branches/pcre16/pcre_try_flipped.c

/*************************************************
*      Perl-Compatible Regular Expressions       *
*************************************************/

/* PCRE is a library of functions to support regular expressions whose syntax
and semantics are as close as possible to those of the Perl 5 language.

                       Written by Philip Hazel
           Copyright (c) 1997-2007 University of Cambridge

-----------------------------------------------------------------------------
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.

    * Neither the name of the University of Cambridge nor the names of its
      contributors may be used to endorse or promote products derived from
      this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
-----------------------------------------------------------------------------
*/


/* This module contains an internal function that tests a compiled pattern to
see if it was compiled with the opposite endianness. If so, it uses an
auxiliary local function to flip the appropriate bytes. */


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "pcre_internal.h"


/*************************************************
*         Flip bytes in an integer               *
*************************************************/

/* This function is called when the magic number in a regex doesn't match, in
order to flip its bytes to see if we are dealing with a pattern that was
compiled on a host of different endianness. If so, this function is used to
flip other byte values.

Arguments:
  value        the number to flip
  n            the number of bytes to flip (assumed to be 2 or 4)

Returns:       the flipped value
*/

static unsigned long int
byteflip(unsigned long int value, int n)
{
if (n == 2) return ((value & 0x00ff) << 8) | ((value & 0xff00) >> 8);
return ((value & 0x000000ff) << 24) |
       ((value & 0x0000ff00) <<  8) |
       ((value & 0x00ff0000) >>  8) |
       ((value & 0xff000000) >> 24);
}


/*************************************************
*       Test for a byte-flipped compiled regex   *
*************************************************/

/* This function is called from pcre_exec(), pcre_dfa_exec(), and also from
pcre_fullinfo(). Its job is to test whether the regex is byte-flipped - that
is, it was compiled on a system of opposite endianness. The function is called
only when the native MAGIC_NUMBER test fails. If the regex is indeed flipped,
we flip all the relevant values into a different data block, and return it.

Arguments:
  re               points to the regex
  study            points to study data, or NULL
  internal_re      points to a new regex block
  internal_study   points to a new study block

Returns:           the new block if is is indeed a byte-flipped regex
                   NULL if it is not
*/

real_pcre *
_pcre_try_flipped(const real_pcre *re, real_pcre *internal_re,
  const pcre_study_data *study, pcre_study_data *internal_study)
{
if (byteflip(re->magic_number, sizeof(re->magic_number)) != MAGIC_NUMBER)
  return NULL;

*internal_re = *re;           /* To copy other fields */
internal_re->size = byteflip(re->size, sizeof(re->size));
internal_re->options = byteflip(re->options, sizeof(re->options));
internal_re->top_bracket =
  (pcre_uint16)byteflip(re->top_bracket, sizeof(re->top_bracket));
internal_re->top_backref =
  (pcre_uint16)byteflip(re->top_backref, sizeof(re->top_backref));
internal_re->first_byte =
  (pcre_uint16)byteflip(re->first_byte, sizeof(re->first_byte));
internal_re->req_byte =
  (pcre_uint16)byteflip(re->req_byte, sizeof(re->req_byte));
internal_re->name_table_offset =
  (pcre_uint16)byteflip(re->name_table_offset, sizeof(re->name_table_offset));
internal_re->name_entry_size =
  (pcre_uint16)byteflip(re->name_entry_size, sizeof(re->name_entry_size));
internal_re->name_count =
  (pcre_uint16)byteflip(re->name_count, sizeof(re->name_count));

if (study != NULL)
  {
  *internal_study = *study;   /* To copy other fields */
  internal_study->size = byteflip(study->size, sizeof(study->size));
  internal_study->options = byteflip(study->options, sizeof(study->options));
  }

return internal_re;
}

/* End of pcre_tryflipped.c */
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) 1997-2007 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	#ifdef HAVE_CONFIG_H
47	#include <config.h>
48	#endif
49
50	#include "pcre_internal.h"
51
52
53	/*************************************************
54	* Flip bytes in an integer *
55	*************************************************/
56
57	/* This function is called when the magic number in a regex doesn't match, in
58	order to flip its bytes to see if we are dealing with a pattern that was
59	compiled on a host of different endianness. If so, this function is used to
60	flip other byte values.
61
62	Arguments:
63	value the number to flip
64	n the number of bytes to flip (assumed to be 2 or 4)
65
66	Returns: the flipped value
67	*/
68
69	static unsigned long int
70	byteflip(unsigned long int value, int n)
71	{
72	if (n == 2) return ((value & 0x00ff) << 8) \| ((value & 0xff00) >> 8);
73	return ((value & 0x000000ff) << 24) \|
74	((value & 0x0000ff00) << 8) \|
75	((value & 0x00ff0000) >> 8) \|
76	((value & 0xff000000) >> 24);
77	}
78
79
80
81	/*************************************************
82	* Test for a byte-flipped compiled regex *
83	*************************************************/
84
85	/* This function is called from pcre_exec(), pcre_dfa_exec(), and also from
86	pcre_fullinfo(). Its job is to test whether the regex is byte-flipped - that
87	is, it was compiled on a system of opposite endianness. The function is called
88	only when the native MAGIC_NUMBER test fails. If the regex is indeed flipped,
89	we flip all the relevant values into a different data block, and return it.
90
91	Arguments:
92	re points to the regex
93	study points to study data, or NULL
94	internal_re points to a new regex block
95	internal_study points to a new study block
96
97	Returns: the new block if is is indeed a byte-flipped regex
98	NULL if it is not
99	*/
100
101	real_pcre *
102	_pcre_try_flipped(const real_pcre re, real_pcre internal_re,
103	const pcre_study_data study, pcre_study_data internal_study)
104	{
105	if (byteflip(re->magic_number, sizeof(re->magic_number)) != MAGIC_NUMBER)
106	return NULL;
107
108	internal_re = re; /* To copy other fields */
109	internal_re->size = byteflip(re->size, sizeof(re->size));
110	internal_re->options = byteflip(re->options, sizeof(re->options));
111	internal_re->top_bracket =
112	(pcre_uint16)byteflip(re->top_bracket, sizeof(re->top_bracket));
113	internal_re->top_backref =
114	(pcre_uint16)byteflip(re->top_backref, sizeof(re->top_backref));
115	internal_re->first_byte =
116	(pcre_uint16)byteflip(re->first_byte, sizeof(re->first_byte));
117	internal_re->req_byte =
118	(pcre_uint16)byteflip(re->req_byte, sizeof(re->req_byte));
119	internal_re->name_table_offset =
120	(pcre_uint16)byteflip(re->name_table_offset, sizeof(re->name_table_offset));
121	internal_re->name_entry_size =
122	(pcre_uint16)byteflip(re->name_entry_size, sizeof(re->name_entry_size));
123	internal_re->name_count =
124	(pcre_uint16)byteflip(re->name_count, sizeof(re->name_count));
125
126	if (study != NULL)
127	{
128	internal_study = study; /* To copy other fields */
129	internal_study->size = byteflip(study->size, sizeof(study->size));
130	internal_study->options = byteflip(study->options, sizeof(study->options));
131	}
132
133	return internal_re;
134	}
135
136	/* End of pcre_tryflipped.c */
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