138 lines
5.3 KiB
C
138 lines
5.3 KiB
C
/*************************************************
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* Perl-Compatible Regular Expressions *
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*************************************************/
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/* PCRE is a library of functions to support regular expressions whose syntax
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and semantics are as close as possible to those of the Perl 5 language.
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Written by Philip Hazel
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Copyright (c) 1997-2008 University of Cambridge
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-----------------------------------------------------------------------------
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the University of Cambridge nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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-----------------------------------------------------------------------------
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*/
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/* This module contains an internal function that tests a compiled pattern to
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see if it was compiled with the opposite endianness. If so, it uses an
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auxiliary local function to flip the appropriate bytes. */
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "pcre_internal.h"
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/*************************************************
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* Flip bytes in an integer *
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*************************************************/
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/* This function is called when the magic number in a regex doesn't match, in
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order to flip its bytes to see if we are dealing with a pattern that was
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compiled on a host of different endianness. If so, this function is used to
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flip other byte values.
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Arguments:
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value the number to flip
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n the number of bytes to flip (assumed to be 2 or 4)
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Returns: the flipped value
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*/
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static unsigned long int
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byteflip(unsigned long int value, int n)
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{
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if (n == 2) return ((value & 0x00ff) << 8) | ((value & 0xff00) >> 8);
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return ((value & 0x000000ff) << 24) |
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((value & 0x0000ff00) << 8) |
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((value & 0x00ff0000) >> 8) |
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((value & 0xff000000) >> 24);
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}
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/*************************************************
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* Test for a byte-flipped compiled regex *
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*************************************************/
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/* This function is called from pcre_exec(), pcre_dfa_exec(), and also from
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pcre_fullinfo(). Its job is to test whether the regex is byte-flipped - that
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is, it was compiled on a system of opposite endianness. The function is called
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only when the native MAGIC_NUMBER test fails. If the regex is indeed flipped,
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we flip all the relevant values into a different data block, and return it.
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Arguments:
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re points to the regex
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study points to study data, or NULL
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internal_re points to a new regex block
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internal_study points to a new study block
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Returns: the new block if is is indeed a byte-flipped regex
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NULL if it is not
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*/
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real_pcre *
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_pcre_try_flipped(const real_pcre *re, real_pcre *internal_re,
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const pcre_study_data *study, pcre_study_data *internal_study)
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{
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if (byteflip(re->magic_number, sizeof(re->magic_number)) != MAGIC_NUMBER)
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return NULL;
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*internal_re = *re; /* To copy other fields */
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internal_re->size = byteflip(re->size, sizeof(re->size));
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internal_re->options = byteflip(re->options, sizeof(re->options));
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internal_re->flags = (pcre_uint16)byteflip(re->flags, sizeof(re->flags));
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internal_re->top_bracket =
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(pcre_uint16)byteflip(re->top_bracket, sizeof(re->top_bracket));
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internal_re->top_backref =
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(pcre_uint16)byteflip(re->top_backref, sizeof(re->top_backref));
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internal_re->first_byte =
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(pcre_uint16)byteflip(re->first_byte, sizeof(re->first_byte));
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internal_re->req_byte =
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(pcre_uint16)byteflip(re->req_byte, sizeof(re->req_byte));
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internal_re->name_table_offset =
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(pcre_uint16)byteflip(re->name_table_offset, sizeof(re->name_table_offset));
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internal_re->name_entry_size =
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(pcre_uint16)byteflip(re->name_entry_size, sizeof(re->name_entry_size));
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internal_re->name_count =
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(pcre_uint16)byteflip(re->name_count, sizeof(re->name_count));
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if (study != NULL)
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{
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*internal_study = *study; /* To copy other fields */
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internal_study->size = byteflip(study->size, sizeof(study->size));
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internal_study->options = byteflip(study->options, sizeof(study->options));
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}
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return internal_re;
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}
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/* End of pcre_tryflipped.c */
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