ASCIICType.h   [plain text]

/*
 * Copyright (C) 2007, 2008, 2009, 2011 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer. 
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution. 
 * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef WTF_ASCIICType_h
#define WTF_ASCIICType_h

#include <wtf/Assertions.h>
#include <wtf/text/LChar.h>

// The behavior of many of the functions in the <ctype.h> header is dependent
// on the current locale. But in the WebKit project, all uses of those functions
// are in code processing something that's not locale-specific. These equivalents
// for some of the <ctype.h> functions are named more explicitly, not dependent
// on the C library locale, and we should also optimize them as needed.

// All functions return false or leave the character unchanged if passed a character
// that is outside the range 0-7F. So they can be used on Unicode strings or
// characters if the intent is to do processing only if the character is ASCII.

namespace WTF {

const unsigned char asciiCaseFoldTable[256] = {
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
    0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
    0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
    0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
    0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
    0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
    0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
    0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
    0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
    0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
    0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
    0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
    0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
    0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
    0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
};

template<typename CharType> inline bool isASCII(CharType c)
{
    return !(c & ~0x7F);
}

template<typename CharType> inline bool isASCIIAlpha(CharType c)
{
    return (c | 0x20) >= 'a' && (c | 0x20) <= 'z';
}

template<typename CharType> inline bool isASCIIDigit(CharType c)
{
    return c >= '0' && c <= '9';
}

template<typename CharType> inline bool isASCIIAlphanumeric(CharType c)
{
    return isASCIIDigit(c) || isASCIIAlpha(c);
}

template<typename CharType> inline bool isASCIIHexDigit(CharType c)
{
    return isASCIIDigit(c) || ((c | 0x20) >= 'a' && (c | 0x20) <= 'f');
}

template<typename CharType> inline bool isASCIILower(CharType c)
{
    return c >= 'a' && c <= 'z';
}

template<typename CharType> inline bool isASCIIBinaryDigit(CharType c)
{
    return (c == '0') || (c == '1');
}

template<typename CharType> inline bool isASCIIOctalDigit(CharType c)
{
    return (c >= '0') && (c <= '7');
}

template<typename CharType> inline bool isASCIIPrintable(CharType c)
{
    return c >= ' ' && c <= '~';
}

/*
 Statistics from a run of Apple's page load test for callers of isASCIISpace:

 character          count
 ---------          -----
 non-spaces         689383
 20  space          294720
 0A  \n             89059
 09  \t             28320
 0D  \r             0
 0C  \f             0
 0B  \v             0
 */
template<typename CharType> inline bool isASCIISpace(CharType c)
{
    return c <= ' ' && (c == ' ' || (c <= 0xD && c >= 0x9));
}

template<typename CharType> inline bool isASCIIUpper(CharType c)
{
    return c >= 'A' && c <= 'Z';
}

template<typename CharType> inline CharType toASCIILower(CharType c)
{
    return c | ((c >= 'A' && c <= 'Z') << 5);
}

template<>
inline char toASCIILower(char c)
{
    return static_cast<char>(asciiCaseFoldTable[static_cast<unsigned char>(c)]);
}

template<>
inline LChar toASCIILower(LChar c)
{
    return asciiCaseFoldTable[c];
}

template<typename CharType> inline CharType toASCIILowerUnchecked(CharType character)
{
    // This function can be used for comparing any input character
    // to a lowercase English character. The isASCIIAlphaCaselessEqual
    // below should be used for regular comparison of ASCII alpha
    // characters, but switch statements in CSS tokenizer require
    // direct use of this function.
    return character | 0x20;
}

template<typename CharType> inline CharType toASCIIUpper(CharType c)
{
    return c & ~((c >= 'a' && c <= 'z') << 5);
}

template<typename CharType> inline int toASCIIHexValue(CharType c)
{
    ASSERT(isASCIIHexDigit(c));
    return c < 'A' ? c - '0' : (c - 'A' + 10) & 0xF;
}

template<typename CharType> inline int toASCIIHexValue(CharType upperValue, CharType lowerValue)
{
    ASSERT(isASCIIHexDigit(upperValue) && isASCIIHexDigit(lowerValue));
    return ((toASCIIHexValue(upperValue) << 4) & 0xF0) | toASCIIHexValue(lowerValue);
}

inline char lowerNibbleToASCIIHexDigit(char c)
{
    char nibble = c & 0xF;
    return nibble < 10 ? '0' + nibble : 'A' + nibble - 10;
}

inline char upperNibbleToASCIIHexDigit(char c)
{
    char nibble = (c >> 4) & 0xF;
    return nibble < 10 ? '0' + nibble : 'A' + nibble - 10;
}

template<typename CharType> inline bool isASCIIAlphaCaselessEqual(CharType cssCharacter, char character)
{
    // This function compares a (preferrably) constant ASCII
    // lowercase letter to any input character.
    ASSERT(character >= 'a' && character <= 'z');
    return LIKELY(toASCIILowerUnchecked(cssCharacter) == character);
}

}

using WTF::isASCII;
using WTF::isASCIIAlpha;
using WTF::isASCIIAlphanumeric;
using WTF::isASCIIDigit;
using WTF::isASCIIHexDigit;
using WTF::isASCIILower;
using WTF::isASCIIBinaryDigit;
using WTF::isASCIIOctalDigit;
using WTF::isASCIIPrintable;
using WTF::isASCIISpace;
using WTF::isASCIIUpper;
using WTF::toASCIIHexValue;
using WTF::toASCIILower;
using WTF::toASCIILowerUnchecked;
using WTF::toASCIIUpper;
using WTF::lowerNibbleToASCIIHexDigit;
using WTF::upperNibbleToASCIIHexDigit;
using WTF::isASCIIAlphaCaselessEqual;

#endif