pcre/pcre_valid_utf8.cpp

   1 #include "avmplus.h"
   2
   3 /*************************************************
   4 *      Perl-Compatible Regular Expressions       *
   5 *************************************************/
   6
   7 /* PCRE is a library of functions to support regular expressions whose syntax
   8 and semantics are as close as possible to those of the Perl 5 language.
   9
  10                        Written by Philip Hazel
  11            Copyright (c) 1997-2007 University of Cambridge
  12
  13 -----------------------------------------------------------------------------
  14 Redistribution and use in source and binary forms, with or without
  15 modification, are permitted provided that the following conditions are met:
  16
  17     * Redistributions of source code must retain the above copyright notice,
  18       this list of conditions and the following disclaimer.
  19
  20     * Redistributions in binary form must reproduce the above copyright
  21       notice, this list of conditions and the following disclaimer in the
  22       documentation and/or other materials provided with the distribution.
  23
  24     * Neither the name of the University of Cambridge nor the names of its
  25       contributors may be used to endorse or promote products derived from
  26       this software without specific prior written permission.
  27
  28 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  29 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  32 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  33 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  34 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  35 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  36 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  37 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 POSSIBILITY OF SUCH DAMAGE.
  39 -----------------------------------------------------------------------------
  40 */
  41
  42
  43 /* This module contains an internal function for validating UTF-8 character
  44 strings. */
  45
  46
  47 #include "config.h"
  48
  49 #include "pcre_internal.h"
  50
  51
  52 /*************************************************
  53 *         Validate a UTF-8 string                *
  54 *************************************************/
  55
  56 /* This function is called (optionally) at the start of compile or match, to
  57 validate that a supposed UTF-8 string is actually valid. The early check means
  58 that subsequent code can assume it is dealing with a valid string. The check
  59 can be turned off for maximum performance, but the consequences of supplying
  60 an invalid string are then undefined.
  61
  62 Originally, this function checked according to RFC 2279, allowing for values in
  63 the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in
  64 the canonical format. Once somebody had pointed out RFC 3629 to me (it
  65 obsoletes 2279), additional restrictions were applies. The values are now
  66 limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the
  67 subrange 0xd000 to 0xdfff is excluded.
  68
  69 Arguments:
  70   string       points to the string
  71   length       length of string, or -1 if the string is zero-terminated
  72
  73 Returns:       < 0    if the string is a valid UTF-8 string
  74                >= 0   otherwise; the value is the offset of the bad byte
  75 */
  76
  77 int
  78 _pcre_valid_utf8(const uschar *string, int length)
  79 {
  80 #ifdef SUPPORT_UTF8
  81 register const uschar *p;
  82
  83 if (length < 0)
  84   {
  85   for (p = string; *p != 0; p++){ /*nothing*/ }
  86   length = p - string;
  87   }
  88
  89 for (p = string; length-- > 0; p++)
  90   {
  91   register int ab;
  92   register int c = *p;
  93   if (c < 128) continue;
  94   if (c < 0xc0) return p - string;
  95   ab = _pcre_utf8_table4[c & 0x3f];     /* Number of additional bytes */
  96   if (length < ab || ab > 3) return p - string;
  97   length -= ab;
  98
  99   /* Check top bits in the second byte */
 100   if ((*(++p) & 0xc0) != 0x80) return p - string;
 101
 102   /* Check for overlong sequences for each different length, and for the
 103   excluded range 0xd000 to 0xdfff.  */
 104
 105   switch (ab)
 106     {
 107     /* Check for xx00 000x (overlong sequence) */
 108
 109     case 1:
 110     if ((c & 0x3e) == 0) return p - string;
 111     continue;   /* We know there aren't any more bytes to check */
 112
 113     /* Check for 1110 0000, xx0x xxxx (overlong sequence) or
 114                  1110 1101, 1010 xxxx (0xd000 - 0xdfff) */
 115
 116     case 2:
 117     if ((c == 0xe0 && (*p & 0x20) == 0) ||
 118         (c == 0xed && *p >= 0xa0))
 119       return p - string;
 120     break;
 121
 122     /* Check for 1111 0000, xx00 xxxx (overlong sequence) or
 123        greater than 0x0010ffff (f4 8f bf bf) */
 124
 125     case 3:
 126     if ((c == 0xf0 && (*p & 0x30) == 0) ||
 127         (c > 0xf4 ) ||
 128         (c == 0xf4 && *p > 0x8f))
 129       return p - string;
 130     break;
 131
 132 #if 0
 133     /* These cases can no longer occur, as we restrict to a maximum of four
 134     bytes nowadays. Leave the code here in case we ever want to add an option
 135     for longer sequences. */
 136
 137     /* Check for 1111 1000, xx00 0xxx */
 138     case 4:
 139     if (c == 0xf8 && (*p & 0x38) == 0) return p - string;
 140     break;
 141
 142     /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */
 143     case 5:
 144     if (c == 0xfe || c == 0xff ||
 145        (c == 0xfc && (*p & 0x3c) == 0)) return p - string;
 146     break;
 147 #endif
 148
 149     }
 150
 151   /* Check for valid bytes after the 2nd, if any; all must start 10 */
 152   while (--ab > 0)
 153     {
 154     if ((*(++p) & 0xc0) != 0x80) return p - string;
 155     }
 156   }
 157 #endif
 158
 159 return -1;
 160 }
 161
 162 /* End of pcre_valid_utf8.c */