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Contents
module Lvm2Thin
class BTree
FLAGS = { :internal => 1, :leaf => 2}
attr_accessor :root_address
def initialize(superblock, root_address, value_type)
@superblock = superblock
@root_address = root_address
@value_type = value_type
end
def root
@root ||= begin
@superblock.seek root_address
@superblock.read_struct DISK_NODE
end
end
def internal?
(root['flags'] & FLAGS[:internal]) != 0
end
def leaf?
(root['flags'] & FLAGS[:leaf]) != 0
end
def num_entries
@num_entries ||= root['nr_entries']
end
def max_entries
@max_entries ||= root['max_entries']
end
def key_base
root_address + DISK_NODE.size
end
def key_address(i)
key_base + i * 8
end
def value_base
key_address(max_entries)
end
def value_address(i)
value_base + @value_type.size * i
end
def keys
@keys ||= begin
@superblock.seek key_base
@superblock.read(num_entries * 8).unpack("Q#{num_entries}")
end
end
def entries
@entries ||= begin
@superblock.seek value_base
@superblock.read_structs @value_type, num_entries
end
end
def entry_for(key)
entries[keys.index(key)]
end
def to_h
@h ||=
Hash[0.upto(num_entries-1).collect do |i|
k = keys[i]
e = entries[i].kind_of?(BTree) ? entries[i].to_h : entries[i]
[k, e]
end]
end
def [](key)
return to_h[key]
end
end
end # module Lvm2Thin
Version data entries
67 entries across 67 versions & 1 rubygems