--
This commit is contained in:
Denis Knauf
parent
1063201b64
commit
0621370cec
2 changed files with 295 additions and 0 deletions
103
lib/aodbm.rb
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103
lib/aodbm.rb
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require 'ffi'
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module AODBM
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class DB
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attr_reader :c
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def initialize name, flags = nil
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flags ||= 0
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@c = Lib::open name, flags
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end
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def open name, flags = nil
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db = new name, flags
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block_given? ? yield( db) : db
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end
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def close
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Lib::close @c
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end
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def current
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Version.new @c, Lib::current( @c)
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end
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def commit version
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Lib::commit @c, version
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end
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end
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class Version
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attr_reader :db, :c
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def initialize db, c
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@db, @c = db, c
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end
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def previous
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Version.new @db, Lib::previous( @db.c, @c)
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end
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def has? data
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Lib::has @db.c, @c, Lib::Data.new( data)
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end
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def set key, val
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Lib::set @db.c, @c, Lib::Data.new( key), Lib::Data.new( val)
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end
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end
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module Lib
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extend FFI::Library
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ffi_lib "libaodbm.so"
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typedef :pointer, :aodbm
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typedef :uint64, :version
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class Data < FFI::Struct
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def initialilze data
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end
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layout :dat, :buffer, :sz, :size_t
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end
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typedef :pointer, :data
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attach_function :open, :aodbm_open, [:string, :int], :aodbm
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attach_function :close, :aodbm_close, [:aodbm], :void
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attach_function :current, :aodbm_current, [:aodbm], :version
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attach_function :commit, :aodbm_commit, [:aodbm, :version], :bool
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attach_function :has, :aodbm_has, [:aodbm, :version, :data], :bool
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attach_function :set, :aodbm_set, [:aodbm, :version, :data, :data], :version
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attach_function :get, :aodbm_get, [:aodbm, :version, :data], :data
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attach_function :del, :aodbm_del, [:aodbm, :version, :data], :version
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attach_function :is_based_on, :aodbm_is_based_on, [:aodbm, :version, :data], :bool
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attach_function :previous, :aodbm_previous_version, [:aodbm, :version], :version
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attach_function :common_ancestor, :aodbm_common_ancestor, [:aodbm, :version, :version], :version
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#typedef :changeset, :pointer
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#attach_function :aodbm_diff_prev, [:aodbm, :version], :changeset
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#attach_function :aodbm_diff_prev_rev, [:aodbm, :version], :changeset
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#attach_function :aodbm_diff, [:aodbm, :version, :version], :changeset
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#attach_function :aodbm_apply, [:aodbm, :version, :changeset], :version
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#attach_function :aodbm_apply_di, [:aodbm, :version, :changeset], :version
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#attach_function :aodbm_merge, [:aodbm, :version, :version], :version
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typedef :pointer, :iterator
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class Record < FFI::Struct
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layout :key, :data, :val, :data
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end
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typedef :pointer, :record
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attach_function :new_iterator, :aodbm_new_iterator, [:aodbm, :version], :iterator
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attach_function :iterator_from, :aodbm_iterate_from, [:aodbm, :version, :data], :iterator
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attach_function :iterate_next, :aodbm_iterator_next, [:aodbm, :iterator], :record
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attach_function :iterate_goto, :aodbm_iterator_goto, [:aodbm, :iterator, :data], :void
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attach_function :free_iterator, :aodbm_free_iterator, [:iterator], :void
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attach_function :free_data, :aodbm_free_data, [:data], :void
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end
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end
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192
lib/plain.rb
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192
lib/plain.rb
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@ -0,0 +1,192 @@
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require 'zlib' # Zlib::crc32
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require 'uuidtools'
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# Maximum Filesize: 4GB because #pack("N")
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class Plain < File
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UUID_SIZE = 16 # Size of an key (UUID as raw 16byte string)
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INT_SIZE = 4
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CRCR32_SIZE = INT_SIZE # Size of CRC32 (32Bit)
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KEY_SIZE = UUID_SIZE
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IDX_SIZE = INT_SIZE # Size of an index (big-endian 32bit integer)
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SIZE_SIZE = INT_SIZE # Size of size_t
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CHK_SIZE = CRCR32_SIZE
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IDXE_SIZE = KEY_SIZE + IDX_SIZE # Size of an entry in index-file
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DBP_SIZE = KEY_SIZE + SIZE_SIZE + CHK_SIZE
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UUID_PACK = "a16"
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INT_PACK = "N"
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STR_PACK = "a*"
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CRC32_PACK = INT_PACK
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KEY_PACK = UUID_PACK
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IDX_PACK = INT_PACK
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SIZE_PACK = INT_PACK
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CHK_PACK = CRC32_PACK
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IDXE_PACK = KEY_PACK + IDX_PACK
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DBP_PACK = KEY_PACK + SIZE_PACK + CHK_PACK
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VAL_PACK = STR_PACK
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ENTRY_PACK = DBP_PACK + VAL_PACK
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class Corrupt < Exception
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end
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module UUIDConv
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class <<self
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# Converts a UUIDTools::UUID to raw-String: UUIDTools::UUID#raw
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def cto_s x
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x.raw
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end
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# Converts a String to UUIDTools::UUID: UUIDTools::UUID.parse_raw
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def cto_key x
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UUIDTools::UUID.parse_raw x
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end
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end
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end
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# Converting-helper.
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# To methods are required:
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# #cto_str # obj => 16-byte-String
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# #cto_key # 16-byte-String => obj
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attr_accessor :conv
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attr_reader :idx
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def initialize *a
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super *a
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@conv = @@conv
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@idx = File.open "#{path}.idx", a[1]
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end
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class <<self
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# Default we use UUIDTool for keys.
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@@conv = UUIDConv
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def new *a
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a[1] ||= 'a'
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r = super *a
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block_given? ? yield(r) : r
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end
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def open *a, &e
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a[1] ||= 'r'
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new *a, &e
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end
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end
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def sync
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super
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@idx.sync
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end
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def close
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super
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@idx.close
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end
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def gen_entry key, val
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[key, val.length, Zlib::crc32( val), val].pack( ENTRY_PACK)
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end
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def gen_idx key, pos = self.pos
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[key, pos].pack IDXE_PACK
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end
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# Store an entry in DB
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def push key, val
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key = @conv.cto_s key
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idx = gen_idx key
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print gen_entry( key, val)
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@idx.print idx
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sync
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@idx.sync
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true
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end
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def put val
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push UUIDTools::UUID.timestamp_create, val
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end
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# Read the entry.
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# First you should seek, if you won't read sequential
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def get
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if m = read( DBP_SIZE)
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key, length, chk = m.unpack DBP_PACK
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val = read length
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valchk = Zlib::crc32 val
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raise Corrupt, "#{path} is corrupt: #{pos-length-CHK_SIZE-DBP_SIZE} #{chk} -- #{valchk}" unless chk == valchk
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[@conv.cto_key( key), length, val, chk]
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end
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end
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alias next get
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# yield(idx): must return:
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# -1: to small
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# 0: found! return true
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# 1: to big
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# else: like you use break nil
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# yield is allowed to use break
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def self.binary_search size
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idx = 1
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begin
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i = size
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while 0 < i
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idx <<= 1
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i >>= 1
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end
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end
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idx >>= 1
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t = idx
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p idx
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while t > 0
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t >>= 1
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i = yield idx
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case i
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when -1 then idx -= t
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when 1 then idx += t
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when 0 then return true
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else return nil
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end
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end
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end
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# Get the value.
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# key must provide: #<=> uuid
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def search_ key
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idx = self.length
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position = nil
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self.class.binary_search( idx) do |idx|
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p idx
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idx *= IDXE_SIZE
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if idx > size
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size = @idx.size
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break if idx > size
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end
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# Read entry i. p is position and k is key
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@idx.seek idx
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k, position = @idx.read( IDXE_SIZE).unpack IDXE_PACK
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p pos: position, key: k
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key <=> @conv.cto_key( k)
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end ? position : nil
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end
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def [] key
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if position = search_( key)
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self.pos = position+KEY_SIZE
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length,_ = read( SIZE_SIZE).unpack( SIZE_PACK)
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read( length)[2]
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end
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end
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def each
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return Enumerator.new( self) unless block_given?
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yield *get while !eof?
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end
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# counts entries (size of the idx): O(1)
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def length
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@idx.size/IDXE_SIZE
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end
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end
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