diff --git a/index.html b/index.html
index 2214d1f..b42eed0 100644
--- a/index.html
+++ b/index.html
@@ -25,9 +25,8 @@
     </div>
     <input type="checkbox" id="download"> Download decompressed output (Recommended for .tar.bz2 and other compressed binary data)
     <pre id="out"></pre>
-    <script type="module">
-      import { decompress } from 'https://unpkg.com/bz2?module';
-
+    <script src="https://unpkg.com/bz2"></script>
+    <script>
       document.querySelector('#drop').addEventListener('drop', (event) => {
         event.preventDefault();
         let file;
@@ -41,7 +40,7 @@
 
         const reader = new FileReader();
         reader.addEventListener('load', (e) => {
-          const bytes = decompress(new Uint8Array(reader.result));
+          const bytes = window.bz2.decompress(new Uint8Array(reader.result));
           const result = new TextDecoder('utf8').decode(bytes);
           if (download) {
             const blob = new Blob([result], { type: 'application/octet-stream' });
diff --git a/index.js b/index.js
index ed58dea..5987cdb 100644
--- a/index.js
+++ b/index.js
@@ -2,334 +2,342 @@
 
 'use strict';
 
+(function bz2() {
 // https://www.ncbi.nlm.nih.gov/IEB/ToolBox/CPP_DOC/lxr/source/src/util/compress/bzip2/crctable.c
-const crc32Table = [
-  0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
-  0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
-  0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
-  0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
-  0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
-  0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
-  0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
-  0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
-  0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
-  0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
-  0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
-  0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
-  0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
-  0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
-  0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
-  0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
-  0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
-  0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
-  0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
-  0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
-  0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
-  0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
-  0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
-  0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
-  0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
-  0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
-  0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
-  0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
-  0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
-  0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
-  0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
-  0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4,
-];
+  const crc32Table = [
+    0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
+    0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
+    0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
+    0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
+    0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
+    0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
+    0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
+    0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
+    0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
+    0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
+    0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
+    0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
+    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
+    0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
+    0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
+    0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
+    0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
+    0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
+    0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
+    0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
+    0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
+    0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
+    0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
+    0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
+    0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
+    0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
+    0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
+    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
+    0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
+    0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
+    0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
+    0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4,
+  ];
 
-// generated from 1 << i, except for 32
-const masks = [
-  0x00000000, 0x00000001, 0x00000003, 0x00000007,
-  0x0000000f, 0x0000001f, 0x0000003f, 0x0000007f,
-  0x000000ff, 0x000001ff, 0x000003ff, 0x000007ff,
-  0x00000fff, 0x00001fff, 0x00003fff, 0x00007fff,
-  0x0000ffff, 0x0001ffff, 0x0003ffff, 0x0007ffff,
-  0x000fffff, 0x001fffff, 0x003fffff, 0x007fffff,
-  0x00ffffff, 0x01ffffff, 0x03ffffff, 0x07ffffff,
-  0x0fffffff, 0x1fffffff, 0x3fffffff, -0x80000000,
-];
+  // generated from 1 << i, except for 32
+  const masks = [
+    0x00000000, 0x00000001, 0x00000003, 0x00000007,
+    0x0000000f, 0x0000001f, 0x0000003f, 0x0000007f,
+    0x000000ff, 0x000001ff, 0x000003ff, 0x000007ff,
+    0x00000fff, 0x00001fff, 0x00003fff, 0x00007fff,
+    0x0000ffff, 0x0001ffff, 0x0003ffff, 0x0007ffff,
+    0x000fffff, 0x001fffff, 0x003fffff, 0x007fffff,
+    0x00ffffff, 0x01ffffff, 0x03ffffff, 0x07ffffff,
+    0x0fffffff, 0x1fffffff, 0x3fffffff, -0x80000000,
+  ];
 
-function createOrderedHuffmanTable(lengths) {
-  const z = [];
-  for (let i = 0; i < lengths.length; i += 1) {
-    z.push([i, lengths[i]]);
-  }
-  z.push([lengths.length, -1]);
-  const table = [];
-  let start = z[0][0];
-  let bits = z[0][1];
-  for (let i = 0; i < z.length; i += 1) {
-    const finish = z[i][0];
-    const endbits = z[i][1];
-    if (bits) {
-      for (let code = start; code < finish; code += 1) {
-        table.push({ code, bits, symbol: undefined });
+  function createOrderedHuffmanTable(lengths) {
+    const z = [];
+    for (let i = 0; i < lengths.length; i += 1) {
+      z.push([i, lengths[i]]);
+    }
+    z.push([lengths.length, -1]);
+    const table = [];
+    let start = z[0][0];
+    let bits = z[0][1];
+    for (let i = 0; i < z.length; i += 1) {
+      const finish = z[i][0];
+      const endbits = z[i][1];
+      if (bits) {
+        for (let code = start; code < finish; code += 1) {
+          table.push({ code, bits, symbol: undefined });
+        }
+      }
+      start = finish;
+      bits = endbits;
+      if (endbits === -1) {
+        break;
       }
     }
-    start = finish;
-    bits = endbits;
-    if (endbits === -1) {
-      break;
+    table.sort((a, b) => ((a.bits - b.bits) || (a.code - b.code)));
+    let tempBits = 0;
+    let symbol = -1;
+    const fastAccess = [];
+    let current;
+    for (let i = 0; i < table.length; i += 1) {
+      const t = table[i];
+      symbol += 1;
+      if (t.bits !== tempBits) {
+        symbol <<= t.bits - tempBits;
+        tempBits = t.bits;
+        current = fastAccess[tempBits] = {};
+      }
+      t.symbol = symbol;
+      current[symbol] = t;
     }
+    return {
+      table,
+      fastAccess,
+    };
   }
-  table.sort((a, b) => ((a.bits - b.bits) || (a.code - b.code)));
-  let tempBits = 0;
-  let symbol = -1;
-  const fastAccess = [];
-  let current;
-  for (let i = 0; i < table.length; i += 1) {
-    const t = table[i];
-    symbol += 1;
-    if (t.bits !== tempBits) {
-      symbol <<= t.bits - tempBits;
-      tempBits = t.bits;
-      current = fastAccess[tempBits] = {};
-    }
-    t.symbol = symbol;
-    current[symbol] = t;
-  }
-  return {
-    table,
-    fastAccess,
-  };
-}
 
-function bwtReverse(src, primary) {
-  if (primary < 0 || primary >= src.length) {
-    throw RangeError('Out of bound');
+  function bwtReverse(src, primary) {
+    if (primary < 0 || primary >= src.length) {
+      throw RangeError('Out of bound');
+    }
+    const unsorted = src.slice();
+    src.sort((a, b) => a - b);
+    const start = {};
+    for (let i = src.length - 1; i >= 0; i -= 1) {
+      start[src[i]] = i;
+    }
+    const links = [];
+    for (let i = 0; i < src.length; i += 1) {
+      links.push(start[unsorted[i]]++); // eslint-disable-line no-plusplus
+    }
+    let i;
+    const first = src[i = primary];
+    const ret = [];
+    for (let j = 1; j < src.length; j += 1) {
+      const x = src[i = links[i]];
+      if (x === undefined) {
+        ret.push(255);
+      } else {
+        ret.push(x);
+      }
+    }
+    ret.push(first);
+    ret.reverse();
+    return ret;
   }
-  const unsorted = src.slice();
-  src.sort((a, b) => a - b);
-  const start = {};
-  for (let i = src.length - 1; i >= 0; i -= 1) {
-    start[src[i]] = i;
-  }
-  const links = [];
-  for (let i = 0; i < src.length; i += 1) {
-    links.push(start[unsorted[i]]++); // eslint-disable-line no-plusplus
-  }
-  let i;
-  const first = src[i = primary];
-  const ret = [];
-  for (let j = 1; j < src.length; j += 1) {
-    const x = src[i = links[i]];
-    if (x === undefined) {
-      ret.push(255);
+
+  function decompress(bytes, checkCRC = false) {
+    let index = 0;
+    let bitfield = 0;
+    let bits = 0;
+    const read = (n) => {
+      if (n >= 32) {
+        const nd = n >> 1;
+        return read(nd) * (1 << nd) + read(n - nd);
+      }
+      while (bits < n) {
+        bitfield = (bitfield << 8) + bytes[index];
+        index += 1;
+        bits += 8;
+      }
+      const m = masks[n];
+      const r = (bitfield >> (bits - n)) & m;
+      bits -= n;
+      bitfield &= ~(m << bits);
+      return r;
+    };
+
+    const magic = read(16);
+    if (magic !== 0x425A) { // 'BZ'
+      throw new Error('Invalid magic');
+    }
+    const method = read(8);
+    if (method !== 0x68) { // h for huffman
+      throw new Error('Invalid method');
+    }
+
+    let blocksize = read(8);
+    if (blocksize >= 49 && blocksize <= 57) { // 1..9
+      blocksize -= 48;
     } else {
-      ret.push(x);
+      throw new Error('Invalid blocksize');
     }
-  }
-  ret.push(first);
-  ret.reverse();
-  return ret;
-}
 
-function decompress(bytes, checkCRC = false) {
-  let index = 0;
-  let bitfield = 0;
-  let bits = 0;
-  const read = (n) => {
-    if (n >= 32) {
-      const nd = n >> 1;
-      return read(nd) * (1 << nd) + read(n - nd);
-    }
-    while (bits < n) {
-      bitfield = (bitfield << 8) + bytes[index];
-      index += 1;
-      bits += 8;
-    }
-    const m = masks[n];
-    const r = (bitfield >> (bits - n)) & m;
-    bits -= n;
-    bitfield &= ~(m << bits);
-    return r;
-  };
-
-  const magic = read(16);
-  if (magic !== 0x425A) { // 'BZ'
-    throw new Error('Invalid magic');
-  }
-  const method = read(8);
-  if (method !== 0x68) { // h for huffman
-    throw new Error('Invalid method');
-  }
-
-  let blocksize = read(8);
-  if (blocksize >= 49 && blocksize <= 57) { // 1..9
-    blocksize -= 48;
-  } else {
-    throw new Error('Invalid blocksize');
-  }
-
-  let out = new Uint8Array(bytes.length * 1.5);
-  let outIndex = 0;
-  let newCRC = -1;
-  while (true) {
-    const blocktype = read(48);
-    const crc = read(32) | 0;
-    if (blocktype === 0x314159265359) {
-      if (read(1)) {
-        throw new Error('do not support randomised');
-      }
-      const pointer = read(24);
-      const used = [];
-      const usedGroups = read(16);
-      for (let i = 1 << 15; i > 0; i >>= 1) {
-        if (!(usedGroups & i)) {
-          for (let j = 0; j < 16; j += 1) {
-            used.push(false);
-          }
-          continue; // eslint-disable-line no-continue
+    let out = new Uint8Array(bytes.length * 1.5);
+    let outIndex = 0;
+    let newCRC = -1;
+    while (true) {
+      const blocktype = read(48);
+      const crc = read(32) | 0;
+      if (blocktype === 0x314159265359) {
+        if (read(1)) {
+          throw new Error('do not support randomised');
         }
-        const usedChars = read(16);
-        for (let j = 1 << 15; j > 0; j >>= 1) {
-          used.push(!!(usedChars & j));
-        }
-      }
-      const groups = read(3);
-      if (groups < 2 || groups > 6) {
-        throw new Error('Invalid number of huffman groups');
-      }
-      const selectorsUsed = read(15);
-      const selectors = [];
-      const mtf = Array.from({ length: groups }, (_, i) => i);
-      for (let i = 0; i < selectorsUsed; i += 1) {
-        let c = 0;
-        while (read(1)) {
-          c += 1;
-          if (c >= groups) {
-            throw new Error('MTF table out of range');
-          }
-        }
-        const v = mtf[c];
-        for (let j = c; j > 0; mtf[j] = mtf[--j]) { // eslint-disable-line no-plusplus
-          // nothing
-        }
-        selectors.push(v);
-        mtf[0] = v;
-      }
-      const symbolsInUse = used.reduce((a, b) => a + b, 0) + 2;
-      const tables = [];
-      for (let i = 0; i < groups; i += 1) {
-        let length = read(5);
-        const lengths = [];
-        for (let j = 0; j < symbolsInUse; j += 1) {
-          if (length < 0 || length > 20) {
-            throw new Error('Huffman group length outside range');
-          }
-          while (read(1)) {
-            length -= (read(1) * 2) - 1;
-          }
-          lengths.push(length);
-        }
-        tables.push(createOrderedHuffmanTable(lengths));
-      }
-      const favourites = [];
-      for (let i = 0; i < used.length - 1; i += 1) {
-        if (used[i]) {
-          favourites.push(i);
-        }
-      }
-      let decoded = 0;
-      let selectorPointer = 0;
-      let t;
-      let r;
-      let repeat = 0;
-      let repeatPower = 0;
-      const buffer = [];
-      while (true) {
-        decoded -= 1;
-        if (decoded <= 0) {
-          decoded = 50;
-          if (selectorPointer <= selectors.length) {
-            t = tables[selectors[selectorPointer]];
-            selectorPointer += 1;
-          }
-        }
-        for (const b in t.fastAccess) {
-          if (!Object.prototype.hasOwnProperty.call(t.fastAccess, b)) {
+        const pointer = read(24);
+        const used = [];
+        const usedGroups = read(16);
+        for (let i = 1 << 15; i > 0; i >>= 1) {
+          if (!(usedGroups & i)) {
+            for (let j = 0; j < 16; j += 1) {
+              used.push(false);
+            }
             continue; // eslint-disable-line no-continue
           }
-          if (bits < b) {
-            bitfield = (bitfield << 8) + bytes[index];
-            index += 1;
-            bits += 8;
-          }
-          r = t.fastAccess[b][bitfield >> (bits - b)];
-          if (r) {
-            bitfield &= masks[bits -= b];
-            r = r.code;
-            break;
+          const usedChars = read(16);
+          for (let j = 1 << 15; j > 0; j >>= 1) {
+            used.push(!!(usedChars & j));
           }
         }
-        if (r >= 0 && r <= 1) {
-          if (repeat === 0) {
-            repeatPower = 1;
+        const groups = read(3);
+        if (groups < 2 || groups > 6) {
+          throw new Error('Invalid number of huffman groups');
+        }
+        const selectorsUsed = read(15);
+        const selectors = [];
+        const mtf = Array.from({ length: groups }, (_, i) => i);
+        for (let i = 0; i < selectorsUsed; i += 1) {
+          let c = 0;
+          while (read(1)) {
+            c += 1;
+            if (c >= groups) {
+              throw new Error('MTF table out of range');
+            }
           }
-          repeat += repeatPower << r;
-          repeatPower <<= 1;
-          continue; // eslint-disable-line no-continue
-        } else {
-          const v = favourites[0];
-          for (; repeat > 0; repeat -= 1) {
+          const v = mtf[c];
+          for (let j = c; j > 0; mtf[j] = mtf[--j]) { // eslint-disable-line no-plusplus
+          // nothing
+          }
+          selectors.push(v);
+          mtf[0] = v;
+        }
+        const symbolsInUse = used.reduce((a, b) => a + b, 0) + 2;
+        const tables = [];
+        for (let i = 0; i < groups; i += 1) {
+          let length = read(5);
+          const lengths = [];
+          for (let j = 0; j < symbolsInUse; j += 1) {
+            if (length < 0 || length > 20) {
+              throw new Error('Huffman group length outside range');
+            }
+            while (read(1)) {
+              length -= (read(1) * 2) - 1;
+            }
+            lengths.push(length);
+          }
+          tables.push(createOrderedHuffmanTable(lengths));
+        }
+        const favourites = [];
+        for (let i = 0; i < used.length - 1; i += 1) {
+          if (used[i]) {
+            favourites.push(i);
+          }
+        }
+        let decoded = 0;
+        let selectorPointer = 0;
+        let t;
+        let r;
+        let repeat = 0;
+        let repeatPower = 0;
+        const buffer = [];
+        while (true) {
+          decoded -= 1;
+          if (decoded <= 0) {
+            decoded = 50;
+            if (selectorPointer <= selectors.length) {
+              t = tables[selectors[selectorPointer]];
+              selectorPointer += 1;
+            }
+          }
+          for (const b in t.fastAccess) {
+            if (!Object.prototype.hasOwnProperty.call(t.fastAccess, b)) {
+              continue; // eslint-disable-line no-continue
+            }
+            if (bits < b) {
+              bitfield = (bitfield << 8) + bytes[index];
+              index += 1;
+              bits += 8;
+            }
+            r = t.fastAccess[b][bitfield >> (bits - b)];
+            if (r) {
+              bitfield &= masks[bits -= b];
+              r = r.code;
+              break;
+            }
+          }
+          if (r >= 0 && r <= 1) {
+            if (repeat === 0) {
+              repeatPower = 1;
+            }
+            repeat += repeatPower << r;
+            repeatPower <<= 1;
+            continue; // eslint-disable-line no-continue
+          } else {
+            const v = favourites[0];
+            for (; repeat > 0; repeat -= 1) {
+              buffer.push(v);
+            }
+          }
+          if (r === symbolsInUse - 1) {
+            break;
+          } else {
+            const v = favourites[r - 1];
+            // eslint-disable-next-line no-plusplus
+            for (let j = r - 1; j > 0; favourites[j] = favourites[--j]) {
+            // nothing
+            }
+            favourites[0] = v;
             buffer.push(v);
           }
         }
-        if (r === symbolsInUse - 1) {
-          break;
-        } else {
-          const v = favourites[r - 1];
-          // eslint-disable-next-line no-plusplus
-          for (let j = r - 1; j > 0; favourites[j] = favourites[--j]) {
-            // nothing
-          }
-          favourites[0] = v;
-          buffer.push(v);
-        }
-      }
-      const nt = bwtReverse(buffer, pointer);
-      let i = 0;
-      while (i < nt.length) {
-        const c = nt[i];
-        let count = 1;
-        if ((i < nt.length - 4)
+        const nt = bwtReverse(buffer, pointer);
+        let i = 0;
+        while (i < nt.length) {
+          const c = nt[i];
+          let count = 1;
+          if ((i < nt.length - 4)
             && nt[i + 1] === c
             && nt[i + 2] === c
             && nt[i + 3] === c) {
-          count = nt[i + 4] + 4;
-          i += 5;
-        } else {
-          i += 1;
-        }
-        if (outIndex + count >= out.length) {
-          const old = out;
-          out = new Uint8Array(old.length * 2);
-          out.set(old);
-        }
-        for (let j = 0; j < count; j += 1) {
-          if (checkCRC) {
-            newCRC = (newCRC << 8) ^ crc32Table[((newCRC >> 24) ^ c) & 0xff];
+            count = nt[i + 4] + 4;
+            i += 5;
+          } else {
+            i += 1;
+          }
+          if (outIndex + count >= out.length) {
+            const old = out;
+            out = new Uint8Array(old.length * 2);
+            out.set(old);
+          }
+          for (let j = 0; j < count; j += 1) {
+            if (checkCRC) {
+              newCRC = (newCRC << 8) ^ crc32Table[((newCRC >> 24) ^ c) & 0xff];
+            }
+            out[outIndex] = c;
+            outIndex += 1;
           }
-          out[outIndex] = c;
-          outIndex += 1;
         }
-      }
-      if (checkCRC) {
-        const calculatedCRC = newCRC ^ -1;
-        if (calculatedCRC !== crc) {
-          throw new Error(`CRC mismatch: ${calculatedCRC} !== ${crc}`);
+        if (checkCRC) {
+          const calculatedCRC = newCRC ^ -1;
+          if (calculatedCRC !== crc) {
+            throw new Error(`CRC mismatch: ${calculatedCRC} !== ${crc}`);
+          }
+          newCRC = -1;
         }
-        newCRC = -1;
+      } else if (blocktype === 0x177245385090) {
+        read(bits & 0x07); // pad align
+        break;
+      } else {
+        throw new Error('Invalid bz2 blocktype');
       }
-    } else if (blocktype === 0x177245385090) {
-      read(bits & 0x07); // pad align
-      break;
-    } else {
-      throw new Error('Invalid bz2 blocktype');
     }
+    return out.subarray(0, outIndex);
   }
-  return out.subarray(0, outIndex);
-}
 
-module.exports = { decompress };
+  const exports = { decompress };
+
+  if (typeof window !== 'undefined') {
+    window.bz2 = exports; // eslint-disable-line no-undef
+  } else {
+    module.exports = exports;
+  }
+}());
diff --git a/package.json b/package.json
index af62362..eabc885 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "bz2",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "description": "bzip2 for JavaScript",
   "main": "index.js",
   "directories": {