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gecko-dev/xpcom/string/nsCharTraits.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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
// 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;
// integer representation of characters:
typedef int int_type;
static char_type
to_char_type(int_type aChar)
{
return char_type(aChar);
}
static int_type
to_int_type(char_type aChar)
{
return int_type(static_cast<unsigned_char_type>(aChar));
}
static bool
eq_int_type(int_type aLhs, int_type aRhs)
{
return aLhs == aRhs;
}
// |char_type| comparisons:
static bool
eq(char_type aLhs, char_type aRhs)
{
return aLhs == aRhs;
}
static bool
lt(char_type aLhs, char_type aRhs)
{
return aLhs < aRhs;
}
// operations on s[n] arrays:
static char_type*
move(char_type* aStr1, const char_type* aStr2, size_t aN)
{
return static_cast<char_type*>(memmove(aStr1, aStr2,
aN * sizeof(char_type)));
}
static char_type*
copy(char_type* aStr1, const char_type* aStr2, size_t aN)
{
return static_cast<char_type*>(memcpy(aStr1, aStr2,
aN * sizeof(char_type)));
}
static char_type*
copyASCII(char_type* aStr1, const char* aStr2, size_t aN)
{
for (char_type* s = aStr1; aN--; ++s, ++aStr2) {
NS_ASSERTION(!(*aStr2 & ~0x7F), "Unexpected non-ASCII character");
*s = static_cast<char_type>(*aStr2);
}
return aStr1;
}
static int
compare(const char_type* aStr1, const char_type* aStr2, size_t aN)
{
for (; aN--; ++aStr1, ++aStr2) {
if (!eq(*aStr1, *aStr2)) {
return to_int_type(*aStr1) - to_int_type(*aStr2);
}
}
return 0;
}
static int
compareASCII(const char_type* aStr1, const char* aStr2, size_t aN)
{
for (; aN--; ++aStr1, ++aStr2) {
NS_ASSERTION(!(*aStr2 & ~0x7F), "Unexpected non-ASCII character");
if (!eq_int_type(to_int_type(*aStr1),
to_int_type(static_cast<char_type>(*aStr2)))) {
return to_int_type(*aStr1) -
to_int_type(static_cast<char_type>(*aStr2));
}
}
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* aStr1, size_t aN,
const char* aStr2)
{
for (; aN--; ++aStr1, ++aStr2) {
if (!*aStr2) {
return 1;
}
NS_ASSERTION(!(*aStr2 & ~0x7F), "Unexpected non-ASCII character");
if (!eq_int_type(to_int_type(*aStr1),
to_int_type(static_cast<char_type>(*aStr2)))) {
return to_int_type(*aStr1) -
to_int_type(static_cast<char_type>(*aStr2));
}
}
if (*aStr2) {
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 aChar)
{
if (aChar >= 'A' && aChar <= 'Z') {
return char_type(aChar + ('a' - 'A'));
}
return aChar;
}
static int
compareLowerCaseToASCII(const char_type* aStr1, const char* aStr2, size_t aN)
{
for (; aN--; ++aStr1, ++aStr2) {
NS_ASSERTION(!(*aStr2 & ~0x7F), "Unexpected non-ASCII character");
NS_ASSERTION(!(*aStr2 >= 'A' && *aStr2 <= 'Z'),
"Unexpected uppercase character");
char_type lower_s1 = ASCIIToLower(*aStr1);
if (lower_s1 != static_cast<char_type>(*aStr2)) {
return to_int_type(lower_s1) -
to_int_type(static_cast<char_type>(*aStr2));
}
}
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* aStr1,
size_t aN, const char* aStr2)
{
for (; aN--; ++aStr1, ++aStr2) {
if (!*aStr2) {
return 1;
}
NS_ASSERTION(!(*aStr2 & ~0x7F), "Unexpected non-ASCII character");
NS_ASSERTION(!(*aStr2 >= 'A' && *aStr2 <= 'Z'),
"Unexpected uppercase character");
char_type lower_s1 = ASCIIToLower(*aStr1);
if (lower_s1 != static_cast<char_type>(*aStr2)) {
return to_int_type(lower_s1) -
to_int_type(static_cast<char_type>(*aStr2));
}
}
if (*aStr2) {
return -1;
}
return 0;
}
static size_t
length(const char_type* aStr)
{
size_t result = 0;
while (!eq(*aStr++, char_type(0))) {
++result;
}
return result;
}
static const char_type*
find(const char_type* aStr, size_t aN, char_type aChar)
{
while (aN--) {
if (eq(*aStr, aChar)) {
return aStr;
}
++aStr;
}
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;
// integer representation of characters:
typedef int int_type;
static char_type
to_char_type(int_type aChar)
{
return char_type(aChar);
}
static int_type
to_int_type(char_type aChar)
{
return int_type(static_cast<unsigned_char_type>(aChar));
}
static bool
eq_int_type(int_type aLhs, int_type aRhs)
{
return aLhs == aRhs;
}
// |char_type| comparisons:
static bool eq(char_type aLhs, char_type aRhs)
{
return aLhs == aRhs;
}
static bool
lt(char_type aLhs, char_type aRhs)
{
return aLhs < aRhs;
}
// operations on s[n] arrays:
static char_type*
move(char_type* aStr1, const char_type* aStr2, size_t aN)
{
return static_cast<char_type*>(memmove(aStr1, aStr2,
aN * sizeof(char_type)));
}
static char_type*
copy(char_type* aStr1, const char_type* aStr2, size_t aN)
{
return static_cast<char_type*>(memcpy(aStr1, aStr2,
aN * sizeof(char_type)));
}
static char_type*
copyASCII(char_type* aStr1, const char* aStr2, size_t aN)
{
return copy(aStr1, aStr2, aN);
}
static int
compare(const char_type* aStr1, const char_type* aStr2, size_t aN)
{
return memcmp(aStr1, aStr2, aN);
}
static int
compareASCII(const char_type* aStr1, const char* aStr2, size_t aN)
{
#ifdef DEBUG
for (size_t i = 0; i < aN; ++i) {
NS_ASSERTION(!(aStr2[i] & ~0x7F), "Unexpected non-ASCII character");
}
#endif
return compare(aStr1, aStr2, aN);
}
// 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* aStr1, size_t aN,
const char* aStr2)
{
// can't use strcmp here because we don't want to stop when aStr1
// contains a null
for (; aN--; ++aStr1, ++aStr2) {
if (!*aStr2) {
return 1;
}
NS_ASSERTION(!(*aStr2 & ~0x7F), "Unexpected non-ASCII character");
if (*aStr1 != *aStr2) {
return to_int_type(*aStr1) - to_int_type(*aStr2);
}
}
if (*aStr2) {
return -1;
}
return 0;
}
/**
* Convert c to its lower-case form, but only if c is ASCII.
*/
static char_type
ASCIIToLower(char_type aChar)
{
if (aChar >= 'A' && aChar <= 'Z') {
return char_type(aChar + ('a' - 'A'));
}
return aChar;
}
static int
compareLowerCaseToASCII(const char_type* aStr1, const char* aStr2, size_t aN)
{
for (; aN--; ++aStr1, ++aStr2) {
NS_ASSERTION(!(*aStr2 & ~0x7F), "Unexpected non-ASCII character");
NS_ASSERTION(!(*aStr2 >= 'A' && *aStr2 <= 'Z'),
"Unexpected uppercase character");
char_type lower_s1 = ASCIIToLower(*aStr1);
if (lower_s1 != *aStr2) {
return to_int_type(lower_s1) - to_int_type(*aStr2);
}
}
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* aStr1, size_t aN,
const char* aStr2)
{
for (; aN--; ++aStr1, ++aStr2) {
if (!*aStr2) {
return 1;
}
NS_ASSERTION(!(*aStr2 & ~0x7F), "Unexpected non-ASCII character");
NS_ASSERTION(!(*aStr2 >= 'A' && *aStr2 <= 'Z'),
"Unexpected uppercase character");
char_type lower_s1 = ASCIIToLower(*aStr1);
if (lower_s1 != *aStr2) {
return to_int_type(lower_s1) - to_int_type(*aStr2);
}
}
if (*aStr2) {
return -1;
}
return 0;
}
static size_t
length(const char_type* aStr)
{
return strlen(aStr);
}
static const char_type*
find(const char_type* aStr, size_t aN, char_type aChar)
{
return reinterpret_cast<const char_type*>(memchr(aStr, to_int_type(aChar),
aN));
}
};
template <class InputIterator>
struct nsCharSourceTraits
{
typedef typename InputIterator::difference_type difference_type;
static uint32_t
readable_distance(const InputIterator& aFirst, const InputIterator& aLast)
{
// assumes single fragment
return uint32_t(aLast.get() - aFirst.get());
}
static const typename InputIterator::value_type*
read(const InputIterator& aIter)
{
return aIter.get();
}
static void
advance(InputIterator& aStr, difference_type aN)
{
aStr.advance(aN);
}
};
template <class CharT>
struct nsCharSourceTraits<CharT*>
{
typedef ptrdiff_t difference_type;
static uint32_t
readable_distance(CharT* aStr)
{
return uint32_t(nsCharTraits<CharT>::length(aStr));
// return numeric_limits<uint32_t>::max();
}
static uint32_t
readable_distance(CharT* aFirst, CharT* aLast)
{
return uint32_t(aLast - aFirst);
}
static const CharT*
read(CharT* aStr)
{
return aStr;
}
static void
advance(CharT*& aStr, difference_type aN)
{
aStr += aN;
}
};
template <class OutputIterator>
struct nsCharSinkTraits
{
static void
write(OutputIterator& aIter, const typename OutputIterator::value_type* aStr,
uint32_t aN)
{
aIter.write(aStr, aN);
}
};
template <class CharT>
struct nsCharSinkTraits<CharT*>
{
static void
write(CharT*& aIter, const CharT* aStr, uint32_t aN)
{
nsCharTraits<CharT>::move(aIter, aStr, aN);
aIter += aN;
}
};
#endif // !defined(nsCharTraits_h___)
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