AK-21/Graphite-Industrial-Intelligence

1'use strict'2 3const { Buffer } = require('buffer')4const symbol = Symbol.for('BufferList')5 6function BufferList (buf) {7  if (!(this instanceof BufferList)) {8    return new BufferList(buf)9  }10 11  BufferList._init.call(this, buf)12}13 14BufferList._init = function _init (buf) {15  Object.defineProperty(this, symbol, { value: true })16 17  this._bufs = []18  this.length = 019 20  if (buf) {21    this.append(buf)22  }23}24 25BufferList.prototype._new = function _new (buf) {26  return new BufferList(buf)27}28 29BufferList.prototype._offset = function _offset (offset) {30  if (offset === 0) {31    return [0, 0]32  }33 34  let tot = 035 36  for (let i = 0; i < this._bufs.length; i++) {37    const _t = tot + this._bufs[i].length38    if (offset < _t || i === this._bufs.length - 1) {39      return [i, offset - tot]40    }41    tot = _t42  }43}44 45BufferList.prototype._reverseOffset = function (blOffset) {46  const bufferId = blOffset[0]47  let offset = blOffset[1]48 49  for (let i = 0; i < bufferId; i++) {50    offset += this._bufs[i].length51  }52 53  return offset54}55 56BufferList.prototype.get = function get (index) {57  if (index > this.length || index < 0) {58    return undefined59  }60 61  const offset = this._offset(index)62 63  return this._bufs[offset[0]][offset[1]]64}65 66BufferList.prototype.slice = function slice (start, end) {67  if (typeof start === 'number' && start < 0) {68    start += this.length69  }70 71  if (typeof end === 'number' && end < 0) {72    end += this.length73  }74 75  return this.copy(null, 0, start, end)76}77 78BufferList.prototype.copy = function copy (dst, dstStart, srcStart, srcEnd) {79  if (typeof srcStart !== 'number' || srcStart < 0) {80    srcStart = 081  }82 83  if (typeof srcEnd !== 'number' || srcEnd > this.length) {84    srcEnd = this.length85  }86 87  if (srcStart >= this.length) {88    return dst || Buffer.alloc(0)89  }90 91  if (srcEnd <= 0) {92    return dst || Buffer.alloc(0)93  }94 95  const copy = !!dst96  const off = this._offset(srcStart)97  const len = srcEnd - srcStart98  let bytes = len99  let bufoff = (copy && dstStart) || 0100  let start = off[1]101 102  // copy/slice everything103  if (srcStart === 0 && srcEnd === this.length) {104    if (!copy) {105      // slice, but full concat if multiple buffers106      return this._bufs.length === 1107        ? this._bufs[0]108        : Buffer.concat(this._bufs, this.length)109    }110 111    // copy, need to copy individual buffers112    for (let i = 0; i < this._bufs.length; i++) {113      this._bufs[i].copy(dst, bufoff)114      bufoff += this._bufs[i].length115    }116 117    return dst118  }119 120  // easy, cheap case where it's a subset of one of the buffers121  if (bytes <= this._bufs[off[0]].length - start) {122    return copy123      ? this._bufs[off[0]].copy(dst, dstStart, start, start + bytes)124      : this._bufs[off[0]].slice(start, start + bytes)125  }126 127  if (!copy) {128    // a slice, we need something to copy in to129    dst = Buffer.allocUnsafe(len)130  }131 132  for (let i = off[0]; i < this._bufs.length; i++) {133    const l = this._bufs[i].length - start134 135    if (bytes > l) {136      this._bufs[i].copy(dst, bufoff, start)137      bufoff += l138    } else {139      this._bufs[i].copy(dst, bufoff, start, start + bytes)140      bufoff += l141      break142    }143 144    bytes -= l145 146    if (start) {147      start = 0148    }149  }150 151  // safeguard so that we don't return uninitialized memory152  if (dst.length > bufoff) return dst.slice(0, bufoff)153 154  return dst155}156 157BufferList.prototype.shallowSlice = function shallowSlice (start, end) {158  start = start || 0159  end = typeof end !== 'number' ? this.length : end160 161  if (start < 0) {162    start += this.length163  }164 165  if (end < 0) {166    end += this.length167  }168 169  if (start === end) {170    return this._new()171  }172 173  const startOffset = this._offset(start)174  const endOffset = this._offset(end)175  const buffers = this._bufs.slice(startOffset[0], endOffset[0] + 1)176 177  if (endOffset[1] === 0) {178    buffers.pop()179  } else {180    buffers[buffers.length - 1] = buffers[buffers.length - 1].slice(0, endOffset[1])181  }182 183  if (startOffset[1] !== 0) {184    buffers[0] = buffers[0].slice(startOffset[1])185  }186 187  return this._new(buffers)188}189 190BufferList.prototype.toString = function toString (encoding, start, end) {191  return this.slice(start, end).toString(encoding)192}193 194BufferList.prototype.consume = function consume (bytes) {195  // first, normalize the argument, in accordance with how Buffer does it196  bytes = Math.trunc(bytes)197  // do nothing if not a positive number198  if (Number.isNaN(bytes) || bytes <= 0) return this199 200  while (this._bufs.length) {201    if (bytes >= this._bufs[0].length) {202      bytes -= this._bufs[0].length203      this.length -= this._bufs[0].length204      this._bufs.shift()205    } else {206      this._bufs[0] = this._bufs[0].slice(bytes)207      this.length -= bytes208      break209    }210  }211 212  return this213}214 215BufferList.prototype.duplicate = function duplicate () {216  const copy = this._new()217 218  for (let i = 0; i < this._bufs.length; i++) {219    copy.append(this._bufs[i])220  }221 222  return copy223}224 225BufferList.prototype.append = function append (buf) {226  if (buf == null) {227    return this228  }229 230  if (buf.buffer) {231    // append a view of the underlying ArrayBuffer232    this._appendBuffer(Buffer.from(buf.buffer, buf.byteOffset, buf.byteLength))233  } else if (Array.isArray(buf)) {234    for (let i = 0; i < buf.length; i++) {235      this.append(buf[i])236    }237  } else if (this._isBufferList(buf)) {238    // unwrap argument into individual BufferLists239    for (let i = 0; i < buf._bufs.length; i++) {240      this.append(buf._bufs[i])241    }242  } else {243    // coerce number arguments to strings, since Buffer(number) does244    // uninitialized memory allocation245    if (typeof buf === 'number') {246      buf = buf.toString()247    }248 249    this._appendBuffer(Buffer.from(buf))250  }251 252  return this253}254 255BufferList.prototype._appendBuffer = function appendBuffer (buf) {256  this._bufs.push(buf)257  this.length += buf.length258}259 260BufferList.prototype.indexOf = function (search, offset, encoding) {261  if (encoding === undefined && typeof offset === 'string') {262    encoding = offset263    offset = undefined264  }265 266  if (typeof search === 'function' || Array.isArray(search)) {267    throw new TypeError('The "value" argument must be one of type string, Buffer, BufferList, or Uint8Array.')268  } else if (typeof search === 'number') {269    search = Buffer.from([search])270  } else if (typeof search === 'string') {271    search = Buffer.from(search, encoding)272  } else if (this._isBufferList(search)) {273    search = search.slice()274  } else if (Array.isArray(search.buffer)) {275    search = Buffer.from(search.buffer, search.byteOffset, search.byteLength)276  } else if (!Buffer.isBuffer(search)) {277    search = Buffer.from(search)278  }279 280  offset = Number(offset || 0)281 282  if (isNaN(offset)) {283    offset = 0284  }285 286  if (offset < 0) {287    offset = this.length + offset288  }289 290  if (offset < 0) {291    offset = 0292  }293 294  if (search.length === 0) {295    return offset > this.length ? this.length : offset296  }297 298  const blOffset = this._offset(offset)299  let blIndex = blOffset[0] // index of which internal buffer we're working on300  let buffOffset = blOffset[1] // offset of the internal buffer we're working on301 302  // scan over each buffer303  for (; blIndex < this._bufs.length; blIndex++) {304    const buff = this._bufs[blIndex]305 306    while (buffOffset < buff.length) {307      const availableWindow = buff.length - buffOffset308 309      if (availableWindow >= search.length) {310        const nativeSearchResult = buff.indexOf(search, buffOffset)311 312        if (nativeSearchResult !== -1) {313          return this._reverseOffset([blIndex, nativeSearchResult])314        }315 316        buffOffset = buff.length - search.length + 1 // end of native search window317      } else {318        const revOffset = this._reverseOffset([blIndex, buffOffset])319 320        if (this._match(revOffset, search)) {321          return revOffset322        }323 324        buffOffset++325      }326    }327 328    buffOffset = 0329  }330 331  return -1332}333 334BufferList.prototype._match = function (offset, search) {335  if (this.length - offset < search.length) {336    return false337  }338 339  for (let searchOffset = 0; searchOffset < search.length; searchOffset++) {340    if (this.get(offset + searchOffset) !== search[searchOffset]) {341      return false342    }343  }344  return true345}346 347;(function () {348  const methods = {349    readDoubleBE: 8,350    readDoubleLE: 8,351    readFloatBE: 4,352    readFloatLE: 4,353    readInt32BE: 4,354    readInt32LE: 4,355    readUInt32BE: 4,356    readUInt32LE: 4,357    readInt16BE: 2,358    readInt16LE: 2,359    readUInt16BE: 2,360    readUInt16LE: 2,361    readInt8: 1,362    readUInt8: 1,363    readIntBE: null,364    readIntLE: null,365    readUIntBE: null,366    readUIntLE: null367  }368 369  for (const m in methods) {370    (function (m) {371      if (methods[m] === null) {372        BufferList.prototype[m] = function (offset, byteLength) {373          return this.slice(offset, offset + byteLength)[m](0, byteLength)374        }375      } else {376        BufferList.prototype[m] = function (offset = 0) {377          return this.slice(offset, offset + methods[m])[m](0)378        }379      }380    }(m))381  }382}())383 384// Used internally by the class and also as an indicator of this object being385// a `BufferList`. It's not possible to use `instanceof BufferList` in a browser386// environment because there could be multiple different copies of the387// BufferList class and some `BufferList`s might be `BufferList`s.388BufferList.prototype._isBufferList = function _isBufferList (b) {389  return b instanceof BufferList || BufferList.isBufferList(b)390}391 392BufferList.isBufferList = function isBufferList (b) {393  return b != null && b[symbol]394}395 396module.exports = BufferList397