gecko-dev/xpcom/string/public/nsCharTraits.h

612 lines
15 KiB
C++

/* -*- 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
#ifndef nscore_h___
#include "nscore.h"
// for |PRUnichar|
#endif
// 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
#ifndef nsDebug_h__
#include "nsDebug.h"
// for NS_ASSERTION
#endif
#endif
/*
* Some macros for converting PRUnichar (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) PRUnichar(PRUnichar(uint32_t(c) >> 10) + \
PRUnichar(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) PRUnichar(PRUnichar(uint32_t(c) & uint32_t(0x03FF)) | \
PRUnichar(0xDC00))
#define IS_IN_BMP(ucs) (uint32_t(ucs) < PLANE1_BASE)
#define UCS2_REPLACEMENT_CHAR PRUnichar(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<PRUnichar>
{
typedef PRUnichar char_type;
typedef uint16_t unsigned_char_type;
typedef char incompatible_char_type;
static char_type *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 PRUnichar incompatible_char_type;
static char_type *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___)