V8 API Reference, 7.2.502.16 (for Deno 0.2.4)
unicode.h
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1 // Copyright 2011 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_UNICODE_H_
6 #define V8_UNICODE_H_
7 
8 #include <sys/types.h>
9 #include "src/globals.h"
10 #include "src/third_party/utf8-decoder/utf8-decoder.h"
11 #include "src/utils.h"
17 namespace unibrow {
18 
19 typedef unsigned int uchar;
20 typedef unsigned char byte;
21 
26 const int kMaxMappingSize = 4;
27 
28 template <class T, int size = 256>
29 class Predicate {
30  public:
31  inline Predicate() = default;
32  inline bool get(uchar c);
33 
34  private:
35  friend class Test;
36  bool CalculateValue(uchar c);
37  class CacheEntry {
38  public:
39  inline CacheEntry()
40  : bit_field_(CodePointField::encode(0) | ValueField::encode(0)) {}
41  inline CacheEntry(uchar code_point, bool value)
42  : bit_field_(
43  CodePointField::encode(CodePointField::kMask & code_point) |
44  ValueField::encode(value)) {
45  DCHECK_IMPLIES((CodePointField::kMask & code_point) != code_point,
46  code_point == static_cast<uchar>(-1));
47  }
48 
49  uchar code_point() const { return CodePointField::decode(bit_field_); }
50  bool value() const { return ValueField::decode(bit_field_); }
51 
52  private:
53  class CodePointField : public v8::internal::BitField<uchar, 0, 21> {};
54  class ValueField : public v8::internal::BitField<bool, 21, 1> {};
55 
56  uint32_t bit_field_;
57  };
58  static const int kSize = size;
59  static const int kMask = kSize - 1;
60  CacheEntry entries_[kSize];
61 };
62 
63 
64 // A cache used in case conversion. It caches the value for characters
65 // that either have no mapping or map to a single character independent
66 // of context. Characters that map to more than one character or that
67 // map differently depending on context are always looked up.
68 template <class T, int size = 256>
69 class Mapping {
70  public:
71  inline Mapping() = default;
72  inline int get(uchar c, uchar n, uchar* result);
73  private:
74  friend class Test;
75  int CalculateValue(uchar c, uchar n, uchar* result);
76  struct CacheEntry {
77  inline CacheEntry() : code_point_(kNoChar), offset_(0) { }
78  inline CacheEntry(uchar code_point, signed offset)
79  : code_point_(code_point),
80  offset_(offset) { }
81  uchar code_point_;
82  signed offset_;
83  static const int kNoChar = (1 << 21) - 1;
84  };
85  static const int kSize = size;
86  static const int kMask = kSize - 1;
87  CacheEntry entries_[kSize];
88 };
89 
90 
91 class UnicodeData {
92  private:
93  friend class Test;
94  static int GetByteCount();
95  static const uchar kMaxCodePoint;
96 };
97 
98 
99 class Utf16 {
100  public:
101  static const int kNoPreviousCharacter = -1;
102  static inline bool IsSurrogatePair(int lead, int trail) {
103  return IsLeadSurrogate(lead) && IsTrailSurrogate(trail);
104  }
105  static inline bool IsLeadSurrogate(int code) {
106  return (code & 0xfc00) == 0xd800;
107  }
108  static inline bool IsTrailSurrogate(int code) {
109  return (code & 0xfc00) == 0xdc00;
110  }
111 
112  static inline int CombineSurrogatePair(uchar lead, uchar trail) {
113  return 0x10000 + ((lead & 0x3ff) << 10) + (trail & 0x3ff);
114  }
115  static const uchar kMaxNonSurrogateCharCode = 0xffff;
116  // Encoding a single UTF-16 code unit will produce 1, 2 or 3 bytes
117  // of UTF-8 data. The special case where the unit is a surrogate
118  // trail produces 1 byte net, because the encoding of the pair is
119  // 4 bytes and the 3 bytes that were used to encode the lead surrogate
120  // can be reclaimed.
121  static const int kMaxExtraUtf8BytesForOneUtf16CodeUnit = 3;
122  // One UTF-16 surrogate is endoded (illegally) as 3 UTF-8 bytes.
123  // The illegality stems from the surrogate not being part of a pair.
124  static const int kUtf8BytesToCodeASurrogate = 3;
125  static inline uint16_t LeadSurrogate(uint32_t char_code) {
126  return 0xd800 + (((char_code - 0x10000) >> 10) & 0x3ff);
127  }
128  static inline uint16_t TrailSurrogate(uint32_t char_code) {
129  return 0xdc00 + (char_code & 0x3ff);
130  }
131 };
132 
133 class V8_EXPORT_PRIVATE Utf8 {
134  public:
135  using State = Utf8DfaDecoder::State;
136 
137  static inline uchar Length(uchar chr, int previous);
138  static inline unsigned EncodeOneByte(char* out, uint8_t c);
139  static inline unsigned Encode(char* out,
140  uchar c,
141  int previous,
142  bool replace_invalid = false);
143  static uchar CalculateValue(const byte* str, size_t length, size_t* cursor);
144 
145  // The unicode replacement character, used to signal invalid unicode
146  // sequences (e.g. an orphan surrogate) when converting to a UTF-8 encoding.
147  static const uchar kBadChar = 0xFFFD;
148  static const uchar kBufferEmpty = 0x0;
149  static const uchar kIncomplete = 0xFFFFFFFC; // any non-valid code point.
150  static const unsigned kMaxEncodedSize = 4;
151  static const unsigned kMaxOneByteChar = 0x7f;
152  static const unsigned kMaxTwoByteChar = 0x7ff;
153  static const unsigned kMaxThreeByteChar = 0xffff;
154  static const unsigned kMaxFourByteChar = 0x1fffff;
155 
156  // A single surrogate is coded as a 3 byte UTF-8 sequence, but two together
157  // that match are coded as a 4 byte UTF-8 sequence.
158  static const unsigned kBytesSavedByCombiningSurrogates = 2;
159  static const unsigned kSizeOfUnmatchedSurrogate = 3;
160  // The maximum size a single UTF-16 code unit may take up when encoded as
161  // UTF-8.
162  static const unsigned kMax16BitCodeUnitSize = 3;
163  static inline uchar ValueOf(const byte* str, size_t length, size_t* cursor);
164 
166  static uchar ValueOfIncremental(byte next_byte, size_t* cursor, State* state,
167  Utf8IncrementalBuffer* buffer);
168  static uchar ValueOfIncrementalFinish(State* state);
169 
170  // Excludes non-characters from the set of valid code points.
171  static inline bool IsValidCharacter(uchar c);
172 
173  // Validate if the input has a valid utf-8 encoding. Unlike JS source code
174  // this validation function will accept any unicode code point, including
175  // kBadChar and BOMs.
176  //
177  // This method checks for:
178  // - valid utf-8 endcoding (e.g. no over-long encodings),
179  // - absence of surrogates,
180  // - valid code point range.
181  static bool ValidateEncoding(const byte* str, size_t length);
182 };
183 
184 struct Uppercase {
185  static bool Is(uchar c);
186 };
187 struct Letter {
188  static bool Is(uchar c);
189 };
190 #ifndef V8_INTL_SUPPORT
191 struct V8_EXPORT_PRIVATE ID_Start {
192  static bool Is(uchar c);
193 };
194 struct V8_EXPORT_PRIVATE ID_Continue {
195  static bool Is(uchar c);
196 };
197 struct V8_EXPORT_PRIVATE WhiteSpace {
198  static bool Is(uchar c);
199 };
200 #endif // !V8_INTL_SUPPORT
201 
202 // LineTerminator: 'JS_Line_Terminator' in point.properties
203 // ES#sec-line-terminators lists exactly 4 code points:
204 // LF (U+000A), CR (U+000D), LS(U+2028), PS(U+2029)
205 V8_INLINE bool IsLineTerminator(uchar c) {
206  return c == 0x000A || c == 0x000D || c == 0x2028 || c == 0x2029;
207 }
208 
209 V8_INLINE bool IsStringLiteralLineTerminator(uchar c) {
210  return c == 0x000A || c == 0x000D;
211 }
212 
213 #ifndef V8_INTL_SUPPORT
214 struct ToLowercase {
215  static const int kMaxWidth = 3;
216  static const bool kIsToLower = true;
217  static int Convert(uchar c,
218  uchar n,
219  uchar* result,
220  bool* allow_caching_ptr);
221 };
222 struct ToUppercase {
223  static const int kMaxWidth = 3;
224  static const bool kIsToLower = false;
225  static int Convert(uchar c,
226  uchar n,
227  uchar* result,
228  bool* allow_caching_ptr);
229 };
230 #endif
232  static const int kMaxWidth = 1;
233  static int Convert(uchar c,
234  uchar n,
235  uchar* result,
236  bool* allow_caching_ptr);
237 };
239  static const int kMaxWidth = 4;
240  static int Convert(uchar c,
241  uchar n,
242  uchar* result,
243  bool* allow_caching_ptr);
244 };
246  static const int kMaxWidth = 1;
247  static int Convert(uchar c,
248  uchar n,
249  uchar* result,
250  bool* allow_caching_ptr);
251 };
252 
253 } // namespace unibrow
254 
255 #endif // V8_UNICODE_H_
const int kMaxMappingSize
Definition: unicode.h:26