1 files changed, 36 insertions, 0 deletions
diff --git a/net/ioutil.ts b/net/ioutil.ts
new file mode 100644
index 000000000..68d6e5190
--- /dev/null
+++ b/net/ioutil.ts
@@ -0,0 +1,36 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { BufReader } from "./bufio.ts";
+
+/* Read big endian 16bit short from BufReader */
+export async function readShort(buf: BufReader): Promise<number> {
+  const [high, low] = [await buf.readByte(), await buf.readByte()];
+  return (high << 8) | low;
+}
+
+/* Read big endian 32bit integer from BufReader */
+export async function readInt(buf: BufReader): Promise<number> {
+  const [high, low] = [await readShort(buf), await readShort(buf)];
+  return (high << 16) | low;
+}
+
+const BIT32 = 0xffffffff;
+/* Read big endian 64bit long from BufReader */
+export async function readLong(buf: BufReader): Promise<number> {
+  const [high, low] = [await readInt(buf), await readInt(buf)];
+  // ECMAScript doesn't support 64bit bit ops.
+  return high ? high * (BIT32 + 1) + low : low;
+}
+
+/* Slice number into 64bit big endian byte array */
+export function sliceLongToBytes(d: number, dest = new Array(8)): number[] {
+  let mask = 0xff;
+  let low = (d << 32) >>> 32;
+  let high = (d - low) / (BIT32 + 1);
+  let shift = 24;
+  for (let i = 0; i < 4; i++) {
+    dest[i] = (high >>> shift) & mask;
+    dest[i + 4] = (low >>> shift) & mask;
+    shift -= 8;
+  }
+  return dest;
+}