The Tor Browser / file revision

 /*  GRAPHITE2 LICENSING

     Copyright 2011, SIL International

     All rights reserved.

     This library is free software; you can redistribute it and/or modify

     it under the terms of the GNU Lesser General Public License as published

     by the Free Software Foundation; either version 2.1 of License, or

     (at your option) any later version.

     This program is distributed in the hope that it will be useful,

     but WITHOUT ANY WARRANTY; without even the implied warranty of

     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

     Lesser General Public License for more details.

     You should also have received a copy of the GNU Lesser General Public

     License along with this library in the file named "LICENSE".

     If not, write to the Free Software Foundation, 51 Franklin Street,

     Suite 500, Boston, MA 02110-1335, USA or visit their web page on the

     internet at http://www.fsf.org/licenses/lgpl.html.

 Alternatively, the contents of this file may be used under the terms of the

 Mozilla Public License (http://mozilla.org/MPL) or the GNU General Public

 License, as published by the Free Software Foundation, either version 2

 of the License or (at your option) any later version.

 */

 #pragma once

 #include <cstdlib>

 #include "inc/Main.h"

 namespace graphite2 {

 typedef uint32  uchar_t;

 template <int N>

 struct _utf_codec

 {

     typedef uchar_t codeunit_t;

     static void     put(codeunit_t * cp, const uchar_t , int8 & len) throw();

     static uchar_t  get(const codeunit_t * cp, int8 & len) throw();

 };

 template <>

 struct _utf_codec<32>

 {

 private:

     static const uchar_t    limit = 0x110000;

 public:

     typedef uint32  codeunit_t;

     inline

     static void put(codeunit_t * cp, const uchar_t usv, int8 & l) throw()

     {

         *cp = usv; l = 1;

     }

     inline

     static uchar_t get(const codeunit_t * cp, int8 & l) throw()

     {

         if (cp[0] < limit)  { l = 1;  return cp[0]; }

         else                { l = -1; return 0xFFFD; }

     }

 };

 template <>

 struct _utf_codec<16>

 {

 private:

     static const int32  lead_offset      = 0xD800 - (0x10000 >> 10);

     static const int32  surrogate_offset = 0x10000 - (0xD800 << 10) - 0xDC00;

 public:

     typedef uint16  codeunit_t;

     inline

     static void put(codeunit_t * cp, const uchar_t usv, int8 & l) throw()

     {

         if (usv < 0x10000)  { l = 1; cp[0] = codeunit_t(usv); }

         else

         {

             cp[0] = codeunit_t(lead_offset + (usv >> 10));

             cp[1] = codeunit_t(0xDC00 + (usv & 0x3FF));

             l = 2;

         }

     }

     inline

     static uchar_t get(const codeunit_t * cp, int8 & l) throw()

     {

         const uint32    uh = cp[0];

         l = 1;

         if (0xD800 > uh || uh > 0xDFFF) { return uh; }

         const uint32 ul = cp[1];

         if (uh > 0xDBFF || 0xDC00 > ul || ul > 0xDFFF) { l = -1; return 0xFFFD; }

         ++l;

         return (uh<<10) + ul + surrogate_offset;

     }

 };

 template <>

 struct _utf_codec<8>

 {

 private:

     static const int8 sz_lut[16];

     static const byte mask_lut[5];

 public:

     typedef uint8   codeunit_t;

     inline

     static void put(codeunit_t * cp, const uchar_t usv, int8 & l) throw()

     {

         if (usv < 0x80)     {l = 1; cp[0] = usv; return; }

         if (usv < 0x0800)   {l = 2; cp[0] = 0xC0 + (usv >> 6);  cp[1] = 0x80 + (usv & 0x3F); return; }

         if (usv < 0x10000)  {l = 3; cp[0] = 0xE0 + (usv >> 12); cp[1] = 0x80 + ((usv >> 6) & 0x3F);  cp[2] = 0x80 + (usv & 0x3F); return; }

         else                {l = 4; cp[0] = 0xF0 + (usv >> 18); cp[1] = 0x80 + ((usv >> 12) & 0x3F); cp[2] = 0x80 + ((usv >> 6) & 0x3F); cp[3] = 0x80 + (usv & 0x3F); return; }

     }

     inline

     static uchar_t get(const codeunit_t * cp, int8 & l) throw()

     {

         const int8 seq_sz = sz_lut[*cp >> 4];

         uchar_t u = *cp & mask_lut[seq_sz];

         l = 1;

         bool toolong = false;

         switch(seq_sz) {

             case 4:     u <<= 6; u |= *++cp & 0x3F; if (*cp >> 6 != 2) break; ++l; toolong  = (u < 0x10); // no break

             case 3:     u <<= 6; u |= *++cp & 0x3F; if (*cp >> 6 != 2) break; ++l; toolong |= (u < 0x20); // no break

             case 2:     u <<= 6; u |= *++cp & 0x3F; if (*cp >> 6 != 2) break; ++l; toolong |= (u < 0x80); // no break

             case 1:     break;

             case 0:     l = -1; return 0xFFFD;

         }

         if (l != seq_sz || toolong)

         {

             l = -l;

             return 0xFFFD;

         }

         return u;

     }

 };

 template <typename C>

 class _utf_iterator

 {

     typedef _utf_codec<sizeof(C)*8> codec;

     C             * cp;

     mutable int8    sl;

 public:

     typedef C           codeunit_type;

     typedef uchar_t     value_type;

     typedef uchar_t   * pointer;

     class reference

     {

         const _utf_iterator & _i;

         reference(const _utf_iterator & i): _i(i) {}

     public:

         operator value_type () const throw ()                   { return codec::get(_i.cp, _i.sl); }

         reference & operator = (const value_type usv) throw()   { codec::put(_i.cp, usv, _i.sl); return *this; }

         friend class _utf_iterator;

     };

     _utf_iterator(const void * us=0)    : cp(reinterpret_cast<C *>(const_cast<void *>(us))), sl(1) { }

     _utf_iterator   & operator ++ ()    { cp += abs(sl); return *this; }

     _utf_iterator   operator ++ (int)   { _utf_iterator tmp(*this); operator++(); return tmp; }

     bool operator == (const _utf_iterator & rhs) const throw() { return cp >= rhs.cp; }

     bool operator != (const _utf_iterator & rhs) const throw() { return !operator==(rhs); }

     reference   operator * () const throw() { return *this; }

     pointer     operator ->() const throw() { return &operator *(); }

     operator codeunit_type * () const throw() { return cp; }

     bool error() const throw()  { return sl < 1; }

 };

 template <typename C>

 struct utf

 {

     typedef typename _utf_codec<sizeof(C)*8>::codeunit_t codeunit_t;

     typedef _utf_iterator<C>        iterator;

     typedef _utf_iterator<const C>  const_iterator;

 };

 typedef utf<uint32> utf32;

 typedef utf<uint16> utf16;

 typedef utf<uint8>  utf8;

 } // namespace graphite2