Move everything into std subdir

1 files changed, 79 insertions, 0 deletions

diff --git a/std/io/ioutil.ts b/std/io/ioutil.ts
new file mode 100644
index 000000000..f1ca54e14
--- /dev/null
+++ b/std/io/ioutil.ts
@@ -0,0 +1,79 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { BufReader, UnexpectedEOFError } from "./bufio.ts";
+type Reader = Deno.Reader;
+type Writer = Deno.Writer;
+import { assert } from "../testing/asserts.ts";
+
+/** copy N size at the most.
+ *  If read size is lesser than N, then returns nread
+ * */
+export async function copyN(
+  dest: Writer,
+  r: Reader,
+  size: number
+): Promise<number> {
+  let bytesRead = 0;
+  let buf = new Uint8Array(1024);
+  while (bytesRead < size) {
+    if (size - bytesRead < 1024) {
+      buf = new Uint8Array(size - bytesRead);
+    }
+    const result = await r.read(buf);
+    const nread = result === Deno.EOF ? 0 : result;
+    bytesRead += nread;
+    if (nread > 0) {
+      const n = await dest.write(buf.slice(0, nread));
+      assert(n === nread, "could not write");
+    }
+    if (result === Deno.EOF) {
+      break;
+    }
+  }
+  return bytesRead;
+}
+
+/** Read big endian 16bit short from BufReader */
+export async function readShort(buf: BufReader): Promise<number | Deno.EOF> {
+  const high = await buf.readByte();
+  if (high === Deno.EOF) return Deno.EOF;
+  const low = await buf.readByte();
+  if (low === Deno.EOF) throw new UnexpectedEOFError();
+  return (high << 8) | low;
+}
+
+/** Read big endian 32bit integer from BufReader */
+export async function readInt(buf: BufReader): Promise<number | Deno.EOF> {
+  const high = await readShort(buf);
+  if (high === Deno.EOF) return Deno.EOF;
+  const low = await readShort(buf);
+  if (low === Deno.EOF) throw new UnexpectedEOFError();
+  return (high << 16) | low;
+}
+
+const MAX_SAFE_INTEGER = BigInt(Number.MAX_SAFE_INTEGER);
+
+/** Read big endian 64bit long from BufReader */
+export async function readLong(buf: BufReader): Promise<number | Deno.EOF> {
+  const high = await readInt(buf);
+  if (high === Deno.EOF) return Deno.EOF;
+  const low = await readInt(buf);
+  if (low === Deno.EOF) throw new UnexpectedEOFError();
+  const big = (BigInt(high) << 32n) | BigInt(low);
+  // We probably should provide a similar API that returns BigInt values.
+  if (big > MAX_SAFE_INTEGER) {
+    throw new RangeError(
+      "Long value too big to be represented as a Javascript number."
+    );
+  }
+  return Number(big);
+}
+
+/** Slice number into 64bit big endian byte array */
+export function sliceLongToBytes(d: number, dest = new Array(8)): number[] {
+  let big = BigInt(d);
+  for (let i = 0; i < 8; i++) {
+    dest[7 - i] = Number(big & 0xffn);
+    big >>= 8n;
+  }
+  return dest;
+}