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146 lines (136 loc) · 4.41 KB
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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 {
ArrayBufferIsView,
ObjectDefineProperties,
Symbol,
TypedArrayPrototypeSubarray,
} = primordials;
const { Buffer } = require('buffer');
const {
kIncompleteCharactersStart,
kIncompleteCharactersEnd,
kMissingBytes,
kBufferedBytes,
kEncodingField,
kSize,
decode,
flush,
} = internalBinding('string_decoder');
const {
encodingsMap,
normalizeEncoding,
} = require('internal/util');
const {
ERR_INVALID_ARG_TYPE,
ERR_INVALID_THIS,
ERR_UNKNOWN_ENCODING,
} = require('internal/errors').codes;
const kNativeDecoder = Symbol('kNativeDecoder');
/**
* StringDecoder provides an interface for efficiently splitting a series of
* buffers into a series of JS strings without breaking apart multibyte
* characters.
* @param {string} [encoding]
*/
function StringDecoder(encoding) {
this.encoding = normalizeEncoding(encoding);
if (this.encoding === undefined) {
throw new ERR_UNKNOWN_ENCODING(encoding);
}
this[kNativeDecoder] = Buffer.alloc(kSize);
this[kNativeDecoder][kEncodingField] = encodingsMap[this.encoding];
}
/**
* Returns a decoded string, omitting any incomplete multi-bytes
* characters at the end of the Buffer, or TypedArray, or DataView
* @param {string | Buffer | TypedArray | DataView} buf
* @returns {string}
* @throws {TypeError} Throws when buf is not in one of supported types
*/
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);
if (!this[kNativeDecoder]) {
throw new ERR_INVALID_THIS('StringDecoder');
}
return decode(this[kNativeDecoder], buf);
};
/**
* Returns any remaining input stored in the internal buffer as a string.
* After end() is called, the stringDecoder object can be reused for new
* input.
* @param {string | Buffer | TypedArray | DataView} [buf]
* @returns {string}
*/
StringDecoder.prototype.end = function end(buf) {
const ret = buf === undefined ? '' : this.write(buf);
if (this[kNativeDecoder][kBufferedBytes] > 0)
return ret + flush(this[kNativeDecoder]);
return ret;
};
/* Everything below this line is undocumented legacy stuff. */
/**
*
* @param {string | Buffer | TypedArray | DataView} buf
* @param {number} offset
* @returns {string}
*/
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: {
__proto__: null,
configurable: true,
enumerable: true,
get() {
return TypedArrayPrototypeSubarray(this[kNativeDecoder],
kIncompleteCharactersStart,
kIncompleteCharactersEnd);
},
},
lastNeed: {
__proto__: null,
configurable: true,
enumerable: true,
get() {
return this[kNativeDecoder][kMissingBytes];
},
},
lastTotal: {
__proto__: null,
configurable: true,
enumerable: true,
get() {
return this[kNativeDecoder][kBufferedBytes] +
this[kNativeDecoder][kMissingBytes];
},
},
});
exports.StringDecoder = StringDecoder;