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Create empty root directly
+19
-9
+6
-9
lib/btree/btree.ex
+6
-9
lib/btree/btree.ex
···
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defmodule Hobbes.BTree do
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alias Hobbes.BTree
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alias Hobbes.BTree.{Store, FreeList, Page}
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alias Hobbes.BTree.{Store, FreeList}
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import ExUnit.Assertions, only: [assert: 1]
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···
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free_list_tail_address: nil,
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free_list_max_index: nil,
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}
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:ok = create_root_pages(btree)
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:ok = create_root(btree)
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btree
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end
···
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}
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end
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@keyspace_end_key "\xFF\xFF\xFF\xFF"
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defp create_root_pages(%BTree{} = btree) do
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defp create_root(%BTree{} = btree) do
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%{
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store: store,
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free_list: free_list,
···
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page_size: opt_page_size,
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},
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} = btree
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assert not :ets.member(btree.root_store, :root_address)
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root_data = BTree.Writer.empty_leaf(opt_page_size)
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[root_index] = FreeList.reserve_pages(free_list, 1)
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[{_ek, root_data}] = Page.encode_page_from_pairs(:leaf, opt_page_size, [], @keyspace_end_key)
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root_checksum = Store.checksum(root_data)
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:ok = Store.write_page(store, root_index, root_data)
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:ets.insert(root_store, {:root_address, {root_index, root_checksum}})
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:ets.insert(root_store, {:root_address, {root_index, root_checksum}})
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:ok
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end
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+13
lib/btree/writer.ex
+13
lib/btree/writer.ex
···
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>>
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encode_offset_slots(offsets_rest, slots_acc)
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end
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@spec empty_leaf(pos_integer) :: binary
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def empty_leaf(opt_page_size) do
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pad_bytes = opt_page_size - c_page_trailer_bytes()
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pair_count = 0
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type_byte = 0x01
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# See constant: c_page_trailer_bytes()
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<<
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0::integer-unit(8)-size(pad_bytes),
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pair_count::integer-16,
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type_byte::integer-8,
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>>
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end
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end