From 6394aaa46277530dc673601e344c8dfbc32c912d Mon Sep 17 00:00:00 2001
From: RedDwarfian <reddwarf86esb@gmail.com>
Date: Sat, 20 Jul 2019 22:36:16 -0400
Subject: [PATCH] [Implement] Buffer.writeUInt8

---
 assembly/buffer/index.ts | 6 ++++++
 assembly/node.d.ts       | 2 ++
 tests/buffer.spec.ts     | 8 ++++++++
 3 files changed, 16 insertions(+)

diff --git a/assembly/buffer/index.ts b/assembly/buffer/index.ts
index 66866bf..86a5894 100644
--- a/assembly/buffer/index.ts
+++ b/assembly/buffer/index.ts
@@ -22,4 +22,10 @@ export class Buffer extends Uint8Array {
     result.dataLength = size;
     return result;
   }
+
+  writeUInt8(value: u8, offset: i32 = 0): i32 {
+    if(<u32>offset > this.dataLength) throw new RangeError(E_INDEXOUTOFRANGE);
+    store<u8>(this.dataStart + offset, value);
+    return offset + 1;
+  }
 }
diff --git a/assembly/node.d.ts b/assembly/node.d.ts
index 80075a8..5c1ebe7 100644
--- a/assembly/node.d.ts
+++ b/assembly/node.d.ts
@@ -3,4 +3,6 @@ declare class Buffer extends Uint8Array {
   static alloc(size: i32): Buffer;
   /** This method allocates a new Buffer of indicated size. This is unsafe because the data is not zeroed. */
   static allocUnsafe(size: i32): Buffer;
+  /** Writes an inputted u8 value to the buffer, at the desired offset. */
+  writeUInt8(value:u8, offset?:i32): i32;
 }
diff --git a/tests/buffer.spec.ts b/tests/buffer.spec.ts
index 1596845..e19ff74 100644
--- a/tests/buffer.spec.ts
+++ b/tests/buffer.spec.ts
@@ -42,4 +42,12 @@ describe("buffer", () => {
     // TODO: expectFn(() => { Buffer.allocUnsafe(-1); }).toThrow();
     // TODO: expectFn(() => { Buffer.allocUnsafe(BLOCK_MAXSIZE + 1); }).toThrow();
   });
+
+  test("#writeUInt8", () => {
+    let buff = new Buffer(5);
+    expect<i32>(buff.writeUInt8(4)).toBe(1);
+    expect<i32>(buff.writeUInt8(252,4)).toBe(5);
+    expect<u8>(buff[0]).toBe(4);
+    expect<u8>(buff[4]).toBe(252);
+  });  
 });