-- license = "See nmaps COPYING for license" module("strbuf" ,package.seeall) -- String buffer functions. Concatenation is not efficient in -- lua as strings are immutable. If a large amount of '..' -- operations are needed a string buffer should be used instead --[[ local buf = strbuf.new() -- from here buf may be used like a string for concatenation operations -- (the lefthand-operand has to be a strbuf, the righthand-operand may be -- a string or a strbuf) -- alternativly you can assign a value (which will become the first string -- inside the buffer) with new local buf2 = strbuf.new('hello') buf = buf .. 'string' buf = buf .. 'data' print(buf) -- default seperator is a new line print(strbuf.dump(buf)) -- no seperator print(strbuf.dump(buf, ' ')) -- seperated by spaces strbuf.clear(buf) --]] dump = table.concat concatbuf =function(sbuf, s) if sbuf == s then error("refusing to concat the same buffer (recursion)!") end if getmetatable(sbuf) ~= mt then error("left-hand operand of the concat operation has to be a strbuf!") end if type(s)=="string" then table.insert(sbuf, s) elseif getmetatable(s) == mt then for _,v in ipairs(s) do table.insert(sbuf, v) end else error("right-hand operand of concat has to be either string or strbuf!") end return sbuf end local eqbuf = function(sbuf1, sbuf2) if getmetatable(sbuf1) ~= mt then error("equal function expects a value of type strbuf as left-hand operand") end if getmetatable(sbuf1) ~= getmetatable(sbuf2) then return false end if #sbuf1 ~= #sbuf2 then return false end for i=1, #sbuf1 do if sbuf1[i] ~= sbuf2[i] then return false end end return true end clear = function(sbuf) for i, v in pairs(sbuf) do sbuf[i] = nil end end mt = { __concat = concatbuf, __tostring = function(s) return dump(s, '\n') end , __eq=eqbuf} new = function(val) local tmp ={} setmetatable(tmp, mt) if val ~=nil then table.insert(tmp, val) end return tmp end
