Annotation of embedaddon/php/ext/pcre/pcrelib/pcre_try_flipped.c, revision 1.1.1.1
1.1 misho 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) 1997-2009 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 "config.h"
47:
48: #include "pcre_internal.h"
49:
50:
51: /*************************************************
52: * Flip bytes in an integer *
53: *************************************************/
54:
55: /* This function is called when the magic number in a regex doesn't match, in
56: order to flip its bytes to see if we are dealing with a pattern that was
57: compiled on a host of different endianness. If so, this function is used to
58: flip other byte values.
59:
60: Arguments:
61: value the number to flip
62: n the number of bytes to flip (assumed to be 2 or 4)
63:
64: Returns: the flipped value
65: */
66:
67: static unsigned long int
68: byteflip(unsigned long int value, int n)
69: {
70: if (n == 2) return ((value & 0x00ff) << 8) | ((value & 0xff00) >> 8);
71: return ((value & 0x000000ff) << 24) |
72: ((value & 0x0000ff00) << 8) |
73: ((value & 0x00ff0000) >> 8) |
74: ((value & 0xff000000) >> 24);
75: }
76:
77:
78:
79: /*************************************************
80: * Test for a byte-flipped compiled regex *
81: *************************************************/
82:
83: /* This function is called from pcre_exec(), pcre_dfa_exec(), and also from
84: pcre_fullinfo(). Its job is to test whether the regex is byte-flipped - that
85: is, it was compiled on a system of opposite endianness. The function is called
86: only when the native MAGIC_NUMBER test fails. If the regex is indeed flipped,
87: we flip all the relevant values into a different data block, and return it.
88:
89: Arguments:
90: re points to the regex
91: study points to study data, or NULL
92: internal_re points to a new regex block
93: internal_study points to a new study block
94:
95: Returns: the new block if is is indeed a byte-flipped regex
96: NULL if it is not
97: */
98:
99: real_pcre *
100: _pcre_try_flipped(const real_pcre *re, real_pcre *internal_re,
101: const pcre_study_data *study, pcre_study_data *internal_study)
102: {
103: if (byteflip(re->magic_number, sizeof(re->magic_number)) != MAGIC_NUMBER)
104: return NULL;
105:
106: *internal_re = *re; /* To copy other fields */
107: internal_re->size = byteflip(re->size, sizeof(re->size));
108: internal_re->options = byteflip(re->options, sizeof(re->options));
109: internal_re->flags = (pcre_uint16)byteflip(re->flags, sizeof(re->flags));
110: internal_re->top_bracket =
111: (pcre_uint16)byteflip(re->top_bracket, sizeof(re->top_bracket));
112: internal_re->top_backref =
113: (pcre_uint16)byteflip(re->top_backref, sizeof(re->top_backref));
114: internal_re->first_byte =
115: (pcre_uint16)byteflip(re->first_byte, sizeof(re->first_byte));
116: internal_re->req_byte =
117: (pcre_uint16)byteflip(re->req_byte, sizeof(re->req_byte));
118: internal_re->name_table_offset =
119: (pcre_uint16)byteflip(re->name_table_offset, sizeof(re->name_table_offset));
120: internal_re->name_entry_size =
121: (pcre_uint16)byteflip(re->name_entry_size, sizeof(re->name_entry_size));
122: internal_re->name_count =
123: (pcre_uint16)byteflip(re->name_count, sizeof(re->name_count));
124:
125: if (study != NULL)
126: {
127: *internal_study = *study; /* To copy other fields */
128: internal_study->size = byteflip(study->size, sizeof(study->size));
129: internal_study->flags = byteflip(study->flags, sizeof(study->flags));
130: internal_study->minlength = byteflip(study->minlength,
131: sizeof(study->minlength));
132: }
133:
134: return internal_re;
135: }
136:
137: /* End of pcre_tryflipped.c */
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