[Implement] Buffer.writeUInt8 (#12)

RedDwarfian · jtenner · commit 00e1d25a2517 · 2019-07-21T17:55:47.000-04:00
diff --git a/assembly/buffer/index.ts b/assembly/buffer/index.ts
@@ -23,6 +23,12 @@ export class Buffer extends Uint8Array {
     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;
+  }
+
   writeInt8(value: i8, offset: i32 = 0): i32 {
     if(<u32>offset > this.dataLength) throw new RangeError(E_INDEXOUTOFRANGE);
     store<i8>(this.dataStart + offset, value);
diff --git a/assembly/node.d.ts b/assembly/node.d.ts
@@ -3,6 +3,8 @@ 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;
   /** Writes an inputted value to the buffer, at the desired offset. */
   writeInt8(value:i8, offset?:i32): i32;
   /** Reads a signed integer at the designated offset. */
diff --git a/tests/buffer.spec.ts b/tests/buffer.spec.ts
@@ -43,6 +43,14 @@ describe("buffer", () => {
     // 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);
+  });  
+
   test("#writeInt8", () => {
     let buff = new Buffer(5);
     expect<i32>(buff.writeInt8(9)).toBe(1);
@@ -65,5 +73,4 @@ describe("buffer", () => {
     //   newBuff.readInt8(5);
     // }).toThrow();
   })
-
 });
