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/* $Id$ */ |
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|
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/************************************************* |
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* Perl-Compatible Regular Expressions * |
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*************************************************/ |
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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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|
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Written by Philip Hazel |
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Copyright (c) 1997-2005 University of Cambridge |
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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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|
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#include "pcre_internal.h" |
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|
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|
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/************************************************* |
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* Flip bytes in an integer * |
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*************************************************/ |
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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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|
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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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|
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Returns: the flipped value |
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*/ |
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|
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static long int |
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byteflip(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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|
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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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|
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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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|
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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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|
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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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|
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EXPORT 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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|
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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->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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|
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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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|
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return internal_re; |
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} |
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|
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/* End of pcre_tryflipped.c */ |