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// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef VM_UNICODE_H_
#define VM_UNICODE_H_
#include "vm/allocation.h"
#include "vm/globals.h"
namespace dart {
class String;
class Utf : AllStatic {
public:
static const int32_t kMaxCodePoint = 0x10FFFF;
static bool IsLatin1(int32_t code_point) {
return (code_point >= 0) && (code_point <= 0xFF);
}
static bool IsBmp(int32_t code_point) {
return (code_point >= 0) && (code_point <= 0xFFFF);
}
static bool IsSupplementary(int32_t code_point) {
return (code_point > 0xFFFF) && (code_point <= kMaxCodePoint);
}
// Returns true if the code point value is above Plane 17.
static bool IsOutOfRange(int32_t code_point) {
return (code_point < 0) || (code_point > kMaxCodePoint);
}
};
class Utf8 : AllStatic {
public:
enum Type {
kLatin1 = 0, // Latin-1 code point [U+0000, U+00FF].
kBMP, // Basic Multilingual Plane code point [U+0000, U+FFFF].
kSupplementary, // Supplementary code point [U+010000, U+10FFFF].
};
// Returns the most restricted coding form in which the sequence of utf8
// characters in 'utf8_array' can be represented in, and the number of
// code units needed in that form.
static intptr_t CodeUnitCount(const uint8_t* utf8_array,
intptr_t array_len,
Type* type);
// Returns true if 'utf8_array' is a valid UTF-8 string.
static bool IsValid(const uint8_t* utf8_array, intptr_t array_len);
static intptr_t Length(int32_t ch);
static intptr_t Length(const String& str);
static intptr_t Encode(int32_t ch, char* dst);
static intptr_t Encode(const String& src, char* dst, intptr_t len);
static intptr_t Decode(const uint8_t* utf8_array,
intptr_t array_len,
int32_t* ch);
static bool DecodeToLatin1(const uint8_t* utf8_array,
intptr_t array_len,
uint8_t* dst,
intptr_t len);
static bool DecodeToUTF16(const uint8_t* utf8_array,
intptr_t array_len,
uint16_t* dst,
intptr_t len);
static bool DecodeToUTF32(const uint8_t* utf8_array,
intptr_t array_len,
int32_t* dst,
intptr_t len);
static bool DecodeCStringToUTF32(const char* str,
int32_t* dst,
intptr_t len);
static const int32_t kMaxOneByteChar = 0x7F;
static const int32_t kMaxTwoByteChar = 0x7FF;
static const int32_t kMaxThreeByteChar = 0xFFFF;
static const int32_t kMaxFourByteChar = Utf::kMaxCodePoint;
private:
static bool IsTrailByte(uint8_t code_unit) {
return (code_unit & 0xC0) == 0x80;
}
static bool IsNonShortestForm(uint32_t code_point, size_t num_code_units) {
return code_point < kOverlongMinimum[num_code_units];
}
static bool IsLatin1SequenceStart(uint8_t code_unit) {
// Check if utf8 sequence is the start of a codepoint <= U+00FF
return (code_unit <= 0xC3);
}
static bool IsSupplementarySequenceStart(uint8_t code_unit) {
// Check if utf8 sequence is the start of a codepoint >= U+10000.
return (code_unit >= 0xF0);
}
static const int8_t kTrailBytes[];
static const uint32_t kMagicBits[];
static const uint32_t kOverlongMinimum[];
};
class Utf16 : AllStatic {
public:
// Returns the length of the code point in UTF-16 code units.
static intptr_t Length(int32_t ch) {
return (ch <= Utf16::kMaxCodeUnit) ? 1 : 2;
}
// Returns true if ch is a lead or trail surrogate.
static bool IsSurrogate(int32_t ch) {
return (ch & 0xFFFFF800) == 0xD800;
}
// Returns true if ch is a lead surrogate.
static bool IsLeadSurrogate(int32_t ch) {
return (ch & 0xFFFFFC00) == 0xD800;
}
// Returns true if ch is a low surrogate.
static bool IsTrailSurrogate(int32_t ch) {
return (ch & 0xFFFFFC00) == 0xDC00;
}
// Returns the character at i and advances i to the next character
// boundary.
static int32_t Next(const uint16_t* characters, intptr_t* i, intptr_t len) {
int32_t ch = characters[*i];
if (Utf16::IsLeadSurrogate(ch) && (*i < (len - 1))) {
int32_t ch2 = characters[*i + 1];
if (Utf16::IsTrailSurrogate(ch2)) {
ch = Utf16::Decode(ch, ch2);
*i += 1;
}
}
*i += 1;
return ch;
}
// Decodes a surrogate pair into a supplementary code point.
static int32_t Decode(int32_t lead, int32_t trail) {
return 0x10000 + ((lead & 0x3FF) << 10) + (trail & 0x3FF);
}
// Encodes a single code point.
static void Encode(int32_t codepoint, uint16_t* dst);
private:
static const int32_t kMaxCodeUnit = 0xFFFF;
static const int32_t kLeadSurrogateOffset = (0xD800 - (0x10000 >> 10));
static const int32_t kSurrogateOffset = (0x10000 - (0xD800 << 10) - 0xDC00);
};
class CaseMapping : AllStatic {
public:
// Maps a code point to uppercase.
static int32_t ToUpper(int32_t code_point) {
return Convert(code_point, kUppercase);
}
// Maps a code point to lowercase.
static int32_t ToLower(int32_t code_point) {
return Convert(code_point, kLowercase);
}
private:
// Property is a delta to the uppercase mapping.
static const int32_t kUppercase = 1;
// Property is a delta to the uppercase mapping.
static const int32_t kLowercase = 2;
// Property is an index into the exception table.
static const int32_t kException = 3;
// Type bit-field parameters
static const int32_t kTypeShift = 2;
static const int32_t kTypeMask = 3;
// The size of the stage 1 index.
// TODO(cshapiro): improve indexing so this value is unnecessary.
static const int kStage1Size = 261;
// The size of a stage 2 block in bytes.
static const int kBlockSizeLog2 = 8;
static const int kBlockSize = 1 << kBlockSizeLog2;
static int32_t Convert(int32_t ch, int32_t mapping) {
if (Utf::IsLatin1(ch)) {
int32_t info = stage2_[ch];
if ((info & kTypeMask) == mapping) {
ch += info >> kTypeShift;
}
} else if (ch <= (kStage1Size << kBlockSizeLog2)) {
int16_t offset = stage1_[ch >> kBlockSizeLog2] << kBlockSizeLog2;
int32_t info = stage2_[offset + (ch & (kBlockSize - 1))];
int32_t type = info & kTypeMask;
if (type == mapping) {
ch += (info >> kTypeShift);
} else if (type == kException) {
ch += stage2_exception_[info >> kTypeShift][mapping - 1];
}
}
return ch;
}
// Index into the data array.
static const uint8_t stage1_[];
// Data for small code points with one mapping
static const int16_t stage2_[];
// Data for large code points or code points with both mappings.
static const int32_t stage2_exception_[][2];
};
} // namespace dart
#endif // VM_UNICODE_H_