tools/node-hermes/nodelib/string_decoder.js

// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
'use strict';

var _primordials = primordials,
    ArrayBufferIsView = _primordials.ArrayBufferIsView,
    ObjectDefineProperties = _primordials.ObjectDefineProperties,
    _Symbol = _primordials.Symbol,
    TypedArrayPrototypeSubarray = _primordials.TypedArrayPrototypeSubarray;

var _require = require('buffer'),
    Buffer = _require.Buffer;

var _internalBinding = internalBinding('string_decoder'),
    kIncompleteCharactersStart = _internalBinding.kIncompleteCharactersStart,
    kIncompleteCharactersEnd = _internalBinding.kIncompleteCharactersEnd,
    kMissingBytes = _internalBinding.kMissingBytes,
    kBufferedBytes = _internalBinding.kBufferedBytes,
    kEncodingField = _internalBinding.kEncodingField,
    kSize = _internalBinding.kSize,
    decode = _internalBinding.decode,
    flush = _internalBinding.flush,
    encodings = _internalBinding.encodings;

var internalUtil = require('internal/util');

var _require$codes = require('internal/errors').codes,
    ERR_INVALID_ARG_TYPE = _require$codes.ERR_INVALID_ARG_TYPE,
    ERR_UNKNOWN_ENCODING = _require$codes.ERR_UNKNOWN_ENCODING;

var isEncoding = Buffer[internalUtil.kIsEncodingSymbol];

var kNativeDecoder = _Symbol('kNativeDecoder'); // Do not cache `Buffer.isEncoding` when checking encoding names as some
// modules monkey-patch it to support additional encodings


function normalizeEncoding(enc) {
  var nenc = internalUtil.normalizeEncoding(enc);

  if (nenc === undefined) {
    if (Buffer.isEncoding === isEncoding || !Buffer.isEncoding(enc)) throw new ERR_UNKNOWN_ENCODING(enc);
    return enc;
  }

  return nenc;
}

var encodingsMap = {};

for (var i = 0; i < encodings.length; ++i) {
  encodingsMap[encodings[i]] = i;
} // StringDecoder provides an interface for efficiently splitting a series of
// buffers into a series of JS strings without breaking apart multi-byte
// characters.


function StringDecoder(encoding) {
  this.encoding = normalizeEncoding(encoding);
  this[kNativeDecoder] = Buffer.alloc(kSize);
  this[kNativeDecoder][kEncodingField] = encodingsMap[this.encoding];
}

StringDecoder.prototype.write = function write(buf) {
  if (typeof buf === 'string') return buf;
  if (!ArrayBufferIsView(buf)) throw new ERR_INVALID_ARG_TYPE('buf', ['Buffer', 'TypedArray', 'DataView'], buf);
  return decode(this[kNativeDecoder], buf);
};

StringDecoder.prototype.end = function end(buf) {
  var ret = '';
  if (buf !== undefined) ret = this.write(buf);
  if (this[kNativeDecoder][kBufferedBytes] > 0) ret += flush(this[kNativeDecoder]);
  return ret;
};
/* Everything below this line is undocumented legacy stuff. */


StringDecoder.prototype.text = function text(buf, offset) {
  this[kNativeDecoder][kMissingBytes] = 0;
  this[kNativeDecoder][kBufferedBytes] = 0;
  return this.write(buf.slice(offset));
};

ObjectDefineProperties(StringDecoder.prototype, {
  lastChar: {
    configurable: true,
    enumerable: true,
    get: function get() {
      return TypedArrayPrototypeSubarray(this[kNativeDecoder], kIncompleteCharactersStart, kIncompleteCharactersEnd);
    }
  },
  lastNeed: {
    configurable: true,
    enumerable: true,
    get: function get() {
      return this[kNativeDecoder][kMissingBytes];
    }
  },
  lastTotal: {
    configurable: true,
    enumerable: true,
    get: function get() {
      return this[kNativeDecoder][kBufferedBytes] + this[kNativeDecoder][kMissingBytes];
    }
  }
});
exports.StringDecoder = StringDecoder;