/[pcre]/code/trunk/pcre_compile.c
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revision 623 by ph10, Mon Jul 18 10:14:09 2011 UTC revision 624 by ph10, Tue Jul 19 10:43:28 2011 UTC
# Line 1975  for (code = first_significant_code(code Line 1975  for (code = first_significant_code(code
1975      }      }
1976    
1977    /* For a recursion/subroutine call, if its end has been reached, which    /* For a recursion/subroutine call, if its end has been reached, which
1978    implies a subroutine call, we can scan it. */    implies a backward reference subroutine call, we can scan it. If it's a
1979      forward reference subroutine call, we can't. To detect forward reference
1980      we have to scan up the list that is kept in the workspace. This function is
1981      called only when doing the real compile, not during the pre-compile that
1982      measures the size of the compiled pattern. */
1983    
1984    if (c == OP_RECURSE)    if (c == OP_RECURSE)
1985      {      {
1986      BOOL empty_branch = FALSE;      const uschar *scode;
1987      const uschar *scode = cd->start_code + GET(code, 1);      BOOL empty_branch;
1988    
1989        /* Test for forward reference */
1990    
1991        for (scode = cd->start_workspace; scode < cd->hwm; scode += LINK_SIZE)
1992          if (GET(scode, 0) == code + 1 - cd->start_code) return TRUE;
1993    
1994        /* Not a forward reference, test for completed backward reference */
1995    
1996        empty_branch = FALSE;
1997        scode = cd->start_code + GET(code, 1);
1998      if (GET(scode, 1) == 0) return TRUE;    /* Unclosed */      if (GET(scode, 1) == 0) return TRUE;    /* Unclosed */
1999    
2000        /* Completed backwards reference */
2001    
2002      do      do
2003        {        {
2004        if (could_be_empty_branch(scode, endcode, utf8, cd))        if (could_be_empty_branch(scode, endcode, utf8, cd))
# Line 1992  for (code = first_significant_code(code Line 2009  for (code = first_significant_code(code
2009        scode += GET(scode, 1);        scode += GET(scode, 1);
2010        }        }
2011      while (*scode == OP_ALT);      while (*scode == OP_ALT);
2012    
2013      if (!empty_branch) return FALSE;  /* All branches are non-empty */      if (!empty_branch) return FALSE;  /* All branches are non-empty */
2014      continue;      continue;
2015      }      }
# Line 2217  return TRUE; Line 2235  return TRUE;
2235  the current branch of the current pattern to see if it could match the empty  the current branch of the current pattern to see if it could match the empty
2236  string. If it could, we must look outwards for branches at other levels,  string. If it could, we must look outwards for branches at other levels,
2237  stopping when we pass beyond the bracket which is the subject of the recursion.  stopping when we pass beyond the bracket which is the subject of the recursion.
2238    This function is called only during the real compile, not during the
2239    pre-compile.
2240    
2241  Arguments:  Arguments:
2242    code        points to start of the recursion    code        points to start of the recursion
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