JavaScriptCore/pcre/pcre_xclass.cpp

   1 /* This is JavaScriptCore's variant of the PCRE library. While this library
   2 started out as a copy of PCRE, many of the features of PCRE have been
   3 removed. This library now supports only the regular expression features
   4 required by the JavaScript language specification, and has only the functions
   5 needed by JavaScriptCore and the rest of WebKit.
   6
   7                  Originally written by Philip Hazel
   8            Copyright (c) 1997-2006 University of Cambridge
   9     Copyright (C) 2002, 2004, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  10
  11 -----------------------------------------------------------------------------
  12 Redistribution and use in source and binary forms, with or without
  13 modification, are permitted provided that the following conditions are met:
  14
  15     * Redistributions of source code must retain the above copyright notice,
  16       this list of conditions and the following disclaimer.
  17
  18     * Redistributions in binary form must reproduce the above copyright
  19       notice, this list of conditions and the following disclaimer in the
  20       documentation and/or other materials provided with the distribution.
  21
  22     * Neither the name of the University of Cambridge nor the names of its
  23       contributors may be used to endorse or promote products derived from
  24       this software without specific prior written permission.
  25
  26 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  27 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  30 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  32 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  33 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  34 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  36 POSSIBILITY OF SUCH DAMAGE.
  37 -----------------------------------------------------------------------------
  38 */
  39
  40 /* This module contains an internal function that is used to match an extended
  41 class (one that contains characters whose values are > 255). */
  42
  43 #include "config.h"
  44 #include "pcre_internal.h"
  45
  46 /*************************************************
  47 *       Match character against an XCLASS        *
  48 *************************************************/
  49
  50 /* This function is called to match a character against an extended class that
  51 might contain values > 255.
  52
  53 Arguments:
  54   c           the character
  55   data        points to the flag byte of the XCLASS data
  56
  57 Returns:      true if character matches, else false
  58 */
  59
  60 /* Get the next UTF-8 character, advancing the pointer. This is called when we
  61  know we are in UTF-8 mode. */
  62
  63 static inline void getUTF8CharAndAdvancePointer(int& c, const unsigned char*& subjectPtr)
  64 {
  65     c = *subjectPtr++;
  66     if ((c & 0xc0) == 0xc0) {
  67         int gcaa = jsc_pcre_utf8_table4[c & 0x3f];  /* Number of additional bytes */
  68         int gcss = 6 * gcaa;
  69         c = (c & jsc_pcre_utf8_table3[gcaa]) << gcss;
  70         while (gcaa-- > 0) {
  71             gcss -= 6;
  72             c |= (*subjectPtr++ & 0x3f) << gcss;
  73         }
  74     }
  75 }
  76
  77 bool jsc_pcre_xclass(int c, const unsigned char* data)
  78 {
  79     bool negated = (*data & XCL_NOT);
  80
  81     /* Character values < 256 are matched against a bitmap, if one is present. If
  82      not, we still carry on, because there may be ranges that start below 256 in the
  83      additional data. */
  84
  85     if (c < 256) {
  86         if ((*data & XCL_MAP) != 0 && (data[1 + c/8] & (1 << (c&7))) != 0)
  87             return !negated;   /* char found */
  88     }
  89
  90     /* First skip the bit map if present. Then match against the list of Unicode
  91      properties or large chars or ranges that end with a large char. We won't ever
  92      encounter XCL_PROP or XCL_NOTPROP when UCP support is not compiled. */
  93
  94     if ((*data++ & XCL_MAP) != 0)
  95         data += 32;
  96
  97     int t;
  98     while ((t = *data++) != XCL_END) {
  99         if (t == XCL_SINGLE) {
 100             int x;
 101             getUTF8CharAndAdvancePointer(x, data);
 102             if (c == x)
 103                 return !negated;
 104         }
 105         else if (t == XCL_RANGE) {
 106             int x, y;
 107             getUTF8CharAndAdvancePointer(x, data);
 108             getUTF8CharAndAdvancePointer(y, data);
 109             if (c >= x && c <= y)
 110                 return !negated;
 111         }
 112     }
 113
 114     return negated;   /* char did not match */
 115 }