedef ConvertInputOptimizer input_optimizer;
-  typedef uint64_t accu_type;
-  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 };
-  
-  template<typename input_value_type, class output_string_type>
-  inline static void append(const input_value_type* addr, output_string_type& s)
-  {
-   if constexpr(sizeof(input_value_type) == sizeof(typename output_string_type::value_type)) {
-    s.append(reinterpret_cast<const typename output_string_type::value_type*>(addr), accu_size / sizeof(input_value_type));
-   } else if constexpr(is_utf_8_v<input_value_type>) {
-    s.append({static_cast<typename output_string_type::value_type>(addr[0]),
-              static_cast<typename output_string_type::value_type>(addr[1]),
-              static_cast<typename output_string_type::value_type>(addr[2]),
-              static_cast<typename output_string_type::value_type>(addr[3]),
-              static_cast<typename output_string_type::value_type>(addr[4]),
-              static_cast<typename output_string_type::value_type>(addr[5]),
-              static_cast<typename output_string_type::value_type>(addr[6]),
-              static_cast<typename output_string_type::value_type>(addr[7])});
-   } else if constexpr(is_utf_16_v<input_value_type>) {
-    s.append({static_cast<typename output_string_type::value_type>(addr[0]),
-              static_cast<typename output_string_type::value_type>(addr[1]),
-              static_cast<typename output_string_type::value_type>(addr[2]),
-              static_cast<typename output_string_type::value_type>(addr[3])});
-   } else if constexpr(is_utf_32_v<input_value_type>) {
-    s.append({static_cast<typename output_string_type::value_type>(addr[0]),
-              static_cast<typename output_string_type::value_type>(addr[1])});
-   }
-  }
-
- }; // class ArchitectureOptimizer
-
- // Optimize for the case of all ASCII (7-bit) data in a accu size row
- // From and To are Encodings
- template<typename From, typename To, std::enable_if_t<is_encoding_v<From> && is_encoding_v<To>, bool> = true>
- typename To::string_type convert_optimized(const typename From::string_type& s)
- {
-  typename To::string_type result;
-  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_bytes(begin, end) >= accu_size) {
-   if (((uintptr_t)(void*)addr & arch_optimizer::addr_mask) == 0) {
-    while (input_distance_bytes(begin, end) >= accu_size) {
-     typename arch_optimizer::accu_type data{*addr};
-     if ((data & arch_optimizer::ascii_mask) == arch_optimizer::ascii_value)
-#if __cplusplus >= 202002L
-     [[likely]]
-#endif
-     {
-      arch_optimizer::template append(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 and break to trigger unoptimized
-      // version until next accu boundary
-      back_inserter = *begin;
-      ++begin;
-      break;
-     }
-    }
-   }
-
-   // 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) {
-    back_inserter = *begin;
-    ++begin;
-   }
-  }
-
-  // remainder < 8 bytes   
-  while (begin != end) {
-   back_inserter = *begin;
-   ++begin;
-  }
-
-  return result;
- }
-
- template<size_t bits_to_compare = 32, typename To, typename std::enable_if_t<is_utf_8_v<To>, bool> = true>
- inline void append_utf(std::basic_string<To>& result, const char32_t& value)
- {
-  using From = char32_t;
-  if (bits_to_compare <= 7 || value < 0x80) { // 1 byte
-   result.push_back(static_cast<To>(value));
-  } else if (bits_to_compare <= 11 || value < 0x800) { // 2 bytes
-   result.append({utf8_byte_n_of_m<0,2,From,To>(value), utf8_byte_n_of_m<1,2,From,To>(value)});
-  } else if (bits_to_compare <= 16 || value < 0x10000) { // 3 bytes
-   result.append({utf8_byte_n_of_m<0,3,From,To>(value), utf8_byte_n_of_m<1,3,From,To>(value), utf8_byte_n_of_m<2,3,From,To>(value)});
-  } else { // 4 bytes
-   // expect value to be already valid Unicode values
-   result.append({utf8_byte_n_of_m<0,4,From,To>(value), utf8_byte_n_of_m<1,4,From,To>(value), utf8_byte_n_of_m<2,4,From,To>(value), utf8_byte_n_of_m<3,4,From,To>(value)});
-  }
- }
-
- template<size_t bits_to_compare = 32, typename To, typename std::enable_if_t<is_utf_16_v<To>, bool> = true>
- inline void append_utf(std::basic_string<To>& result, const char32_t& value)
- {
-  if (bits_to_compare <= 16 || value <= 0xFFFF) { // expect value to be already valid Unicode values
-   result.push_back(static_cast<To>(value));
-  } else {
-   char32_t value_reduced{value - 0x10000};
-   result.append({static_cast<To>((value_reduced >> 10) + 0xD800), static_cast<To>((value_reduced & 0x3FF) + 0xDC00)});
-  }
- }
-
- template<size_t bits_to_compare = 32, typename To, typename std::enable_if_t<is_utf_32_v<To>, bool> = true>
- inline void append_utf(std::basic_string<To>& result, const char32_t& value)
- {
-  // expect value to be already valid Unicode values (checked in input iterator)
-  result.push_back(static_cast<To>(value));
- }
-
- // Little Endian optimized version for UTF-8
- // In block_mode, at least 4 bytes are in accu. On first call, even 8.
- // otherwise, at least one code unit is in accu
- template<typename From, typename To, bool block_mode = true, typename std::enable_if_t<is_utf_8_v<From>, bool> = true>
- inline static void append_accu(std::basic_string<To>& result, uint64_t& accu, int& bytes_in_accu)
- {
-  if (block_mode && bytes_in_accu == 8 && (accu & 0x8080808080808080) == 0)
-#if __cplusplus >= 202002L
-  [[likely]]
-#endif
-  {
-   result.append({
-                 static_cast<To>(accu & 0x7F),
-                 static_cast<To>((accu >> 8) & 0x7F),
-                 static_cast<To>((accu >> 16) & 0x7F),
-                 static_cast<To>((accu >> 24) & 0x7F),
-                 static_cast<To>((accu >> 32) & 0x7F),
-                 static_cast<To>((accu >> 40) & 0x7F),
-                 static_cast<To>((accu >> 48) & 0x7F),
-                 static_cast<To>((accu >> 56) & 0x7F),
-                 });
-   accu = 0;
-   bytes_in_accu = 0;
-  } else if ((accu & 0x80) == 0) { // 1 byte sequence
-   append_utf<7>(result, static_cast<char32_t>(accu & 0x7F));
-   accu >>= 8;
-   bytes_in_accu -= 1;
-  } else if ((block_mode || bytes_in_accu >= 2) && (accu & 0xC0E0) == 0x80C0) { // 2 byte sequence
-   char32_t value {static_cast<char32_t>(((accu & 0x1F) << 6) | ((accu >> 8) & 0x3f))};
-   accu >>= 16;
-   bytes_in_accu -= 2;
-   if (is_valid_unicode<11>(value))
-    append_utf<11>(result, value);
-   else
-#if __cplusplus >= 202002L
-    [[unlikely]]
-#endif
-    throw std::invalid_argument("Invalid Unicode character in 2 byte UTF-8 sequence");
-  } else if ((block_mode || bytes_in_accu >= 3) && (accu & 0xC0C0F0) == 0x8080E0) { // 3 byte sequence
-   char32_t value {static_cast<char32_t>(((accu & 0x0F) << 12) | ((accu >> 2) & 0x0FC0) | ((accu >> 16) & 0x3f))};
-   accu >>= 24;
-   bytes_in_accu -= 3;
-   if (is_valid_unicode<16>(value))
-    append_utf<16>(result, value);
-   else
-#if __cplusplus >= 202002L
-    [[unlikely]]
-#endif
-    throw std::invalid_argument("Invalid Unicode character in 3 byte UTF-8 sequence");
-  } else if ((block_mode || bytes_in_accu >= 4) && (accu & 0xC0C0C0F8) == 0x808080F0) { // 4 byte sequence
-   char32_t value {static_cast<char32_t>(((accu & 0x07) << 18) | ((accu << 4) & 0x3f000) | ((accu >> 10) & 0xFC0) | ((accu >> 24) & 0x3f))};
-   accu >>= 32;
-   bytes_in_accu -= 4;
-   if (is_valid_unicode<21>(value))
-    append_utf(result, value);
-   else
-#if __cplusplus >= 202002L
-    [[unlikely]]
-#endif
-    throw std::invalid_argument("Invalid Unicode character in 4 byte UTF-8 sequence");
-  } else
-#if __cplusplus >= 202002L
-   [[unlikely]]
-#endif
-   throw std::invalid_argument("Invalid UTF-8 byte sequence");
- }
-
- // Little Endian optimized version
- template<typename From, typename To, std::enable_if_t<is_encoding_v<From> && is_encoding_v<To>, bool> = true>
- typename To::string_type convert_optimized_utf(const typename From::string_type& s)
- {
-  typename To::string_type result;
-  uint64_t accu{};
-  int bytes_in_accu{};
-
-  size_t s_index{};
-  size_t s_size{s.size()};
-  while (s_index + 8 / sizeof(typename From::value_type) <= s_size) {
-   // read input
-   // assume: bytes_in_accu < 8
-   accu |= (*reinterpret_cast<const uint64_t*>(&(s.data()[s_index]))) << (bytes_in_accu * 8);
-   s_index += (8 - bytes_in_accu) / sizeof(typename From::value_type);
-   bytes_in_accu = 8;
-
-   while (bytes_in_accu >= 4) {
-    append_accu<typename From::value_type, typename To::value_type, true>(result, accu, bytes_in_accu);
-   }
-  }
-
-  // 0..3 bytes left in accu
-  // 0..7 bytes left in s
-
-  while (s_index < s_size || bytes_in_accu > 0) {
-   while (s_index < s_size && bytes_in_accu < 8) {
-    accu |= static_cast<uint64_t>(*reinterpret_cast<const uint8_t*>(&(s.data()[s_index]))) << (bytes_in_accu * 8);
-    ++s_index;
-    bytes_in_accu += sizeof(typename From::value_type);
-   }
-
-   append_accu<typename From::value_type, typename To::value_type, false>(result, accu, bytes_in_accu);
-  }
-  return result;
- }
-
- // From and To are Encodings
- template<typename From, typename To, std::enable_if_t<is_encoding_v<From> && is_encoding_v<To>, bool> = true>
- typename To::string_type convert(const typename From::string_type& s)
- {
-  // if input type == output type, only validate and return input, if appropriate
-  if constexpr(sizeof(typename From::value_type) == sizeof(typename To::value_type) &&
-               is_utf_encoding_v<From> && is_utf_encoding_v<To>) {
-   if (validate_utf<typename From::value_type>(s)) {
-    return s;
-   } else {
-    throw std::invalid_argument("Invalid UTF input");
-   }
-  } else if constexpr(accu_size == 8 && is_little_endian() && is_utf_8_v<typename From::value_type> &&
-                      is_utf_encoding_v<From> && is_utf_encoding_v<To>) { // endian specific optimization
-   return convert_optimized_utf<From, To>(s);
-  } else if constexpr(accu_size == 4 || accu_size == 8) { // accu size specific optimization with speedup for 7bit input
-   return convert_optimized<From, To>(s);
-  } else {
-   typename To::string_type result;
-   std::copy(From::begin(s), From::end(s), To::back_inserter(result));
-   return result;
-  }
- }
-
- // From and To are from: utf8_t (i.e. char or char8_t (C++20)), char16_t and char32_t, char, wchar_t, uint8_t, uint16_t, uint32_t
- template<typename From, typename To,
-  typename FromContainer=std::basic_string<From>,
-  typename ToContainer=std::basic_string<To>,
-  std::enable_if_t<is_char_v<From> && is_char_v<To>, bool> = true>
- ToContainer convert(const FromContainer& s)
- {
-  typedef UTF<utf_iterator<From>, utf_back_insert_iterator<To>> UTF_Trait;
-
-  ToContainer result;
-
-  std::copy(UTF_Trait::begin(s), UTF_Trait::end(s), UTF_Trait::back_inserter(result));
-
-  return result;
- }
-
- // From and To are containers
- template<typename FromContainer, typename ToContainer,
-  std::enable_if_t<is_container_v<FromContainer> && is_container_v<ToContainer>, bool> = true
- >
- ToContainer convert(const FromContainer& s)
- {
-  typedef UTF<utf_iterator<typename FromContainer::value_type, FromContainer>, utf_back_insert_iterator<typename ToContainer::value_type, ToContainer>> UTF_Trait;
-  
-  ToContainer result;
-
-  std::copy(UTF_Trait::begin(s), UTF_Trait::end(s), UTF_Trait::back_inserter(result));
-
-  return result;
- }
-
- // Container version
- template<typename Container, std::enable_if_t<is_container_v<Container>, bool> = true>
- bool is_valid_utf(const Container& s)
- {
-  typedef UTF<utf_iterator<typename Container::value_type, Container>, utf_back_insert_iterator<typename Container::value_type, Container>> UTF_Trait;
-  
-  try {
-   std::for_each(UTF_Trait::begin(s), UTF_Trait::end(s), [](const char32_t& c){});
-  } catch (const std::invalid_argument&) {
-   return false;
-  }
-  return true;
- }
-
- // basic type version
- template<typename T,
-  typename Container=std::basic_string<T>,
-  std::enable_if_t<is_char_v<T>, bool> = true>
- bool is_valid_utf(const Container& s)
- {
-  typedef UTF<utf_iterator<T>, utf_back_insert_iterator<T>> UTF_Trait;
-  
-  try {
-   std::for_each(UTF_Trait::begin(s), UTF_Trait::end(s), [](const char32_t& c){});
-  } catch (const std::invalid_argument&) {
-   return false;
-  }
-  return true;
- }
-
- // Encoding version
- template<typename Encoding, std::enable_if_t<is_encoding_v<Encoding>, bool> = true>
- bool is_valid_utf(const typename Encoding::string_type& s)
- {
-  return validate_utf<typename Encoding::value_type>(s);
- }
-
-} // namespace unicode
+#include "unicode/validation.h"
 
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