1 files changed, 29 insertions, 0 deletions
diff --git a/io/util.ts b/io/util.ts
new file mode 100644
index 000000000..811940b4d
--- /dev/null
+++ b/io/util.ts
@@ -0,0 +1,29 @@
+import { Buffer, Reader } from "deno";
+
+export function assert(cond: boolean, msg = "assert") {
+  if (!cond) {
+    throw Error(msg);
+  }
+}
+
+// `off` is the offset into `dst` where it will at which to begin writing values
+// from `src`.
+// Returns the number of bytes copied.
+export function copyBytes(dst: Uint8Array, src: Uint8Array, off = 0): number {
+  const r = dst.byteLength - off;
+  if (src.byteLength > r) {
+    src = src.subarray(0, r);
+  }
+  dst.set(src, off);
+  return src.byteLength;
+}
+
+export function charCode(s: string): number {
+  return s.charCodeAt(0);
+}
+
+const encoder = new TextEncoder();
+export function stringsReader(s: string): Reader {
+  const ui8 = encoder.encode(s);
+  return new Buffer(ui8.buffer as ArrayBuffer);
+}