pcre_refcount.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) 1997-2008 University of Cambridge

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*/


/* This module contains the external function pcre_refcount(), which is an
auxiliary function that can be used to maintain a reference count in a compiled
pattern data block. This might be helpful in applications where the block is
shared by different users. */


#include "config.h"

#include "pcre_internal.h"


/*************************************************
*           Maintain reference count             *
*************************************************/

/* The reference count is a 16-bit field, initialized to zero. It is not
possible to transfer a non-zero count from one host to a different host that
has a different byte order - though I can't see why anyone in their right mind
would ever want to do that!

Arguments:
  argument_re   points to compiled code
  adjust        value to add to the count

Returns:        the (possibly updated) count value (a non-negative number), or
                a negative error number
*/

PCRE_EXP_DEFN int PCRE_CALL_CONVENTION
pcre_refcount(pcre *argument_re, int adjust)
{
real_pcre *re = (real_pcre *)argument_re;
if (re == NULL) return PCRE_ERROR_NULL;
re->ref_count = (-adjust > re->ref_count)? 0 :
                (adjust + re->ref_count > 65535)? 65535 :
                re->ref_count + adjust;
return re->ref_count;
}

/* End of pcre_refcount.c */