upgrade utfcpp to v2.3.5

From https://github.com/nemtrif/utfcpp/releases/tag/v2.3.5

* utf8/utf8.h, utf8/utf8/checked.h, utf8/utf8/core.h,
utf8/utf8/unchecked.h: Update.
* utf8/doc/utf8cpp.html, utf8/doc/ReleaseNotes: Delete.
* utf8/README.md: New file.
* Makefile.am: Adjust.

Makefile.am

 ## -*- coding: utf-8 -*-
-## Copyright (C) 2011, 2012, 2013, 2014, 2015, 2016 Laboratoire de
-## Recherche et Développement de l'Epita (LRDE).
+## Copyright (C) 2011-2017 Laboratoire de Recherche et Développement
+## de l'Epita (LRDE).
 ## Copyright (C) 2003, 2005  Laboratoire d'Informatique de Paris 6 (LIP6),
 ## département Systèmes Répartis Coopératifs (SRC), Université Pierre
 ## et Marie Curie.
@@ -35,7 +35,7 @@ endif
 SUBDIRS = picosat buddy lib ltdl spot bin tests $(PYTHON_SUBDIR) doc \
 					$(NEVER_SUBDIRS)
 
-UTF8 = utf8/doc/ReleaseNotes utf8/doc/utf8cpp.html utf8/utf8.h	\
+UTF8 = utf8/README.md utf8/utf8.h	\
   utf8/utf8/checked.h utf8/utf8/core.h utf8/utf8/unchecked.h
 
 DEBIAN =					\

utf8/doc/ReleaseNotes

-utf8 cpp library
-Release 2.3.1
-
-A bug fix release. Special thanks to dalle and Ivan Sorokin who reported the bugs.
-
-Changes from version 2.3
-- Bug fix [3025042]: is_bom documentation issue.
-- Bug fix [3083640]: is_code_point_valid incorrectly returns false.
-- Bug fix [3167987]: prior moves it before start.
-- Bug fix [3185087]: utf8::prior and utf8::previous documentation issue.
-
-Files included in the release: utf8.h, core.h, checked.h, unchecked.h, utf8cpp.html, ReleaseNotes

utf8/utf8.h

-// Copyright 2006 Nemanja Trifunovic
-
-/*
-Permission is hereby granted, free of charge, to any person or organization
-obtaining a copy of the software and accompanying documentation covered by
-this license (the "Software") to use, reproduce, display, distribute,
-execute, and transmit the Software, and to prepare derivative works of the
-Software, and to permit third-parties to whom the Software is furnished to
-do so, all subject to the following:
-
-The copyright notices in the Software and this entire statement, including
-the above license grant, this restriction and the following disclaimer,
-must be included in all copies of the Software, in whole or in part, and
-all derivative works of the Software, unless such copies or derivative
-works are solely in the form of machine-executable object code generated by
-a source language processor.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
-SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
-FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
-ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-DEALINGS IN THE SOFTWARE.
-*/
-
-
-#ifndef UTF8_FOR_CPP_2675DCD0_9480_4c0c_B92A_CC14C027B731
-#define UTF8_FOR_CPP_2675DCD0_9480_4c0c_B92A_CC14C027B731
-
-#include "utf8/checked.h"
-#include "utf8/unchecked.h"
-
-#endif // header guard
+// Copyright 2006 Nemanja Trifunovic
+
+/*
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+*/
+
+
+#ifndef UTF8_FOR_CPP_2675DCD0_9480_4c0c_B92A_CC14C027B731
+#define UTF8_FOR_CPP_2675DCD0_9480_4c0c_B92A_CC14C027B731
+
+#include "utf8/checked.h"
+#include "utf8/unchecked.h"
+
+#endif // header guard

utf8/utf8/checked.h

-// Copyright 2006 Nemanja Trifunovic
+// Copyright 2006-2016 Nemanja Trifunovic
 
 /*
 Permission is hereby granted, free of charge, to any person or organization
@@ -34,14 +34,14 @@ DEALINGS IN THE SOFTWARE.
 namespace utf8
 {
     // Base for the exceptions that may be thrown from the library
-    class exception : public std::exception {
+    class exception : public ::std::exception {
     };
 
     // Exceptions that may be thrown from the library functions.
     class invalid_code_point : public exception {
         uint32_t cp;
     public:
-        invalid_code_point(uint32_t cp) : cp(cp) {}
+        invalid_code_point(uint32_t codepoint) : cp(codepoint) {}
         virtual const char* what() const throw() { return "Invalid code point"; }
         uint32_t code_point() const {return cp;}
     };
@@ -69,12 +69,38 @@ namespace utf8
 
     /// The library API - functions intended to be called by the users
 
+    template <typename octet_iterator>
+    octet_iterator append(uint32_t cp, octet_iterator result)
+    {
+        if (!utf8::internal::is_code_point_valid(cp))
+            throw invalid_code_point(cp);
+
+        if (cp < 0x80)                        // one octet
+            *(result++) = static_cast<uint8_t>(cp);
+        else if (cp < 0x800) {                // two octets
+            *(result++) = static_cast<uint8_t>((cp >> 6)            | 0xc0);
+            *(result++) = static_cast<uint8_t>((cp & 0x3f)          | 0x80);
+        }
+        else if (cp < 0x10000) {              // three octets
+            *(result++) = static_cast<uint8_t>((cp >> 12)           | 0xe0);
+            *(result++) = static_cast<uint8_t>(((cp >> 6) & 0x3f)   | 0x80);
+            *(result++) = static_cast<uint8_t>((cp & 0x3f)          | 0x80);
+        }
+        else {                                // four octets
+            *(result++) = static_cast<uint8_t>((cp >> 18)           | 0xf0);
+            *(result++) = static_cast<uint8_t>(((cp >> 12) & 0x3f)  | 0x80);
+            *(result++) = static_cast<uint8_t>(((cp >> 6) & 0x3f)   | 0x80);
+            *(result++) = static_cast<uint8_t>((cp & 0x3f)          | 0x80);
+        }
+        return result;
+    }
+
     template <typename octet_iterator, typename output_iterator>
     output_iterator replace_invalid(octet_iterator start, octet_iterator end, output_iterator out, uint32_t replacement)
     {
         while (start != end) {
             octet_iterator sequence_start = start;
-            internal::utf_error err_code = internal::validate_next(start, end);
+            internal::utf_error err_code = utf8::internal::validate_next(start, end);
             switch (err_code) {
                 case internal::UTF8_OK :
                     for (octet_iterator it = sequence_start; it != start; ++it)
@@ -83,16 +109,16 @@ namespace utf8
                 case internal::NOT_ENOUGH_ROOM:
                     throw not_enough_room();
                 case internal::INVALID_LEAD:
-                    append (replacement, out);
+                    out = utf8::append (replacement, out);
                     ++start;
                     break;
                 case internal::INCOMPLETE_SEQUENCE:
                 case internal::OVERLONG_SEQUENCE:
                 case internal::INVALID_CODE_POINT:
-                    append (replacement, out);
+                    out = utf8::append (replacement, out);
                     ++start;
                     // just one replacement mark for the sequence
-                    while (internal::is_trail(*start) && start != end)
+                    while (start != end && utf8::internal::is_trail(*start))
                         ++start;
                     break;
             }
@@ -103,41 +129,15 @@ namespace utf8
     template <typename octet_iterator, typename output_iterator>
     inline output_iterator replace_invalid(octet_iterator start, octet_iterator end, output_iterator out)
     {
-        static const uint32_t replacement_marker = internal::mask16(0xfffd);
-        return replace_invalid(start, end, out, replacement_marker);
-    }
-
-    template <typename octet_iterator>
-    octet_iterator append(uint32_t cp, octet_iterator result)
-    {
-        if (!internal::is_code_point_valid(cp))
-            throw invalid_code_point(cp);
-
-        if (cp < 0x80)                        // one octet
-            *(result++) = static_cast<uint8_t>(cp);
-        else if (cp < 0x800) {                // two octets
-            *(result++) = static_cast<uint8_t>((cp >> 6)            | 0xc0);
-            *(result++) = static_cast<uint8_t>((cp & 0x3f)          | 0x80);
-        }
-        else if (cp < 0x10000) {              // three octets
-            *(result++) = static_cast<uint8_t>((cp >> 12)           | 0xe0);
-            *(result++) = static_cast<uint8_t>(((cp >> 6) & 0x3f)   | 0x80);
-            *(result++) = static_cast<uint8_t>((cp & 0x3f)          | 0x80);
-        }
-        else {      // four octets
-            *(result++) = static_cast<uint8_t>((cp >> 18)           | 0xf0);
-            *(result++) = static_cast<uint8_t>(((cp >> 12) & 0x3f)  | 0x80);
-            *(result++) = static_cast<uint8_t>(((cp >> 6) & 0x3f)   | 0x80);
-            *(result++) = static_cast<uint8_t>((cp & 0x3f)          | 0x80);
-        }
-        return result;
+        static const uint32_t replacement_marker = utf8::internal::mask16(0xfffd);
+        return utf8::replace_invalid(start, end, out, replacement_marker);
     }
 
     template <typename octet_iterator>
     uint32_t next(octet_iterator& it, octet_iterator end)
     {
         uint32_t cp = 0;
-        internal::utf_error err_code = internal::validate_next(it, end, &cp);
+        internal::utf_error err_code = utf8::internal::validate_next(it, end, cp);
         switch (err_code) {
             case internal::UTF8_OK :
                 break;
@@ -156,22 +156,22 @@ namespace utf8
     template <typename octet_iterator>
     uint32_t peek_next(octet_iterator it, octet_iterator end)
     {
-        return next(it, end);
+        return utf8::next(it, end);
     }
 
     template <typename octet_iterator>
     uint32_t prior(octet_iterator& it, octet_iterator start)
-    {
+    {
         // can't do much if it == start
-        if (it == start)
+        if (it == start)
             throw not_enough_room();
 
-        octet_iterator end = it;
+        octet_iterator end = it;
         // Go back until we hit either a lead octet or start
-        while (internal::is_trail(*(--it)))
+        while (utf8::internal::is_trail(*(--it)))
             if (it == start)
                 throw invalid_utf8(*it); // error - no lead byte in the sequence
-        return peek_next(it, end);
+        return utf8::peek_next(it, end);
     }
 
     /// Deprecated in versions that include "prior"
@@ -179,18 +179,18 @@ namespace utf8
     uint32_t previous(octet_iterator& it, octet_iterator pass_start)
     {
         octet_iterator end = it;
-        while (internal::is_trail(*(--it)))
+        while (utf8::internal::is_trail(*(--it)))
             if (it == pass_start)
                 throw invalid_utf8(*it); // error - no lead byte in the sequence
         octet_iterator temp = it;
-        return next(temp, end);
+        return utf8::next(temp, end);
     }
 
     template <typename octet_iterator, typename distance_type>
     void advance (octet_iterator& it, distance_type n, octet_iterator end)
     {
         for (distance_type i = 0; i < n; ++i)
-            next(it, end);
+            utf8::next(it, end);
     }
 
     template <typename octet_iterator>
@@ -199,7 +199,7 @@ namespace utf8
     {
         typename std::iterator_traits<octet_iterator>::difference_type dist;
         for (dist = 0; first < last; ++dist)
-            next(first, last);
+            utf8::next(first, last);
         return dist;
     }
 
@@ -207,12 +207,12 @@ namespace utf8
     octet_iterator utf16to8 (u16bit_iterator start, u16bit_iterator end, octet_iterator result)
     {
         while (start != end) {
-            uint32_t cp = internal::mask16(*start++);
+            uint32_t cp = utf8::internal::mask16(*start++);
             // Take care of surrogate pairs first
-            if (internal::is_lead_surrogate(cp)) {
+            if (utf8::internal::is_lead_surrogate(cp)) {
                 if (start != end) {
-                    uint32_t trail_surrogate = internal::mask16(*start++);
-                    if (internal::is_trail_surrogate(trail_surrogate))
+                    uint32_t trail_surrogate = utf8::internal::mask16(*start++);
+                    if (utf8::internal::is_trail_surrogate(trail_surrogate))
                         cp = (cp << 10) + trail_surrogate + internal::SURROGATE_OFFSET;
                     else
                         throw invalid_utf16(static_cast<uint16_t>(trail_surrogate));
@@ -222,10 +222,10 @@ namespace utf8
 
             }
             // Lone trail surrogate
-            else if (internal::is_trail_surrogate(cp))
+            else if (utf8::internal::is_trail_surrogate(cp))
                 throw invalid_utf16(static_cast<uint16_t>(cp));
 
-            result = append(cp, result);
+            result = utf8::append(cp, result);
         }
         return result;
     }
@@ -233,8 +233,8 @@ namespace utf8
     template <typename u16bit_iterator, typename octet_iterator>
     u16bit_iterator utf8to16 (octet_iterator start, octet_iterator end, u16bit_iterator result)
     {
-        while (start != end) {
-            uint32_t cp = next(start, end);
+        while (start < end) {
+            uint32_t cp = utf8::next(start, end);
             if (cp > 0xffff) { //make a surrogate pair
                 *result++ = static_cast<uint16_t>((cp >> 10)   + internal::LEAD_OFFSET);
                 *result++ = static_cast<uint16_t>((cp & 0x3ff) + internal::TRAIL_SURROGATE_MIN);
@@ -249,7 +249,7 @@ namespace utf8
     octet_iterator utf32to8 (u32bit_iterator start, u32bit_iterator end, octet_iterator result)
     {
         while (start != end)
-            result = append(*(start++), result);
+            result = utf8::append(*(start++), result);
 
         return result;
     }
@@ -257,8 +257,8 @@ namespace utf8
     template <typename octet_iterator, typename u32bit_iterator>
     u32bit_iterator utf8to32 (octet_iterator start, octet_iterator end, u32bit_iterator result)
     {
-        while (start != end)
-            (*result++) = next(start, end);
+        while (start < end)
+            (*result++) = utf8::next(start, end);
 
         return result;
     }
@@ -270,11 +270,11 @@ namespace utf8
       octet_iterator range_start;
       octet_iterator range_end;
       public:
-      iterator () {};
+      iterator () {}
       explicit iterator (const octet_iterator& octet_it,
-                         const octet_iterator& range_start,
-                         const octet_iterator& range_end) :
-               it(octet_it), range_start(range_start), range_end(range_end)
+                         const octet_iterator& rangestart,
+                         const octet_iterator& rangeend) :
+               it(octet_it), range_start(rangestart), range_end(rangeend)
       {
           if (it < range_start || it > range_end)
               throw std::out_of_range("Invalid utf-8 iterator position");
@@ -284,7 +284,7 @@ namespace utf8
       uint32_t operator * () const
       {
           octet_iterator temp = it;
-          return next(temp, range_end);
+          return utf8::next(temp, range_end);
       }
       bool operator == (const iterator& rhs) const
       {
@@ -298,24 +298,24 @@ namespace utf8
       }
       iterator& operator ++ ()
       {
-          next(it, range_end);
+          utf8::next(it, range_end);
           return *this;
       }
       iterator operator ++ (int)
       {
           iterator temp = *this;
-          next(it, range_end);
+          utf8::next(it, range_end);
           return temp;
       }
       iterator& operator -- ()
       {
-          prior(it, range_start);
+          utf8::prior(it, range_start);
           return *this;
       }
       iterator operator -- (int)
       {
           iterator temp = *this;
-          prior(it, range_start);
+          utf8::prior(it, range_start);
           return temp;
       }
     }; // class iterator

utf8/utf8/core.h

@@ -68,7 +68,7 @@ namespace internal
     template<typename octet_type>
     inline bool is_trail(octet_type oc)
     {
-        return ((mask8(oc) >> 6) == 0x2);
+        return ((utf8::internal::mask8(oc) >> 6) == 0x2);
     }
 
     template <typename u16>
@@ -92,14 +92,14 @@ namespace internal
     template <typename u32>
     inline bool is_code_point_valid(u32 cp)
     {
-        return (cp <= CODE_POINT_MAX && !is_surrogate(cp));
+        return (cp <= CODE_POINT_MAX && !utf8::internal::is_surrogate(cp));
     }
 
     template <typename octet_iterator>
     inline typename std::iterator_traits<octet_iterator>::difference_type
     sequence_length(octet_iterator lead_it)
     {
-        uint8_t lead = mask8(*lead_it);
+        uint8_t lead = utf8::internal::mask8(*lead_it);
         if (lead < 0x80)
             return 1;
         else if ((lead >> 5) == 0x6)
@@ -116,15 +116,15 @@ namespace internal
     inline bool is_overlong_sequence(uint32_t cp, octet_difference_type length)
     {
         if (cp < 0x80) {
-            if (length != 1)
+            if (length != 1) 
                 return true;
         }
         else if (cp < 0x800) {
-            if (length != 2)
+            if (length != 2) 
                 return true;
         }
         else if (cp < 0x10000) {
-            if (length != 3)
+            if (length != 3) 
                 return true;
         }
 
@@ -133,124 +133,98 @@ namespace internal
 
     enum utf_error {UTF8_OK, NOT_ENOUGH_ROOM, INVALID_LEAD, INCOMPLETE_SEQUENCE, OVERLONG_SEQUENCE, INVALID_CODE_POINT};
 
-    /// get_sequence_x functions decode utf-8 sequences of the length x
+    /// Helper for get_sequence_x
+    template <typename octet_iterator>
+    utf_error increase_safely(octet_iterator& it, octet_iterator end)
+    {
+        if (++it == end)
+            return NOT_ENOUGH_ROOM;
+
+        if (!utf8::internal::is_trail(*it))
+            return INCOMPLETE_SEQUENCE;
+        
+        return UTF8_OK;
+    }
 
+    #define UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(IT, END) {utf_error ret = increase_safely(IT, END); if (ret != UTF8_OK) return ret;}    
+
+    /// get_sequence_x functions decode utf-8 sequences of the length x
     template <typename octet_iterator>
-    utf_error get_sequence_1(octet_iterator& it, octet_iterator end, uint32_t* code_point)
+    utf_error get_sequence_1(octet_iterator& it, octet_iterator end, uint32_t& code_point)
     {
-        if (it != end) {
-            if (code_point)
-                *code_point = mask8(*it);
-            return UTF8_OK;
-        }
-        return NOT_ENOUGH_ROOM;
+        if (it == end)
+            return NOT_ENOUGH_ROOM;
+
+        code_point = utf8::internal::mask8(*it);
+
+        return UTF8_OK;
     }
 
     template <typename octet_iterator>
-    utf_error get_sequence_2(octet_iterator& it, octet_iterator end, uint32_t* code_point)
+    utf_error get_sequence_2(octet_iterator& it, octet_iterator end, uint32_t& code_point)
     {
-        utf_error ret_code = NOT_ENOUGH_ROOM;
+        if (it == end) 
+            return NOT_ENOUGH_ROOM;
+        
+        code_point = utf8::internal::mask8(*it);
 
-        if (it != end) {
-            uint32_t cp = mask8(*it);
-            if (++it != end) {
-                if (is_trail(*it)) {
-                    cp = ((cp << 6) & 0x7ff) + ((*it) & 0x3f);
+        UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
 
-                    if (code_point)
-                        *code_point = cp;
-                    ret_code = UTF8_OK;
-                }
-                else
-                    ret_code = INCOMPLETE_SEQUENCE;
-            }
-            else
-                ret_code = NOT_ENOUGH_ROOM;
-        }
+        code_point = ((code_point << 6) & 0x7ff) + ((*it) & 0x3f);
 
-        return ret_code;
+        return UTF8_OK;
     }
 
     template <typename octet_iterator>
-    utf_error get_sequence_3(octet_iterator& it, octet_iterator end, uint32_t* code_point)
+    utf_error get_sequence_3(octet_iterator& it, octet_iterator end, uint32_t& code_point)
     {
-        utf_error ret_code = NOT_ENOUGH_ROOM;
-
-        if (it != end) {
-            uint32_t cp = mask8(*it);
-            if (++it != end) {
-                if (is_trail(*it)) {
-                    cp = ((cp << 12) & 0xffff) + ((mask8(*it) << 6) & 0xfff);
-                    if (++it != end) {
-                        if (is_trail(*it)) {
-                            cp += (*it) & 0x3f;
-
-                            if (code_point)
-                                *code_point = cp;
-                            ret_code = UTF8_OK;
-                        }
-                        else
-                            ret_code = INCOMPLETE_SEQUENCE;
-                    }
-                    else
-                        ret_code = NOT_ENOUGH_ROOM;
-                }
-                else
-                    ret_code = INCOMPLETE_SEQUENCE;
-            }
-            else
-                ret_code = NOT_ENOUGH_ROOM;
-        }
+        if (it == end)
+            return NOT_ENOUGH_ROOM;
+            
+        code_point = utf8::internal::mask8(*it);
+
+        UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
 
-        return ret_code;
+        code_point = ((code_point << 12) & 0xffff) + ((utf8::internal::mask8(*it) << 6) & 0xfff);
+
+        UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
+
+        code_point += (*it) & 0x3f;
+
+        return UTF8_OK;
     }
 
     template <typename octet_iterator>
-    utf_error get_sequence_4(octet_iterator& it, octet_iterator end, uint32_t* code_point)
+    utf_error get_sequence_4(octet_iterator& it, octet_iterator end, uint32_t& code_point)
     {
-        utf_error ret_code = NOT_ENOUGH_ROOM;
-
-        if (it != end) {
-            uint32_t cp = mask8(*it);
-            if (++it != end) {
-                if (is_trail(*it)) {
-                    cp = ((cp << 18) & 0x1fffff) + ((mask8(*it) << 12) & 0x3ffff);
-                    if (++it != end) {
-                        if (is_trail(*it)) {
-                            cp += (mask8(*it) << 6) & 0xfff;
-                            if (++it != end) {
-                                if (is_trail(*it)) {
-                                    cp += (*it) & 0x3f;
-
-                                    if (code_point)
-                                        *code_point = cp;
-                                    ret_code = UTF8_OK;
-                                }
-                                else
-                                    ret_code = INCOMPLETE_SEQUENCE;
-                            }
-                            else
-                                ret_code = NOT_ENOUGH_ROOM;
-                        }
-                        else
-                            ret_code = INCOMPLETE_SEQUENCE;
-                    }
-                    else
-                        ret_code = NOT_ENOUGH_ROOM;
-                }
-                else
-                    ret_code = INCOMPLETE_SEQUENCE;
-            }
-            else
-                ret_code = NOT_ENOUGH_ROOM;
-        }
+        if (it == end)
+           return NOT_ENOUGH_ROOM;
+
+        code_point = utf8::internal::mask8(*it);
+
+        UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
+
+        code_point = ((code_point << 18) & 0x1fffff) + ((utf8::internal::mask8(*it) << 12) & 0x3ffff);
 
-        return ret_code;
+        UTF8_CPP_INCREASE_AND_RETURN_ON_ERROR(it, end)
+
+        code_point += (utf8::internal::mask8(*it) << 6) & 0xfff;