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-- Copyright (c) 2020, CZ.NIC, z.s.p.o.
-- All rights reserved.
--
-- This file is part of dnsjit.
--
-- dnsjit is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- dnsjit is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with dnsjit. If not, see <http://www.gnu.org/licenses/>.
-- dnsjit.lib.trie.iter
-- Iterator of the trie.
-- .SS Iterate over all trie's key-value pairs
-- local trie = require("dnsjit.lib.trie").new("uint64_t")
-- local iter = trie:iter()
-- local node = iter:node()
-- while node ~= nil do
-- local key = node:key()
-- local value = tonumber(node:get())
-- print(key..": "..value)
-- iter:next()
-- node = iter:node()
-- end
--
-- Beware that iterator is only valid as long as the trie's key-set
-- remains unchanged.
module(...,package.seeall)
require("dnsjit.lib.trie_h")
local ffi = require("ffi")
local C = ffi.C
local log = require("dnsjit.core.log")
local module_log = log.new("lib.trie.iter")
local TrieNode = require("dnsjit.lib.trie.node")
TrieIter = {}
-- Create a new iterator pointing to the first element (if any).
function TrieIter.new(trie)
local self = setmetatable({
obj = C.trie_it_begin(trie.obj),
_trie = trie,
_log = log.new("lib.trie.iter", module_log),
}, { __index = TrieIter })
ffi.gc(self.obj, C.trie_it_free)
return self
end
-- Return the Log object to control logging of this instance or module.
function TrieIter:log()
if self == nil then
return module_log
end
return self._log
end
-- Return the node pointer to by the iterator.
-- Returns nil when iterator has gone past the last element.
function TrieIter:node()
if C.trie_it_finished(self.obj) then
return nil
end
local keylen_ptr = ffi.new("size_t[1]")
local key = C.trie_it_key(self.obj, keylen_ptr)
local keylen = tonumber(keylen_ptr[0])
local val = C.trie_it_val(self.obj)
return TrieNode.new(self._trie, val, key, keylen)
end
-- Advance the iterator to the next element.
--
-- Iteration is in ascending lexicographical order.
-- Empty string would be considered as the very first.
--
-- You may not use this function if the trie's key-set has been modified during the lifetime of the iterator (modifying only values is OK).
function TrieIter:next()
C.trie_it_next(self.obj)
end
-- dnsjit.lib.trie (3), dnsjit.lib.trie.node (3)
return TrieIter
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