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buffer-stream.coffee
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buffer-stream.coffee
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{ Stream } = require 'stream'
fn = require './fn'
[isArray, isBuffer] = [Array.isArray, Buffer.isBuffer]
split = () ->
return unless @buffer.length
can_split = @enabled and @splitters.length
while can_split
cur = null
pos = buflen = @buffer.length
for splitter in @splitters
continue if buflen < splitter.length
i = fn.indexOf.call(@buffer, splitter)
if i isnt -1 and i < pos and i < buflen
cur = splitter
pos = i
can_split = cur isnt null
break unless can_split
[found, rest] = fn.split(@buffer, pos, cur.length)
@buffer = rest
@emit('split', found, cur)
break if not @enabled or @buffer.length is 0
class BufferStream extends Stream
constructor: (opts = {}) ->
if typeof opts is 'string'
opts = encoding:opts
# defaults
opts.size ?= 'none'
opts.encoding ?= null
opts.blocking ?= yes
# values
@size = opts.size
@blocking = opts.blocking
@splitters = []
@__defineGetter__ 'length', () => @buffer.length
@setEncoding(opts.encoding)
# states
@enabled = on
@writable = on
@readable = on
@finished = off
@paused = off
#init
@reset()
super()
# shortcuts
if opts.split?
if isArray(opts.split)
@split opts.split
else
@split opts.split, (data) ->
@emit('data', data)
@disable() if opts.disabled
getBuffer: () => @buffer
toString: => @buffer.toString(arguments...)
setEncoding: (@encoding) =>
setSize: (@size) =>
@clear() if not @paused and @size is 'none'
enable: () => @enabled = on
disable: (args...) =>
if args.length is 1 and isArray(args[0])
args = args[0]
for splitter in args
i = @splitters.indexOf(splitter)
continue if i is -1
@splitters.splice(i, 1)
break unless @splitters.length
unless @splitters.length
@enabled = off
unless args.length
@enabled = off
@clear() unless @paused
split: (args...) =>
if args.length is 1 and isArray(args[0])
args = args[0]
if args.length is 2 and typeof args[1] is 'function'
[splitter, callback] = args
@splitters.push(splitter)
return @on 'split', (_, token) ->
callback.apply(this, arguments) if token is splitter
@splitters = @splitters.concat(args)
write: (buffer, encoding) =>
unless @writable
@emit 'error', new Error("Stream is not writable.")
return false
if isBuffer(buffer)
# no action required
else if typeof buffer is 'string'
buffer = new Buffer(buffer, encoding ? @encoding)
else @emit('error',
new Error("Argument should be either a buffer or a string."))
if @buffer.length is 0
@buffer = buffer
else
@buffer = fn.concat(@buffer, buffer)
return false if @paused
if @size is 'none'
split.call(this) if @enabled
return @clear()
else if @size is 'flexible'
# we buffer everything
split.call(this) if @enabled
if @finished # currently finishing
return @clear()
if @blocking
@clear() unless @enabled
return true # it's safe to immediately write again
else
# prevent write calls from blocking the whole process
process.nextTick =>
@emit 'drain'
return false
else # size is a number
throw new Error("not implemented yet :(") # TODO
clear: () =>
return true unless @buffer.length
buffer = @buffer # get before reset
@reset()
@emit 'data', buffer # sync call
return not @paused # can be changed after emit('data', data)
reset: () =>
if typeof @size is 'number'
@buffer = new Buffer(@size)
else
@buffer = new Buffer(0)
pause: () ->
return if @paused
@paused = yes
@emit 'pause'
resume: () ->
return unless @paused
if not @enabled or @size is 'none' or @finished
@paused = no
return unless @clear()
@emit 'drain'
@emit 'resume' if @size is 'none'
if @finished
@emit 'end'
@emit 'close'
end: (data, encoding) ->
return if @finished
@finished = yes # we give write the change to eg clear the buffer
@write(data, encoding) if data?
@writable = off
unless @paused
@emit 'end'
@emit 'close'
# exports
BufferStream.fn = fn
module.exports = BufferStream