initial changes

src/utils/byte_order.js

@@ -0,0 +1,112 @@
+export const is_big_endian_system =
+    new Uint8Array(new Uint32Array([ 0x12345678 ]).buffer)[0] === 0x12;
+
+export const is_little_endian_system =
+    new Uint8Array(new Uint32Array([ 0x12345678 ]).buffer)[0] === 0x78;
+
+export const i8_to_ui8_array = num => {
+  if (typeof num === 'string' || num instanceof String) {
+    num = parseInt(num, 10);
+  }
+
+  const buffer = Buffer.alloc(1);
+  buffer.writeInt8(num);
+  return new Uint8Array(buffer);
+};
+
+export const ui8_array_to_i8 = (ar, offset) => {
+  const buffer = Buffer.alloc(1);
+  buffer[0] = ar[offset];
+
+  return buffer.readInt8(0);
+};
+
+export const ui8_to_ui8_array = num => {
+  if (typeof num === 'string' || num instanceof String) {
+    num = parseInt(num, 10);
+  }
+
+  const buffer = Buffer.alloc(1);
+  buffer.writeUInt8(num);
+  return new Uint8Array(buffer);
+};
+
+export const ui8_array_to_ui8 = (ar, offset) => {
+  const buffer = Buffer.alloc(1);
+  buffer[0] = ar[offset];
+
+  return buffer.readUInt8(0);
+};
+
+export const i16_to_be_ui8_array = num => {
+  if (typeof num === 'string' || num instanceof String) {
+    num = parseInt(num, 10);
+  }
+
+  const buffer = Buffer.alloc(2);
+  buffer.writeInt16BE(num);
+  return new Uint8Array(buffer);
+};
+
+export const be_ui8_array_to_i16 = (ar, offset) => {
+  const buffer = Buffer.alloc(2);
+  for (let i = offset; i < buffer.length + offset; i++) {
+    buffer[i - offset] = ar[i];
+  }
+  return buffer.readInt16BE(0);
+};
+
+export const ui16_to_be_ui8_array = num => {
+  if (typeof num === 'string' || num instanceof String) {
+    num = parseInt(num, 10);
+  }
+
+  const buffer = Buffer.alloc(2);
+  buffer.writeUInt16BE(num);
+  return new Uint8Array(buffer);
+};
+
+export const be_ui8_array_to_ui16 = (ar, offset) => {
+  const buffer = Buffer.alloc(2);
+  for (let i = offset; i < buffer.length + offset; i++) {
+    buffer[i - offset] = ar[i];
+  }
+  return buffer.readUInt16BE(0);
+};
+
+export const i32_to_be_ui8_array = num => {
+  if (typeof num === 'string' || num instanceof String) {
+    num = parseInt(num, 10);
+  }
+
+  const buffer = Buffer.alloc(4);
+  buffer.writeInt32BE(num);
+  return new Uint8Array(buffer);
+};
+
+export const be_ui8_array_to_i32 = (ar, offset) => {
+  const buffer = Buffer.alloc(4);
+  for (let i = offset; i < buffer.length + offset; i++) {
+    buffer[i - offset] = ar[i];
+  }
+  return buffer.readInt32BE(0);
+};
+
+export const ui32_to_be_ui8_array = num => {
+  if (typeof num === 'string' || num instanceof String) {
+    num = parseInt(num, 10);
+  }
+
+  const buffer = Buffer.alloc(4);
+  buffer.writeUInt32BE(num);
+  return new Uint8Array(buffer);
+};
+
+export const be_ui8_array_to_ui32 = (ar, offset) => {
+  const buffer = Buffer.alloc(4);
+  for (let i = offset; i < buffer.length + offset; i++) {
+    buffer[i - offset] = ar[i];
+  }
+
+  return buffer.readUInt32BE(0);
+};