typescript
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TypeScript is a language for application scale JavaScript development
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JavaScript
// Minimal msgpack encoder/decoder.
// Supports: arrays, unsigned integers, strings, booleans, binary data.
import { Wtf8Decoder } from "./wtf8.js";
// ── MessagePack format constants ────────────────────────────────────
export const MSGPACK_FIXARRAY3 = 0x93; // 3-element fixarray
export const MSGPACK_BIN8 = 0xc4;
export const MSGPACK_BIN16 = 0xc5;
export const MSGPACK_BIN32 = 0xc6;
export const MSGPACK_UINT8 = 0xcc;
// ── Bin header helpers ──────────────────────────────────────────────
/** Compute the MessagePack bin header size for a given data length. */
export function binHeaderSize(len) {
if (len < 0x100)
return 2; // BIN8: marker + 1-byte size
if (len < 0x10000)
return 3; // BIN16: marker + 2-byte size
return 5; // BIN32: marker + 4-byte size
}
/** Write a MessagePack bin header into `buf` at `off`, return new offset. */
export function writeBinHeader(buf, off, len) {
if (len < 0x100) {
buf[off++] = MSGPACK_BIN8;
buf[off++] = len;
}
else if (len < 0x10000) {
buf[off++] = MSGPACK_BIN16;
buf[off++] = (len >>> 8) & 0xff;
buf[off++] = len & 0xff;
}
else {
buf[off++] = MSGPACK_BIN32;
buf[off++] = (len >>> 24) & 0xff;
buf[off++] = (len >>> 16) & 0xff;
buf[off++] = (len >>> 8) & 0xff;
buf[off++] = len & 0xff;
}
return off;
}
const encoder = new TextEncoder();
const decoder = new Wtf8Decoder();
export class MsgpackWriter {
buf;
view;
pos;
constructor(initialSize = 256) {
this.buf = new Uint8Array(initialSize);
this.view = new DataView(this.buf.buffer);
this.pos = 0;
}
ensure(n) {
if (this.pos + n > this.buf.length) {
let newSize = this.buf.length * 2;
while (newSize < this.pos + n)
newSize *= 2;
const next = new Uint8Array(newSize);
next.set(this.buf);
this.buf = next;
this.view = new DataView(this.buf.buffer);
}
}
writeArrayHeader(length) {
if (length <= 0x0f) {
this.ensure(1);
this.buf[this.pos++] = 0x90 | length;
}
else if (length <= 0xffff) {
this.ensure(3);
this.buf[this.pos++] = 0xdc;
this.view.setUint16(this.pos, length, false);
this.pos += 2;
}
else {
this.ensure(5);
this.buf[this.pos++] = 0xdd;
this.view.setUint32(this.pos, length, false);
this.pos += 4;
}
}
writeUint(value) {
if (value <= 0x7f) {
this.ensure(1);
this.buf[this.pos++] = value;
}
else if (value <= 0xff) {
this.ensure(2);
this.buf[this.pos++] = 0xcc;
this.buf[this.pos++] = value;
}
else if (value <= 0xffff) {
this.ensure(3);
this.buf[this.pos++] = 0xcd;
this.view.setUint16(this.pos, value, false);
this.pos += 2;
}
else {
this.ensure(5);
this.buf[this.pos++] = 0xce;
this.view.setUint32(this.pos, value, false);
this.pos += 4;
}
}
writeString(str) {
const encoded = encoder.encode(str);
const len = encoded.length;
if (len <= 0x1f) {
this.ensure(1 + len);
this.buf[this.pos++] = 0xa0 | len;
}
else if (len <= 0xff) {
this.ensure(2 + len);
this.buf[this.pos++] = 0xd9;
this.buf[this.pos++] = len;
}
else if (len <= 0xffff) {
this.ensure(3 + len);
this.buf[this.pos++] = 0xda;
this.view.setUint16(this.pos, len, false);
this.pos += 2;
}
else {
this.ensure(5 + len);
this.buf[this.pos++] = 0xdb;
this.view.setUint32(this.pos, len, false);
this.pos += 4;
}
this.buf.set(encoded, this.pos);
this.pos += len;
}
writeBool(value) {
this.ensure(1);
this.buf[this.pos++] = value ? 0xc3 : 0xc2;
}
finish() {
return this.buf.subarray(0, this.pos);
}
}
export class MsgpackReader {
buf;
view;
pos;
constructor(data, offset = 0) {
this.buf = data;
this.view = new DataView(data.buffer, data.byteOffset, data.byteLength);
this.pos = offset;
}
readArrayHeader() {
const byte = this.buf[this.pos++];
if ((byte & 0xf0) === 0x90)
return byte & 0x0f;
if (byte === 0xdc) {
const len = this.view.getUint16(this.pos, false);
this.pos += 2;
return len;
}
if (byte === 0xdd) {
const len = this.view.getUint32(this.pos, false);
this.pos += 4;
return len;
}
throw new Error(`Expected array header, got 0x${byte.toString(16)}`);
}
readUint() {
const byte = this.buf[this.pos++];
if (byte <= 0x7f)
return byte;
if (byte === 0xcc)
return this.buf[this.pos++];
if (byte === 0xcd) {
const val = this.view.getUint16(this.pos, false);
this.pos += 2;
return val;
}
if (byte === 0xce) {
const val = this.view.getUint32(this.pos, false);
this.pos += 4;
return val;
}
throw new Error(`Expected uint, got 0x${byte.toString(16)}`);
}
readString() {
const byte = this.buf[this.pos++];
let len;
if ((byte & 0xe0) === 0xa0) {
len = byte & 0x1f;
}
else if (byte === 0xd9) {
len = this.buf[this.pos++];
}
else if (byte === 0xda) {
len = this.view.getUint16(this.pos, false);
this.pos += 2;
}
else if (byte === 0xdb) {
len = this.view.getUint32(this.pos, false);
this.pos += 4;
}
else {
throw new Error(`Expected string, got 0x${byte.toString(16)}`);
}
const str = decoder.decode(this.buf.subarray(this.pos, this.pos + len));
this.pos += len;
return str;
}
readBool() {
const byte = this.buf[this.pos++];
if (byte === 0xc3)
return true;
if (byte === 0xc2)
return false;
throw new Error(`Expected bool, got 0x${byte.toString(16)}`);
}
}
//# sourceMappingURL=msgpack.js.map