BREAKING CHANGE(SmartArchive): Refactor public API: rename factory/extraction methods, introduce typed interfaces and improved compression tools

ts/bzip2/bititerator.ts

@@ -1,44 +1,60 @@
-var BITMASK = [0, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff];
+import type { IBitReader } from '../interfaces.js';
 
-// returns a function that reads bits.
-// takes a buffer iterator as input
-export function bitIterator(nextBuffer: () => Buffer) {
-  var bit = 0,
-    byte = 0;
-  var bytes = nextBuffer();
-  var f = function (n) {
-    if (n === null && bit != 0) {
+const BITMASK = [0, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff] as const;
+
+/**
+ * Creates a bit reader function for BZIP2 decompression.
+ * Takes a buffer iterator as input and returns a function that reads bits.
+ */
+export function bitIterator(nextBuffer: () => Buffer): IBitReader {
+  let bit = 0;
+  let byte = 0;
+  let bytes = nextBuffer();
+  let _bytesRead = 0;
+
+  const reader = function (n: number | null): number | void {
+    if (n === null && bit !== 0) {
       // align to byte boundary
       bit = 0;
       byte++;
       return;
     }
-    var result = 0;
-    while (n > 0) {
+
+    let result = 0;
+    let remaining = n as number;
+
+    while (remaining > 0) {
       if (byte >= bytes.length) {
         byte = 0;
         bytes = nextBuffer();
       }
-      var left = 8 - bit;
-      if (bit === 0 && n > 0)
-        // @ts-ignore
-        f.bytesRead++;
-      if (n >= left) {
+
+      const left = 8 - bit;
+
+      if (bit === 0 && remaining > 0) {
+        _bytesRead++;
+      }
+
+      if (remaining >= left) {
         result <<= left;
         result |= BITMASK[left] & bytes[byte++];
         bit = 0;
-        n -= left;
+        remaining -= left;
       } else {
-        result <<= n;
-        result |=
-          (bytes[byte] & (BITMASK[n] << (8 - n - bit))) >> (8 - n - bit);
-        bit += n;
-        n = 0;
+        result <<= remaining;
+        result |= (bytes[byte] & (BITMASK[remaining] << (8 - remaining - bit))) >> (8 - remaining - bit);
+        bit += remaining;
+        remaining = 0;
       }
     }
+
     return result;
-  };
-  // @ts-ignore
-  f.bytesRead = 0;
-  return f;
+  } as IBitReader;
+
+  Object.defineProperty(reader, 'bytesRead', {
+    get: () => _bytesRead,
+    enumerable: true,
+  });
+
+  return reader;
 }