pcre/ucpinternal.h

   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 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 /*************************************************
  41 *           Unicode Property Table handler       *
  42 *************************************************/
  43
  44 /* Internal header file defining the layout of the bits in each pair of 32-bit
  45 words that form a data item in the table. */
  46
  47 typedef struct cnode {
  48   unsigned f0;
  49   unsigned f1;
  50 } cnode;
  51
  52 /* Things for the f0 field */
  53
  54 #define f0_scriptmask   0xff000000  /* Mask for script field */
  55 #define f0_scriptshift          24  /* Shift for script value */
  56 #define f0_rangeflag    0x00f00000  /* Flag for a range item */
  57 #define f0_charmask     0x001fffff  /* Mask for code point value */
  58
  59 /* Things for the f1 field */
  60
  61 #define f1_typemask     0xfc000000  /* Mask for char type field */
  62 #define f1_typeshift            26  /* Shift for the type field */
  63 #define f1_rangemask    0x0000ffff  /* Mask for a range offset */
  64 #define f1_casemask     0x0000ffff  /* Mask for a case offset */
  65 #define f1_caseneg      0xffff8000  /* Bits for negation */
  66
  67 /* The data consists of a vector of structures of type cnode. The two unsigned
  68 32-bit integers are used as follows:
  69
  70 (f0) (1) The most significant byte holds the script number. The numbers are
  71          defined by the enum in ucp.h.
  72
  73      (2) The 0x00800000 bit is set if this entry defines a range of characters.
  74          It is not set if this entry defines a single character
  75
  76      (3) The 0x00600000 bits are spare.
  77
  78      (4) The 0x001fffff bits contain the code point. No Unicode code point will
  79          ever be greater than 0x0010ffff, so this should be OK for ever.
  80
  81 (f1) (1) The 0xfc000000 bits contain the character type number. The numbers are
  82          defined by an enum in ucp.h.
  83
  84      (2) The 0x03ff0000 bits are spare.
  85
  86      (3) The 0x0000ffff bits contain EITHER the unsigned offset to the top of
  87          range if this entry defines a range, OR the *signed* offset to the
  88          character's "other case" partner if this entry defines a single
  89          character. There is no partner if the value is zero.
  90
  91 -------------------------------------------------------------------------------
  92 | script (8) |.|.|.| codepoint (21) || type (6) |.|.| spare (8) | offset (16) |
  93 -------------------------------------------------------------------------------
  94               | | |                              | |
  95               | | |-> spare                      | |-> spare
  96               | |                                |
  97               | |-> spare                        |-> spare
  98               |
  99               |-> range flag
 100
 101 The upper/lower casing information is set only for characters that come in
 102 pairs. The non-one-to-one mappings in the Unicode data are ignored.
 103
 104 When searching the data, proceed as follows:
 105
 106 (1) Set up for a binary chop search.
 107
 108 (2) If the top is not greater than the bottom, the character is not in the
 109     table. Its type must therefore be "Cn" ("Undefined").
 110
 111 (3) Find the middle vector element.
 112
 113 (4) Extract the code point and compare. If equal, we are done.
 114
 115 (5) If the test character is smaller, set the top to the current point, and
 116     goto (2).
 117
 118 (6) If the current entry defines a range, compute the last character by adding
 119     the offset, and see if the test character is within the range. If it is,
 120     we are done.
 121
 122 (7) Otherwise, set the bottom to one element past the current point and goto
 123     (2).
 124 */
 125
 126 /* End of ucpinternal.h */