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pcre_refcount.c
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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) 1997-2008 University of Cambridge
10 
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12 Redistribution and use in source and binary forms, with or without
13 modification, are permitted provided that the following conditions are met:
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15  * Redistributions of source code must retain the above copyright notice,
16  this list of conditions and the following disclaimer.
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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"
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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 the external function pcre_refcount(), which is an
42 auxiliary function that can be used to maintain a reference count in a compiled
43 pattern data block. This might be helpful in applications where the block is
44 shared by different users. */
45 
46 
47 #define HAVE_CONFIG_H
48 #ifdef HAVE_CONFIG_H
49 #include "config.h"
50 #endif
51 
52 #include "pcre_internal.h"
53 
54 
55 /*************************************************
56 * Maintain reference count *
57 *************************************************/
58 
59 /* The reference count is a 16-bit field, initialized to zero. It is not
60 possible to transfer a non-zero count from one host to a different host that
61 has a different byte order - though I can't see why anyone in their right mind
62 would ever want to do that!
63 
64 Arguments:
65  argument_re points to compiled code
66  adjust value to add to the count
67 
68 Returns: the (possibly updated) count value (a non-negative number), or
69  a negative error number
70 */
71 
72 PCRE_EXP_DEFN int PCRE_CALL_CONVENTION
73 pcre_refcount(pcre *argument_re, int adjust)
74 {
75 real_pcre *re = (real_pcre *)argument_re;
76 if (re == NULL) return PCRE_ERROR_NULL;
77 re->ref_count = (-adjust > re->ref_count)? 0 :
78  (adjust + re->ref_count > 65535)? 65535 :
79  re->ref_count + adjust;
80 return re->ref_count;
81 }
82 
83 /* End of pcre_refcount.c */