Class: PEROBS::SpaceTreeNode
- Inherits:
-
Object
- Object
- PEROBS::SpaceTreeNode
- Defined in:
- lib/perobs/SpaceTreeNode.rb
Overview
The SpaceTree keeps a complete list of all empty spaces in the FlatFile. Spaces are stored with size and address. The Tree is Tenerary Tree. The nodes can link to other nodes with smaller spaces, same spaces and bigger spaces.
Constant Summary collapse
- NODE_BYTES =
Each node can hold a reference to the parent, a lower, equal or larger size node and the actual value and the address in the FlatFile. Each of these entries is 8 bytes long.
6 * 8
- NODE_BYTES_FORMAT =
The pack/unpack format.
'Q6'
Instance Attribute Summary collapse
-
#blob_address ⇒ Object
Returns the value of attribute blob_address.
-
#equal ⇒ Object
readonly
Returns the value of attribute equal.
-
#larger ⇒ Object
readonly
Returns the value of attribute larger.
-
#node_address ⇒ Object
readonly
Returns the value of attribute node_address.
-
#parent ⇒ Object
Returns the value of attribute parent.
-
#size ⇒ Object
Returns the value of attribute size.
-
#smaller ⇒ Object
readonly
Returns the value of attribute smaller.
Class Method Summary collapse
-
.create(tree, blob_address = 0, size = 0, parent = nil) ⇒ Object
Create a new SpaceTreeNode.
-
.load(tree, node_address, unused = nil) ⇒ Object
Restore a node from the backing store at the given address and tree.
Instance Method Summary collapse
-
#==(node) ⇒ Boolean
Compare this node to another node.
-
#add_space(address, size) ⇒ Object
Add a new node for the given address and size to the tree.
-
#check(flat_file, count) ⇒ false, true
Check this node and all sub nodes for possible structural or logical errors.
-
#check_node_link(link, stack) ⇒ Boolean
Check the integrity of the given sub-node link and the parent link pointing back to this node.
- #delete_node ⇒ Object
-
#each ⇒ Object
Depth-first iterator for all nodes.
-
#find_equal_or_larger_space(size) ⇒ Array or nil
Return an address/size touple that matches the requested size or is larger than the requested size plus the overhead for another blob.
-
#find_largest_node ⇒ SpaceTreeNode
Find the node with the largest size in this sub-tree.
-
#find_matching_space(size) ⇒ Array or nil
Return an address/size touple that matches exactly the requested size.
-
#find_smallest_node ⇒ SpaceTreeNode
Find the node with the smallest size in this sub-tree.
-
#has_space?(address, size) ⇒ Boolean
Check if this node or any sub-node has an entry for the given address and size.
-
#initialize(tree, node_address, blob_address = 0, size = 0, parent = nil, smaller = nil, equal = nil, larger = nil) ⇒ SpaceTreeNode
constructor
Create a new SpaceTreeNode object.
-
#relink_parent(node) ⇒ Object
Replace the link in the parent node of the current node that points to the current node with the given node.
-
#save ⇒ Object
Save the node into the blob file.
- #set_link(name, node_or_address) ⇒ Object
- #set_size_and_address(size, address) ⇒ Object
-
#text_tree_prefix ⇒ String
The indentation and arch routing for the text tree.
-
#to_a ⇒ Array
Collects address and size touples of all nodes in the tree with a depth-first strategy and stores them in an Array.
-
#to_s ⇒ String
Textual version of the node data.
-
#to_tree_s ⇒ String
Convert the node and all child nodes into a tree like text form.
-
#uid ⇒ Integer
The node address since it uniquely identifies the Node.
-
#unlink_node(child_node) ⇒ Object
Remove a smaller/equal/larger link from the current node.
Constructor Details
#initialize(tree, node_address, blob_address = 0, size = 0, parent = nil, smaller = nil, equal = nil, larger = nil) ⇒ SpaceTreeNode
Create a new SpaceTreeNode object. If node_address is not nil, the data will be read from the SpaceTree file at the given node_address.
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# File 'lib/perobs/SpaceTreeNode.rb', line 61 def initialize(tree, node_address, blob_address = 0, size = 0, parent = nil, smaller = nil, equal = nil, larger = nil) @tree = tree if node_address <= 0 PEROBS.log.fatal "Node address (#{node_address}) must be larger than 0" end @node_address = node_address if blob_address < 0 PEROBS.log.fatal "Blob address (#{node_address}) must be larger than 0" end @blob_address = blob_address @size = size @parent = parent @smaller = smaller @equal = equal @larger = larger end |
Instance Attribute Details
#blob_address ⇒ Object
Returns the value of attribute blob_address.
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# File 'lib/perobs/SpaceTreeNode.rb', line 41 def blob_address @blob_address end |
#equal ⇒ Object (readonly)
Returns the value of attribute equal.
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# File 'lib/perobs/SpaceTreeNode.rb', line 42 def equal @equal end |
#larger ⇒ Object (readonly)
Returns the value of attribute larger.
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# File 'lib/perobs/SpaceTreeNode.rb', line 42 def larger @larger end |
#node_address ⇒ Object (readonly)
Returns the value of attribute node_address.
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# File 'lib/perobs/SpaceTreeNode.rb', line 42 def node_address @node_address end |
#parent ⇒ Object
Returns the value of attribute parent.
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# File 'lib/perobs/SpaceTreeNode.rb', line 42 def parent @parent end |
#size ⇒ Object
Returns the value of attribute size.
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# File 'lib/perobs/SpaceTreeNode.rb', line 41 def size @size end |
#smaller ⇒ Object (readonly)
Returns the value of attribute smaller.
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# File 'lib/perobs/SpaceTreeNode.rb', line 42 def smaller @smaller end |
Class Method Details
.create(tree, blob_address = 0, size = 0, parent = nil) ⇒ Object
Create a new SpaceTreeNode. This method should be used for the creation of new nodes instead of calling the constructor directly.
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# File 'lib/perobs/SpaceTreeNode.rb', line 85 def SpaceTreeNode::create(tree, blob_address = 0, size = 0, parent = nil) node_address = tree.nodes.free_address node = SpaceTreeNode.new(tree, node_address, blob_address, size, parent) tree.cache.insert(node) node end |
.load(tree, node_address, unused = nil) ⇒ Object
Restore a node from the backing store at the given address and tree.
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# File 'lib/perobs/SpaceTreeNode.rb', line 97 def SpaceTreeNode::load(tree, node_address, unused = nil) unless node_address > 0 PEROBS.log.fatal "node_address (#{node_address}) must be larger than 0" end unless (bytes = tree.nodes.retrieve_blob(node_address)) PEROBS.log.fatal "SpaceTreeNode at address #{node_address} does " + "not exist" end blob_address, size, parent_node_address, smaller_node_address, equal_node_address, larger_node_address = bytes.unpack(NODE_BYTES_FORMAT) parent = parent_node_address != 0 ? SpaceTreeNodeLink.new(tree, parent_node_address) : nil smaller = smaller_node_address != 0 ? SpaceTreeNodeLink.new(tree, smaller_node_address) : nil equal = equal_node_address != 0 ? SpaceTreeNodeLink.new(tree, equal_node_address) : nil larger = larger_node_address != 0 ? SpaceTreeNodeLink.new(tree, larger_node_address) : nil node = SpaceTreeNode.new(tree, node_address, blob_address, size, parent, smaller, equal, larger) tree.cache.insert(node, false) node end |
Instance Method Details
#==(node) ⇒ Boolean
Compare this node to another node.
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# File 'lib/perobs/SpaceTreeNode.rb', line 460 def ==(node) node && @node_address == node.node_address end |
#add_space(address, size) ⇒ Object
Add a new node for the given address and size to the tree.
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# File 'lib/perobs/SpaceTreeNode.rb', line 140 def add_space(address, size) node = self loop do if node.size == 0 # This happens only for the root node if the tree is empty. node.set_size_and_address(size, address) break elsif size < node.size # The new size is smaller than this node. if node.smaller # There is already a smaller node, so pass it on. node = node.smaller else # There is no smaller node yet, so we create a new one as a # smaller child of the current node. node.set_link('@smaller', SpaceTreeNode::create(@tree, address, size, node)) break end elsif size > node.size # The new size is larger than this node. if node.larger # There is already a larger node, so pass it on. node = node.larger else # There is no larger node yet, so we create a new one as a larger # child of the current node. node.set_link('@larger', SpaceTreeNode::create(@tree, address, size, node)) break end else # Same size as current node. Insert new node as equal child at top of # equal list. new_node = SpaceTreeNode::create(@tree, address, size, node) new_node.set_link('@equal', node.equal) node.set_link('@equal', new_node) break end end end |
#check(flat_file, count) ⇒ false, true
Check this node and all sub nodes for possible structural or logical errors.
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# File 'lib/perobs/SpaceTreeNode.rb', line 523 def check(flat_file, count) node_counter = 0 max_depth = 0 @tree.progressmeter.start('Checking space list entries', count) do |pm| each do |node, mode, stack| max_depth = stack.size if stack.size > max_depth case mode when :smaller if node.smaller return false unless node.check_node_link('smaller', stack) smaller_node = node.smaller if smaller_node.size >= node.size PEROBS.log.error "Smaller SpaceTreeNode size " + "(#{smaller_node}) is not smaller than #{node}" return false end end when :equal if node.equal return false unless node.check_node_link('equal', stack) equal_node = node.equal if equal_node.smaller || equal_node.larger PEROBS.log.error "Equal node #{equal_node} must not have " + "smaller/larger childs" return false end if node.size != equal_node.size PEROBS.log.error "Equal SpaceTreeNode size (#{equal_node}) " + "is not equal parent node #{node}" return false end end when :larger if node.larger return false unless node.check_node_link('larger', stack) larger_node = node.larger if larger_node.size <= node.size PEROBS.log.error "Larger SpaceTreeNode size " + "(#{larger_node}) is not larger than #{node}" return false end end when :on_exit if flat_file && !flat_file.has_space?(node.blob_address, node.size) PEROBS.log.error "SpaceTreeNode has space at offset " + "#{node.blob_address} of size #{node.size} that isn't " + "available in the FlatFile." return false end pm.update(node_counter += 1) end end end PEROBS.log.debug "#{node_counter} SpaceTree nodes checked" PEROBS.log.debug "Maximum tree depth is #{max_depth}" return true end |
#check_node_link(link, stack) ⇒ Boolean
Check the integrity of the given sub-node link and the parent link pointing back to this node.
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# File 'lib/perobs/SpaceTreeNode.rb', line 593 def check_node_link(link, stack) if (node = instance_variable_get('@' + link)) # Node links must only be of class SpaceTreeNodeLink unless node.nil? || node.is_a?(SpaceTreeNodeLink) PEROBS.log.error "Node link #{link} of node #{to_s} " + "is of class #{node.class}" return false end # Link must not point back to self. if node == self PEROBS.log.error "#{link} address of node " + "#{node.to_s} points to self #{to_s}" return false end # Link must not point to any of the parent nodes. if stack.include?(node) PEROBS.log.error "#{link} address of node #{to_s} " + "points to parent node #{node}" return false end # Parent link of node must point back to self. if node.parent != self PEROBS.log.error "@#{link} node #{node.to_s} does not have parent " + "link pointing " + "to parent node #{to_s}. Pointing at " + "#{node.parent.nil? ? 'nil' : node.parent.to_s} instead." return false end end true end |
#delete_node ⇒ Object
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# File 'lib/perobs/SpaceTreeNode.rb', line 340 def delete_node if @equal # Replace the current node with the next @equal node. @equal.set_link('@smaller', @smaller) if @smaller @equal.set_link('@larger', @larger) if @larger relink_parent(@equal) elsif @smaller && @larger.nil? # We have no @larger node, so we can just replace the current node # with the @smaller node. relink_parent(@smaller) elsif @larger && @smaller.nil? # We have no @smaller node, wo we can just replace the current node # with the @larger node. relink_parent(@larger) elsif @smaller && @larger # Find the largest node in the smaller sub-node. This node will # replace the current node. node = @smaller.find_largest_node if node != @smaller # If the found node is not the direct @smaller node, attach the # smaller sub-node of the found node to the parent of the found # node. node.relink_parent(node.smaller) # The @smaller sub node of the current node is attached to the # @smaller link of the found node. node.set_link('@smaller', @smaller) end # Attach the @larger sub-node of the current node to the @larger link # of the found node. node.set_link('@larger', @larger) # Point the link in the parent of the current node to the found node. relink_parent(node) else # The node is a leaf node. relink_parent(nil) end @tree.delete_node(@node_address) if @parent end |
#each ⇒ Object
Depth-first iterator for all nodes. The iterator yields the given block at 5 points for any found node. The mode variable indicates the point. :on_enter Coming from the parent we’ve entered the node for the first
time
:smaller We are about to follow the link to the smaller sub-node :equal We are about to follow the link to the equal sub-node :larger We are about to follow the link to the larger sub-node :on_exit We have completed this node
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# File 'lib/perobs/SpaceTreeNode.rb', line 306 def each # We use a non-recursive implementation to traverse the tree. This stack # keeps track of all the known still to be checked nodes. stack = [ [ self, :on_enter ] ] while !stack.empty? node, mode = stack.pop # Empty trees only have a dummy node that has no parent, and a size # and address of 0. break if node.size == 0 && node.blob_address == 0 && node.parent.nil? case mode when :on_enter yield(node, mode, stack) stack.push([ node, :smaller ]) when :smaller yield(node, mode, stack) if node.smaller stack.push([ node, :equal ]) stack.push([ node.smaller, :on_enter]) if node.smaller when :equal yield(node, mode, stack) if node.equal stack.push([ node, :larger ]) stack.push([ node.equal, :on_enter]) if node.equal when :larger yield(node, mode, stack) if node.larger stack.push([ node, :on_exit]) stack.push([ node.larger, :on_enter]) if node.larger when :on_exit yield(node, mode, stack) end end end |
#find_equal_or_larger_space(size) ⇒ Array or nil
Return an address/size touple that matches the requested size or is larger than the requested size plus the overhead for another blob. Return nil if nothing was found.
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# File 'lib/perobs/SpaceTreeNode.rb', line 242 def find_equal_or_larger_space(size) node = self loop do if node.size < size if node.larger # The current space is not yet large enough. If we have a larger sub # node check that one next. node = node.larger else break end elsif node.size == size || node.size >= size * 2 + FlatFileBlobHeader::LENGTH # We've found a space that is either a perfect match or is large # enough to hold at least one more record. Remove it from the list and # return it. actual_size = node.size address = node.blob_address node.delete_node return [ address, actual_size ] elsif node.smaller # The current space is larger than size but not large enough for an # additional record. So check if we have a perfect match in the # smaller brach if available. node = node.smaller else break end end return nil end |
#find_largest_node ⇒ SpaceTreeNode
Find the node with the largest size in this sub-tree.
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# File 'lib/perobs/SpaceTreeNode.rb', line 420 def find_largest_node node = self loop do if node.larger node = node.larger else # We've found a 'leaf' node. return node end end end |
#find_matching_space(size) ⇒ Array or nil
Return an address/size touple that matches exactly the requested size. Return nil if nothing was found.
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# File 'lib/perobs/SpaceTreeNode.rb', line 211 def find_matching_space(size) node = self loop do if node.size < size if node.larger # The current space is not yet large enough. If we have a larger sub # node check that one next. node = node.larger else break end elsif node.size == size # We've found a space that is an exact match. Remove it from the # list and return it. address = node.blob_address node.delete_node return [ address, size ] else break end end return nil end |
#find_smallest_node ⇒ SpaceTreeNode
Find the node with the smallest size in this sub-tree.
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# File 'lib/perobs/SpaceTreeNode.rb', line 406 def find_smallest_node node = self loop do if node.smaller node = node.smaller else # We've found a 'leaf' node. return node end end end |
#has_space?(address, size) ⇒ Boolean
Check if this node or any sub-node has an entry for the given address and size.
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# File 'lib/perobs/SpaceTreeNode.rb', line 190 def has_space?(address, size) node = self loop do if node.blob_address == address return size == node.size elsif size < node.size && node.smaller node = node.smaller elsif size > node.size && node.larger node = node.larger elsif size == node.size && node.equal node = node.equal else return false end end end |
#relink_parent(node) ⇒ Object
Replace the link in the parent node of the current node that points to the current node with the given node.
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# File 'lib/perobs/SpaceTreeNode.rb', line 382 def relink_parent(node) if @parent if @parent.smaller == self @parent.set_link('@smaller', node) elsif @parent.equal == self @parent.set_link('@equal', node) elsif @parent.larger == self @parent.set_link('@larger', node) else PEROBS.log.fatal "Cannot relink unknown child node with address " + "#{node.node_address} from #{parent.to_s}" end else if node @tree.set_root(node) node.parent = nil else set_size_and_address(0, 0) end end end |
#save ⇒ Object
Save the node into the blob file.
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# File 'lib/perobs/SpaceTreeNode.rb', line 128 def save bytes = [ @blob_address, @size, @parent ? @parent.node_address : 0, @smaller ? @smaller.node_address : 0, @equal ? @equal.node_address : 0, @larger ? @larger.node_address : 0].pack(NODE_BYTES_FORMAT) @tree.nodes.store_blob(@node_address, bytes) end |
#set_link(name, node_or_address) ⇒ Object
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# File 'lib/perobs/SpaceTreeNode.rb', line 438 def set_link(name, node_or_address) if node_or_address # Set the link to the given SpaceTreeNode or node address. instance_variable_set(name, node = node_or_address.is_a?(SpaceTreeNodeLink) ? node_or_address : SpaceTreeNodeLink.new(@tree, node_or_address)) # Link the node back to this node via the parent variable. node.parent = self else # Clear the node link. instance_variable_set(name, nil) end @tree.cache.insert(self) end |
#set_size_and_address(size, address) ⇒ Object
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# File 'lib/perobs/SpaceTreeNode.rb', line 432 def set_size_and_address(size, address) @size = size @blob_address = address @tree.cache.insert(self) end |
#text_tree_prefix ⇒ String
The indentation and arch routing for the text tree.
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# File 'lib/perobs/SpaceTreeNode.rb', line 658 def text_tree_prefix if (node = @parent) str = '+' else # Prefix start for root node line str = 'o' end while node last_child = false if node.parent if node.parent.smaller == node last_child = node.parent.equal.nil? && node.parent.larger.nil? elsif node.parent.equal == node last_child = node.parent.larger.nil? elsif node.parent.larger == node last_child = true end else # Padding for the root node str = ' ' + str break end str = (last_child ? ' ' : '| ') + str node = node.parent end str end |
#to_a ⇒ Array
Collects address and size touples of all nodes in the tree with a depth-first strategy and stores them in an Array.
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# File 'lib/perobs/SpaceTreeNode.rb', line 467 def to_a ary = [] each do |node, mode, stack| if mode == :on_enter ary << [ node.blob_address, node.size ] end end ary end |
#to_s ⇒ String
Textual version of the node data. It has the form node_address:[blob_address, size] ^parent_node_address <smaller_node_address >larger_node_address
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# File 'lib/perobs/SpaceTreeNode.rb', line 483 def to_s s = "#{@node_address}:[#{@blob_address}, #{@size}]" if @parent begin s += " ^#{@parent.node_address}" rescue s += ' ^@' end end if @smaller begin s += " <#{@smaller.node_address}" rescue s += ' <@' end end if @equal begin s += " =#{@equal.node_address}" rescue s += ' =@' end end if @larger begin s += " >#{@larger.node_address}" rescue s += ' >@' end end s end |
#to_tree_s ⇒ String
Convert the node and all child nodes into a tree like text form.
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# File 'lib/perobs/SpaceTreeNode.rb', line 633 def to_tree_s str = '' each do |node, mode, stack| if mode == :on_enter begin branch_mark = node.parent.nil? ? '' : node.parent.smaller == node ? '<' : node.parent.equal == node ? '=' : node.parent.larger == node ? '>' : '@' str += "#{node.text_tree_prefix}#{branch_mark}-" + "#{node.smaller || node.equal || node.larger ? 'v-' : '--'}" + "#{node.to_s}\n" rescue str += "#{node.text_tree_prefix}- @@@@@@@@@@\n" end end end str end |
#uid ⇒ Integer
Returns The node address since it uniquely identifies the Node.
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# File 'lib/perobs/SpaceTreeNode.rb', line 294 def uid @node_address end |
#unlink_node(child_node) ⇒ Object
Remove a smaller/equal/larger link from the current node.
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# File 'lib/perobs/SpaceTreeNode.rb', line 278 def unlink_node(child_node) if @smaller == child_node @smaller = nil elsif @equal == child_node @equal = nil elsif @larger == child_node @larger = nil else PEROBS.log.fatal "Cannot unlink unknown child node with address " + "#{child_node.node_address} from #{to_s}" end @tree.cache.insert(self) end |