增加晶全app静态页面

node_modules/mqtt-packet/numbers.js

@@ -0,0 +1,58 @@
+const max = 65536
+const cache = {}
+
+// in node 6 Buffer.subarray returns a Uint8Array instead of a Buffer
+// later versions return a Buffer
+// alternative is Buffer.slice but that creates a new buffer
+// creating new buffers takes time
+// SubOk is only false on node < 8
+const SubOk = Buffer.isBuffer(Buffer.from([1, 2]).subarray(0, 1))
+
+function generateBuffer (i) {
+  const buffer = Buffer.allocUnsafe(2)
+  buffer.writeUInt8(i >> 8, 0)
+  buffer.writeUInt8(i & 0x00FF, 0 + 1)
+
+  return buffer
+}
+
+function generateCache () {
+  for (let i = 0; i < max; i++) {
+    cache[i] = generateBuffer(i)
+  }
+}
+
+function genBufVariableByteInt (num) {
+  const maxLength = 4 // max 4 bytes
+  let digit = 0
+  let pos = 0
+  const buffer = Buffer.allocUnsafe(maxLength)
+
+  do {
+    digit = num % 128 | 0
+    num = num / 128 | 0
+    if (num > 0) digit = digit | 0x80
+
+    buffer.writeUInt8(digit, pos++)
+  } while (num > 0 && pos < maxLength)
+
+  if (num > 0) {
+    pos = 0
+  }
+
+  return SubOk ? buffer.subarray(0, pos) : buffer.slice(0, pos)
+}
+
+function generate4ByteBuffer (num) {
+  const buffer = Buffer.allocUnsafe(4)
+  buffer.writeUInt32BE(num, 0)
+  return buffer
+}
+
+module.exports = {
+  cache,
+  generateCache,
+  generateNumber: generateBuffer,
+  genBufVariableByteInt,
+  generate4ByteBuffer
+}