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- 'use strict';
- var Buffer = require('safe-buffer').Buffer;
- var isEncoding = Buffer.isEncoding || function (encoding) {
- encoding = '' + encoding;
- switch (encoding && encoding.toLowerCase()) {
- case 'hex':case 'utf8':case 'utf-8':case 'ascii':case 'binary':case 'base64':case 'ucs2':case 'ucs-2':case 'utf16le':case 'utf-16le':case 'raw':
- return true;
- default:
- return false;
- }
- };
- function _normalizeEncoding(enc) {
- if (!enc) return 'utf8';
- var retried;
- while (true) {
- switch (enc) {
- case 'utf8':
- case 'utf-8':
- return 'utf8';
- case 'ucs2':
- case 'ucs-2':
- case 'utf16le':
- case 'utf-16le':
- return 'utf16le';
- case 'latin1':
- case 'binary':
- return 'latin1';
- case 'base64':
- case 'ascii':
- case 'hex':
- return enc;
- default:
- if (retried) return;
- enc = ('' + enc).toLowerCase();
- retried = true;
- }
- }
- };
- function normalizeEncoding(enc) {
- var nenc = _normalizeEncoding(enc);
- if (typeof nenc !== 'string' && (Buffer.isEncoding === isEncoding || !isEncoding(enc))) throw new Error('Unknown encoding: ' + enc);
- return nenc || enc;
- }
- exports.StringDecoder = StringDecoder;
- function StringDecoder(encoding) {
- this.encoding = normalizeEncoding(encoding);
- var nb;
- switch (this.encoding) {
- case 'utf16le':
- this.text = utf16Text;
- this.end = utf16End;
- nb = 4;
- break;
- case 'utf8':
- this.fillLast = utf8FillLast;
- nb = 4;
- break;
- case 'base64':
- this.text = base64Text;
- this.end = base64End;
- nb = 3;
- break;
- default:
- this.write = simpleWrite;
- this.end = simpleEnd;
- return;
- }
- this.lastNeed = 0;
- this.lastTotal = 0;
- this.lastChar = Buffer.allocUnsafe(nb);
- }
- StringDecoder.prototype.write = function (buf) {
- if (buf.length === 0) return '';
- var r;
- var i;
- if (this.lastNeed) {
- r = this.fillLast(buf);
- if (r === undefined) return '';
- i = this.lastNeed;
- this.lastNeed = 0;
- } else {
- i = 0;
- }
- if (i < buf.length) return r ? r + this.text(buf, i) : this.text(buf, i);
- return r || '';
- };
- StringDecoder.prototype.end = utf8End;
- StringDecoder.prototype.text = utf8Text;
- StringDecoder.prototype.fillLast = function (buf) {
- if (this.lastNeed <= buf.length) {
- buf.copy(this.lastChar, this.lastTotal - this.lastNeed, 0, this.lastNeed);
- return this.lastChar.toString(this.encoding, 0, this.lastTotal);
- }
- buf.copy(this.lastChar, this.lastTotal - this.lastNeed, 0, buf.length);
- this.lastNeed -= buf.length;
- };
- function utf8CheckByte(byte) {
- if (byte <= 0x7F) return 0;else if (byte >> 5 === 0x06) return 2;else if (byte >> 4 === 0x0E) return 3;else if (byte >> 3 === 0x1E) return 4;
- return byte >> 6 === 0x02 ? -1 : -2;
- }
- function utf8CheckIncomplete(self, buf, i) {
- var j = buf.length - 1;
- if (j < i) return 0;
- var nb = utf8CheckByte(buf[j]);
- if (nb >= 0) {
- if (nb > 0) self.lastNeed = nb - 1;
- return nb;
- }
- if (--j < i || nb === -2) return 0;
- nb = utf8CheckByte(buf[j]);
- if (nb >= 0) {
- if (nb > 0) self.lastNeed = nb - 2;
- return nb;
- }
- if (--j < i || nb === -2) return 0;
- nb = utf8CheckByte(buf[j]);
- if (nb >= 0) {
- if (nb > 0) {
- if (nb === 2) nb = 0;else self.lastNeed = nb - 3;
- }
- return nb;
- }
- return 0;
- }
- function utf8CheckExtraBytes(self, buf, p) {
- if ((buf[0] & 0xC0) !== 0x80) {
- self.lastNeed = 0;
- return '\ufffd';
- }
- if (self.lastNeed > 1 && buf.length > 1) {
- if ((buf[1] & 0xC0) !== 0x80) {
- self.lastNeed = 1;
- return '\ufffd';
- }
- if (self.lastNeed > 2 && buf.length > 2) {
- if ((buf[2] & 0xC0) !== 0x80) {
- self.lastNeed = 2;
- return '\ufffd';
- }
- }
- }
- }
- function utf8FillLast(buf) {
- var p = this.lastTotal - this.lastNeed;
- var r = utf8CheckExtraBytes(this, buf, p);
- if (r !== undefined) return r;
- if (this.lastNeed <= buf.length) {
- buf.copy(this.lastChar, p, 0, this.lastNeed);
- return this.lastChar.toString(this.encoding, 0, this.lastTotal);
- }
- buf.copy(this.lastChar, p, 0, buf.length);
- this.lastNeed -= buf.length;
- }
- function utf8Text(buf, i) {
- var total = utf8CheckIncomplete(this, buf, i);
- if (!this.lastNeed) return buf.toString('utf8', i);
- this.lastTotal = total;
- var end = buf.length - (total - this.lastNeed);
- buf.copy(this.lastChar, 0, end);
- return buf.toString('utf8', i, end);
- }
- function utf8End(buf) {
- var r = buf && buf.length ? this.write(buf) : '';
- if (this.lastNeed) return r + '\ufffd';
- return r;
- }
- function utf16Text(buf, i) {
- if ((buf.length - i) % 2 === 0) {
- var r = buf.toString('utf16le', i);
- if (r) {
- var c = r.charCodeAt(r.length - 1);
- if (c >= 0xD800 && c <= 0xDBFF) {
- this.lastNeed = 2;
- this.lastTotal = 4;
- this.lastChar[0] = buf[buf.length - 2];
- this.lastChar[1] = buf[buf.length - 1];
- return r.slice(0, -1);
- }
- }
- return r;
- }
- this.lastNeed = 1;
- this.lastTotal = 2;
- this.lastChar[0] = buf[buf.length - 1];
- return buf.toString('utf16le', i, buf.length - 1);
- }
- function utf16End(buf) {
- var r = buf && buf.length ? this.write(buf) : '';
- if (this.lastNeed) {
- var end = this.lastTotal - this.lastNeed;
- return r + this.lastChar.toString('utf16le', 0, end);
- }
- return r;
- }
- function base64Text(buf, i) {
- var n = (buf.length - i) % 3;
- if (n === 0) return buf.toString('base64', i);
- this.lastNeed = 3 - n;
- this.lastTotal = 3;
- if (n === 1) {
- this.lastChar[0] = buf[buf.length - 1];
- } else {
- this.lastChar[0] = buf[buf.length - 2];
- this.lastChar[1] = buf[buf.length - 1];
- }
- return buf.toString('base64', i, buf.length - n);
- }
- function base64End(buf) {
- var r = buf && buf.length ? this.write(buf) : '';
- if (this.lastNeed) return r + this.lastChar.toString('base64', 0, 3 - this.lastNeed);
- return r;
- }
- function simpleWrite(buf) {
- return buf.toString(this.encoding);
- }
- function simpleEnd(buf) {
- return buf && buf.length ? this.write(buf) : '';
- }
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