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      1 // Copyright 2007-2008 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_INL_H_
     29 #define V8_UNICODE_INL_H_
     30 
     31 #include "unicode.h"
     32 
     33 namespace unibrow {
     34 
     35 template <class T, int s> bool Predicate<T, s>::get(uchar code_point) {
     36   CacheEntry entry = entries_[code_point & kMask];
     37   if (entry.code_point_ == code_point) return entry.value_;
     38   return CalculateValue(code_point);
     39 }
     40 
     41 template <class T, int s> bool Predicate<T, s>::CalculateValue(
     42     uchar code_point) {
     43   bool result = T::Is(code_point);
     44   entries_[code_point & kMask] = CacheEntry(code_point, result);
     45   return result;
     46 }
     47 
     48 template <class T, int s> int Mapping<T, s>::get(uchar c, uchar n,
     49     uchar* result) {
     50   CacheEntry entry = entries_[c & kMask];
     51   if (entry.code_point_ == c) {
     52     if (entry.offset_ == 0) {
     53       return 0;
     54     } else {
     55       result[0] = c + entry.offset_;
     56       return 1;
     57     }
     58   } else {
     59     return CalculateValue(c, n, result);
     60   }
     61 }
     62 
     63 template <class T, int s> int Mapping<T, s>::CalculateValue(uchar c, uchar n,
     64     uchar* result) {
     65   bool allow_caching = true;
     66   int length = T::Convert(c, n, result, &allow_caching);
     67   if (allow_caching) {
     68     if (length == 1) {
     69       entries_[c & kMask] = CacheEntry(c, result[0] - c);
     70       return 1;
     71     } else {
     72       entries_[c & kMask] = CacheEntry(c, 0);
     73       return 0;
     74     }
     75   } else {
     76     return length;
     77   }
     78 }
     79 
     80 
     81 unsigned Utf8::Encode(char* str, uchar c) {
     82   static const int kMask = ~(1 << 6);
     83   if (c <= kMaxOneByteChar) {
     84     str[0] = c;
     85     return 1;
     86   } else if (c <= kMaxTwoByteChar) {
     87     str[0] = 0xC0 | (c >> 6);
     88     str[1] = 0x80 | (c & kMask);
     89     return 2;
     90   } else if (c <= kMaxThreeByteChar) {
     91     str[0] = 0xE0 | (c >> 12);
     92     str[1] = 0x80 | ((c >> 6) & kMask);
     93     str[2] = 0x80 | (c & kMask);
     94     return 3;
     95   } else {
     96     str[0] = 0xF0 | (c >> 18);
     97     str[1] = 0x80 | ((c >> 12) & kMask);
     98     str[2] = 0x80 | ((c >> 6) & kMask);
     99     str[3] = 0x80 | (c & kMask);
    100     return 4;
    101   }
    102 }
    103 
    104 
    105 uchar Utf8::ValueOf(const byte* bytes, unsigned length, unsigned* cursor) {
    106   if (length <= 0) return kBadChar;
    107   byte first = bytes[0];
    108   // Characters between 0000 and 0007F are encoded as a single character
    109   if (first <= kMaxOneByteChar) {
    110     *cursor += 1;
    111     return first;
    112   }
    113   return CalculateValue(bytes, length, cursor);
    114 }
    115 
    116 unsigned Utf8::Length(uchar c) {
    117   if (c <= kMaxOneByteChar) {
    118     return 1;
    119   } else if (c <= kMaxTwoByteChar) {
    120     return 2;
    121   } else if (c <= kMaxThreeByteChar) {
    122     return 3;
    123   } else {
    124     return 4;
    125   }
    126 }
    127 
    128 uchar CharacterStream::GetNext() {
    129   uchar result = DecodeCharacter(buffer_, &cursor_);
    130   if (remaining_ == 1) {
    131     cursor_ = 0;
    132     FillBuffer();
    133   } else {
    134     remaining_--;
    135   }
    136   return result;
    137 }
    138 
    139 #if __BYTE_ORDER == __LITTLE_ENDIAN
    140 #define IF_LITTLE(expr) expr
    141 #define IF_BIG(expr)    ((void) 0)
    142 #elif __BYTE_ORDER == __BIG_ENDIAN
    143 #define IF_LITTLE(expr) ((void) 0)
    144 #define IF_BIG(expr)    expr
    145 #else
    146 #warning Unknown byte ordering
    147 #endif
    148 
    149 bool CharacterStream::EncodeAsciiCharacter(uchar c, byte* buffer,
    150     unsigned capacity, unsigned& offset) {
    151   if (offset >= capacity) return false;
    152   buffer[offset] = c;
    153   offset += 1;
    154   return true;
    155 }
    156 
    157 bool CharacterStream::EncodeNonAsciiCharacter(uchar c, byte* buffer,
    158     unsigned capacity, unsigned& offset) {
    159   unsigned aligned = (offset + 0x3) & ~0x3;
    160   if ((aligned + sizeof(uchar)) > capacity)
    161     return false;
    162   if (offset == aligned) {
    163     IF_LITTLE(*reinterpret_cast<uchar*>(buffer + aligned) = (c << 8) | 0x80);
    164     IF_BIG(*reinterpret_cast<uchar*>(buffer + aligned) = c | (1 << 31));
    165   } else {
    166     buffer[offset] = 0x80;
    167     IF_LITTLE(*reinterpret_cast<uchar*>(buffer + aligned) = c << 8);
    168     IF_BIG(*reinterpret_cast<uchar*>(buffer + aligned) = c);
    169   }
    170   offset = aligned + sizeof(uchar);
    171   return true;
    172 }
    173 
    174 bool CharacterStream::EncodeCharacter(uchar c, byte* buffer, unsigned capacity,
    175     unsigned& offset) {
    176   if (c <= Utf8::kMaxOneByteChar) {
    177     return EncodeAsciiCharacter(c, buffer, capacity, offset);
    178   } else {
    179     return EncodeNonAsciiCharacter(c, buffer, capacity, offset);
    180   }
    181 }
    182 
    183 uchar CharacterStream::DecodeCharacter(const byte* buffer, unsigned* offset) {
    184   byte b = buffer[*offset];
    185   if (b <= Utf8::kMaxOneByteChar) {
    186     (*offset)++;
    187     return b;
    188   } else {
    189     unsigned aligned = (*offset + 0x3) & ~0x3;
    190     *offset = aligned + sizeof(uchar);
    191     IF_LITTLE(return *reinterpret_cast<const uchar*>(buffer + aligned) >> 8);
    192     IF_BIG(return *reinterpret_cast<const uchar*>(buffer + aligned) &
    193                     ~(1 << 31));
    194   }
    195 }
    196 
    197 #undef IF_LITTLE
    198 #undef IF_BIG
    199 
    200 template <class R, class I, unsigned s>
    201 void InputBuffer<R, I, s>::FillBuffer() {
    202   buffer_ = R::ReadBlock(input_, util_buffer_, s, &remaining_, &offset_);
    203 }
    204 
    205 template <class R, class I, unsigned s>
    206 void InputBuffer<R, I, s>::Rewind() {
    207   Reset(input_);
    208 }
    209 
    210 template <class R, class I, unsigned s>
    211 void InputBuffer<R, I, s>::Reset(unsigned position, I input) {
    212   input_ = input;
    213   remaining_ = 0;
    214   cursor_ = 0;
    215   offset_ = position;
    216   buffer_ = R::ReadBlock(input_, util_buffer_, s, &remaining_, &offset_);
    217 }
    218 
    219 template <class R, class I, unsigned s>
    220 void InputBuffer<R, I, s>::Reset(I input) {
    221   Reset(0, input);
    222 }
    223 
    224 template <class R, class I, unsigned s>
    225 void InputBuffer<R, I, s>::Seek(unsigned position) {
    226   offset_ = position;
    227   buffer_ = R::ReadBlock(input_, util_buffer_, s, &remaining_, &offset_);
    228 }
    229 
    230 template <unsigned s>
    231 Utf8InputBuffer<s>::Utf8InputBuffer(const char* data, unsigned length)
    232     : InputBuffer<Utf8, Buffer<const char*>, s>(Buffer<const char*>(data,
    233                                                                     length)) {
    234 }
    235 
    236 }  // namespace unibrow
    237 
    238 #endif  // V8_UNICODE_INL_H_
    239