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Member "tin-2.4.1/pcre/pcre_try_flipped.c" (28 Aug 2013, 5354 Bytes) of package /linux/misc/tin-2.4.1.tar.gz:


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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) 1997-2006 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 that tests a compiled pattern to
   42 see if it was compiled with the opposite endianness. If so, it uses an
   43 auxiliary local function to flip the appropriate bytes. */
   44 
   45 
   46 #include "pcre_internal.h"
   47 
   48 
   49 /*************************************************
   50 *         Flip bytes in an integer               *
   51 *************************************************/
   52 
   53 /* This function is called when the magic number in a regex doesn't match, in
   54 order to flip its bytes to see if we are dealing with a pattern that was
   55 compiled on a host of different endianness. If so, this function is used to
   56 flip other byte values.
   57 
   58 Arguments:
   59   value        the number to flip
   60   n            the number of bytes to flip (assumed to be 2 or 4)
   61 
   62 Returns:       the flipped value
   63 */
   64 
   65 static unsigned long int
   66 byteflip(unsigned long int value, int n)
   67 {
   68 if (n == 2) return ((value & 0x00ff) << 8) | ((value & 0xff00) >> 8);
   69 return ((value & 0x000000ff) << 24) |
   70        ((value & 0x0000ff00) <<  8) |
   71        ((value & 0x00ff0000) >>  8) |
   72        ((value & 0xff000000) >> 24);
   73 }
   74 
   75 
   76 
   77 /*************************************************
   78 *       Test for a byte-flipped compiled regex   *
   79 *************************************************/
   80 
   81 /* This function is called from pcre_exec(), pcre_dfa_exec(), and also from
   82 pcre_fullinfo(). Its job is to test whether the regex is byte-flipped - that
   83 is, it was compiled on a system of opposite endianness. The function is called
   84 only when the native MAGIC_NUMBER test fails. If the regex is indeed flipped,
   85 we flip all the relevant values into a different data block, and return it.
   86 
   87 Arguments:
   88   re               points to the regex
   89   study            points to study data, or NULL
   90   internal_re      points to a new regex block
   91   internal_study   points to a new study block
   92 
   93 Returns:           the new block if is is indeed a byte-flipped regex
   94                    NULL if it is not
   95 */
   96 
   97 real_pcre *
   98 _pcre_try_flipped(const real_pcre *re, real_pcre *internal_re,
   99   const pcre_study_data *study, pcre_study_data *internal_study)
  100 {
  101 if (byteflip(re->magic_number, sizeof(re->magic_number)) != MAGIC_NUMBER)
  102   return NULL;
  103 
  104 *internal_re = *re;           /* To copy other fields */
  105 internal_re->size = byteflip(re->size, sizeof(re->size));
  106 internal_re->options = byteflip(re->options, sizeof(re->options));
  107 internal_re->top_bracket =
  108   (pcre_uint16)byteflip(re->top_bracket, sizeof(re->top_bracket));
  109 internal_re->top_backref =
  110   (pcre_uint16)byteflip(re->top_backref, sizeof(re->top_backref));
  111 internal_re->first_byte =
  112   (pcre_uint16)byteflip(re->first_byte, sizeof(re->first_byte));
  113 internal_re->req_byte =
  114   (pcre_uint16)byteflip(re->req_byte, sizeof(re->req_byte));
  115 internal_re->name_table_offset =
  116   (pcre_uint16)byteflip(re->name_table_offset, sizeof(re->name_table_offset));
  117 internal_re->name_entry_size =
  118   (pcre_uint16)byteflip(re->name_entry_size, sizeof(re->name_entry_size));
  119 internal_re->name_count =
  120   (pcre_uint16)byteflip(re->name_count, sizeof(re->name_count));
  121 
  122 if (study != NULL)
  123   {
  124   *internal_study = *study;   /* To copy other fields */
  125   internal_study->size = byteflip(study->size, sizeof(study->size));
  126   internal_study->options = byteflip(study->options, sizeof(study->options));
  127   }
  128 
  129 return internal_re;
  130 }
  131 
  132 /* End of pcre_tryflipped.c */