5 Several common useful Lua functions
11 Copyright 2008 Steven Barth <steven@midlink.org>
13 Licensed under the Apache License, Version 2.0 (the "License");
14 you may not use this file except in compliance with the License.
15 You may obtain a copy of the License at
17 http://www.apache.org/licenses/LICENSE-2.0
19 Unless required by applicable law or agreed to in writing, software
20 distributed under the License is distributed on an "AS IS" BASIS,
21 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
22 See the License for the specific language governing permissions and
23 limitations under the License.
27 module("luci.util", package.seeall)
30 -- Lua simplified Python-style OO class support emulation
34 local create = function(class, ...)
36 setmetatable(inst, {__index = class})
39 local stat, err = pcall(inst.__init__, inst, ...)
48 local classmeta = {__call = create}
51 classmeta.__index = base
54 setmetatable(class, classmeta)
59 -- Clones an object (deep on-demand)
60 function clone(object, deep)
63 for k, v in pairs(object) do
64 if deep and type(v) == "table" then
70 setmetatable(copy, getmetatable(object))
76 -- Combines two or more numerically indexed tables into one
79 for i, a in ipairs(arg) do
80 for j, v in ipairs(a) do
81 table.insert(result, v)
88 -- Checks whether a table has an object "value" in it
89 function contains(table, value)
90 for k,v in pairs(table) do
99 -- Dumps and strips a Lua-Function
101 local d = string.dump(f)
102 return d and strip_bytecode(d)
106 -- Dumps a table to stdout (useful for testing and debugging)
107 function dumptable(t, i)
109 for k,v in pairs(t) do
110 print(string.rep("\t", i) .. tostring(k), tostring(v))
111 if type(v) == "table" then
118 -- Escapes all occurences of c in s
119 function escape(s, c)
121 return s:gsub(c, "\\" .. c)
125 -- Populate obj in the scope of f as key
126 function extfenv(f, key, obj)
127 local scope = getfenv(f)
132 -- Checks whether an object is an instanceof class
133 function instanceof(object, class)
134 local meta = getmetatable(object)
135 while meta and meta.__index do
136 if meta.__index == class then
139 meta = getmetatable(meta.__index)
145 -- Creates valid XML PCDATA from a string
146 function pcdata(value)
147 value = value:gsub("&", "&")
148 value = value:gsub('"', """)
149 value = value:gsub("'", "'")
150 value = value:gsub("<", "<")
151 return value:gsub(">", ">")
155 -- Resets the scope of f doing a shallow copy of its scope into a new table
157 setfenv(f, clone(getfenv(f)))
161 -- Splits a string into an array
162 function split(str, pat, max, regex)
182 local s, e = str:find(pat, c, not regex)
183 table.insert(t, str:sub(c, s and s - 1))
185 c = e and e + 1 or #str + 1
186 until not s or max < 0
192 -- Strips lua bytecode
193 -- Original version by Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
194 function strip_bytecode(dump)
195 local version, format, endian, int, size, ins, num, lnum = dump:byte(5, 12)
198 subint = function(dump, i, l)
201 val = val * 256 + dump:byte(i + n - 1)
206 subint = function(dump, i, l)
209 val = val * 256 + dump:byte(i + n - 1)
216 strip_function = function(dump)
217 local count, offset = subint(dump, 1, size)
218 local stripped, dirty = string.rep("\0", size), offset + count
219 offset = offset + count + int * 2 + 4
220 offset = offset + int + subint(dump, offset, int) * ins
221 count, offset = subint(dump, offset, int)
224 t, offset = subint(dump, offset, 1)
228 offset = offset + size + subint(dump, offset, size)
230 offset = offset + num
232 offset = offset + lnum
235 count, offset = subint(dump, offset, int)
236 stripped = stripped .. dump:sub(dirty, offset - 1)
238 local proto, off = strip_function(dump:sub(offset, -1))
239 stripped, offset = stripped .. proto, offset + off - 1
241 offset = offset + subint(dump, offset, int) * int + int
242 count, offset = subint(dump, offset, int)
244 offset = offset + subint(dump, offset, size) + size + int * 2
246 count, offset = subint(dump, offset, int)
248 offset = offset + subint(dump, offset, size) + size
250 stripped = stripped .. string.rep("\0", int * 3)
251 return stripped, offset
254 return dump:sub(1,12) .. strip_function(dump:sub(13,-1))
258 -- Removes whitespace from beginning and end of a string
260 local s = str:gsub("^%s*(.-)%s*$", "%1")
265 -- Updates given table with new values
266 function update(t, updates)
267 for k, v in pairs(updates) do
273 -- Updates the scope of f with "extscope"
274 function updfenv(f, extscope)
275 update(getfenv(f), extscope)
279 -- Parse units from a string and return integer value
280 function parse_units(ustr)
287 y = 60 * 60 * 24 * 366,
288 m = 60 * 60 * 24 * 31,
289 w = 60 * 60 * 24 * 7,
297 gb = 1024 * 1024 * 1024,
299 -- storage sizes (si)
302 gib = 1000 * 1000 * 1000
305 -- parse input string
306 for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do
308 local num = spec:gsub("[^0-9%.]+$","")
309 local spn = spec:gsub("^[0-9%.]+", "")
311 if map[spn] or map[spn:sub(1,1)] then
312 val = val + num * ( map[spn] or map[spn:sub(1,1)] )
323 -- Provide various sorting iterators
324 function _sortiter( t, f )
327 for k, v in pairs(t) do
328 table.insert( keys, k )
332 local _len = table.getn( keys )
334 table.sort( keys, f )
339 return keys[_pos], t[keys[_pos]]
344 -- Return key, value pairs sorted by provided callback function
346 return _sortiter( t, f )
349 -- Return key, value pairs sorted by keys
351 return _sortiter( t )
354 -- Return key, value pairs sorted by values
356 return _sortiter( t, function (a,b) return t[a] < t[b] end )