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      1 // Copyright 2011 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 #ifndef V8_UNICODE_H_
     29 #define V8_UNICODE_H_
     30 
     31 #include <sys/types.h>
     32 #include "globals.h"
     33 /**
     34  * \file
     35  * Definitions and convenience functions for working with unicode.
     36  */
     37 
     38 namespace unibrow {
     39 
     40 typedef unsigned int uchar;
     41 typedef unsigned char byte;
     42 
     43 /**
     44  * The max length of the result of converting the case of a single
     45  * character.
     46  */
     47 const int kMaxMappingSize = 4;
     48 
     49 template <class T, int size = 256>
     50 class Predicate {
     51  public:
     52   inline Predicate() { }
     53   inline bool get(uchar c);
     54  private:
     55   friend class Test;
     56   bool CalculateValue(uchar c);
     57   struct CacheEntry {
     58     inline CacheEntry() : code_point_(0), value_(0) { }
     59     inline CacheEntry(uchar code_point, bool value)
     60       : code_point_(code_point),
     61         value_(value) { }
     62     uchar code_point_ : 21;
     63     bool value_ : 1;
     64   };
     65   static const int kSize = size;
     66   static const int kMask = kSize - 1;
     67   CacheEntry entries_[kSize];
     68 };
     69 
     70 // A cache used in case conversion.  It caches the value for characters
     71 // that either have no mapping or map to a single character independent
     72 // of context.  Characters that map to more than one character or that
     73 // map differently depending on context are always looked up.
     74 template <class T, int size = 256>
     75 class Mapping {
     76  public:
     77   inline Mapping() { }
     78   inline int get(uchar c, uchar n, uchar* result);
     79  private:
     80   friend class Test;
     81   int CalculateValue(uchar c, uchar n, uchar* result);
     82   struct CacheEntry {
     83     inline CacheEntry() : code_point_(kNoChar), offset_(0) { }
     84     inline CacheEntry(uchar code_point, signed offset)
     85       : code_point_(code_point),
     86         offset_(offset) { }
     87     uchar code_point_;
     88     signed offset_;
     89     static const int kNoChar = (1 << 21) - 1;
     90   };
     91   static const int kSize = size;
     92   static const int kMask = kSize - 1;
     93   CacheEntry entries_[kSize];
     94 };
     95 
     96 class UnicodeData {
     97  private:
     98   friend class Test;
     99   static int GetByteCount();
    100   static const uchar kMaxCodePoint;
    101 };
    102 
    103 class Utf16 {
    104  public:
    105   static inline bool IsLeadSurrogate(int code) {
    106     if (code == kNoPreviousCharacter) return false;
    107     return (code & 0xfc00) == 0xd800;
    108   }
    109   static inline bool IsTrailSurrogate(int code) {
    110     if (code == kNoPreviousCharacter) return false;
    111     return (code & 0xfc00) == 0xdc00;
    112   }
    113 
    114   static inline int CombineSurrogatePair(uchar lead, uchar trail) {
    115     return 0x10000 + ((lead & 0x3ff) << 10) + (trail & 0x3ff);
    116   }
    117   static const int kNoPreviousCharacter = -1;
    118   static const uchar kMaxNonSurrogateCharCode = 0xffff;
    119   // Encoding a single UTF-16 code unit will produce 1, 2 or 3 bytes
    120   // of UTF-8 data.  The special case where the unit is a surrogate
    121   // trail produces 1 byte net, because the encoding of the pair is
    122   // 4 bytes and the 3 bytes that were used to encode the lead surrogate
    123   // can be reclaimed.
    124   static const int kMaxExtraUtf8BytesForOneUtf16CodeUnit = 3;
    125   // One UTF-16 surrogate is endoded (illegally) as 3 UTF-8 bytes.
    126   // The illegality stems from the surrogate not being part of a pair.
    127   static const int kUtf8BytesToCodeASurrogate = 3;
    128   static inline uint16_t LeadSurrogate(uint32_t char_code) {
    129     return 0xd800 + (((char_code - 0x10000) >> 10) & 0x3ff);
    130   }
    131   static inline uint16_t TrailSurrogate(uint32_t char_code) {
    132     return 0xdc00 + (char_code & 0x3ff);
    133   }
    134 };
    135 
    136 class Latin1 {
    137  public:
    138   static const unsigned kMaxChar = 0xff;
    139   // Returns 0 if character does not convert to single latin-1 character
    140   // or if the character doesn't not convert back to latin-1 via inverse
    141   // operation (upper to lower, etc).
    142   static inline uint16_t ConvertNonLatin1ToLatin1(uint16_t);
    143 };
    144 
    145 class Utf8 {
    146  public:
    147   static inline uchar Length(uchar chr, int previous);
    148   static inline unsigned EncodeOneByte(char* out, uint8_t c);
    149   static inline unsigned Encode(
    150       char* out, uchar c, int previous);
    151   static uchar CalculateValue(const byte* str,
    152                               unsigned length,
    153                               unsigned* cursor);
    154   static const uchar kBadChar = 0xFFFD;
    155   static const unsigned kMaxEncodedSize   = 4;
    156   static const unsigned kMaxOneByteChar   = 0x7f;
    157   static const unsigned kMaxTwoByteChar   = 0x7ff;
    158   static const unsigned kMaxThreeByteChar = 0xffff;
    159   static const unsigned kMaxFourByteChar  = 0x1fffff;
    160 
    161   // A single surrogate is coded as a 3 byte UTF-8 sequence, but two together
    162   // that match are coded as a 4 byte UTF-8 sequence.
    163   static const unsigned kBytesSavedByCombiningSurrogates = 2;
    164   static const unsigned kSizeOfUnmatchedSurrogate = 3;
    165   static inline uchar ValueOf(const byte* str,
    166                               unsigned length,
    167                               unsigned* cursor);
    168 };
    169 
    170 
    171 class Utf8DecoderBase {
    172  public:
    173   // Initialization done in subclass.
    174   inline Utf8DecoderBase();
    175   inline Utf8DecoderBase(uint16_t* buffer,
    176                          unsigned buffer_length,
    177                          const uint8_t* stream,
    178                          unsigned stream_length);
    179   inline unsigned Utf16Length() const { return utf16_length_; }
    180  protected:
    181   // This reads all characters and sets the utf16_length_.
    182   // The first buffer_length utf16 chars are cached in the buffer.
    183   void Reset(uint16_t* buffer,
    184              unsigned buffer_length,
    185              const uint8_t* stream,
    186              unsigned stream_length);
    187   static void WriteUtf16Slow(const uint8_t* stream,
    188                              uint16_t* data,
    189                              unsigned length);
    190   const uint8_t* unbuffered_start_;
    191   unsigned utf16_length_;
    192   bool last_byte_of_buffer_unused_;
    193  private:
    194   DISALLOW_COPY_AND_ASSIGN(Utf8DecoderBase);
    195 };
    196 
    197 template <unsigned kBufferSize>
    198 class Utf8Decoder : public Utf8DecoderBase {
    199  public:
    200   inline Utf8Decoder() {}
    201   inline Utf8Decoder(const char* stream, unsigned length);
    202   inline void Reset(const char* stream, unsigned length);
    203   inline unsigned WriteUtf16(uint16_t* data, unsigned length) const;
    204  private:
    205   uint16_t buffer_[kBufferSize];
    206 };
    207 
    208 
    209 struct Uppercase {
    210   static bool Is(uchar c);
    211 };
    212 struct Lowercase {
    213   static bool Is(uchar c);
    214 };
    215 struct Letter {
    216   static bool Is(uchar c);
    217 };
    218 struct Space {
    219   static bool Is(uchar c);
    220 };
    221 struct Number {
    222   static bool Is(uchar c);
    223 };
    224 struct WhiteSpace {
    225   static bool Is(uchar c);
    226 };
    227 struct LineTerminator {
    228   static bool Is(uchar c);
    229 };
    230 struct CombiningMark {
    231   static bool Is(uchar c);
    232 };
    233 struct ConnectorPunctuation {
    234   static bool Is(uchar c);
    235 };
    236 struct ToLowercase {
    237   static const int kMaxWidth = 3;
    238   static const bool kIsToLower = true;
    239   static int Convert(uchar c,
    240                      uchar n,
    241                      uchar* result,
    242                      bool* allow_caching_ptr);
    243 };
    244 struct ToUppercase {
    245   static const int kMaxWidth = 3;
    246   static const bool kIsToLower = false;
    247   static int Convert(uchar c,
    248                      uchar n,
    249                      uchar* result,
    250                      bool* allow_caching_ptr);
    251 };
    252 struct Ecma262Canonicalize {
    253   static const int kMaxWidth = 1;
    254   static int Convert(uchar c,
    255                      uchar n,
    256                      uchar* result,
    257                      bool* allow_caching_ptr);
    258 };
    259 struct Ecma262UnCanonicalize {
    260   static const int kMaxWidth = 4;
    261   static int Convert(uchar c,
    262                      uchar n,
    263                      uchar* result,
    264                      bool* allow_caching_ptr);
    265 };
    266 struct CanonicalizationRange {
    267   static const int kMaxWidth = 1;
    268   static int Convert(uchar c,
    269                      uchar n,
    270                      uchar* result,
    271                      bool* allow_caching_ptr);
    272 };
    273 
    274 }  // namespace unibrow
    275 
    276 #endif  // V8_UNICODE_H_
    277