1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
7 // Memory -------------------------------------------------------------------
9 function store8(memory, pointer, val) {
10 memory[pointer] = val;
13 function store16(memory, pointer, val) {
14 memory[pointer + 0] = val >> 0;
15 memory[pointer + 1] = val >> 8;
18 function store32(memory, pointer, val) {
19 memory[pointer + 0] = val >> 0;
20 memory[pointer + 1] = val >> 8;
21 memory[pointer + 2] = val >> 16;
22 memory[pointer + 3] = val >> 24;
25 function store64(memory, pointer, val) {
26 store32(memory, pointer, val);
27 var high = (val / 0x10000) | 0;
28 store32(memory, pointer + 4, high);
31 function load8(memory, pointer) {
32 return memory[pointer];
35 function load16(memory, pointer) {
36 return (memory[pointer + 0] << 0) +
37 (memory[pointer + 1] << 8);
40 function load32(memory, pointer) {
41 return (memory[pointer + 0] << 0) +
42 (memory[pointer + 1] << 8) +
43 (memory[pointer + 2] << 16) +
44 (memory[pointer + 3] << 24);
49 function align(size) {
50 return size + (kAlignment - (size % kAlignment)) % kAlignment;
53 // Buffer -------------------------------------------------------------------
55 function Buffer(size) {
56 this.memory = new Uint8Array(size);
60 Buffer.prototype.alloc = function(size) {
61 var pointer = this.next;
63 if (this.next > this.memory.length) {
64 var newSize = (1.5 * (this.memory.length + size)) | 0;
70 Buffer.prototype.grow = function(size) {
71 var newMemory = new Uint8Array(size);
72 var oldMemory = this.memory;
73 for (var i = 0; i < oldMemory.length; ++i)
74 newMemory[i] = oldMemory[i];
75 this.memory = newMemory;
78 Buffer.prototype.createViewOfAllocatedMemory = function() {
79 return new Uint8Array(this.memory.buffer, 0, this.next);
82 // Constants ----------------------------------------------------------------
84 var kArrayHeaderSize = 8;
85 var kStructHeaderSize = 8;
86 var kMessageHeaderSize = 8;
88 // Decoder ------------------------------------------------------------------
90 function Decoder(memory, handles, base) {
92 this.handles = handles;
95 this.viewU32 = new Uint32Array(
96 this.memory.buffer, 0,
97 Math.floor(this.memory.length / Uint32Array.BYTES_PER_ELEMENT));
98 this.viewFloat = new Float32Array(
99 this.memory.buffer, 0,
100 Math.floor(this.memory.length / Float32Array.BYTES_PER_ELEMENT));
103 Decoder.prototype.skip = function(offset) {
107 Decoder.prototype.read8 = function() {
108 var result = load8(this.memory, this.next);
113 Decoder.prototype.read32 = function() {
114 var result = this.viewU32[this.next / this.viewU32.BYTES_PER_ELEMENT];
115 this.next += this.viewU32.BYTES_PER_ELEMENT;
119 Decoder.prototype.read64 = function() {
120 var low = this.read32();
121 var high = this.read32();
122 return low + high * 0x100000000;
125 Decoder.prototype.decodeFloat = function() {
126 var result = this.viewFloat[this.next / this.viewFloat.BYTES_PER_ELEMENT];
127 this.next += this.viewFloat.BYTES_PER_ELEMENT;
131 Decoder.prototype.decodePointer = function() {
132 // TODO(abarth): To correctly decode a pointer, we need to know the real
133 // base address of the array buffer.
134 var offsetPointer = this.next;
135 var offset = this.read64();
138 return offsetPointer + offset;
141 Decoder.prototype.decodeAndCreateDecoder = function() {
142 return new Decoder(this.memory, this.handles, this.decodePointer());
145 Decoder.prototype.decodeHandle = function() {
146 return this.handles[this.read32()];
149 Decoder.prototype.decodeString = function() {
150 // TODO(abarth): We should really support UTF-8. We might want to
151 // jump out of the VM to decode the string directly from the array
152 // buffer using v8::String::NewFromUtf8.
153 var numberOfBytes = this.read32();
154 var numberOfElements = this.read32();
155 var val = new Array(numberOfElements);
156 var memory = this.memory;
157 var base = this.next;
158 for (var i = 0; i < numberOfElements; ++i) {
159 val[i] = String.fromCharCode(memory[base + i] & 0x7F);
161 this.next += numberOfElements;
165 Decoder.prototype.decodeArray = function(cls) {
166 var numberOfBytes = this.read32();
167 var numberOfElements = this.read32();
168 var val = new Array(numberOfElements);
169 for (var i = 0; i < numberOfElements; ++i) {
170 val[i] = cls.decode(this);
175 Decoder.prototype.decodeStructPointer = function(cls) {
176 return cls.decode(this.decodeAndCreateDecoder());
179 Decoder.prototype.decodeArrayPointer = function(cls) {
180 return this.decodeAndCreateDecoder().decodeArray(cls);
183 Decoder.prototype.decodeStringPointer = function() {
184 return this.decodeAndCreateDecoder().decodeString();
187 // Encoder ------------------------------------------------------------------
189 function Encoder(buffer, handles, base) {
190 this.buffer = buffer;
191 this.handles = handles;
196 Encoder.prototype.skip = function(offset) {
200 Encoder.prototype.write8 = function(val) {
201 store8(this.buffer.memory, this.next, val);
205 Encoder.prototype.write32 = function(val) {
206 store32(this.buffer.memory, this.next, val);
210 Encoder.prototype.write64 = function(val) {
211 store64(this.buffer.memory, this.next, val);
215 Encoder.prototype.encodeFloat = function(val) {
216 var floatBuffer = new Float32Array(1);
217 floatBuffer[0] = val;
218 var buffer = new Uint8Array(floatBuffer.buffer, 0);
219 for (var i = 0; i < buffer.length; ++i)
220 this.buffer.memory[this.next++] = buffer[i];
223 Encoder.prototype.encodePointer = function(pointer) {
225 return this.write64(0);
226 // TODO(abarth): To correctly encode a pointer, we need to know the real
227 // base address of the array buffer.
228 var offset = pointer - this.next;
229 this.write64(offset);
232 Encoder.prototype.createAndEncodeEncoder = function(size) {
233 var pointer = this.buffer.alloc(align(size));
234 this.encodePointer(pointer);
235 return new Encoder(this.buffer, this.handles, pointer);
238 Encoder.prototype.encodeHandle = function(handle) {
239 this.handles.push(handle);
240 this.write32(this.handles.length - 1);
243 Encoder.prototype.encodeString = function(val) {
244 var numberOfElements = val.length;
245 var numberOfBytes = kArrayHeaderSize + numberOfElements;
246 this.write32(numberOfBytes);
247 this.write32(numberOfElements);
248 // TODO(abarth): We should really support UTF-8. We might want to
249 // jump out of the VM to encode the string directly from the array
250 // buffer using v8::String::WriteUtf8.
251 var memory = this.buffer.memory;
252 var base = this.next;
253 var len = val.length;
254 for (var i = 0; i < len; ++i) {
255 memory[base + i] = val.charCodeAt(i) & 0x7F;
260 Encoder.prototype.encodeArray = function(cls, val) {
261 var numberOfElements = val.length;
262 var numberOfBytes = kArrayHeaderSize + cls.encodedSize * numberOfElements;
263 this.write32(numberOfBytes);
264 this.write32(numberOfElements);
265 for (var i = 0; i < numberOfElements; ++i) {
266 cls.encode(this, val[i]);
270 Encoder.prototype.encodeStructPointer = function(cls, val) {
271 var encoder = this.createAndEncodeEncoder(cls.encodedSize);
272 cls.encode(encoder, val);
275 Encoder.prototype.encodeArrayPointer = function(cls, val) {
276 var encodedSize = kArrayHeaderSize + cls.encodedSize * val.length;
277 var encoder = this.createAndEncodeEncoder(encodedSize);
278 encoder.encodeArray(cls, val);
281 Encoder.prototype.encodeStringPointer = function(val) {
282 // TODO(abarth): This won't be right once we support UTF-8.
283 var encodedSize = kArrayHeaderSize + val.length;
284 var encoder = this.createAndEncodeEncoder(encodedSize);
285 encoder.encodeString(val);
288 // Message ------------------------------------------------------------------
290 function Message(memory, handles) {
291 this.memory = memory;
292 this.handles = handles;
295 // MessageBuilder -----------------------------------------------------------
297 function MessageBuilder(messageName, payloadSize) {
298 // Currently, we don't compute the payload size correctly ahead of time.
299 // Instead, we overwrite this field at the end.
300 var numberOfBytes = kMessageHeaderSize + payloadSize;
301 this.buffer = new Buffer(numberOfBytes);
303 var encoder = this.createEncoder(kMessageHeaderSize);
304 encoder.write32(numberOfBytes);
305 encoder.write32(messageName);
308 MessageBuilder.prototype.createEncoder = function(size) {
309 var pointer = this.buffer.alloc(size);
310 return new Encoder(this.buffer, this.handles, pointer);
313 MessageBuilder.prototype.encodeStruct = function(cls, val) {
314 cls.encode(this.createEncoder(cls.encodedSize), val);
317 MessageBuilder.prototype.finish = function() {
318 // TODO(abarth): Rather than resizing the buffer at the end, we could
319 // compute the size we need ahead of time, like we do in C++.
320 var memory = this.buffer.createViewOfAllocatedMemory();
321 store32(memory, 0, memory.length);
322 var message = new Message(memory, this.handles);
329 // MessageReader ------------------------------------------------------------
331 function MessageReader(message) {
332 this.decoder = new Decoder(message.memory, message.handles, 0);
333 this.payloadSize = this.decoder.read32() - kMessageHeaderSize;
334 this.messageName = this.decoder.read32();
337 MessageReader.prototype.decodeStruct = function(cls) {
338 return cls.decode(this.decoder);
341 // Built-in types -----------------------------------------------------------
346 Uint8.encodedSize = 1;
348 Uint8.decode = function(decoder) {
349 return decoder.read8();
352 Uint8.encode = function(encoder, val) {
359 Uint16.encodedSize = 2;
361 Uint16.decode = function(decoder) {
362 return decoder.read16();
365 Uint16.encode = function(encoder, val) {
366 encoder.write16(val);
372 Uint32.encodedSize = 4;
374 Uint32.decode = function(decoder) {
375 return decoder.read32();
378 Uint32.encode = function(encoder, val) {
379 encoder.write32(val);
385 Uint64.encodedSize = 8;
387 Uint64.decode = function(decoder) {
388 return decoder.read64();
391 Uint64.encode = function(encoder, val) {
392 encoder.write64(val);
395 function PointerTo(cls) {
399 // TODO(abarth): Add missing types:
405 PointerTo.prototype.encodedSize = 8;
407 PointerTo.prototype.decode = function(decoder) {
408 return this.cls.decode(decoder.decodeAndCreateDecoder());
411 PointerTo.prototype.encode = function(encoder, val) {
412 var objectEncoder = encoder.createAndEncodeEncoder(this.cls.encodedSize);
413 this.cls.encode(objectEncoder, val);
416 function ArrayOf(cls) {
420 ArrayOf.prototype.encodedSize = 8;
422 ArrayOf.prototype.decode = function(decoder) {
423 return decoder.decodeArrayPointer(self.cls);
426 ArrayOf.prototype.encode = function(encoder, val) {
427 encoder.encodeArrayPointer(self.cls, val);
433 Handle.encodedSize = 4;
435 Handle.decode = function(decoder) {
436 return decoder.decodeHandle();
439 Handle.encode = function(encoder, val) {
440 encoder.encodeHandle(val);
444 exports.align = align;
445 exports.Message = Message;
446 exports.MessageBuilder = MessageBuilder;
447 exports.MessageReader = MessageReader;
448 exports.kArrayHeaderSize = kArrayHeaderSize;
449 exports.kStructHeaderSize = kStructHeaderSize;
450 exports.kMessageHeaderSize = kMessageHeaderSize;
451 exports.Uint8 = Uint8;
452 exports.Uint16 = Uint16;
453 exports.Uint32 = Uint32;
454 exports.Uint64 = Uint64;
455 exports.PointerTo = PointerTo;
456 exports.ArrayOf = ArrayOf;
457 exports.Handle = Handle;