writer.js
11.6 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
"use strict";
module.exports = Writer;
var util = require("./util/minimal");
var BufferWriter; // cyclic
var LongBits = util.LongBits,
base64 = util.base64,
utf8 = util.utf8;
/**
* Constructs a new writer operation instance.
* @classdesc Scheduled writer operation.
* @constructor
* @param {function(*, Uint8Array, number)} fn Function to call
* @param {number} len Value byte length
* @param {*} val Value to write
* @ignore
*/
function Op(fn, len, val) {
/**
* Function to call.
* @type {function(Uint8Array, number, *)}
*/
this.fn = fn;
/**
* Value byte length.
* @type {number}
*/
this.len = len;
/**
* Next operation.
* @type {Writer.Op|undefined}
*/
this.next = undefined;
/**
* Value to write.
* @type {*}
*/
this.val = val; // type varies
}
/* istanbul ignore next */
function noop() {} // eslint-disable-line no-empty-function
/**
* Constructs a new writer state instance.
* @classdesc Copied writer state.
* @memberof Writer
* @constructor
* @param {Writer} writer Writer to copy state from
* @ignore
*/
function State(writer) {
/**
* Current head.
* @type {Writer.Op}
*/
this.head = writer.head;
/**
* Current tail.
* @type {Writer.Op}
*/
this.tail = writer.tail;
/**
* Current buffer length.
* @type {number}
*/
this.len = writer.len;
/**
* Next state.
* @type {State|null}
*/
this.next = writer.states;
}
/**
* Constructs a new writer instance.
* @classdesc Wire format writer using `Uint8Array` if available, otherwise `Array`.
* @constructor
*/
function Writer() {
/**
* Current length.
* @type {number}
*/
this.len = 0;
/**
* Operations head.
* @type {Object}
*/
this.head = new Op(noop, 0, 0);
/**
* Operations tail
* @type {Object}
*/
this.tail = this.head;
/**
* Linked forked states.
* @type {Object|null}
*/
this.states = null;
// When a value is written, the writer calculates its byte length and puts it into a linked
// list of operations to perform when finish() is called. This both allows us to allocate
// buffers of the exact required size and reduces the amount of work we have to do compared
// to first calculating over objects and then encoding over objects. In our case, the encoding
// part is just a linked list walk calling operations with already prepared values.
}
/**
* Creates a new writer.
* @function
* @returns {BufferWriter|Writer} A {@link BufferWriter} when Buffers are supported, otherwise a {@link Writer}
*/
Writer.create = util.Buffer
? function create_buffer_setup() {
return (Writer.create = function create_buffer() {
return new BufferWriter();
})();
}
/* istanbul ignore next */
: function create_array() {
return new Writer();
};
/**
* Allocates a buffer of the specified size.
* @param {number} size Buffer size
* @returns {Uint8Array} Buffer
*/
Writer.alloc = function alloc(size) {
return new util.Array(size);
};
// Use Uint8Array buffer pool in the browser, just like node does with buffers
/* istanbul ignore else */
if (util.Array !== Array)
Writer.alloc = util.pool(Writer.alloc, util.Array.prototype.subarray);
/**
* Pushes a new operation to the queue.
* @param {function(Uint8Array, number, *)} fn Function to call
* @param {number} len Value byte length
* @param {number} val Value to write
* @returns {Writer} `this`
* @private
*/
Writer.prototype._push = function push(fn, len, val) {
this.tail = this.tail.next = new Op(fn, len, val);
this.len += len;
return this;
};
function writeByte(val, buf, pos) {
buf[pos] = val & 255;
}
function writeVarint32(val, buf, pos) {
while (val > 127) {
buf[pos++] = val & 127 | 128;
val >>>= 7;
}
buf[pos] = val;
}
/**
* Constructs a new varint writer operation instance.
* @classdesc Scheduled varint writer operation.
* @extends Op
* @constructor
* @param {number} len Value byte length
* @param {number} val Value to write
* @ignore
*/
function VarintOp(len, val) {
this.len = len;
this.next = undefined;
this.val = val;
}
VarintOp.prototype = Object.create(Op.prototype);
VarintOp.prototype.fn = writeVarint32;
/**
* Writes an unsigned 32 bit value as a varint.
* @param {number} value Value to write
* @returns {Writer} `this`
*/
Writer.prototype.uint32 = function write_uint32(value) {
// here, the call to this.push has been inlined and a varint specific Op subclass is used.
// uint32 is by far the most frequently used operation and benefits significantly from this.
this.len += (this.tail = this.tail.next = new VarintOp(
(value = value >>> 0)
< 128 ? 1
: value < 16384 ? 2
: value < 2097152 ? 3
: value < 268435456 ? 4
: 5,
value)).len;
return this;
};
/**
* Writes a signed 32 bit value as a varint.
* @function
* @param {number} value Value to write
* @returns {Writer} `this`
*/
Writer.prototype.int32 = function write_int32(value) {
return value < 0
? this._push(writeVarint64, 10, LongBits.fromNumber(value)) // 10 bytes per spec
: this.uint32(value);
};
/**
* Writes a 32 bit value as a varint, zig-zag encoded.
* @param {number} value Value to write
* @returns {Writer} `this`
*/
Writer.prototype.sint32 = function write_sint32(value) {
return this.uint32((value << 1 ^ value >> 31) >>> 0);
};
function writeVarint64(val, buf, pos) {
while (val.hi) {
buf[pos++] = val.lo & 127 | 128;
val.lo = (val.lo >>> 7 | val.hi << 25) >>> 0;
val.hi >>>= 7;
}
while (val.lo > 127) {
buf[pos++] = val.lo & 127 | 128;
val.lo = val.lo >>> 7;
}
buf[pos++] = val.lo;
}
/**
* Writes an unsigned 64 bit value as a varint.
* @param {Long|number|string} value Value to write
* @returns {Writer} `this`
* @throws {TypeError} If `value` is a string and no long library is present.
*/
Writer.prototype.uint64 = function write_uint64(value) {
var bits = LongBits.from(value);
return this._push(writeVarint64, bits.length(), bits);
};
/**
* Writes a signed 64 bit value as a varint.
* @function
* @param {Long|number|string} value Value to write
* @returns {Writer} `this`
* @throws {TypeError} If `value` is a string and no long library is present.
*/
Writer.prototype.int64 = Writer.prototype.uint64;
/**
* Writes a signed 64 bit value as a varint, zig-zag encoded.
* @param {Long|number|string} value Value to write
* @returns {Writer} `this`
* @throws {TypeError} If `value` is a string and no long library is present.
*/
Writer.prototype.sint64 = function write_sint64(value) {
var bits = LongBits.from(value).zzEncode();
return this._push(writeVarint64, bits.length(), bits);
};
/**
* Writes a boolish value as a varint.
* @param {boolean} value Value to write
* @returns {Writer} `this`
*/
Writer.prototype.bool = function write_bool(value) {
return this._push(writeByte, 1, value ? 1 : 0);
};
function writeFixed32(val, buf, pos) {
buf[pos ] = val & 255;
buf[pos + 1] = val >>> 8 & 255;
buf[pos + 2] = val >>> 16 & 255;
buf[pos + 3] = val >>> 24;
}
/**
* Writes an unsigned 32 bit value as fixed 32 bits.
* @param {number} value Value to write
* @returns {Writer} `this`
*/
Writer.prototype.fixed32 = function write_fixed32(value) {
return this._push(writeFixed32, 4, value >>> 0);
};
/**
* Writes a signed 32 bit value as fixed 32 bits.
* @function
* @param {number} value Value to write
* @returns {Writer} `this`
*/
Writer.prototype.sfixed32 = Writer.prototype.fixed32;
/**
* Writes an unsigned 64 bit value as fixed 64 bits.
* @param {Long|number|string} value Value to write
* @returns {Writer} `this`
* @throws {TypeError} If `value` is a string and no long library is present.
*/
Writer.prototype.fixed64 = function write_fixed64(value) {
var bits = LongBits.from(value);
return this._push(writeFixed32, 4, bits.lo)._push(writeFixed32, 4, bits.hi);
};
/**
* Writes a signed 64 bit value as fixed 64 bits.
* @function
* @param {Long|number|string} value Value to write
* @returns {Writer} `this`
* @throws {TypeError} If `value` is a string and no long library is present.
*/
Writer.prototype.sfixed64 = Writer.prototype.fixed64;
/**
* Writes a float (32 bit).
* @function
* @param {number} value Value to write
* @returns {Writer} `this`
*/
Writer.prototype.float = function write_float(value) {
return this._push(util.float.writeFloatLE, 4, value);
};
/**
* Writes a double (64 bit float).
* @function
* @param {number} value Value to write
* @returns {Writer} `this`
*/
Writer.prototype.double = function write_double(value) {
return this._push(util.float.writeDoubleLE, 8, value);
};
var writeBytes = util.Array.prototype.set
? function writeBytes_set(val, buf, pos) {
buf.set(val, pos); // also works for plain array values
}
/* istanbul ignore next */
: function writeBytes_for(val, buf, pos) {
for (var i = 0; i < val.length; ++i)
buf[pos + i] = val[i];
};
/**
* Writes a sequence of bytes.
* @param {Uint8Array|string} value Buffer or base64 encoded string to write
* @returns {Writer} `this`
*/
Writer.prototype.bytes = function write_bytes(value) {
var len = value.length >>> 0;
if (!len)
return this._push(writeByte, 1, 0);
if (util.isString(value)) {
var buf = Writer.alloc(len = base64.length(value));
base64.decode(value, buf, 0);
value = buf;
}
return this.uint32(len)._push(writeBytes, len, value);
};
/**
* Writes a string.
* @param {string} value Value to write
* @returns {Writer} `this`
*/
Writer.prototype.string = function write_string(value) {
var len = utf8.length(value);
return len
? this.uint32(len)._push(utf8.write, len, value)
: this._push(writeByte, 1, 0);
};
/**
* Forks this writer's state by pushing it to a stack.
* Calling {@link Writer#reset|reset} or {@link Writer#ldelim|ldelim} resets the writer to the previous state.
* @returns {Writer} `this`
*/
Writer.prototype.fork = function fork() {
this.states = new State(this);
this.head = this.tail = new Op(noop, 0, 0);
this.len = 0;
return this;
};
/**
* Resets this instance to the last state.
* @returns {Writer} `this`
*/
Writer.prototype.reset = function reset() {
if (this.states) {
this.head = this.states.head;
this.tail = this.states.tail;
this.len = this.states.len;
this.states = this.states.next;
} else {
this.head = this.tail = new Op(noop, 0, 0);
this.len = 0;
}
return this;
};
/**
* Resets to the last state and appends the fork state's current write length as a varint followed by its operations.
* @returns {Writer} `this`
*/
Writer.prototype.ldelim = function ldelim() {
var head = this.head,
tail = this.tail,
len = this.len;
this.reset().uint32(len);
if (len) {
this.tail.next = head.next; // skip noop
this.tail = tail;
this.len += len;
}
return this;
};
/**
* Finishes the write operation.
* @returns {Uint8Array} Finished buffer
*/
Writer.prototype.finish = function finish() {
var head = this.head.next, // skip noop
buf = this.constructor.alloc(this.len),
pos = 0;
while (head) {
head.fn(head.val, buf, pos);
pos += head.len;
head = head.next;
}
// this.head = this.tail = null;
return buf;
};
Writer._configure = function(BufferWriter_) {
BufferWriter = BufferWriter_;
};