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pswalk.c revision 1.1.1.6 
      1 /******************************************************************************
      2  *
      3  * Module Name: pswalk - Parser routines to walk parsed op tree(s)
      4  *
      5  *****************************************************************************/
      6 
      7 /*
      8  * Copyright (C) 2000 - 2016, Intel Corp.
      9  * All rights reserved.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions, and the following disclaimer,
     16  *    without modification.
     17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
     18  *    substantially similar to the "NO WARRANTY" disclaimer below
     19  *    ("Disclaimer") and any redistribution must be conditioned upon
     20  *    including a substantially similar Disclaimer requirement for further
     21  *    binary redistribution.
     22  * 3. Neither the names of the above-listed copyright holders nor the names
     23  *    of any contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * Alternatively, this software may be distributed under the terms of the
     27  * GNU General Public License ("GPL") version 2 as published by the Free
     28  * Software Foundation.
     29  *
     30  * NO WARRANTY
     31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
     34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
     40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     41  * POSSIBILITY OF SUCH DAMAGES.
     42  */
     43 
     44 #include "acpi.h"
     45 #include "accommon.h"
     46 #include "acparser.h"
     47 
     48 #define _COMPONENT          ACPI_PARSER
     49         ACPI_MODULE_NAME    ("pswalk")
     50 
     51 
     52 /*******************************************************************************
     53  *
     54  * FUNCTION:    AcpiPsDeleteParseTree
     55  *
     56  * PARAMETERS:  SubtreeRoot         - Root of tree (or subtree) to delete
     57  *
     58  * RETURN:      None
     59  *
     60  * DESCRIPTION: Delete a portion of or an entire parse tree.
     61  *
     62  ******************************************************************************/
     63 
     64 void
     65 AcpiPsDeleteParseTree (
     66     ACPI_PARSE_OBJECT       *SubtreeRoot)
     67 {
     68     ACPI_PARSE_OBJECT       *Op = SubtreeRoot;
     69     ACPI_PARSE_OBJECT       *Next = NULL;
     70     ACPI_PARSE_OBJECT       *Parent = NULL;
     71 
     72 
     73     ACPI_FUNCTION_TRACE_PTR (PsDeleteParseTree, SubtreeRoot);
     74 
     75 
     76     /* Visit all nodes in the subtree */
     77 
     78     while (Op)
     79     {
     80         /* Check if we are not ascending */
     81 
     82         if (Op != Parent)
     83         {
     84             /* Look for an argument or child of the current op */
     85 
     86             Next = AcpiPsGetArg (Op, 0);
     87             if (Next)
     88             {
     89                 /* Still going downward in tree (Op is not completed yet) */
     90 
     91                 Op = Next;
     92                 continue;
     93             }
     94         }
     95 
     96         /* No more children, this Op is complete. */
     97 
     98         Next = Op->Common.Next;
     99         Parent = Op->Common.Parent;
    100 
    101         AcpiPsFreeOp (Op);
    102 
    103         /* If we are back to the starting point, the walk is complete. */
    104 
    105         if (Op == SubtreeRoot)
    106         {
    107             return_VOID;
    108         }
    109 
    110         if (Next)
    111         {
    112             Op = Next;
    113         }
    114         else
    115         {
    116             Op = Parent;
    117         }
    118     }
    119 
    120     return_VOID;
    121 }
    122