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/utils.h"
11 /**
12  * \file
13  * Definitions and convenience functions for working with unicode.
14  */
15 
16 namespace unibrow {
17 
18 typedef unsigned int uchar;
19 typedef unsigned char byte;
20 
21 /**
22  * The max length of the result of converting the case of a single
23  * character.
24  */
25 const int kMaxMappingSize = 4;
26 
27 template <class T, int size = 256>
28 class Predicate {
29  public:
Predicate()30   inline Predicate() { }
31   inline bool get(uchar c);
32 
33  private:
34   friend class Test;
35   bool CalculateValue(uchar c);
36   class CacheEntry {
37    public:
CacheEntry()38     inline CacheEntry()
39         : bit_field_(CodePointField::encode(0) | ValueField::encode(0)) {}
CacheEntry(uchar code_point,bool value)40     inline CacheEntry(uchar code_point, bool value)
41         : bit_field_(CodePointField::encode(code_point) |
42                      ValueField::encode(value)) {}
43 
code_point()44     uchar code_point() const { return CodePointField::decode(bit_field_); }
value()45     bool value() const { return ValueField::decode(bit_field_); }
46 
47    private:
48     class CodePointField : public v8::internal::BitField<uchar, 0, 21> {};
49     class ValueField : public v8::internal::BitField<bool, 21, 1> {};
50 
51     uint32_t bit_field_;
52   };
53   static const int kSize = size;
54   static const int kMask = kSize - 1;
55   CacheEntry entries_[kSize];
56 };
57 
58 
59 // A cache used in case conversion.  It caches the value for characters
60 // that either have no mapping or map to a single character independent
61 // of context.  Characters that map to more than one character or that
62 // map differently depending on context are always looked up.
63 template <class T, int size = 256>
64 class Mapping {
65  public:
Mapping()66   inline Mapping() { }
67   inline int get(uchar c, uchar n, uchar* result);
68  private:
69   friend class Test;
70   int CalculateValue(uchar c, uchar n, uchar* result);
71   struct CacheEntry {
CacheEntryCacheEntry72     inline CacheEntry() : code_point_(kNoChar), offset_(0) { }
CacheEntryCacheEntry73     inline CacheEntry(uchar code_point, signed offset)
74       : code_point_(code_point),
75         offset_(offset) { }
76     uchar code_point_;
77     signed offset_;
78     static const int kNoChar = (1 << 21) - 1;
79   };
80   static const int kSize = size;
81   static const int kMask = kSize - 1;
82   CacheEntry entries_[kSize];
83 };
84 
85 
86 class UnicodeData {
87  private:
88   friend class Test;
89   static int GetByteCount();
90   static const uchar kMaxCodePoint;
91 };
92 
93 
94 class Utf16 {
95  public:
IsSurrogatePair(int lead,int trail)96   static inline bool IsSurrogatePair(int lead, int trail) {
97     return IsLeadSurrogate(lead) && IsTrailSurrogate(trail);
98   }
IsLeadSurrogate(int code)99   static inline bool IsLeadSurrogate(int code) {
100     if (code == kNoPreviousCharacter) return false;
101     return (code & 0xfc00) == 0xd800;
102   }
IsTrailSurrogate(int code)103   static inline bool IsTrailSurrogate(int code) {
104     if (code == kNoPreviousCharacter) return false;
105     return (code & 0xfc00) == 0xdc00;
106   }
107 
CombineSurrogatePair(uchar lead,uchar trail)108   static inline int CombineSurrogatePair(uchar lead, uchar trail) {
109     return 0x10000 + ((lead & 0x3ff) << 10) + (trail & 0x3ff);
110   }
111   static const int kNoPreviousCharacter = -1;
112   static const uchar kMaxNonSurrogateCharCode = 0xffff;
113   // Encoding a single UTF-16 code unit will produce 1, 2 or 3 bytes
114   // of UTF-8 data.  The special case where the unit is a surrogate
115   // trail produces 1 byte net, because the encoding of the pair is
116   // 4 bytes and the 3 bytes that were used to encode the lead surrogate
117   // can be reclaimed.
118   static const int kMaxExtraUtf8BytesForOneUtf16CodeUnit = 3;
119   // One UTF-16 surrogate is endoded (illegally) as 3 UTF-8 bytes.
120   // The illegality stems from the surrogate not being part of a pair.
121   static const int kUtf8BytesToCodeASurrogate = 3;
LeadSurrogate(uint32_t char_code)122   static inline uint16_t LeadSurrogate(uint32_t char_code) {
123     return 0xd800 + (((char_code - 0x10000) >> 10) & 0x3ff);
124   }
TrailSurrogate(uint32_t char_code)125   static inline uint16_t TrailSurrogate(uint32_t char_code) {
126     return 0xdc00 + (char_code & 0x3ff);
127   }
128 };
129 
130 
131 class Utf8 {
132  public:
133   static inline uchar Length(uchar chr, int previous);
134   static inline unsigned EncodeOneByte(char* out, uint8_t c);
135   static inline unsigned Encode(char* out,
136                                 uchar c,
137                                 int previous,
138                                 bool replace_invalid = false);
139   static uchar CalculateValue(const byte* str, size_t length, size_t* cursor);
140 
141   // The unicode replacement character, used to signal invalid unicode
142   // sequences (e.g. an orphan surrogate) when converting to a UTF-8 encoding.
143   static const uchar kBadChar = 0xFFFD;
144   static const unsigned kMaxEncodedSize   = 4;
145   static const unsigned kMaxOneByteChar   = 0x7f;
146   static const unsigned kMaxTwoByteChar   = 0x7ff;
147   static const unsigned kMaxThreeByteChar = 0xffff;
148   static const unsigned kMaxFourByteChar  = 0x1fffff;
149 
150   // A single surrogate is coded as a 3 byte UTF-8 sequence, but two together
151   // that match are coded as a 4 byte UTF-8 sequence.
152   static const unsigned kBytesSavedByCombiningSurrogates = 2;
153   static const unsigned kSizeOfUnmatchedSurrogate = 3;
154   // The maximum size a single UTF-16 code unit may take up when encoded as
155   // UTF-8.
156   static const unsigned kMax16BitCodeUnitSize  = 3;
157   static inline uchar ValueOf(const byte* str, size_t length, size_t* cursor);
158 };
159 
160 struct Uppercase {
161   static bool Is(uchar c);
162 };
163 struct Lowercase {
164   static bool Is(uchar c);
165 };
166 struct Letter {
167   static bool Is(uchar c);
168 };
169 struct ID_Start {
170   static bool Is(uchar c);
171 };
172 struct ID_Continue {
173   static bool Is(uchar c);
174 };
175 struct WhiteSpace {
176   static bool Is(uchar c);
177 };
178 struct LineTerminator {
179   static bool Is(uchar c);
180 };
181 struct ToLowercase {
182   static const int kMaxWidth = 3;
183   static const bool kIsToLower = true;
184   static int Convert(uchar c,
185                      uchar n,
186                      uchar* result,
187                      bool* allow_caching_ptr);
188 };
189 struct ToUppercase {
190   static const int kMaxWidth = 3;
191   static const bool kIsToLower = false;
192   static int Convert(uchar c,
193                      uchar n,
194                      uchar* result,
195                      bool* allow_caching_ptr);
196 };
197 struct Ecma262Canonicalize {
198   static const int kMaxWidth = 1;
199   static int Convert(uchar c,
200                      uchar n,
201                      uchar* result,
202                      bool* allow_caching_ptr);
203 };
204 struct Ecma262UnCanonicalize {
205   static const int kMaxWidth = 4;
206   static int Convert(uchar c,
207                      uchar n,
208                      uchar* result,
209                      bool* allow_caching_ptr);
210 };
211 struct CanonicalizationRange {
212   static const int kMaxWidth = 1;
213   static int Convert(uchar c,
214                      uchar n,
215                      uchar* result,
216                      bool* allow_caching_ptr);
217 };
218 
219 }  // namespace unibrow
220 
221 #endif  // V8_UNICODE_H_
222