Fix: root user password change #93, Change: link to series filter on ab page #90, Add: basic mobi and azw3 ereader support

client/assets/mobi.js

@@ -0,0 +1,405 @@
+function ab2str(buf) {
+  if (buf instanceof ArrayBuffer) {
+    buf = new Uint8Array(buf);
+  }
+  return new TextDecoder("utf-8").decode(buf);
+}
+
+var domParser = new DOMParser();
+
+class Buffer {
+  constructor(capacity) {
+    this.capacity = capacity;
+    this.fragment_list = [];
+    this.cur_fragment = new Fragment(capacity);
+    this.fragment_list.push(this.cur_fragment);
+  }
+  write(byte) {
+    var result = this.cur_fragment.write(byte);
+    if (!result) {
+      this.cur_fragment = new Fragment(this.capacity);
+      this.fragment_list.push(this.cur_fragment);
+      this.cur_fragment.write(byte);
+    }
+  }
+  get(idx) {
+    var fi = 0;
+    while (fi < this.fragment_list.length) {
+      var frag = this.fragment_list[fi];
+      if (idx < frag.size) {
+        return frag.get(idx);
+      }
+      idx -= frag.size;
+      fi += 1;
+    }
+    return null;
+  }
+  size() {
+    var s = 0;
+    for (var i = 0; i < this.fragment_list.length; i++) {
+      s += this.fragment_list[i].size;
+    }
+    return s;
+  }
+  shrink() {
+    var total_buffer = new Uint8Array(this.size());
+    var offset = 0;
+    for (var i = 0; i < this.fragment_list.length; i++) {
+      var frag = this.fragment_list[i];
+      if (frag.full()) {
+        total_buffer.set(frag.buffer, offset);
+      } else {
+        total_buffer.set(frag.buffer.slice(0, frag.size), offset);
+      }
+      offset += frag.size;
+    }
+    return total_buffer;
+  }
+}
+
+var combine_uint8array = function (buffers) {
+  var total_size = 0;
+  for (var i = 0; i < buffers.length; i++) {
+    var buffer = buffers[i];
+    total_size += buffer.length;
+  }
+  var total_buffer = new Uint8Array(total_size);
+  var offset = 0;
+  for (var i = 0; i < buffers.length; i++) {
+    var buffer = buffers[i];
+    total_buffer.set(buffer, offset);
+    offset += buffer.length;
+  }
+  return total_buffer;
+}
+
+class Fragment {
+  constructor(capacity) {
+    this.buffer = new Uint8Array(capacity);
+    this.capacity = capacity;
+    this.size = 0;
+  }
+
+  write(byte) {
+    if (this.size >= this.capacity) {
+      return false;
+    }
+    this.buffer[this.size] = byte;
+    this.size += 1;
+    return true;
+  }
+  full() {
+    return this.size === this.capacity;
+  }
+  get(idx) {
+    return this.buffer[idx];
+  }
+}
+
+var uncompression_lz77 = function (data) {
+  var length = data.length;
+  var offset = 0;   // Current offset into data
+  var buffer = new Buffer(data.length);
+
+  while (offset < length) {
+    var char = data[offset];
+    offset += 1;
+
+    if (char == 0) {
+      buffer.write(char);
+    } else if (char <= 8) {
+      for (var i = offset; i < offset + char; i++) {
+        buffer.write(data[i]);
+      }
+      offset += char;
+    } else if (char <= 0x7f) {
+      buffer.write(char);
+    } else if (char <= 0xbf) {
+      var next = data[offset];
+      offset += 1;
+      var distance = ((char << 8 | next) >> 3) & 0x7ff;
+      var lz_length = (next & 0x7) + 3;
+
+      var buffer_size = buffer.size();
+      for (var i = 0; i < lz_length; i++) {
+        buffer.write(buffer.get(buffer_size - distance))
+        buffer_size += 1;
+      }
+    } else {
+      buffer.write(32);
+      buffer.write(char ^ 0x80);
+    }
+  }
+  return buffer;
+};
+
+class MobiFile {
+  constructor(data) {
+    this.view = new DataView(data);
+    this.buffer = this.view.buffer;
+    this.offset = 0;
+    this.header = null;
+  }
+
+  parse() {
+
+  }
+
+  getUint8() {
+    var v = this.view.getUint8(this.offset);
+    this.offset += 1;
+    return v;
+  }
+
+  getUint16() {
+    var v = this.view.getUint16(this.offset);
+    this.offset += 2;
+    return v;
+  }
+
+  getUint32() {
+    var v = this.view.getUint32(this.offset);
+    this.offset += 4;
+    return v;
+  }
+
+  getStr(size) {
+    var v = ab2str(this.buffer.slice(this.offset, this.offset + size));
+    this.offset += size;
+    return v;
+  }
+
+  skip(size) {
+    this.offset += size;
+  }
+
+  setoffset(_of) {
+    this.offset = _of;
+  }
+
+  get_record_extrasize(data, flags) {
+    var pos = data.length - 1;
+    var extra = 0;
+    for (var i = 15; i > 0; i--) {
+      if (flags & (1 << i)) {
+        var res = this.buffer_get_varlen(data, pos);
+        var size = res[0];
+        var l = res[1];
+        pos = res[2];
+        pos -= size - l;
+        extra += size;
+      }
+    }
+    if (flags & 1) {
+      var a = data[pos];
+      extra += (a & 0x3) + 1;
+    }
+    return extra;
+  }
+
+  // data should be uint8array
+  buffer_get_varlen(data, pos) {
+    var l = 0;
+    var size = 0;
+    var byte_count = 0;
+    var mask = 0x7f;
+    var stop_flag = 0x80;
+    var shift = 0;
+    for (var i = 0; ; i++) {
+      var byte = data[pos];
+      size |= (byte & mask) << shift;
+      shift += 7;
+      l += 1;
+      byte_count += 1;
+      pos -= 1;
+
+      var to_stop = byte & stop_flag;
+      if (byte_count >= 4 || to_stop > 0) {
+        break;
+      }
+    }
+    return [size, l, pos];
+  }
+
+  read_text() {
+    var text_end = this.palm_header.record_count;
+    var buffers = [];
+    for (var i = 1; i <= text_end; i++) {
+      buffers.push(this.read_text_record(i));
+    }
+    var all = combine_uint8array(buffers)
+    return ab2str(all);
+  }
+
+  read_text_record(i) {
+    var flags = this.mobi_header.extra_flags;
+    var begin = this.reclist[i].offset;
+    var end = this.reclist[i + 1].offset;
+
+    var data = new Uint8Array(this.buffer.slice(begin, end))
+    var ex = this.get_record_extrasize(data, flags);
+
+    data = new Uint8Array(this.buffer.slice(begin, end - ex));
+    if (this.palm_header.compression === 2) {
+      var buffer = uncompression_lz77(data);
+      return buffer.shrink();
+    } else {
+      return data;
+    }
+  }
+
+  read_image(idx) {
+    var first_image_idx = this.mobi_header.first_image_idx;
+    var begin = this.reclist[first_image_idx + idx].offset;
+    var end = this.reclist[first_image_idx + idx + 1].offset;
+    var data = new Uint8Array(this.buffer.slice(begin, end))
+    return new Blob([data.buffer]);
+  }
+
+  load() {
+    this.header = this.load_pdbheader();
+    this.reclist = this.load_reclist();
+    this.load_record0();
+  }
+
+  load_pdbheader() {
+    var header = {};
+    header.name = this.getStr(32);
+    header.attr = this.getUint16();
+    header.version = this.getUint16();
+    header.ctime = this.getUint32();
+    header.mtime = this.getUint32();
+    header.btime = this.getUint32();
+    header.mod_num = this.getUint32();
+    header.appinfo_offset = this.getUint32();
+    header.sortinfo_offset = this.getUint32();
+    header.type = this.getStr(4);
+    header.creator = this.getStr(4);
+    header.uid = this.getUint32();
+    header.next_rec = this.getUint32();
+    header.record_num = this.getUint16();
+
+    return header;
+  }
+
+  load_reclist() {
+    var reclist = [];
+    for (var i = 0; i < this.header.record_num; i++) {
+      var record = {};
+      record.offset = this.getUint32();
+      // TODO(zz) change 
+      record.attr = this.getUint32();
+      reclist.push(record);
+    }
+    return reclist;
+  }
+  load_record0() {
+    this.palm_header = this.load_record0_header();
+    this.mobi_header = this.load_mobi_header();
+  }
+
+  load_record0_header() {
+    var p_header = {};
+    var first_record = this.reclist[0];
+    this.setoffset(first_record.offset);
+
+    p_header.compression = this.getUint16();
+    this.skip(2);
+    p_header.text_length = this.getUint32();
+    p_header.record_count = this.getUint16();
+    p_header.record_size = this.getUint16();
+    p_header.encryption_type = this.getUint16();
+    this.skip(2);
+
+    return p_header;
+  }
+
+  load_mobi_header() {
+    var mobi_header = {};
+
+    var start_offset = this.offset;
+
+    mobi_header.identifier = this.getUint32();
+    mobi_header.header_length = this.getUint32();
+    mobi_header.mobi_type = this.getUint32();
+    mobi_header.text_encoding = this.getUint32();
+    mobi_header.uid = this.getUint32();
+    mobi_header.generator_version = this.getUint32();
+
+    this.skip(40);
+
+    mobi_header.first_nonbook_index = this.getUint32();
+    mobi_header.full_name_offset = this.getUint32();
+    mobi_header.full_name_length = this.getUint32();
+
+    mobi_header.language = this.getUint32();
+    mobi_header.input_language = this.getUint32();
+    mobi_header.output_language = this.getUint32();
+    mobi_header.min_version = this.getUint32();
+    mobi_header.first_image_idx = this.getUint32();
+
+    mobi_header.huff_rec_index = this.getUint32();
+    mobi_header.huff_rec_count = this.getUint32();
+    mobi_header.datp_rec_index = this.getUint32();
+    mobi_header.datp_rec_count = this.getUint32();
+
+    mobi_header.exth_flags = this.getUint32();
+
+    this.skip(36);
+
+    mobi_header.drm_offset = this.getUint32();
+    mobi_header.drm_count = this.getUint32();
+    mobi_header.drm_size = this.getUint32();
+    mobi_header.drm_flags = this.getUint32();
+
+    this.skip(8);
+
+    // TODO (zz) fdst_index
+    this.skip(4);
+
+    this.skip(46);
+
+    mobi_header.extra_flags = this.getUint16();
+
+    this.setoffset(start_offset + mobi_header.header_length)
+
+    return mobi_header;
+  }
+  load_exth_header() {
+    // TODO
+    return {};
+  }
+
+  render_to(id) {
+    this.load();
+    var content = this.read_text();
+
+    var bookDom = document.getElementById(id);
+    while (bookDom.firstChild) {
+      bookDom.removeChild(bookDom.firstChild);
+    }
+
+    var bookDoc = domParser.parseFromString(content, "text/html");
+    bookDoc.body.childNodes.forEach(function (x) {
+      if (x instanceof Element) {
+        bookDom.appendChild(x);
+      }
+    });
+
+    var imgDoms = bookDom.getElementsByTagName("img");
+    for (var i = 0; i < imgDoms.length; i++) {
+      this.render_image(imgDoms, i);
+    }
+  }
+  render_image(imgDoms, i) {
+    var imgDom = imgDoms[i];
+    var idx = +imgDom.getAttribute("recindex");
+    var blob = this.read_image(idx - 1);
+    var imgReader = new FileReader();
+    imgReader.onload = function (e) {
+      imgDom.src = e.target.result;
+    };
+    imgReader.readAsDataURL(blob);
+  }
+}
+module.exports = MobiFile

client/components/app/Reader.vue

@@ -9,11 +9,14 @@
       </select>
     </div> -->
     <div class="absolute top-4 left-4 font-book">
-      <h1 class="text-2xl mb-1">{{ title }}</h1>
+      <h1 class="text-2xl mb-1">{{ title || abTitle }}</h1>
-
+      <p v-if="author || abAuthor">by {{ author || abAuthor }}</p>
-      <p v-if="author">by {{ author }}</p>
     </div>
-    <div class="h-full flex items-center">
+    <div v-if="!epubEbook && mobiEbook" class="absolute top-4 left-0 w-full flex justify-center">
+      <p class="text-error font-semibold">Warning: Reading mobi & azw3 files is in the very early stages</p>
+    </div>
+
+    <div v-if="epubEbook" class="h-full flex items-center">
       <div style="width: 100px; max-width: 100px" class="h-full flex items-center overflow-x-hidden">
         <span v-show="hasPrev" class="material-icons text-black text-opacity-30 hover:text-opacity-80 cursor-pointer text-8xl" @mousedown.prevent @click="pageLeft">chevron_left</span>
       </div>
@@ -28,11 +31,17 @@
         <span v-show="hasNext" class="material-icons text-black text-opacity-30 hover:text-opacity-80 cursor-pointer text-8xl" @mousedown.prevent @click="pageRight">chevron_right</span>
       </div>
     </div>
+    <div v-else class="h-full flex items-center justify-center">
+      <div class="w-full max-w-4xl overflow-y-auto border border-black border-opacity-10 p-4" style="max-height: 80vh">
+        <div id="viewer" />
+      </div>
+    </div>
   </div>
 </template>
 
 <script>
 import ePub from 'epubjs'
+import mobijs from '@/assets/mobi.js'
 
 export default {
   data() {
@@ -65,6 +74,12 @@ export default {
         this.$store.commit('setShowEReader', val)
       }
     },
+    abTitle() {
+      return this.selectedAudiobook.book.title
+    },
+    abAuthor() {
+      return this.selectedAudiobook.book.author
+    },
     selectedAudiobook() {
       return this.$store.state.selectedAudiobook
     },
@@ -83,6 +98,16 @@ export default {
     epubPath() {
       return this.epubEbook ? this.epubEbook.path : null
     },
+    mobiEbook() {
+      return this.ebooks.find((eb) => eb.ext === '.mobi' || eb.ext === '.azw3')
+    },
+    mobiPath() {
+      return this.mobiEbook ? this.mobiEbook.path : null
+    },
+    mobiUrl() {
+      if (!this.mobiPath) return null
+      return `/ebook/${this.libraryId}/${this.folderId}/${this.mobiPath}`
+    },
     url() {
       if (!this.epubPath) return null
       return `/ebook/${this.libraryId}/${this.folderId}/${this.epubPath}`
@@ -134,7 +159,24 @@ export default {
     init() {
       this.registerListeners()
 
-      console.log('epub', this.url, this.epubEbook, this.ebooks)
+      if (this.epubEbook) {
+        this.initEpub()
+      } else if (this.mobiEbook) {
+        this.initMobi()
+      }
+    },
+    async initMobi() {
+      var buff = await this.$axios.$get(this.mobiUrl, {
+        responseType: 'blob'
+      })
+      var reader = new FileReader()
+      reader.onload = function (event) {
+        var file_content = event.target.result
+        new mobijs(file_content).render_to('viewer')
+      }
+      reader.readAsArrayBuffer(buff)
+    },
+    initEpub() {
       // var book = ePub(this.url, {
       //   requestHeaders: {
       //     Authorization: `Bearer ${this.userToken}`

client/package.json

@@ -1,6 +1,6 @@
 {
   "name": "audiobookshelf-client",
-  "version": "1.4.5",
+  "version": "1.4.6",
   "description": "Audiobook manager and player",
   "main": "index.js",
   "scripts": {

client/pages/account.vue

@@ -23,7 +23,7 @@
           <div class="flex items-center py-2">
             <p v-if="isRoot" class="text-error py-2 text-xs">* Root user is the only user that can have an empty password</p>
             <div class="flex-grow" />
-            <ui-btn v-show="password && newPassword && confirmPassword" type="submit" :loading="changingPassword" color="success">Submit</ui-btn>
+            <ui-btn v-show="(password && newPassword && confirmPassword) || isRoot" type="submit" :loading="changingPassword" color="success">Submit</ui-btn>
           </div>
         </form>
       </div>

client/pages/audiobook/_id/index.vue

@@ -22,8 +22,7 @@
                 by <nuxt-link v-if="author" :to="`/library/${libraryId}/bookshelf?filter=authors.${$encode(author)}`" class="hover:underline">{{ author }}</nuxt-link
                 ><span v-else>Unknown</span>
               </p>
-
+              <nuxt-link v-if="series" :to="`/library/${libraryId}/bookshelf?filter=series.${$encode(series)}`" class="hover:underline font-sans text-gray-300 text-lg leading-7 mb-4"> {{ seriesText }}</nuxt-link>
-              <h3 v-if="series" class="font-sans text-gray-300 text-lg leading-7 mb-4">{{ seriesText }}</h3>
 
               <!-- <div class="w-min">
                 <ui-tooltip :text="authorTooltipText" direction="bottom">
@@ -105,7 +104,7 @@
               {{ isMissing ? 'Missing' : 'Incomplete' }}
             </ui-btn>
 
-            <ui-btn v-if="showExperimentalFeatures && epubEbook" color="info" :padding-x="4" small class="flex items-center h-9 mr-2" @click="openEbook">
+            <ui-btn v-if="showExperimentalFeatures && (epubEbook || mobiEbook)" color="info" :padding-x="4" small class="flex items-center h-9 mr-2" @click="openEbook">
               <span class="material-icons -ml-2 pr-2 text-white">auto_stories</span>
               Read
             </ui-btn>
@@ -329,7 +328,10 @@ export default {
       return !this.tracks.length && this.ebooks.length && !this.showExperimentalFeatures
     },
     epubEbook() {
-      return this.audiobook.ebooks.find((eb) => eb.ext === '.epub')
+      return this.ebooks.find((eb) => eb.ext === '.epub')
+    },
+    mobiEbook() {
+      return this.ebooks.find((eb) => eb.ext === '.mobi' || eb.ext === '.azw3')
     },
     userToken() {
       return this.$store.getters['user/getToken']
@@ -455,6 +457,11 @@ export default {
   },
   mounted() {
     this.$store.commit('audiobooks/addListener', { id: 'audiobook', audiobookId: this.audiobookId, meth: this.audiobookUpdated })
+
+    // If a library has not yet been loaded, use this audiobooks library id as the current
+    if (!this.$store.state.audiobooks.loadedLibraryId && this.libraryId) {
+      this.$store.commit('libraries/setCurrentLibrary', this.libraryId)
+    }
   },
   beforeDestroy() {
     this.$store.commit('audiobooks/removeListener', 'audiobook')

client/store/index.js

@@ -113,7 +113,6 @@ export const mutations = {
     state.showEditModal = val
   },
   showEReader(state, audiobook) {
-    console.log('Show EReader', audiobook)
     state.selectedAudiobook = audiobook
     state.showEReader = true
   },

package.json

@@ -1,6 +1,6 @@
 {
   "name": "audiobookshelf",
-  "version": "1.4.5",
+  "version": "1.4.6",
   "description": "Self-hosted audiobook server for managing and playing audiobooks",
   "main": "index.js",
   "scripts": {

server/objects/Audiobook.js

@@ -131,6 +131,10 @@ class Audiobook {
     return this.otherFiles.find(file => file.ext === '.epub')
   }
 
+  get hasMobi() {
+    return this.otherFiles.find(file => file.ext === '.mobi' || file.ext === '.azw3')
+  }
+
   get hasMissingIno() {
     return !this.ino || this._audioFiles.find(abf => !abf.ino) || this._otherFiles.find(f => !f.ino) || this._tracks.find(t => !t.ino)
   }
@@ -202,7 +206,7 @@ class Audiobook {
       hasInvalidParts: this.invalidParts ? this.invalidParts.length : 0,
       // numEbooks: this.ebooks.length,
       ebooks: this.ebooks.map(ebook => ebook.toJSON()),
-      numEbooks: this.hasEpub ? 1 : 0, // Only supporting epubs in the reader currently
+      numEbooks: (this.hasEpub || this.hasMobi) ? 1 : 0, // Only supporting epubs in the reader currently
       numTracks: this.tracks.length,
       chapters: this.chapters || [],
       isMissing: !!this.isMissing,

server/utils/globals.js

@@ -1,7 +1,7 @@
 const globals = {
   SupportedImageTypes: ['png', 'jpg', 'jpeg', 'webp'],
   SupportedAudioTypes: ['m4b', 'mp3', 'm4a', 'flac', 'opus', 'mp4'],
-  SupportedEbookTypes: ['epub', 'pdf', 'mobi']
+  SupportedEbookTypes: ['epub', 'pdf', 'mobi', 'azw3']
 }
 
 module.exports = globals

server/utils/mobi.js

@@ -0,0 +1,404 @@
+function ab2str(buf) {
+  if (buf instanceof ArrayBuffer) {
+    buf = new Uint8Array(buf);
+  }
+  return new TextDecoder("utf-8").decode(buf);
+}
+
+var domParser = new DOMParser();
+
+class Buffer {
+  constructor(capacity) {
+    this.capacity = capacity;
+    this.fragment_list = [];
+    this.cur_fragment = new Fragment(capacity);
+    this.fragment_list.push(this.cur_fragment);
+  }
+  write(byte) {
+    var result = this.cur_fragment.write(byte);
+    if (!result) {
+      this.cur_fragment = new Fragment(this.capacity);
+      this.fragment_list.push(this.cur_fragment);
+      this.cur_fragment.write(byte);
+    }
+  }
+  get(idx) {
+    var fi = 0;
+    while (fi < this.fragment_list.length) {
+      var frag = this.fragment_list[fi];
+      if (idx < frag.size) {
+        return frag.get(idx);
+      }
+      idx -= frag.size;
+      fi += 1;
+    }
+    return null;
+  }
+  size() {
+    var s = 0;
+    for (var i = 0; i < this.fragment_list.length; i++) {
+      s += this.fragment_list[i].size;
+    }
+    return s;
+  }
+  shrink() {
+    var total_buffer = new Uint8Array(this.size());
+    var offset = 0;
+    for (var i = 0; i < this.fragment_list.length; i++) {
+      var frag = this.fragment_list[i];
+      if (frag.full()) {
+        total_buffer.set(frag.buffer, offset);
+      } else {
+        total_buffer.set(frag.buffer.slice(0, frag.size), offset);
+      }
+      offset += frag.size;
+    }
+    return total_buffer;
+  }
+}
+
+var combine_uint8array = function (buffers) {
+  var total_size = 0;
+  for (var i = 0; i < buffers.length; i++) {
+    var buffer = buffers[i];
+    total_size += buffer.length;
+  }
+  var total_buffer = new Uint8Array(total_size);
+  var offset = 0;
+  for (var i = 0; i < buffers.length; i++) {
+    var buffer = buffers[i];
+    total_buffer.set(buffer, offset);
+    offset += buffer.length;
+  }
+  return total_buffer;
+}
+
+class Fragment {
+  constructor(capacity) {
+    this.buffer = new Uint8Array(capacity);
+    this.capacity = capacity;
+    this.size = 0;
+  }
+
+  write(byte) {
+    if (this.size >= this.capacity) {
+      return false;
+    }
+    this.buffer[this.size] = byte;
+    this.size += 1;
+    return true;
+  }
+  full() {
+    return this.size === this.capacity;
+  }
+  get(idx) {
+    return this.buffer[idx];
+  }
+}
+
+var uncompression_lz77 = function (data) {
+  var length = data.length;
+  var offset = 0;   // Current offset into data
+  var buffer = new Buffer(data.length);
+
+  while (offset < length) {
+    var char = data[offset];
+    offset += 1;
+
+    if (char == 0) {
+      buffer.write(char);
+    } else if (char <= 8) {
+      for (var i = offset; i < offset + char; i++) {
+        buffer.write(data[i]);
+      }
+      offset += char;
+    } else if (char <= 0x7f) {
+      buffer.write(char);
+    } else if (char <= 0xbf) {
+      var next = data[offset];
+      offset += 1;
+      var distance = ((char << 8 | next) >> 3) & 0x7ff;
+      var lz_length = (next & 0x7) + 3;
+
+      var buffer_size = buffer.size();
+      for (var i = 0; i < lz_length; i++) {
+        buffer.write(buffer.get(buffer_size - distance))
+        buffer_size += 1;
+      }
+    } else {
+      buffer.write(32);
+      buffer.write(char ^ 0x80);
+    }
+  }
+  return buffer;
+};
+
+class MobiFile {
+  constructor(data) {
+    this.view = new DataView(data);
+    this.buffer = this.view.buffer;
+    this.offset = 0;
+    this.header = null;
+  }
+
+  parse() {
+
+  }
+
+  getUint8() {
+    var v = this.view.getUint8(this.offset);
+    this.offset += 1;
+    return v;
+  }
+
+  getUint16() {
+    var v = this.view.getUint16(this.offset);
+    this.offset += 2;
+    return v;
+  }
+
+  getUint32() {
+    var v = this.view.getUint32(this.offset);
+    this.offset += 4;
+    return v;
+  }
+
+  getStr(size) {
+    var v = ab2str(this.buffer.slice(this.offset, this.offset + size));
+    this.offset += size;
+    return v;
+  }
+
+  skip(size) {
+    this.offset += size;
+  }
+
+  setoffset(_of) {
+    this.offset = _of;
+  }
+
+  get_record_extrasize(data, flags) {
+    var pos = data.length - 1;
+    var extra = 0;
+    for (var i = 15; i > 0; i--) {
+      if (flags & (1 << i)) {
+        var res = this.buffer_get_varlen(data, pos);
+        var size = res[0];
+        var l = res[1];
+        pos = res[2];
+        pos -= size - l;
+        extra += size;
+      }
+    }
+    if (flags & 1) {
+      var a = data[pos];
+      extra += (a & 0x3) + 1;
+    }
+    return extra;
+  }
+
+  // data should be uint8array
+  buffer_get_varlen(data, pos) {
+    var l = 0;
+    var size = 0;
+    var byte_count = 0;
+    var mask = 0x7f;
+    var stop_flag = 0x80;
+    var shift = 0;
+    for (var i = 0; ; i++) {
+      var byte = data[pos];
+      size |= (byte & mask) << shift;
+      shift += 7;
+      l += 1;
+      byte_count += 1;
+      pos -= 1;
+
+      var to_stop = byte & stop_flag;
+      if (byte_count >= 4 || to_stop > 0) {
+        break;
+      }
+    }
+    return [size, l, pos];
+  }
+
+  read_text() {
+    var text_end = this.palm_header.record_count;
+    var buffers = [];
+    for (var i = 1; i <= text_end; i++) {
+      buffers.push(this.read_text_record(i));
+    }
+    var all = combine_uint8array(buffers)
+    return ab2str(all);
+  }
+
+  read_text_record(i) {
+    var flags = this.mobi_header.extra_flags;
+    var begin = this.reclist[i].offset;
+    var end = this.reclist[i + 1].offset;
+
+    var data = new Uint8Array(this.buffer.slice(begin, end))
+    var ex = this.get_record_extrasize(data, flags);
+
+    data = new Uint8Array(this.buffer.slice(begin, end - ex));
+    if (this.palm_header.compression === 2) {
+      var buffer = uncompression_lz77(data);
+      return buffer.shrink();
+    } else {
+      return data;
+    }
+  }
+
+  read_image(idx) {
+    var first_image_idx = this.mobi_header.first_image_idx;
+    var begin = this.reclist[first_image_idx + idx].offset;
+    var end = this.reclist[first_image_idx + idx + 1].offset;
+    var data = new Uint8Array(this.buffer.slice(begin, end))
+    return new Blob([data.buffer]);
+  }
+
+  load() {
+    this.header = this.load_pdbheader();
+    this.reclist = this.load_reclist();
+    this.load_record0();
+  }
+
+  load_pdbheader() {
+    var header = {};
+    header.name = this.getStr(32);
+    header.attr = this.getUint16();
+    header.version = this.getUint16();
+    header.ctime = this.getUint32();
+    header.mtime = this.getUint32();
+    header.btime = this.getUint32();
+    header.mod_num = this.getUint32();
+    header.appinfo_offset = this.getUint32();
+    header.sortinfo_offset = this.getUint32();
+    header.type = this.getStr(4);
+    header.creator = this.getStr(4);
+    header.uid = this.getUint32();
+    header.next_rec = this.getUint32();
+    header.record_num = this.getUint16();
+
+    return header;
+  }
+
+  load_reclist() {
+    var reclist = [];
+    for (var i = 0; i < this.header.record_num; i++) {
+      var record = {};
+      record.offset = this.getUint32();
+      // TODO(zz) change 
+      record.attr = this.getUint32();
+      reclist.push(record);
+    }
+    return reclist;
+  }
+  load_record0() {
+    this.palm_header = this.load_record0_header();
+    this.mobi_header = this.load_mobi_header();
+  }
+
+  load_record0_header() {
+    var p_header = {};
+    var first_record = this.reclist[0];
+    this.setoffset(first_record.offset);
+
+    p_header.compression = this.getUint16();
+    this.skip(2);
+    p_header.text_length = this.getUint32();
+    p_header.record_count = this.getUint16();
+    p_header.record_size = this.getUint16();
+    p_header.encryption_type = this.getUint16();
+    this.skip(2);
+
+    return p_header;
+  }
+
+  load_mobi_header() {
+    var mobi_header = {};
+
+    var start_offset = this.offset;
+
+    mobi_header.identifier = this.getUint32();
+    mobi_header.header_length = this.getUint32();
+    mobi_header.mobi_type = this.getUint32();
+    mobi_header.text_encoding = this.getUint32();
+    mobi_header.uid = this.getUint32();
+    mobi_header.generator_version = this.getUint32();
+
+    this.skip(40);
+
+    mobi_header.first_nonbook_index = this.getUint32();
+    mobi_header.full_name_offset = this.getUint32();
+    mobi_header.full_name_length = this.getUint32();
+
+    mobi_header.language = this.getUint32();
+    mobi_header.input_language = this.getUint32();
+    mobi_header.output_language = this.getUint32();
+    mobi_header.min_version = this.getUint32();
+    mobi_header.first_image_idx = this.getUint32();
+
+    mobi_header.huff_rec_index = this.getUint32();
+    mobi_header.huff_rec_count = this.getUint32();
+    mobi_header.datp_rec_index = this.getUint32();
+    mobi_header.datp_rec_count = this.getUint32();
+
+    mobi_header.exth_flags = this.getUint32();
+
+    this.skip(36);
+
+    mobi_header.drm_offset = this.getUint32();
+    mobi_header.drm_count = this.getUint32();
+    mobi_header.drm_size = this.getUint32();
+    mobi_header.drm_flags = this.getUint32();
+
+    this.skip(8);
+
+    // TODO (zz) fdst_index
+    this.skip(4);
+
+    this.skip(46);
+
+    mobi_header.extra_flags = this.getUint16();
+
+    this.setoffset(start_offset + mobi_header.header_length)
+
+    return mobi_header;
+  }
+  load_exth_header() {
+    // TODO
+    return {};
+  }
+
+  render_to(id) {
+    this.load();
+    var content = this.read_text();
+
+    var bookDom = document.getElementById(id);
+    while (bookDom.firstChild) {
+      bookDom.removeChild(bookDom.firstChild);
+    }
+
+    var bookDoc = domParser.parseFromString(content, "text/html");
+    bookDoc.body.childNodes.forEach(function (x) {
+      if (x instanceof Element) {
+        bookDom.appendChild(x);
+      }
+    });
+
+    var imgDoms = bookDom.getElementsByTagName("img");
+    for (var i = 0; i < imgDoms.length; i++) {
+      this.render_image(imgDoms, i);
+    }
+  }
+  render_image(imgDoms, i) {
+    var imgDom = imgDoms[i];
+    var idx = +imgDom.getAttribute("recindex");
+    var blob = this.read_image(idx - 1);
+    var imgReader = new FileReader();
+    imgReader.onload = function (e) {
+      imgDom.src = e.target.result;
+    };
+    imgReader.readAsDataURL(blob);
+  }
+}