lldb/examples/scripting/tree_utils.py

   1 """
   2 # ===-- tree_utils.py ---------------------------------------*- Python -*-===//
   3 #
   4 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 # See https://llvm.org/LICENSE.txt for license information.
   6 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 #
   8 # ===---------------------------------------------------------------------===//
   9
  10 tree_utils.py  - A set of functions for examining binary
  11 search trees, based on the example search tree defined in
  12 dictionary.c.  These functions contain calls to LLDB API
  13 functions, and assume that the LLDB Python module has been
  14 imported.
  15
  16 For a thorough explanation of how the DFS function works, and
  17 for more information about dictionary.c go to
  18 http://lldb.llvm.org/scripting.html
  19 """
  20
  21 from __future__ import print_function
  22
  23
  24 def DFS(root, word, cur_path):
  25     """
  26     Recursively traverse a binary search tree containing
  27     words sorted alphabetically, searching for a particular
  28     word in the tree.  Also maintains a string representing
  29     the path from the root of the tree to the current node.
  30     If the word is found in the tree, return the path string.
  31     Otherwise return an empty string.
  32
  33     This function assumes the binary search tree is
  34     the one defined in dictionary.c  It uses LLDB API
  35     functions to examine and traverse the tree nodes.
  36     """
  37
  38     # Get pointer field values out of node 'root'
  39
  40     root_word_ptr = root.GetChildMemberWithName("word")
  41     left_child_ptr = root.GetChildMemberWithName("left")
  42     right_child_ptr = root.GetChildMemberWithName("right")
  43
  44     # Get the word out of the word pointer and strip off
  45     # surrounding quotes (added by call to GetSummary).
  46
  47     root_word = root_word_ptr.GetSummary()
  48     end = len(root_word) - 1
  49     if root_word[0] == '"' and root_word[end] == '"':
  50         root_word = root_word[1:end]
  51     end = len(root_word) - 1
  52     if root_word[0] == '\'' and root_word[end] == '\'':
  53         root_word = root_word[1:end]
  54
  55     # Main depth first search
  56
  57     if root_word == word:
  58         return cur_path
  59     elif word < root_word:
  60
  61         # Check to see if left child is NULL
  62
  63         if left_child_ptr.GetValue() is None:
  64             return ""
  65         else:
  66             cur_path = cur_path + "L"
  67             return DFS(left_child_ptr, word, cur_path)
  68     else:
  69
  70         # Check to see if right child is NULL
  71
  72         if right_child_ptr.GetValue() is None:
  73             return ""
  74         else:
  75             cur_path = cur_path + "R"
  76             return DFS(right_child_ptr, word, cur_path)
  77
  78
  79 def tree_size(root):
  80     """
  81     Recursively traverse a binary search tree, counting
  82     the nodes in the tree.  Returns the final count.
  83
  84     This function assumes the binary search tree is
  85     the one defined in dictionary.c  It uses LLDB API
  86     functions to examine and traverse the tree nodes.
  87     """
  88     if (root.GetValue is None):
  89         return 0
  90
  91     if (int(root.GetValue(), 16) == 0):
  92         return 0
  93
  94     left_size = tree_size(root.GetChildAtIndex(1))
  95     right_size = tree_size(root.GetChildAtIndex(2))
  96
  97     total_size = left_size + right_size + 1
  98     return total_size
  99
 100
 101 def print_tree(root):
 102     """
 103     Recursively traverse a binary search tree, printing out
 104     the words at the nodes in alphabetical order (the
 105     search order for the binary tree).
 106
 107     This function assumes the binary search tree is
 108     the one defined in dictionary.c  It uses LLDB API
 109     functions to examine and traverse the tree nodes.
 110     """
 111     if (root.GetChildAtIndex(1).GetValue() is not None) and (
 112             int(root.GetChildAtIndex(1).GetValue(), 16) != 0):
 113         print_tree(root.GetChildAtIndex(1))
 114
 115     print(root.GetChildAtIndex(0).GetSummary())
 116
 117     if (root.GetChildAtIndex(2).GetValue() is not None) and (
 118             int(root.GetChildAtIndex(2).GetValue(), 16) != 0):
 119         print_tree(root.GetChildAtIndex(2))