feat(archive): introduce ts_shared browser-compatible layer, refactor Node-specific tools to wrap/shared implementations, and modernize archive handling

ts_shared/bzip2/bititerator.ts

@@ -0,0 +1,60 @@
+import type { IBitReader } from '../interfaces.js';
+
+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: () => Uint8Array): 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;
+    }
+
+    let result = 0;
+    let remaining = n as number;
+
+    while (remaining > 0) {
+      if (byte >= bytes.length) {
+        byte = 0;
+        bytes = nextBuffer();
+      }
+
+      const left = 8 - bit;
+
+      if (bit === 0 && remaining > 0) {
+        _bytesRead++;
+      }
+
+      if (remaining >= left) {
+        result <<= left;
+        result |= BITMASK[left] & bytes[byte++];
+        bit = 0;
+        remaining -= left;
+      } else {
+        result <<= remaining;
+        result |= (bytes[byte] & (BITMASK[remaining] << (8 - remaining - bit))) >> (8 - remaining - bit);
+        bit += remaining;
+        remaining = 0;
+      }
+    }
+
+    return result;
+  } as IBitReader;
+
+  Object.defineProperty(reader, 'bytesRead', {
+    get: () => _bytesRead,
+    enumerable: true,
+  });
+
+  return reader;
+}