Home | History | Annotate | Download | only in dist 
      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 */
    138