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/*
* Copyright (C) 2011 Apple Inc. All rights reserved.
* Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#ifndef ASCIIFastPath_h
#define ASCIIFastPath_h
#if OS(DARWIN) && (CPU(X86) || CPU(X86_64))
#include <emmintrin.h>
#endif
#include <stdint.h>
#include <wtf/Alignment.h>
#include <wtf/unicode/Unicode.h>
namespace WTF {
// Assuming that a pointer is the size of a "machine word", then
// uintptr_t is an integer type that is also a machine word.
typedef uintptr_t MachineWord;
const uintptr_t machineWordAlignmentMask = sizeof(MachineWord) - 1;
inline bool isAlignedToMachineWord(const void* pointer)
{
return !(reinterpret_cast<uintptr_t>(pointer) & machineWordAlignmentMask);
}
template<typename T> inline T* alignToMachineWord(T* pointer)
{
return reinterpret_cast<T*>(reinterpret_cast<uintptr_t>(pointer) & ~machineWordAlignmentMask);
}
template<size_t size, typename CharacterType> struct NonASCIIMask;
template<> struct NonASCIIMask<4, UChar> {
static inline uint32_t value() { return 0xFF80FF80U; }
};
template<> struct NonASCIIMask<4, LChar> {
static inline uint32_t value() { return 0x80808080U; }
};
template<> struct NonASCIIMask<8, UChar> {
static inline uint64_t value() { return 0xFF80FF80FF80FF80ULL; }
};
template<> struct NonASCIIMask<8, LChar> {
static inline uint64_t value() { return 0x8080808080808080ULL; }
};
template<typename CharacterType>
inline bool isAllASCII(MachineWord word)
{
return !(word & NonASCIIMask<sizeof(MachineWord), CharacterType>::value());
}
// Note: This function assume the input is likely all ASCII, and
// does not leave early if it is not the case.
template<typename CharacterType>
inline bool charactersAreAllASCII(const CharacterType* characters, size_t length)
{
MachineWord allCharBits = 0;
const CharacterType* end = characters + length;
// Prologue: align the input.
while (!isAlignedToMachineWord(characters) && characters != end) {
allCharBits |= *characters;
++characters;
}
// Compare the values of CPU word size.
const CharacterType* wordEnd = alignToMachineWord(end);
const size_t loopIncrement = sizeof(MachineWord) / sizeof(CharacterType);
while (characters < wordEnd) {
allCharBits |= *(reinterpret_cast<const MachineWord*>(characters));
characters += loopIncrement;
}
// Process the remaining bytes.
while (characters != end) {
allCharBits |= *characters;
++characters;
}
MachineWord nonASCIIBitMask = NonASCIIMask<sizeof(MachineWord), CharacterType>::value();
return !(allCharBits & nonASCIIBitMask);
}
inline void copyLCharsFromUCharSource(LChar* destination, const UChar* source, size_t length)
{
#if OS(DARWIN) && (CPU(X86) || CPU(X86_64))
const uintptr_t memoryAccessSize = 16; // Memory accesses on 16 byte (128 bit) alignment
const uintptr_t memoryAccessMask = memoryAccessSize - 1;
size_t i = 0;
for (;i < length && !isAlignedTo<memoryAccessMask>(&source[i]); ++i) {
ASSERT(!(source[i] & 0xff00));
destination[i] = static_cast<LChar>(source[i]);
}
const uintptr_t sourceLoadSize = 32; // Process 32 bytes (16 UChars) each iteration
const unsigned ucharsPerLoop = sourceLoadSize / sizeof(UChar);
if (length > ucharsPerLoop) {
const unsigned endLength = length - ucharsPerLoop + 1;
for (; i < endLength; i += ucharsPerLoop) {
#ifndef NDEBUG
for (unsigned checkIndex = 0; checkIndex < ucharsPerLoop; checkIndex++)
ASSERT(!(source[i+checkIndex] & 0xff00));
#endif
__m128i first8UChars = _mm_load_si128(reinterpret_cast<const __m128i*>(&source[i]));
__m128i second8UChars = _mm_load_si128(reinterpret_cast<const __m128i*>(&source[i+8]));
__m128i packedChars = _mm_packus_epi16(first8UChars, second8UChars);
_mm_storeu_si128(reinterpret_cast<__m128i*>(&destination[i]), packedChars);
}
}
for (; i < length; ++i) {
ASSERT(!(source[i] & 0xff00));
destination[i] = static_cast<LChar>(source[i]);
}
#else
for (size_t i = 0; i < length; ++i) {
ASSERT(!(source[i] & 0xff00));
destination[i] = static_cast<LChar>(source[i]);
}
#endif
}
} // namespace WTF
#endif // ASCIIFastPath_h
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