/usr/share/ettercap/lua/third-party/set.lua is in ettercap-common 1:0.8.2-2build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 | local list = require "list"
-- Primitive methods (know about representation)
-- The representation is a table whose tags are the elements, and
-- whose values are true.
--- Say whether an element is in a set
-- @param s set
-- @param e element
-- @return <code>true</code> if e is in set, <code>false</code>
-- otherwise
local function member (s, e)
return rawget (s.contents, e) == true
end
--- Insert an element into a set
-- @param s set
-- @param e element
local function insert (s, e)
rawset (s.contents, e, true)
end
--- Delete an element from a set
-- @param s set
-- @param e element
local function delete (s, e)
rawset (s.contents, e, nil)
end
--- Make a list into a set
-- @param l list
-- @return set
local metatable = {}
local function new (l)
local s = setmetatable ({contents={}}, metatable)
for e in list.elems (l) do
insert (s, e)
end
return s
end
--- Iterator for sets
-- TODO: Make the iterator return only the key
local function elems (s)
return pairs (s.contents)
end
-- High level methods (representation-independent)
local difference, symmetric_difference, intersection, union, subset, equal
--- Find the difference of two sets
-- @param s set
-- @param t set
-- @return s with elements of t removed
function difference (s, t)
local r = new {}
for e in elems (s) do
if not member (t, e) then
insert (r, e)
end
end
return r
end
--- Find the symmetric difference of two sets
-- @param s set
-- @param t set
-- @return elements of s and t that are in s or t but not both
function symmetric_difference (s, t)
return difference (union (s, t), intersection (t, s))
end
--- Find the intersection of two sets
-- @param s set
-- @param t set
-- @return set intersection of s and t
function intersection (s, t)
local r = new {}
for e in elems (s) do
if member (t, e) then
insert (r, e)
end
end
return r
end
--- Find the union of two sets
-- @param s set
-- @param t set
-- @return set union of s and t
function union (s, t)
local r = new {}
for e in elems (s) do
insert (r, e)
end
for e in elems (t) do
insert (r, e)
end
return r
end
--- Find whether one set is a subset of another
-- @param s set
-- @param t set
-- @return <code>true</code> if s is a subset of t, <code>false</code>
-- otherwise
function subset (s, t)
for e in elems (s) do
if not member (t, e) then
return false
end
end
return true
end
--- Find whether one set is a proper subset of another
-- @param s set
-- @param t set
-- @return <code>true</code> if s is a proper subset of t, false otherwise
function propersubset (s, t)
return subset (s, t) and not subset (t, s)
end
--- Find whether two sets are equal
-- @param s set
-- @param t set
-- @return <code>true</code> if sets are equal, <code>false</code>
-- otherwise
function equal (s, t)
return subset (s, t) and subset (t, s)
end
-- Public interface
local M = {
delete = delete,
difference = difference,
elems = elems,
equal = equal,
insert = insert,
intersection = intersection,
member = member,
new = new,
subset = subset,
symmetric_difference = symmetric_difference,
union = union,
}
--- Metamethods for sets
-- set:method ()
metatable.__index = M
-- set + table = union
metatable.__add = union
-- set - table = set difference
metatable.__sub = difference
-- set * table = intersection
metatable.__mul = intersection
-- set / table = symmetric difference
metatable.__div = symmetric_difference
-- set <= table = subset
metatable.__le = subset
-- set < table = proper subset
metatable.__lt = propersubset
return M
|