The Tor Browser: xpcom/string/public/nsCharTraits.h@b8a032363ba2 (annotated)

xpcom/string/public/nsCharTraits.h@b8a032363ba2 (annotated)

xpcom/string/public/nsCharTraits.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef nsCharTraits_h___
 #define nsCharTraits_h___
 #include <ctype.h> // for |EOF|, |WEOF|
 #include <string.h> // for |memcpy|, et al
 #include "nscore.h" // for |char16_t|
 // This file may be used (through nsUTF8Utils.h) from non-XPCOM code, in
 // particular the standalone software updater. In that case stub out
 // the macros provided by nsDebug.h which are only usable when linking XPCOM
 #ifdef NS_NO_XPCOM
 #define NS_WARNING(msg)
 #define NS_ASSERTION(cond, msg)
 #define NS_ERROR(msg)
 #else
 #include "nsDebug.h"  // for NS_ASSERTION
 #endif
 /*
  * Some macros for converting char16_t (UTF-16) to and from Unicode scalar
  * values.
  *
  * Note that UTF-16 represents all Unicode scalar values up to U+10FFFF by
  * using "surrogate pairs". These consist of a high surrogate, i.e. a code
  * point in the range U+D800 - U+DBFF, and a low surrogate, i.e. a code point
  * in the range U+DC00 - U+DFFF, like this:
  *
  *  U+D800 U+DC00 =  U+10000
  *  U+D800 U+DC01 =  U+10001
  *  ...
  *  U+DBFF U+DFFE = U+10FFFE
  *  U+DBFF U+DFFF = U+10FFFF
  *
  * These surrogate code points U+D800 - U+DFFF are not themselves valid Unicode
  * scalar values and are not well-formed UTF-16 except as high-surrogate /
  * low-surrogate pairs.
  */
 #define PLANE1_BASE          uint32_t(0x00010000)
 // High surrogates are in the range 0xD800 -- OxDBFF
 #define NS_IS_HIGH_SURROGATE(u) ((uint32_t(u) & 0xFFFFFC00) == 0xD800)
 // Low surrogates are in the range 0xDC00 -- 0xDFFF
 #define NS_IS_LOW_SURROGATE(u)  ((uint32_t(u) & 0xFFFFFC00) == 0xDC00)
 // Faster than testing NS_IS_HIGH_SURROGATE || NS_IS_LOW_SURROGATE
 #define IS_SURROGATE(u)      ((uint32_t(u) & 0xFFFFF800) == 0xD800)
 // Everything else is not a surrogate: 0x000 -- 0xD7FF, 0xE000 -- 0xFFFF
 // N = (H - 0xD800) * 0x400 + 0x10000 + (L - 0xDC00)
 // I wonder whether we could somehow assert that H is a high surrogate
 // and L is a low surrogate
 #define SURROGATE_TO_UCS4(h, l) (((uint32_t(h) & 0x03FF) << 10) + \
                                  (uint32_t(l) & 0x03FF) + PLANE1_BASE)
 // Extract surrogates from a UCS4 char
 // Reference: the Unicode standard 4.0, section 3.9
 // Since (c - 0x10000) >> 10 == (c >> 10) - 0x0080 and
 // 0xD7C0 == 0xD800 - 0x0080,
 // ((c - 0x10000) >> 10) + 0xD800 can be simplified to
 #define H_SURROGATE(c) char16_t(char16_t(uint32_t(c) >> 10) + \
                                  char16_t(0xD7C0))
 // where it's to be noted that 0xD7C0 is not bitwise-OR'd
 // but added.
 // Since 0x10000 & 0x03FF == 0,
 // (c - 0x10000) & 0x03FF == c & 0x03FF so that
 // ((c - 0x10000) & 0x03FF) | 0xDC00 is equivalent to
 #define L_SURROGATE(c) char16_t(char16_t(uint32_t(c) & uint32_t(0x03FF)) | \
                                  char16_t(0xDC00))
 #define IS_IN_BMP(ucs) (uint32_t(ucs) < PLANE1_BASE)
 #define UCS2_REPLACEMENT_CHAR char16_t(0xFFFD)
 #define UCS_END uint32_t(0x00110000)
 #define IS_VALID_CHAR(c) ((uint32_t(c) < UCS_END) && !IS_SURROGATE(c))
 #define ENSURE_VALID_CHAR(c) (IS_VALID_CHAR(c) ? (c) : UCS2_REPLACEMENT_CHAR)
 template <class CharT> struct nsCharTraits {};
 template <>
 struct nsCharTraits<char16_t>
   {
     typedef char16_t char_type;
     typedef uint16_t  unsigned_char_type;
     typedef char      incompatible_char_type;
     static char_type* const sEmptyBuffer;
     static
     void
     assign( char_type& lhs, char_type rhs )
       {
         lhs = rhs;
       }
       // integer representation of characters:
     typedef int int_type;
     static
     char_type
     to_char_type( int_type c )
       {
         return char_type(c);
       }
     static
     int_type
     to_int_type( char_type c )
       {
         return int_type( static_cast<unsigned_char_type>(c) );
       }
     static
     bool
     eq_int_type( int_type lhs, int_type rhs )
       {
         return lhs == rhs;
       }
       // |char_type| comparisons:
     static
     bool
     eq( char_type lhs, char_type rhs )
       {
         return lhs == rhs;
       }
     static
     bool
     lt( char_type lhs, char_type rhs )
       {
         return lhs < rhs;
       }
       // operations on s[n] arrays:
     static
     char_type*
     move( char_type* s1, const char_type* s2, size_t n )
       {
         return static_cast<char_type*>(memmove(s1, s2, n * sizeof(char_type)));
       }
     static
     char_type*
     copy( char_type* s1, const char_type* s2, size_t n )
       {
         return static_cast<char_type*>(memcpy(s1, s2, n * sizeof(char_type)));
       }
     static
     char_type*
     copyASCII( char_type* s1, const char* s2, size_t n )
       {
         for (char_type* s = s1; n--; ++s, ++s2) {
           NS_ASSERTION(!(*s2 & ~0x7F), "Unexpected non-ASCII character");
           *s = *s2;
         }
         return s1;
       }
     static
     char_type*
     assign( char_type* s, size_t n, char_type c )
       {
         char_type* result = s;
         while ( n-- )
           assign(*s++, c);
         return result;
       }
     static
     int
     compare( const char_type* s1, const char_type* s2, size_t n )
       {
         for ( ; n--; ++s1, ++s2 )
           {
             if ( !eq(*s1, *s2) )
               return to_int_type(*s1) - to_int_type(*s2);
           }
         return 0;
       }
     static
     int
     compareASCII( const char_type* s1, const char* s2, size_t n )
       {
         for ( ; n--; ++s1, ++s2 )
           {
             NS_ASSERTION(!(*s2 & ~0x7F), "Unexpected non-ASCII character");
             if ( !eq_int_type(to_int_type(*s1), to_int_type(*s2)) )
               return to_int_type(*s1) - to_int_type(*s2);
           }
         return 0;
       }
     // this version assumes that s2 is null-terminated and s1 has length n.
     // if s1 is shorter than s2 then we return -1; if s1 is longer than s2,
     // we return 1.
     static
     int
     compareASCIINullTerminated( const char_type* s1, size_t n, const char* s2 )
       {
         for ( ; n--; ++s1, ++s2 )
           {
             if ( !*s2 )
               return 1;
             NS_ASSERTION(!(*s2 & ~0x7F), "Unexpected non-ASCII character");
             if ( !eq_int_type(to_int_type(*s1), to_int_type(*s2)) )
               return to_int_type(*s1) - to_int_type(*s2);
           }
         if ( *s2 )
           return -1;
         return 0;
       }
     /**
      * Convert c to its lower-case form, but only if c is in the ASCII
      * range. Otherwise leave it alone.
      */
     static
     char_type
     ASCIIToLower( char_type c )
       {
         if (c >= 'A' && c <= 'Z')
           return char_type(c + ('a' - 'A'));
         return c;
       }
     static
     int
     compareLowerCaseToASCII( const char_type* s1, const char* s2, size_t n )
       {
         for ( ; n--; ++s1, ++s2 )
           {
             NS_ASSERTION(!(*s2 & ~0x7F), "Unexpected non-ASCII character");
             NS_ASSERTION(!(*s2 >= 'A' && *s2 <= 'Z'),
                          "Unexpected uppercase character");
             char_type lower_s1 = ASCIIToLower(*s1);
             if ( lower_s1 != to_char_type(*s2) )
               return to_int_type(lower_s1) - to_int_type(*s2);
           }
         return 0;
       }
     // this version assumes that s2 is null-terminated and s1 has length n.
     // if s1 is shorter than s2 then we return -1; if s1 is longer than s2,
     // we return 1.
     static
     int
     compareLowerCaseToASCIINullTerminated( const char_type* s1, size_t n, const char* s2 )
       {
         for ( ; n--; ++s1, ++s2 )
           {
             if ( !*s2 )
               return 1;
             NS_ASSERTION(!(*s2 & ~0x7F), "Unexpected non-ASCII character");
             NS_ASSERTION(!(*s2 >= 'A' && *s2 <= 'Z'),
                          "Unexpected uppercase character");
             char_type lower_s1 = ASCIIToLower(*s1);
             if ( lower_s1 != to_char_type(*s2) )
               return to_int_type(lower_s1) - to_int_type(*s2);
           }
         if ( *s2 )
           return -1;
         return 0;
       }
     static
     size_t
     length( const char_type* s )
       {
         size_t result = 0;
         while ( !eq(*s++, char_type(0)) )
           ++result;
         return result;
       }
     static
     const char_type*
     find( const char_type* s, size_t n, char_type c )
       {
         while ( n-- )
           {
             if ( eq(*s, c) )
               return s;
             ++s;
           }
         return 0;
       }
   };
 template <>
 struct nsCharTraits<char>
   {
     typedef char           char_type;
     typedef unsigned char  unsigned_char_type;
     typedef char16_t      incompatible_char_type;
     static char_type* const sEmptyBuffer;
     static
     void
     assign( char_type& lhs, char_type rhs )
       {
         lhs = rhs;
       }
       // integer representation of characters:
     typedef int int_type;
     static
     char_type
     to_char_type( int_type c )
       {
         return char_type(c);
       }
     static
     int_type
     to_int_type( char_type c )
       {
         return int_type( static_cast<unsigned_char_type>(c) );
       }
     static
     bool
     eq_int_type( int_type lhs, int_type rhs )
       {
         return lhs == rhs;
       }
       // |char_type| comparisons:
     static
     bool
     eq( char_type lhs, char_type rhs )
       {
         return lhs == rhs;
       }
     static
     bool
     lt( char_type lhs, char_type rhs )
       {
         return lhs < rhs;
       }
       // operations on s[n] arrays:
     static
     char_type*
     move( char_type* s1, const char_type* s2, size_t n )
       {
         return static_cast<char_type*>(memmove(s1, s2, n * sizeof(char_type)));
       }
     static
     char_type*
     copy( char_type* s1, const char_type* s2, size_t n )
       {
         return static_cast<char_type*>(memcpy(s1, s2, n * sizeof(char_type)));
       }
     static
     char_type*
     copyASCII( char_type* s1, const char* s2, size_t n )
       {
         return copy(s1, s2, n);
       }
     static
     char_type*
     assign( char_type* s, size_t n, char_type c )
       {
         return static_cast<char_type*>(memset(s, to_int_type(c), n));
       }
     static
     int
     compare( const char_type* s1, const char_type* s2, size_t n )
       {
         return memcmp(s1, s2, n);
       }
     static
     int
     compareASCII( const char_type* s1, const char* s2, size_t n )
       {
 #ifdef DEBUG
         for (size_t i = 0; i < n; ++i)
           {
             NS_ASSERTION(!(s2[i] & ~0x7F), "Unexpected non-ASCII character");
           }
 #endif
         return compare(s1, s2, n);
       }
     // this version assumes that s2 is null-terminated and s1 has length n.
     // if s1 is shorter than s2 then we return -1; if s1 is longer than s2,
     // we return 1.
     static
     int
     compareASCIINullTerminated( const char_type* s1, size_t n, const char* s2 )
       {
         // can't use strcmp here because we don't want to stop when s1
         // contains a null
         for ( ; n--; ++s1, ++s2 )
           {
             if ( !*s2 )
               return 1;
             NS_ASSERTION(!(*s2 & ~0x7F), "Unexpected non-ASCII character");
             if ( *s1 != *s2 )
               return to_int_type(*s1) - to_int_type(*s2);
           }
         if ( *s2 )
           return -1;
         return 0;
       }
     /**
      * Convert c to its lower-case form, but only if c is ASCII.
      */
     static
     char_type
     ASCIIToLower( char_type c )
       {
         if (c >= 'A' && c <= 'Z')
           return char_type(c + ('a' - 'A'));
         return c;
       }
     static
     int
     compareLowerCaseToASCII( const char_type* s1, const char* s2, size_t n )
       {
         for ( ; n--; ++s1, ++s2 )
           {
             NS_ASSERTION(!(*s2 & ~0x7F), "Unexpected non-ASCII character");
             NS_ASSERTION(!(*s2 >= 'A' && *s2 <= 'Z'),
                          "Unexpected uppercase character");
             char_type lower_s1 = ASCIIToLower(*s1);
             if ( lower_s1 != *s2 )
               return to_int_type(lower_s1) - to_int_type(*s2);
           }
         return 0;
       }
     // this version assumes that s2 is null-terminated and s1 has length n.
     // if s1 is shorter than s2 then we return -1; if s1 is longer than s2,
     // we return 1.
     static
     int
     compareLowerCaseToASCIINullTerminated( const char_type* s1, size_t n, const char* s2 )
       {
         for ( ; n--; ++s1, ++s2 )
           {
             if ( !*s2 )
               return 1;
             NS_ASSERTION(!(*s2 & ~0x7F), "Unexpected non-ASCII character");
             NS_ASSERTION(!(*s2 >= 'A' && *s2 <= 'Z'),
                          "Unexpected uppercase character");
             char_type lower_s1 = ASCIIToLower(*s1);
             if ( lower_s1 != *s2 )
               return to_int_type(lower_s1) - to_int_type(*s2);
           }
         if ( *s2 )
           return -1;
         return 0;
       }
     static
     size_t
     length( const char_type* s )
       {
         return strlen(s);
       }
     static
     const char_type*
     find( const char_type* s, size_t n, char_type c )
       {
         return reinterpret_cast<const char_type*>(memchr(s, to_int_type(c), n));
       }
   };
 template <class InputIterator>
 struct nsCharSourceTraits
   {
     typedef typename InputIterator::difference_type difference_type;
     static
     uint32_t
     readable_distance( const InputIterator& first, const InputIterator& last )
       {
         // assumes single fragment
         return uint32_t(last.get() - first.get());
       }
     static
     const typename InputIterator::value_type*
     read( const InputIterator& iter )
       {
         return iter.get();
       }
     static
     void
     advance( InputIterator& s, difference_type n )
       {
         s.advance(n);
       }
   };
 template <class CharT>
 struct nsCharSourceTraits<CharT*>
   {
     typedef ptrdiff_t difference_type;
     static
     uint32_t
     readable_distance( CharT* s )
       {
         return uint32_t(nsCharTraits<CharT>::length(s));
 //      return numeric_limits<uint32_t>::max();
       }
     static
     uint32_t
     readable_distance( CharT* first, CharT* last )
       {
         return uint32_t(last-first);
       }
     static
     const CharT*
     read( CharT* s )
       {
         return s;
       }
     static
     void
     advance( CharT*& s, difference_type n )
       {
         s += n;
       }
   };
 template <class OutputIterator>
 struct nsCharSinkTraits
   {
     static
     void
     write( OutputIterator& iter, const typename OutputIterator::value_type* s, uint32_t n )
       {
         iter.write(s, n);
       }
   };
 template <class CharT>
 struct nsCharSinkTraits<CharT*>
   {
     static
     void
     write( CharT*& iter, const CharT* s, uint32_t n )
       {
         nsCharTraits<CharT>::move(iter, s, n);
         iter += n;
       }
   };
 #endif // !defined(nsCharTraits_h___)

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xpcom/string/public/nsCharTraits.h@b8a032363ba2 (annotated)

xpcom/string/public/nsCharTraits.h