"Fossies" - the Fresh Open Source Software Archive

Member "tin-2.6.2/pcre/pcre_valid_utf8.c" (23 Aug 2021, 4460 Bytes) of package /linux/misc/tin-2.6.2.tar.xz:

    1 /*************************************************
    2 *      Perl-Compatible Regular Expressions       *
    3 *************************************************/
    4 
    5 /* PCRE is a library of functions to support regular expressions whose syntax
    6 and semantics are as close as possible to those of the Perl 5 language.
    7 
    8                        Written by Philip Hazel
    9            Copyright (c) 1997-2006 University of Cambridge
   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 /* This module contains an internal function for validating UTF-8 character
   42 strings. */
   43 
   44 
   45 #include "pcre_internal.h"
   46 
   47 
   48 /*************************************************
   49 *         Validate a UTF-8 string                *
   50 *************************************************/
   51 
   52 /* This function is called (optionally) at the start of compile or match, to
   53 validate that a supposed UTF-8 string is actually valid. The early check means
   54 that subsequent code can assume it is dealing with a valid string. The check
   55 can be turned off for maximum performance, but the consequences of supplying
   56 an invalid string are then undefined.
   57 
   58 Arguments:
   59   string       points to the string
   60   length       length of string, or -1 if the string is zero-terminated
   61 
   62 Returns:       < 0    if the string is a valid UTF-8 string
   63                >= 0   otherwise; the value is the offset of the bad byte
   64 */
   65 
   66 int
   67 _pcre_valid_utf8(const uschar *string, int length)
   68 {
   69 register const uschar *p;
   70 
   71 if (length < 0)
   72   {
   73   for (p = string; *p != 0; p++);
   74   length = p - string;
   75   }
   76 
   77 for (p = string; length-- > 0; p++)
   78   {
   79   register int ab;
   80   register int c = *p;
   81   if (c < 128) continue;
   82   if (c < 0xc0) return p - string;
   83   ab = _pcre_utf8_table4[c & 0x3f];  /* Number of additional bytes */
   84   if (length < ab) return p - string;
   85   length -= ab;
   86 
   87   /* Check top bits in the second byte */
   88   if ((*(++p) & 0xc0) != 0x80) return p - string;
   89 
   90   /* Check for overlong sequences for each different length */
   91   switch (ab)
   92     {
   93     /* Check for xx00 000x */
   94     case 1:
   95     if ((c & 0x3e) == 0) return p - string;
   96     continue;   /* We know there aren't any more bytes to check */
   97 
   98     /* Check for 1110 0000, xx0x xxxx */
   99     case 2:
  100     if (c == 0xe0 && (*p & 0x20) == 0) return p - string;
  101     break;
  102 
  103     /* Check for 1111 0000, xx00 xxxx */
  104     case 3:
  105     if (c == 0xf0 && (*p & 0x30) == 0) return p - string;
  106     break;
  107 
  108     /* Check for 1111 1000, xx00 0xxx */
  109     case 4:
  110     if (c == 0xf8 && (*p & 0x38) == 0) return p - string;
  111     break;
  112 
  113     /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */
  114     case 5:
  115     if (c == 0xfe || c == 0xff ||
  116        (c == 0xfc && (*p & 0x3c) == 0)) return p - string;
  117     break;
  118     }
  119 
  120   /* Check for valid bytes after the 2nd, if any; all must start 10 */
  121   while (--ab > 0)
  122     {
  123     if ((*(++p) & 0xc0) != 0x80) return p - string;
  124     }
  125   }
  126 
  127 return -1;
  128 }
  129 
  130 /* End of pcre_valid_utf8.c */