add bloom filter stub

2 files changed, 200 insertions, 2 deletions

diff --git a/xmake/core/base/bloom_filter.lua b/xmake/core/base/bloom_filter.lua
new file mode 100644
index 000000000..781cfb4da
--- /dev/null
+++ b/xmake/core/base/bloom_filter.lua
@@ -0,0 +1,198 @@
+--!A cross-platform build utility based on Lua
+--
+-- Licensed under the Apache License, Version 2.0 (the "License");
+-- you may not use this file except in compliance with the License.
+-- You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+--
+-- Copyright (C) 2015-present, TBOOX Open Source Group.
+--
+-- @author      ruki
+-- @file        bloom_filter.lua
+--
+
+-- define module: bloom_filter
+local bloom_filter = bloom_filter or {}
+local _instance = _instance or {}
+
+-- load modules
+local io    = require("base/io")
+local utils = require("base/utils")
+local bytes = require("base/bytes")
+local table = require("base/table")
+
+-- save metatable and builtin functions
+bloom_filter._open     = bloom_filter._open or bloom_filter.open
+bloom_filter._close    = bloom_filter._close or bloom_filter.close
+bloom_filter._data     = bloom_filter._data or bloom_filter.data
+bloom_filter._size     = bloom_filter._size or bloom_filter.size
+bloom_filter._data_set = bloom_filter._data_set or bloom_filter.data_set
+bloom_filter._clear    = bloom_filter._clear or bloom_filter.clear
+bloom_filter._set      = bloom_filter._set or bloom_filter.set
+bloom_filter._get      = bloom_filter._get or bloom_filter.get
+
+-- the bloom filter probability
+bloom_filter.PROBABILITY_0_1         = 3  -- 1 / 2^3 = 0.125 ~= 0.1
+bloom_filter.PROBABILITY_0_01        = 6  -- 1 / 2^6 = 0.015625 ~= 0.01
+bloom_filter.PROBABILITY_0_001       = 10 -- 1 / 2^10 = 0.0009765625 ~= 0.001
+bloom_filter.PROBABILITY_0_0001      = 13 -- 1 / 2^13 = 0.0001220703125 ~= 0.0001
+bloom_filter.PROBABILITY_0_00001     = 16 -- 1 / 2^16 = 0.0000152587890625 ~= 0.00001
+bloom_filter.PROBABILITY_0_000001    = 20 -- 1 / 2^20 = 0.00000095367431640625 ~= 0.000001
+
+-- new a bloom filter
+function _instance.new(handle)
+    local instance   = table.inherit(_instance)
+    instance._HANDLE = handle
+    setmetatable(instance, _instance)
+    return instance
+end
+
+-- get cdata of the bloom filter
+function _instance:cdata()
+    return self._HANDLE
+end
+
+-- get the bloom filter data
+function _instance:data()
+    -- ensure opened
+    local ok, errors = self:_ensure_opened()
+    if not ok then
+        return nil, errors
+    end
+
+    -- get the bloom filter data
+    local data = bloom_filter._data(self:cdata())
+    local size = bloom_filter._size(self:cdata())
+    if not data or size == 0 then
+        return nil, "no data!"
+    end
+
+    -- mount this data
+    return bytes(size, data)
+end
+
+-- set the bloom filter data
+function _instance:data_set(data)
+    -- ensure opened
+    local ok, errors = self:_ensure_opened()
+    if not ok then
+        return false, errors
+    end
+
+    -- set data
+    local datasize = data:size()
+    local dataaddr = data:caddr()
+    if not dataaddr or datasize == 0 then
+        return false, "empty data!"
+    end
+    return bloom_filter._data_set(self:cdata(), dataaddr, datasize)
+end
+
+-- clear the bloom filter data
+function _instance:clear()
+    -- ensure opened
+    local ok, errors = self:_ensure_opened()
+    if not ok then
+        return false, errors
+    end
+
+    -- do clear
+    return bloom_filter._clear(self:cdata())
+end
+
+-- set the bloom filter data item
+--
+--@code
+-- if bloom_filter:set(item)) then
+--     print("this data not exists, set ok!")
+-- else
+--     -- note: maybe false positives
+--     print("this data have been existed, set failed!")
+-- end
+--@endcode
+--
+function _instance:set(item)
+
+    -- ensure opened
+    local ok, errors = self:_ensure_opened()
+    if not ok then
+        return false, errors
+    end
+
+    -- do set
+    return bloom_filter._set(self:cdata(), item)
+end
+
+-- get the bloom filter data item
+--
+--@code
+-- if bloom_filter:get(item)) then
+--     -- note: maybe false positives
+--     print("this data have been existed, get ok!")
+-- else
+--     print("this data not exists, get failed!")
+-- end
+--@endcode
+--
+function _instance:get(item)
+
+    -- ensure opened
+    local ok, errors = self:_ensure_opened()
+    if not ok then
+        return false, errors
+    end
+
+    -- do get
+    return bloom_filter._get(self:cdata(), item)
+end
+
+-- ensure it is opened
+function _instance:_ensure_opened()
+    if not self:cdata() then
+        return false, string.format("%s: has been closed!", self)
+    end
+    return true
+end
+
+-- tostring(bloom_filter)
+function _instance:__tostring()
+    return string.format("<bloom_filter: %s>", self:cdata())
+end
+
+-- gc(bloom_filter)
+function _instance:__gc()
+    if self:cdata() and bloom_filter._close(self:cdata()) then
+        self._HANDLE = nil
+    end
+end
+
+-- new a bloom filter, e.g. {probability = 0.001}
+function bloom_filter.new(opt)
+    opt = opt or {}
+    local probability = opt.probability or 0.001
+    local maps = {
+        [0.1] = bloom_filter.PROBABILITY_0_1
+        [0.01] = bloom_filter.PROBABILITY_0_01
+        [0.001] = bloom_filter.PROBABILITY_0_001
+        [0.0001] = bloom_filter.PROBABILITY_0_0001
+        [0.00001] = bloom_filter.PROBABILITY_0_00001
+        [0.000001] = bloom_filter.PROBABILITY_0_000001
+    }
+    probability = assert(maps[probability], "invalid probability(%f)", probability)
+    local handle, errors = bloom_filter._open(probability)
+    if handle then
+        return _instance.new(handle)
+    else
+        return nil, errors or "failed to open a bloom filter!"
+    end
+end
+
+-- return module: bloom_filter
+return bloom_filter
diff --git a/xmake/core/compress/lz4.lua b/xmake/core/compress/lz4.lua
index 6a5c97be0..2e605993a 100644
--- a/xmake/core/compress/lz4.lua
+++ b/xmake/core/compress/lz4.lua
@@ -136,7 +136,7 @@ function _cstream:write(data, opt)
     return write, errors
 end
 
--- ensure the socket is opened
+-- ensure it is opened
 function _cstream:_ensure_opened()
     if not self:cdata() then
         return false, string.format("%s: has been closed!", self)
@@ -247,7 +247,7 @@ function _dstream:write(data, opt)
     return write, errors
 end
 
--- ensure the socket is opened
+-- ensure it is opened
 function _dstream:_ensure_opened()
     if not self:cdata() then
         return false, string.format("%s: has been closed!", self)