| Current Path : /usr/share/lua/5.1/ |
Linux gator3171.hostgator.com 4.19.286-203.ELK.el7.x86_64 #1 SMP Wed Jun 14 04:33:55 CDT 2023 x86_64 |
| Current File : //usr/share/lua/5.1/ltn12.lua |
-----------------------------------------------------------------------------
-- LTN12 - Filters, sources, sinks and pumps.
-- LuaSocket toolkit.
-- Author: Diego Nehab
-----------------------------------------------------------------------------
-----------------------------------------------------------------------------
-- Declare module
-----------------------------------------------------------------------------
local string = require("string")
local table = require("table")
local unpack = unpack or table.unpack
local base = _G
local select = select
local _M = {}
if module then -- heuristic for exporting a global package table
ltn12 = _M -- luacheck: ignore
end
local filter,source,sink,pump = {},{},{},{}
_M.filter = filter
_M.source = source
_M.sink = sink
_M.pump = pump
-- 2048 seems to be better in windows...
_M.BLOCKSIZE = 2048
_M._VERSION = "LTN12 1.0.3"
-----------------------------------------------------------------------------
-- Filter stuff
-----------------------------------------------------------------------------
-- returns a high level filter that cycles a low-level filter
function filter.cycle(low, ctx, extra)
base.assert(low)
return function(chunk)
local ret
ret, ctx = low(ctx, chunk, extra)
return ret
end
end
-- chains a bunch of filters together
-- (thanks to Wim Couwenberg)
function filter.chain(...)
local arg = {...}
local n = select('#',...)
local top, index = 1, 1
local retry = ""
return function(chunk)
retry = chunk and retry
while true do
if index == top then
chunk = arg[index](chunk)
if chunk == "" or top == n then return chunk
elseif chunk then index = index + 1
else
top = top+1
index = top
end
else
chunk = arg[index](chunk or "")
if chunk == "" then
index = index - 1
chunk = retry
elseif chunk then
if index == n then return chunk
else index = index + 1 end
else base.error("filter returned inappropriate nil") end
end
end
end
end
-----------------------------------------------------------------------------
-- Source stuff
-----------------------------------------------------------------------------
-- create an empty source
local function empty()
return nil
end
function source.empty()
return empty
end
-- returns a source that just outputs an error
function source.error(err)
return function()
return nil, err
end
end
-- creates a file source
function source.file(handle, io_err)
if handle then
return function()
local chunk = handle:read(_M.BLOCKSIZE)
if not chunk then handle:close() end
return chunk
end
else return source.error(io_err or "unable to open file") end
end
-- turns a fancy source into a simple source
function source.simplify(src)
base.assert(src)
return function()
local chunk, err_or_new = src()
src = err_or_new or src
if not chunk then return nil, err_or_new
else return chunk end
end
end
-- creates string source
function source.string(s)
if s then
local i = 1
return function()
local chunk = string.sub(s, i, i+_M.BLOCKSIZE-1)
i = i + _M.BLOCKSIZE
if chunk ~= "" then return chunk
else return nil end
end
else return source.empty() end
end
-- creates table source
function source.table(t)
base.assert('table' == type(t))
local i = 0
return function()
i = i + 1
return t[i]
end
end
-- creates rewindable source
function source.rewind(src)
base.assert(src)
local t = {}
return function(chunk)
if not chunk then
chunk = table.remove(t)
if not chunk then return src()
else return chunk end
else
table.insert(t, chunk)
end
end
end
-- chains a source with one or several filter(s)
function source.chain(src, f, ...)
if ... then f=filter.chain(f, ...) end
base.assert(src and f)
local last_in, last_out = "", ""
local state = "feeding"
local err
return function()
if not last_out then
base.error('source is empty!', 2)
end
while true do
if state == "feeding" then
last_in, err = src()
if err then return nil, err end
last_out = f(last_in)
if not last_out then
if last_in then
base.error('filter returned inappropriate nil')
else
return nil
end
elseif last_out ~= "" then
state = "eating"
if last_in then last_in = "" end
return last_out
end
else
last_out = f(last_in)
if last_out == "" then
if last_in == "" then
state = "feeding"
else
base.error('filter returned ""')
end
elseif not last_out then
if last_in then
base.error('filter returned inappropriate nil')
else
return nil
end
else
return last_out
end
end
end
end
end
-- creates a source that produces contents of several sources, one after the
-- other, as if they were concatenated
-- (thanks to Wim Couwenberg)
function source.cat(...)
local arg = {...}
local src = table.remove(arg, 1)
return function()
while src do
local chunk, err = src()
if chunk then return chunk end
if err then return nil, err end
src = table.remove(arg, 1)
end
end
end
-----------------------------------------------------------------------------
-- Sink stuff
-----------------------------------------------------------------------------
-- creates a sink that stores into a table
function sink.table(t)
t = t or {}
local f = function(chunk, err)
if chunk then table.insert(t, chunk) end
return 1
end
return f, t
end
-- turns a fancy sink into a simple sink
function sink.simplify(snk)
base.assert(snk)
return function(chunk, err)
local ret, err_or_new = snk(chunk, err)
if not ret then return nil, err_or_new end
snk = err_or_new or snk
return 1
end
end
-- creates a file sink
function sink.file(handle, io_err)
if handle then
return function(chunk, err)
if not chunk then
handle:close()
return 1
else return handle:write(chunk) end
end
else return sink.error(io_err or "unable to open file") end
end
-- creates a sink that discards data
local function null()
return 1
end
function sink.null()
return null
end
-- creates a sink that just returns an error
function sink.error(err)
return function()
return nil, err
end
end
-- chains a sink with one or several filter(s)
function sink.chain(f, snk, ...)
if ... then
local args = { f, snk, ... }
snk = table.remove(args, #args)
f = filter.chain(unpack(args))
end
base.assert(f and snk)
return function(chunk, err)
if chunk ~= "" then
local filtered = f(chunk)
local done = chunk and ""
while true do
local ret, snkerr = snk(filtered, err)
if not ret then return nil, snkerr end
if filtered == done then return 1 end
filtered = f(done)
end
else return 1 end
end
end
-----------------------------------------------------------------------------
-- Pump stuff
-----------------------------------------------------------------------------
-- pumps one chunk from the source to the sink
function pump.step(src, snk)
local chunk, src_err = src()
local ret, snk_err = snk(chunk, src_err)
if chunk and ret then return 1
else return nil, src_err or snk_err end
end
-- pumps all data from a source to a sink, using a step function
function pump.all(src, snk, step)
base.assert(src and snk)
step = step or pump.step
while true do
local ret, err = step(src, snk)
if not ret then
if err then return nil, err
else return 1 end
end
end
end
return _M