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pswalk.c revision 1.1.1.2 
      1 /******************************************************************************
      2  *
      3  * Module Name: pswalk - Parser routines to walk parsed op tree(s)
      4  *
      5  *****************************************************************************/
      6 
      7 /*
      8  * Copyright (C) 2000 - 2011, 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 
     45 #include "acpi.h"
     46 #include "accommon.h"
     47 #include "acparser.h"
     48 
     49 #define _COMPONENT          ACPI_PARSER
     50         ACPI_MODULE_NAME    ("pswalk")
     51 
     52 
     53 /*******************************************************************************
     54  *
     55  * FUNCTION:    AcpiPsDeleteParseTree
     56  *
     57  * PARAMETERS:  SubtreeRoot         - Root of tree (or subtree) to delete
     58  *
     59  * RETURN:      None
     60  *
     61  * DESCRIPTION: Delete a portion of or an entire parse tree.
     62  *
     63  ******************************************************************************/
     64 
     65 void
     66 AcpiPsDeleteParseTree (
     67     ACPI_PARSE_OBJECT       *SubtreeRoot)
     68 {
     69     ACPI_PARSE_OBJECT       *Op = SubtreeRoot;
     70     ACPI_PARSE_OBJECT       *Next = NULL;
     71     ACPI_PARSE_OBJECT       *Parent = NULL;
     72 
     73 
     74     ACPI_FUNCTION_TRACE_PTR (PsDeleteParseTree, SubtreeRoot);
     75 
     76 
     77     /* Visit all nodes in the subtree */
     78 
     79     while (Op)
     80     {
     81         /* Check if we are not ascending */
     82 
     83         if (Op != Parent)
     84         {
     85             /* Look for an argument or child of the current op */
     86 
     87             Next = AcpiPsGetArg (Op, 0);
     88             if (Next)
     89             {
     90                 /* Still going downward in tree (Op is not completed yet) */
     91 
     92                 Op = Next;
     93                 continue;
     94             }
     95         }
     96 
     97         /* No more children, this Op is complete. */
     98 
     99         Next = Op->Common.Next;
    100         Parent = Op->Common.Parent;
    101 
    102         AcpiPsFreeOp (Op);
    103 
    104         /* If we are back to the starting point, the walk is complete. */
    105 
    106         if (Op == SubtreeRoot)
    107         {
    108             return_VOID;
    109         }
    110         if (Next)
    111         {
    112             Op = Next;
    113         }
    114         else
    115         {
    116             Op = Parent;
    117         }
    118     }
    119 
    120     return_VOID;
    121 }
    122