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// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_UNICODE_DECODER_H_
#define V8_UNICODE_DECODER_H_
#include <sys/types.h>
#include <algorithm>
#include "src/globals.h"
#include "src/unicode.h"
#include "src/utils.h"
#include "src/vector.h"
namespace unibrow {
class Utf8Iterator {
public:
explicit Utf8Iterator(const v8::internal::Vector<const char>& stream)
: Utf8Iterator(stream, 0, false) {}
Utf8Iterator(const v8::internal::Vector<const char>& stream, size_t offset,
bool trailing)
: stream_(stream),
cursor_(offset),
offset_(0),
char_(0),
trailing_(false) {
DCHECK_LE(offset, stream.length());
// Read the first char, setting offset_ to offset in the process.
++*this;
// This must be set after reading the first char, since the offset marks
// the start of the octet sequence that the trailing char is part of.
trailing_ = trailing;
if (trailing) {
DCHECK_GT(char_, Utf16::kMaxNonSurrogateCharCode);
}
}
uint16_t operator*();
Utf8Iterator& operator++();
Utf8Iterator operator++(int);
bool Done();
bool Trailing() { return trailing_; }
size_t Offset() { return offset_; }
private:
const v8::internal::Vector<const char>& stream_;
size_t cursor_;
size_t offset_;
uint32_t char_;
bool trailing_;
};
class V8_EXPORT_PRIVATE Utf8DecoderBase {
public:
// Initialization done in subclass.
inline Utf8DecoderBase();
inline Utf8DecoderBase(uint16_t* buffer, size_t buffer_length,
const v8::internal::Vector<const char>& stream);
inline size_t Utf16Length() const { return utf16_length_; }
protected:
// This reads all characters and sets the utf16_length_.
// The first buffer_length utf16 chars are cached in the buffer.
void Reset(uint16_t* buffer, size_t buffer_length,
const v8::internal::Vector<const char>& vector);
static void WriteUtf16Slow(uint16_t* data, size_t length,
const v8::internal::Vector<const char>& stream,
size_t offset, bool trailing);
size_t bytes_read_;
size_t chars_written_;
size_t utf16_length_;
bool trailing_;
private:
DISALLOW_COPY_AND_ASSIGN(Utf8DecoderBase);
};
template <size_t kBufferSize>
class Utf8Decoder : public Utf8DecoderBase {
public:
inline Utf8Decoder() = default;
explicit inline Utf8Decoder(const v8::internal::Vector<const char>& stream);
inline void Reset(const v8::internal::Vector<const char>& stream);
inline size_t WriteUtf16(
uint16_t* data, size_t length,
const v8::internal::Vector<const char>& stream) const;
private:
uint16_t buffer_[kBufferSize];
};
Utf8DecoderBase::Utf8DecoderBase()
: bytes_read_(0), chars_written_(0), utf16_length_(0), trailing_(false) {}
Utf8DecoderBase::Utf8DecoderBase(
uint16_t* buffer, size_t buffer_length,
const v8::internal::Vector<const char>& stream) {
Reset(buffer, buffer_length, stream);
}
template <size_t kBufferSize>
Utf8Decoder<kBufferSize>::Utf8Decoder(
const v8::internal::Vector<const char>& stream)
: Utf8DecoderBase(buffer_, kBufferSize, stream) {}
template <size_t kBufferSize>
void Utf8Decoder<kBufferSize>::Reset(
const v8::internal::Vector<const char>& stream) {
Utf8DecoderBase::Reset(buffer_, kBufferSize, stream);
}
template <size_t kBufferSize>
size_t Utf8Decoder<kBufferSize>::WriteUtf16(
uint16_t* data, size_t data_length,
const v8::internal::Vector<const char>& stream) const {
DCHECK_GT(data_length, 0);
data_length = std::min(data_length, utf16_length_);
// memcpy everything in buffer.
size_t memcpy_length = std::min(data_length, chars_written_);
v8::internal::MemCopy(data, buffer_, memcpy_length * sizeof(uint16_t));
if (data_length <= chars_written_) return data_length;
// Copy the rest the slow way.
WriteUtf16Slow(data + chars_written_, data_length - chars_written_, stream,
bytes_read_, trailing_);
return data_length;
}
class Latin1 {
public:
static const unsigned kMaxChar = 0xff;
// Convert the character to Latin-1 case equivalent if possible.
static inline uint16_t TryConvertToLatin1(uint16_t);
};
uint16_t Latin1::TryConvertToLatin1(uint16_t c) {
switch (c) {
// This are equivalent characters in unicode.
case 0x39c:
case 0x3bc:
return 0xb5;
// This is an uppercase of a Latin-1 character
// outside of Latin-1.
case 0x178:
return 0xff;
}
return c;
}
} // namespace unibrow
#endif // V8_UNICODE_DECODER_H_
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