LXR linux/drivers/acpi/parser/pswalk.c

   1/******************************************************************************
   2 *
   3 * Module Name: pswalk - Parser routines to walk parsed op tree(s)
   4 *
   5 *****************************************************************************/
   6
   7/*
   8 * Copyright (C) 2000 - 2008, 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/acpi.h>
  45#include <acpi/acparser.h>
  46
  47#define _COMPONENT          ACPI_PARSER
  48ACPI_MODULE_NAME("pswalk")
  49
  50/*******************************************************************************
  51 *
  52 * FUNCTION:    acpi_ps_delete_parse_tree
  53 *
  54 * PARAMETERS:  subtree_root        - Root of tree (or subtree) to delete
  55 *
  56 * RETURN:      None
  57 *
  58 * DESCRIPTION: Delete a portion of or an entire parse tree.
  59 *
  60 ******************************************************************************/
  61void acpi_ps_delete_parse_tree(union acpi_parse_object *subtree_root)
  62{
  63        union acpi_parse_object *op = subtree_root;
  64        union acpi_parse_object *next = NULL;
  65        union acpi_parse_object *parent = NULL;
  66
  67        ACPI_FUNCTION_TRACE_PTR(ps_delete_parse_tree, subtree_root);
  68
  69        /* Visit all nodes in the subtree */
  70
  71        while (op) {
  72
  73                /* Check if we are not ascending */
  74
  75                if (op != parent) {
  76
  77                        /* Look for an argument or child of the current op */
  78
  79                        next = acpi_ps_get_arg(op, 0);
  80                        if (next) {
  81
  82                                /* Still going downward in tree (Op is not completed yet) */
  83
  84                                op = next;
  85                                continue;
  86                        }
  87                }
  88
  89                /* No more children, this Op is complete. */
  90
  91                next = op->common.next;
  92                parent = op->common.parent;
  93
  94                acpi_ps_free_op(op);
  95
  96                /* If we are back to the starting point, the walk is complete. */
  97
  98                if (op == subtree_root) {
  99                        return_VOID;
 100                }
 101                if (next) {
 102                        op = next;
 103                } else {
 104                        op = parent;
 105                }
 106        }
 107
 108        return_VOID;
 109}
 110