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Member "pcre-8.42/pcre16_valid_utf16.c" (31 Jan 2014, 4519 Bytes) of package /linux/misc/pcre-8.42.tar.bz2:


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    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) 1997-2013 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-16 character
   42 strings. */
   43 
   44 
   45 #ifdef HAVE_CONFIG_H
   46 #include "config.h"
   47 #endif
   48 
   49 /* Generate code with 16 bit character support. */
   50 #define COMPILE_PCRE16
   51 
   52 #include "pcre_internal.h"
   53 
   54 
   55 /*************************************************
   56 *         Validate a UTF-16 string                *
   57 *************************************************/
   58 
   59 /* This function is called (optionally) at the start of compile or match, to
   60 check that a supposed UTF-16 string is actually valid. The early check means
   61 that subsequent code can assume it is dealing with a valid string. The check
   62 can be turned off for maximum performance, but the consequences of supplying an
   63 invalid string are then undefined.
   64 
   65 From release 8.21 more information about the details of the error are passed
   66 back in the returned value:
   67 
   68 PCRE_UTF16_ERR0  No error
   69 PCRE_UTF16_ERR1  Missing low surrogate at the end of the string
   70 PCRE_UTF16_ERR2  Invalid low surrogate
   71 PCRE_UTF16_ERR3  Isolated low surrogate
   72 PCRE_UTF16_ERR4  Unused (was non-character)
   73 
   74 Arguments:
   75   string       points to the string
   76   length       length of string, or -1 if the string is zero-terminated
   77   errp         pointer to an error position offset variable
   78 
   79 Returns:       = 0    if the string is a valid UTF-16 string
   80                > 0    otherwise, setting the offset of the bad character
   81 */
   82 
   83 int
   84 PRIV(valid_utf)(PCRE_PUCHAR string, int length, int *erroroffset)
   85 {
   86 #ifdef SUPPORT_UTF
   87 register PCRE_PUCHAR p;
   88 register pcre_uint32 c;
   89 
   90 if (length < 0)
   91   {
   92   for (p = string; *p != 0; p++);
   93   length = p - string;
   94   }
   95 
   96 for (p = string; length-- > 0; p++)
   97   {
   98   c = *p;
   99 
  100   if ((c & 0xf800) != 0xd800)
  101     {
  102     /* Normal UTF-16 code point. Neither high nor low surrogate. */
  103     }
  104   else if ((c & 0x0400) == 0)
  105     {
  106     /* High surrogate. Must be a followed by a low surrogate. */
  107     if (length == 0)
  108       {
  109       *erroroffset = p - string;
  110       return PCRE_UTF16_ERR1;
  111       }
  112     p++;
  113     length--;
  114     if ((*p & 0xfc00) != 0xdc00)
  115       {
  116       *erroroffset = p - string;
  117       return PCRE_UTF16_ERR2;
  118       }
  119     }
  120   else
  121     {
  122     /* Isolated low surrogate. Always an error. */
  123     *erroroffset = p - string;
  124     return PCRE_UTF16_ERR3;
  125     }
  126   }
  127 
  128 #else  /* SUPPORT_UTF */
  129 (void)(string);  /* Keep picky compilers happy */
  130 (void)(length);
  131 (void)(erroroffset);
  132 #endif /* SUPPORT_UTF */
  133 
  134 return PCRE_UTF16_ERR0;   /* This indicates success */
  135 }
  136 
  137 /* End of pcre16_valid_utf16.c */