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293 lines
9.3 KiB
JavaScript

var text = text || {};
text.Decoder = class {
static open(data, encoding) {
if (typeof data === 'string') {
return new text.Decoder.String(data);
}
const assert = (encoding, condition) => {
if (encoding && encoding !== condition) {
throw new text.Error("Invalid encoding '" + encoding + "'.");
}
};
const buffer = data instanceof Uint8Array ? data : data.peek();
const length = buffer.length;
if (length >= 3 && buffer[0] === 0xef && buffer[1] === 0xbb && buffer[2] === 0xbf) {
assert(encoding, 'utf-8');
return new text.Decoder.Utf8(buffer, 3, true);
}
if (length >= 2 && buffer[0] === 0xff && buffer[1] === 0xfe) {
assert(encoding, 'utf-16');
return new text.Decoder.Utf16LE(buffer, 2);
}
if (length >= 2 && buffer[0] === 0xfe && buffer[1] === 0xff) {
assert(encoding, 'utf-16');
return new text.Decoder.Utf16BE(buffer, 2);
}
if (length >= 4 && buffer[0] === 0x00 && buffer[1] === 0x00 && buffer[2] === 0xfe && buffer[3] === 0xff) {
throw new text.Error("Unsupported UTF-32 big-endian encoding.");
}
if (length >= 4 && buffer[0] === 0xff && buffer[1] === 0xfe && buffer[2] === 0x00 && buffer[3] === 0x00) {
throw new text.Error("Unsupported UTF-32 little-endian encoding.");
}
if (length >= 5 && buffer[0] === 0x2B && buffer[1] === 0x2F && buffer[2] === 0x76 && buffer[3] === 0x38 && buffer[4] === 0x2D) {
throw new text.Error("Unsupported UTF-7 encoding.");
}
if (length >= 4 && buffer[0] === 0x2B && buffer[1] === 0x2F && buffer[2] === 0x76 && (buffer[3] === 0x38 || buffer[3] === 0x39 || buffer[3] === 0x2B || buffer[3] === 0x2F)) {
throw new text.Error("Unsupported UTF-7 encoding.");
}
if (length >= 4 && buffer[0] === 0x84 && buffer[1] === 0x31 && buffer[2] === 0x95 && buffer[3] === 0x33) {
throw new text.Error("Unsupported GB-18030 encoding.");
}
if (length > 4 && (length % 2) == 0 && (buffer[0] === 0x00 || buffer[1] === 0x00 || buffer[2] === 0x00 || buffer[3] === 0x00)) {
const lo = new Uint32Array(256);
const hi = new Uint32Array(256);
for (let i = 0; i < length; i += 2) {
lo[buffer[i]]++;
hi[buffer[i + 1]]++;
}
if (lo[0x00] === 0 && (hi[0x00] / (length >> 1)) > 0.5) {
assert(encoding, 'utf-16');
return new text.Decoder.Utf16LE(buffer, 0);
}
if (hi[0x00] === 0 && (lo[0x00] / (length >> 1)) > 0.5) {
assert(encoding, 'utf-16');
return new text.Decoder.Utf16BE(buffer, 0);
}
}
if (encoding && (encoding.startsWith('iso-8859-') || encoding.startsWith('latin-'))) {
return new text.Decoder.Latin1(buffer, 0);
}
assert(encoding, 'utf-8');
return new text.Decoder.Utf8(buffer, 0, encoding === 'utf-8');
}
};
text.Decoder.String = class {
constructor(buffer) {
this.buffer = buffer ? buffer.match(/[\uD800-\uDBFF][\uDC00-\uDFFF]|[^\uD800-\uDFFF]/g) : [];
this.position = 0;
this.length = this.buffer.length;
}
get encoding() {
return null;
}
decode() {
if (this.position < this.length) {
return this.buffer[this.position++];
}
return undefined;
}
};
text.Decoder.Utf8 = class {
constructor(buffer, position, fatal) {
this.position = position || 0;
this.buffer = buffer;
this.fatal = fatal;
}
get encoding() {
return 'utf-8';
}
decode() {
const c = this.buffer[this.position];
if (c === undefined) {
return c;
}
this.position++;
if (c < 0x80) {
return String.fromCodePoint(c);
}
if (c >= 0xC2 && c <= 0xDF) {
if (this.buffer[this.position] !== undefined) {
const c2 = this.buffer[this.position];
this.position++;
return String.fromCharCode(((c & 0x1F) << 6) | (c2 & 0x3F));
}
}
if (c >= 0xE0 && c <= 0xEF) {
if (this.buffer[this.position + 1] !== undefined) {
const c2 = this.buffer[this.position];
if ((c !== 0xE0 || c2 >= 0xA0) && (c !== 0xED || c2 <= 0x9f)) {
const c3 = this.buffer[this.position + 1];
if (c3 >= 0x80 && c3 < 0xFB) {
this.position += 2;
return String.fromCharCode(((c & 0x0F) << 12) | ((c2 & 0x3F) << 6) | ((c3 & 0x3F) << 0));
}
}
}
}
if (c >= 0xF0 && c <= 0xF4) {
if (this.buffer[this.position + 2] !== undefined) {
const c2 = this.buffer[this.position];
if (c2 >= 0x80 && c2 <= 0xBF) {
const c3 = this.buffer[this.position + 1];
if (c3 >= 0x80 && c3 <= 0xBF) {
const c4 = this.buffer[this.position + 2];
if (c4 >= 0x80 && c4 <= 0xBF) {
this.position += 3;
return String.fromCodePoint(((c & 0x07) << 18) | ((c2 & 0x3F) << 12) | ((c3 & 0x3F) << 6) | (c4 & 0x3F));
}
}
}
}
}
if (this.fatal) {
throw new text.Error('Invalid utf-8 character.');
}
return String.fromCharCode(0xfffd);
}
};
text.Decoder.Latin1 = class {
constructor(buffer, position) {
this.position = position || 0;
this.buffer = buffer;
}
get encoding() {
return 'latin-1';
}
decode() {
const c = this.buffer[this.position];
if (c === undefined) {
return c;
}
this.position++;
return String.fromCodePoint(c);
}
};
text.Decoder.Utf16LE = class {
constructor(buffer, position) {
this.buffer = buffer;
this.position = position || 0;
this.length = buffer.length;
}
get encoding() {
return 'utf-16';
}
decode() {
if (this.position + 1 < this.length) {
const c = this.buffer[this.position++] | (this.buffer[this.position++] << 8);
if (c < 0xD800 || c >= 0xDFFF) {
return String.fromCharCode(c);
}
if (c >= 0xD800 && c < 0xDBFF) {
if (this._position + 1 < this._length) {
const c2 = this._buffer[this._position++] | (this._buffer[this._position++] << 8);
if (c >= 0xDC00 || c < 0xDFFF) {
return String.fromCodePoint(0x10000 + ((c & 0x3ff) << 10) + (c2 & 0x3ff));
}
}
}
return String.fromCharCode(0xfffd);
}
return undefined;
}
};
text.Decoder.Utf16BE = class {
constructor(buffer, position) {
this.buffer = buffer;
this.position = position || 0;
this.length = buffer.length;
}
get encoding() {
return 'utf-16';
}
decode() {
if (this.position + 1 < this.length) {
const c = (this.buffer[this.position++] << 8) | this.buffer[this.position++];
if (c < 0xD800 || c >= 0xDFFF) {
return String.fromCharCode(c);
}
if (c >= 0xD800 && c < 0xDBFF) {
if (this._position + 1 < this._length) {
const c2 = (this._buffer[this._position++] << 8) | this._buffer[this._position++];
if (c >= 0xDC00 || c < 0xDFFF) {
return String.fromCodePoint(0x10000 + ((c & 0x3ff) << 10) + (c2 & 0x3ff));
}
}
}
return String.fromCharCode(0xfffd);
}
return undefined;
}
};
text.Reader = class {
constructor(data, length) {
this._decoder = text.Decoder.open(data);
this._position = 0;
this._length = length || Number.MAX_SAFE_INTEGER;
}
static open(data, length) {
return new text.Reader(data, length);
}
read() {
if (this._position >= this._length) {
return undefined;
}
let line = '';
let buffer = null;
for (;;) {
const c = this._decoder.decode();
if (c === undefined) {
this._length = this._position;
break;
}
this._position++;
if (this._position > this._length) {
break;
}
if (c === '\n') {
break;
}
line += c;
if (line.length >= 32) {
buffer = buffer || [];
buffer.push(line);
line = '';
}
}
if (buffer) {
buffer.push(line);
return buffer.join('');
}
return line;
}
};
text.Error = class extends Error {
constructor(message) {
super(message);
this.name = 'Text Error';
}
};
if (typeof module !== 'undefined' && typeof module.exports === 'object') {
module.exports.Decoder = text.Decoder;
module.exports.Reader = text.Reader;
}