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// 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';
const { Buffer } = require('buffer');
const {
kIncompleteCharactersStart,
kIncompleteCharactersEnd,
kMissingBytes,
kBufferedBytes,
kEncodingField,
kSize,
decode,
flush,
encodings
} = internalBinding('string_decoder');
const internalUtil = require('internal/util');
const {
ERR_INVALID_ARG_TYPE,
ERR_UNKNOWN_ENCODING
} = require('internal/errors').codes;
const isEncoding = Buffer[internalUtil.kIsEncodingSymbol];
const 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) {
const nenc = internalUtil.normalizeEncoding(enc);
if (nenc === undefined) {
if (Buffer.isEncoding === isEncoding || !Buffer.isEncoding(enc))
throw new ERR_UNKNOWN_ENCODING(enc);
return enc;
}
return nenc;
}
const 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 (!ArrayBuffer.isView(buf))
throw new ERR_INVALID_ARG_TYPE('buf',
['Buffer', 'TypedArray', 'DataView'],
buf);
return decode(this[kNativeDecoder], buf);
};
StringDecoder.prototype.end = function end(buf) {
let 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));
};
Object.defineProperties(StringDecoder.prototype, {
lastChar: {
configurable: true,
enumerable: true,
get() {
return this[kNativeDecoder].subarray(kIncompleteCharactersStart,
kIncompleteCharactersEnd);
}
},
lastNeed: {
configurable: true,
enumerable: true,
get() {
return this[kNativeDecoder][kMissingBytes];
}
},
lastTotal: {
configurable: true,
enumerable: true,
get() {
return this[kNativeDecoder][kBufferedBytes] +
this[kNativeDecoder][kMissingBytes];
}
}
});
exports.StringDecoder = StringDecoder;
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