wishthis/node_modules/bl/BufferList.js
2022-06-08 12:36:39 +02:00

396 lines
9.3 KiB
JavaScript

'use strict'
const { Buffer } = require('buffer')
const symbol = Symbol.for('BufferList')
function BufferList (buf) {
if (!(this instanceof BufferList)) {
return new BufferList(buf)
}
BufferList._init.call(this, buf)
}
BufferList._init = function _init (buf) {
Object.defineProperty(this, symbol, { value: true })
this._bufs = []
this.length = 0
if (buf) {
this.append(buf)
}
}
BufferList.prototype._new = function _new (buf) {
return new BufferList(buf)
}
BufferList.prototype._offset = function _offset (offset) {
if (offset === 0) {
return [0, 0]
}
let tot = 0
for (let i = 0; i < this._bufs.length; i++) {
const _t = tot + this._bufs[i].length
if (offset < _t || i === this._bufs.length - 1) {
return [i, offset - tot]
}
tot = _t
}
}
BufferList.prototype._reverseOffset = function (blOffset) {
const bufferId = blOffset[0]
let offset = blOffset[1]
for (let i = 0; i < bufferId; i++) {
offset += this._bufs[i].length
}
return offset
}
BufferList.prototype.get = function get (index) {
if (index > this.length || index < 0) {
return undefined
}
const offset = this._offset(index)
return this._bufs[offset[0]][offset[1]]
}
BufferList.prototype.slice = function slice (start, end) {
if (typeof start === 'number' && start < 0) {
start += this.length
}
if (typeof end === 'number' && end < 0) {
end += this.length
}
return this.copy(null, 0, start, end)
}
BufferList.prototype.copy = function copy (dst, dstStart, srcStart, srcEnd) {
if (typeof srcStart !== 'number' || srcStart < 0) {
srcStart = 0
}
if (typeof srcEnd !== 'number' || srcEnd > this.length) {
srcEnd = this.length
}
if (srcStart >= this.length) {
return dst || Buffer.alloc(0)
}
if (srcEnd <= 0) {
return dst || Buffer.alloc(0)
}
const copy = !!dst
const off = this._offset(srcStart)
const len = srcEnd - srcStart
let bytes = len
let bufoff = (copy && dstStart) || 0
let start = off[1]
// copy/slice everything
if (srcStart === 0 && srcEnd === this.length) {
if (!copy) {
// slice, but full concat if multiple buffers
return this._bufs.length === 1
? this._bufs[0]
: Buffer.concat(this._bufs, this.length)
}
// copy, need to copy individual buffers
for (let i = 0; i < this._bufs.length; i++) {
this._bufs[i].copy(dst, bufoff)
bufoff += this._bufs[i].length
}
return dst
}
// easy, cheap case where it's a subset of one of the buffers
if (bytes <= this._bufs[off[0]].length - start) {
return copy
? this._bufs[off[0]].copy(dst, dstStart, start, start + bytes)
: this._bufs[off[0]].slice(start, start + bytes)
}
if (!copy) {
// a slice, we need something to copy in to
dst = Buffer.allocUnsafe(len)
}
for (let i = off[0]; i < this._bufs.length; i++) {
const l = this._bufs[i].length - start
if (bytes > l) {
this._bufs[i].copy(dst, bufoff, start)
bufoff += l
} else {
this._bufs[i].copy(dst, bufoff, start, start + bytes)
bufoff += l
break
}
bytes -= l
if (start) {
start = 0
}
}
// safeguard so that we don't return uninitialized memory
if (dst.length > bufoff) return dst.slice(0, bufoff)
return dst
}
BufferList.prototype.shallowSlice = function shallowSlice (start, end) {
start = start || 0
end = typeof end !== 'number' ? this.length : end
if (start < 0) {
start += this.length
}
if (end < 0) {
end += this.length
}
if (start === end) {
return this._new()
}
const startOffset = this._offset(start)
const endOffset = this._offset(end)
const buffers = this._bufs.slice(startOffset[0], endOffset[0] + 1)
if (endOffset[1] === 0) {
buffers.pop()
} else {
buffers[buffers.length - 1] = buffers[buffers.length - 1].slice(0, endOffset[1])
}
if (startOffset[1] !== 0) {
buffers[0] = buffers[0].slice(startOffset[1])
}
return this._new(buffers)
}
BufferList.prototype.toString = function toString (encoding, start, end) {
return this.slice(start, end).toString(encoding)
}
BufferList.prototype.consume = function consume (bytes) {
// first, normalize the argument, in accordance with how Buffer does it
bytes = Math.trunc(bytes)
// do nothing if not a positive number
if (Number.isNaN(bytes) || bytes <= 0) return this
while (this._bufs.length) {
if (bytes >= this._bufs[0].length) {
bytes -= this._bufs[0].length
this.length -= this._bufs[0].length
this._bufs.shift()
} else {
this._bufs[0] = this._bufs[0].slice(bytes)
this.length -= bytes
break
}
}
return this
}
BufferList.prototype.duplicate = function duplicate () {
const copy = this._new()
for (let i = 0; i < this._bufs.length; i++) {
copy.append(this._bufs[i])
}
return copy
}
BufferList.prototype.append = function append (buf) {
if (buf == null) {
return this
}
if (buf.buffer) {
// append a view of the underlying ArrayBuffer
this._appendBuffer(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength))
} else if (Array.isArray(buf)) {
for (let i = 0; i < buf.length; i++) {
this.append(buf[i])
}
} else if (this._isBufferList(buf)) {
// unwrap argument into individual BufferLists
for (let i = 0; i < buf._bufs.length; i++) {
this.append(buf._bufs[i])
}
} else {
// coerce number arguments to strings, since Buffer(number) does
// uninitialized memory allocation
if (typeof buf === 'number') {
buf = buf.toString()
}
this._appendBuffer(Buffer.from(buf))
}
return this
}
BufferList.prototype._appendBuffer = function appendBuffer (buf) {
this._bufs.push(buf)
this.length += buf.length
}
BufferList.prototype.indexOf = function (search, offset, encoding) {
if (encoding === undefined && typeof offset === 'string') {
encoding = offset
offset = undefined
}
if (typeof search === 'function' || Array.isArray(search)) {
throw new TypeError('The "value" argument must be one of type string, Buffer, BufferList, or Uint8Array.')
} else if (typeof search === 'number') {
search = Buffer.from([search])
} else if (typeof search === 'string') {
search = Buffer.from(search, encoding)
} else if (this._isBufferList(search)) {
search = search.slice()
} else if (Array.isArray(search.buffer)) {
search = Buffer.from(search.buffer, search.byteOffset, search.byteLength)
} else if (!Buffer.isBuffer(search)) {
search = Buffer.from(search)
}
offset = Number(offset || 0)
if (isNaN(offset)) {
offset = 0
}
if (offset < 0) {
offset = this.length + offset
}
if (offset < 0) {
offset = 0
}
if (search.length === 0) {
return offset > this.length ? this.length : offset
}
const blOffset = this._offset(offset)
let blIndex = blOffset[0] // index of which internal buffer we're working on
let buffOffset = blOffset[1] // offset of the internal buffer we're working on
// scan over each buffer
for (; blIndex < this._bufs.length; blIndex++) {
const buff = this._bufs[blIndex]
while (buffOffset < buff.length) {
const availableWindow = buff.length - buffOffset
if (availableWindow >= search.length) {
const nativeSearchResult = buff.indexOf(search, buffOffset)
if (nativeSearchResult !== -1) {
return this._reverseOffset([blIndex, nativeSearchResult])
}
buffOffset = buff.length - search.length + 1 // end of native search window
} else {
const revOffset = this._reverseOffset([blIndex, buffOffset])
if (this._match(revOffset, search)) {
return revOffset
}
buffOffset++
}
}
buffOffset = 0
}
return -1
}
BufferList.prototype._match = function (offset, search) {
if (this.length - offset < search.length) {
return false
}
for (let searchOffset = 0; searchOffset < search.length; searchOffset++) {
if (this.get(offset + searchOffset) !== search[searchOffset]) {
return false
}
}
return true
}
;(function () {
const methods = {
readDoubleBE: 8,
readDoubleLE: 8,
readFloatBE: 4,
readFloatLE: 4,
readInt32BE: 4,
readInt32LE: 4,
readUInt32BE: 4,
readUInt32LE: 4,
readInt16BE: 2,
readInt16LE: 2,
readUInt16BE: 2,
readUInt16LE: 2,
readInt8: 1,
readUInt8: 1,
readIntBE: null,
readIntLE: null,
readUIntBE: null,
readUIntLE: null
}
for (const m in methods) {
(function (m) {
if (methods[m] === null) {
BufferList.prototype[m] = function (offset, byteLength) {
return this.slice(offset, offset + byteLength)[m](0, byteLength)
}
} else {
BufferList.prototype[m] = function (offset = 0) {
return this.slice(offset, offset + methods[m])[m](0)
}
}
}(m))
}
}())
// Used internally by the class and also as an indicator of this object being
// a `BufferList`. It's not possible to use `instanceof BufferList` in a browser
// environment because there could be multiple different copies of the
// BufferList class and some `BufferList`s might be `BufferList`s.
BufferList.prototype._isBufferList = function _isBufferList (b) {
return b instanceof BufferList || BufferList.isBufferList(b)
}
BufferList.isBufferList = function isBufferList (b) {
return b != null && b[symbol]
}
module.exports = BufferList