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- /*
- Copyright (c) 2014-2018, Matteo Collina <hello@matteocollina.com>
- Permission to use, copy, modify, and/or distribute this software for any
- purpose with or without fee is hereby granted, provided that the above
- copyright notice and this permission notice appear in all copies.
- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
- IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
- 'use strict'
- const { Transform } = require('readable-stream')
- const { StringDecoder } = require('string_decoder')
- const kLast = Symbol('last')
- const kDecoder = Symbol('decoder')
- function transform (chunk, enc, cb) {
- var list
- if (this.overflow) { // Line buffer is full. Skip to start of next line.
- var buf = this[kDecoder].write(chunk)
- list = buf.split(this.matcher)
- if (list.length === 1) return cb() // Line ending not found. Discard entire chunk.
- // Line ending found. Discard trailing fragment of previous line and reset overflow state.
- list.shift()
- this.overflow = false
- } else {
- this[kLast] += this[kDecoder].write(chunk)
- list = this[kLast].split(this.matcher)
- }
- this[kLast] = list.pop()
- for (var i = 0; i < list.length; i++) {
- try {
- push(this, this.mapper(list[i]))
- } catch (error) {
- return cb(error)
- }
- }
- this.overflow = this[kLast].length > this.maxLength
- if (this.overflow && !this.skipOverflow) return cb(new Error('maximum buffer reached'))
- cb()
- }
- function flush (cb) {
- // forward any gibberish left in there
- this[kLast] += this[kDecoder].end()
- if (this[kLast]) {
- try {
- push(this, this.mapper(this[kLast]))
- } catch (error) {
- return cb(error)
- }
- }
- cb()
- }
- function push (self, val) {
- if (val !== undefined) {
- self.push(val)
- }
- }
- function noop (incoming) {
- return incoming
- }
- function split (matcher, mapper, options) {
- // Set defaults for any arguments not supplied.
- matcher = matcher || /\r?\n/
- mapper = mapper || noop
- options = options || {}
- // Test arguments explicitly.
- switch (arguments.length) {
- case 1:
- // If mapper is only argument.
- if (typeof matcher === 'function') {
- mapper = matcher
- matcher = /\r?\n/
- // If options is only argument.
- } else if (typeof matcher === 'object' && !(matcher instanceof RegExp)) {
- options = matcher
- matcher = /\r?\n/
- }
- break
- case 2:
- // If mapper and options are arguments.
- if (typeof matcher === 'function') {
- options = mapper
- mapper = matcher
- matcher = /\r?\n/
- // If matcher and options are arguments.
- } else if (typeof mapper === 'object') {
- options = mapper
- mapper = noop
- }
- }
- options = Object.assign({}, options)
- options.transform = transform
- options.flush = flush
- options.readableObjectMode = true
- const stream = new Transform(options)
- stream[kLast] = ''
- stream[kDecoder] = new StringDecoder('utf8')
- stream.matcher = matcher
- stream.mapper = mapper
- stream.maxLength = options.maxLength
- stream.skipOverflow = options.skipOverflow
- stream.overflow = false
- return stream
- }
- module.exports = split
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