File indexing completed on 2024-05-12 16:28:58

 /* POLE - Portable C++ library to access OLE Storage
    Copyright (C) 2002-2005 Ariya Hidayat <ariya@kde.org>
    Copyright (C) 2011-2012 Matus Uzak <matus.uzak@ixonos.com>
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:
    * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.
    * Neither the name of the authors nor the names of its contributors may be
      used to endorse or promote products derived from this software without
      specific prior written permission.
 
    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
    THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 #include "pole.h"
 
 #include <fstream>
 #include <iostream>
 #include <list>
 #include <string>
 #include <vector>
 #include <string.h>
 #include <ios>       // for std::hex
 
 #include <QList>
 #include <QString>
 #include <QDebug>
 
 //Enable to activate debugging output.
 //#define POLE_DEBUG
 
 //Disabled because of too many false positives, both streams and unknown
 //objects MAY be invalid and still have a size set.
 //#define POLE_FAIL_ON_NEMPTY_NVALID_OBJS
 
 //Validate stream object against [MS-CFB] — v20110318.  Disabled because of too
 //many false positives.
 //#define POLE_FAIL_ON_NVALID_STREAM_OBJS
 
 //Validate storage object against [MS-CFB] — v20110318.  Disabled because of
 //too many false positives on Word8 documents.
 //#define POLE_CHECK_STORAGE_OBJS
 
 //Validate sibling names against positions in the black red tree.  Disabled
 //because of too many false positives on Word8 files with embedded documents.
 //#define POLE_CHECK_SIBLINGS
 
 #define OLE_HEADER_SIZE 0x200
 
 namespace POLE
 {
 
 class Header
 {
 public:
     unsigned char id[8];       // signature, or magic identifier
     unsigned b_shift;          // bbat->blockSize = 1 << b_shift
     unsigned s_shift;          // sbat->blockSize = 1 << s_shift
     unsigned num_bat;          // blocks allocated for big bat
     unsigned dirent_start;     // starting block for directory info
     unsigned threshold;        // switch from small to big file (usually 4K)
     unsigned sbat_start;       // starting block index to store small bat
     unsigned num_sbat;         // blocks allocated for small bat
     unsigned mbat_start;       // starting block to store meta bat
     unsigned num_mbat;         // blocks allocated for meta bat
     unsigned long bb_blocks[109];
 
     Header();
     bool valid(const unsigned max_sbat_block, const unsigned max_bbat_block) const;
     void load(const unsigned char* buffer);
     void save(unsigned char* buffer);
     void debug();
 };
 
 class AllocTable
 {
 public:
     static const unsigned Eof;
     static const unsigned Avail;
     static const unsigned Bat;
     static const unsigned MetaBat;
     unsigned blockSize;
     AllocTable();
     bool valid(const unsigned long filesize, const unsigned shift, const bool isFat = true) const;
     void clear();
     unsigned long count();
     void resize(unsigned long newsize);
     void preserve(unsigned long n);
     void set(unsigned long index, unsigned long val);
     unsigned unused();
     void setChain(std::vector<unsigned long>);
     std::vector<unsigned long> follow(unsigned long start, bool& fail);
     unsigned long operator[](unsigned long index);
     void load(const unsigned char* buffer, unsigned len);
     void save(unsigned char* buffer);
     unsigned size();
     void debug();
 private:
     std::vector<unsigned long> data;
     AllocTable(const AllocTable&);
     AllocTable& operator=(const AllocTable&);
 };
 
 class DirEntry
 {
 public:
     bool valid;            // false if invalid (should be skipped)
     std::string name;      // the name, not in unicode anymore
     bool dir;              // true if directory
     unsigned long size;    // size (not valid if directory)
     unsigned long start;   // starting block
     unsigned prev;         // previous sibling
     unsigned next;         // next sibling
     unsigned child;        // first child
 };
 
 class DirTree
 {
 public:
     static const unsigned End;
     DirTree();
     bool valid(void) const;
     void clear();
     unsigned entryCount();
     DirEntry* entry(unsigned index);
     DirEntry* entry(const std::string& name, bool create = false);
     int indexOf(DirEntry* e);
     int parent(unsigned index);
     std::string fullName(unsigned index);
     std::vector<unsigned> children(unsigned index);
     void load(unsigned char* buffer, unsigned len, const unsigned threshold, const unsigned max_sbat, const unsigned max_bbat);
     void save(unsigned char* buffer);
     unsigned size();
     void debug();
 private:
     std::vector<DirEntry> entries;
     DirTree(const DirTree&);
     DirTree& operator=(const DirTree&);
 };
 
 class StorageIO
 {
 public:
     Storage* storage;         // owner
     std::string filename;     // filename
     std::fstream file;        // associated with above name
     int result;               // result of operation
     bool opened;              // true if file is opened
     unsigned long filesize;   // size of the file
 
     Header* header;           // storage header
     DirTree* dirtree;         // directory tree
     AllocTable* bbat;         // allocation table for big blocks
     AllocTable* sbat;         // allocation table for small blocks
 
     std::vector<unsigned long> sb_blocks; // blocks for "small" files
 
     std::list<Stream*> streams;
 
     StorageIO(Storage* storage, const char* filename);
     ~StorageIO();
 
     bool open();
     void close();
     void flush();
     void load();
     void create();
 
     unsigned long loadBigBlocks(const std::vector<unsigned long>& blocks, unsigned char* buffer, unsigned long maxlen);
     unsigned long loadBigBlocks(const unsigned long* blocks, unsigned blockCount, unsigned char* buffer, unsigned long maxlen);
 
     unsigned long loadBigBlock(unsigned long block, unsigned char* buffer, unsigned long maxlen);
 
     unsigned long loadSmallBlocks(const std::vector<unsigned long>& blocks, unsigned char* buffer, unsigned long maxlen);
     unsigned long loadSmallBlocks(const unsigned long* blocks, unsigned blockCount, unsigned char* buffer, unsigned long maxlen);
 
     unsigned long loadSmallBlock(unsigned long block, unsigned char* buffer, unsigned long maxlen);
 
     StreamIO* streamIO(const std::string& name);
 
 private:
     // no copy or assign
     StorageIO(const StorageIO&);
     StorageIO& operator=(const StorageIO&);
 
 };
 
 class StreamIO
 {
 public:
     StorageIO* io;
     DirEntry* entry;
     std::string fullName;
     bool eof;
     bool fail;
 
     StreamIO(StorageIO* io, DirEntry* entry);
     ~StreamIO();
     unsigned long size();
     void seek(unsigned long pos);
     unsigned long tell();
     int getch();
     unsigned long read(unsigned char* data, unsigned long maxlen);
 
 private:
     unsigned long readInternal(unsigned char* data, unsigned long maxlen);
     unsigned long readInternal(unsigned long pos, unsigned char* data, unsigned long maxlen);
 
     std::vector<unsigned long> blocks;
 
     // no copy or assign
     StreamIO(const StreamIO&);
     StreamIO& operator=(const StreamIO&);
 
     // pointer for read
     unsigned long m_pos;
 
     // simple cache system to speed-up getch()
     unsigned char* cache_data;
     unsigned long base_cache_size;
     unsigned long cache_size;
     unsigned long cache_pos;
     void updateCache();
 };
 
 } // namespace POLE
 
 using namespace POLE;
 
 static inline unsigned long readU16(const unsigned char* ptr)
 {
     return ptr[0] + (ptr[1] << 8);
 }
 
 static inline unsigned long readU32(const unsigned char* ptr)
 {
     return unsigned(ptr[0]) + (unsigned(ptr[1]) << 8 ) + (unsigned(ptr[2]) << 16) + (unsigned(ptr[3]) << 24);
 }
 
 static inline void writeU16(unsigned char* ptr, unsigned long data)
 {
     ptr[0] = (unsigned char)(data & 0xff);
     ptr[1] = (unsigned char)((data >> 8) & 0xff);
 }
 
 static inline void writeU32(unsigned char* ptr, unsigned long data)
 {
     ptr[0] = (unsigned char)(data & 0xff);
     ptr[1] = (unsigned char)((data >> 8) & 0xff);
     ptr[2] = (unsigned char)((data >> 16) & 0xff);
     ptr[3] = (unsigned char)((data >> 24) & 0xff);
 }
 
 static const unsigned char pole_magic[] = { 0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1, 0x1a, 0xe1 };
 
 // =========== Header ==========
 
 Header::Header()
 {
     b_shift = 9;
     s_shift = 6;
     num_bat = 0;
     dirent_start = 0;
     threshold = 4096;
     sbat_start = 0;
     num_sbat = 0;
     mbat_start = 0;
     num_mbat = 0;
 
     for (unsigned i = 0; i < 8; i++)
         id[i] = pole_magic[i];
     for (unsigned i = 0; i < 109; i++)
         bb_blocks[i] = AllocTable::Avail;
 }
 
 bool Header::valid(const unsigned max_sbat_block, const unsigned max_bbat_block) const
 {
     if (threshold != 4096) return false;
     if (num_bat == 0) return false;
     if ((num_bat > 109) && (num_bat > (num_mbat * 127) + 109)) return false;
     if ((num_bat < 109) && (num_mbat != 0)) return false;
     if (s_shift > b_shift) return false;
     if (b_shift <= 6) return false;
     if (b_shift > 12) return false;
 
     // additional heuristics to check the header
     if (num_sbat > max_sbat_block) return false;
     if (num_bat > max_bbat_block) return false;
 
 #ifdef POLE_DEBUG
     const unsigned ENDOFCHAIN = 0xfffffffe;
     const unsigned FREESECT = 0xffffffff;
 
     if (num_sbat == 0 &&
         sbat_start != ENDOFCHAIN &&
         sbat_start != FREESECT)
     {
         qDebug() << Q_FUNC_INFO <<
             "There aren't any minifat sectors, but there are links to some!";
     }
 #endif
 
     return true;
 }
 
 void Header::load(const unsigned char* buffer)
 {
     b_shift      = readU16(buffer + 0x1e); // sector shift
     s_shift      = readU16(buffer + 0x20); // mini sector shift
     num_bat      = readU32(buffer + 0x2c); // number of fat sectors
     dirent_start = readU32(buffer + 0x30); // first directory sector location
     threshold    = readU32(buffer + 0x38); // transaction signature number
     sbat_start   = readU32(buffer + 0x3c); // first mini fat sector location
     num_sbat     = readU32(buffer + 0x40); // mini stream cutoff size
     mbat_start   = readU32(buffer + 0x44); // first mini difat sector location
     num_mbat     = readU32(buffer + 0x48); // number of difat sectors
 
     for (unsigned i = 0; i < 8; i++)
         id[i] = buffer[i];
     for (unsigned i = 0; i < 109; i++)
         bb_blocks[i] = readU32(buffer + 0x4C + i * 4);
 }
 
 void Header::save(unsigned char* buffer)
 {
     memset(buffer, 0, 0x4c);
     memcpy(buffer, pole_magic, 8);          // ole signature
     writeU32(buffer + 8, 0);                // unknown
     writeU32(buffer + 12, 0);               // unknown
     writeU32(buffer + 16, 0);               // unknown
     writeU16(buffer + 24, 0x003e);          // revision ?
     writeU16(buffer + 26, 3);               // version ?
     writeU16(buffer + 28, 0xfffe);          // unknown
     writeU16(buffer + 0x1e, b_shift);
     writeU16(buffer + 0x20, s_shift);
     writeU32(buffer + 0x2c, num_bat);
     writeU32(buffer + 0x30, dirent_start);
     writeU32(buffer + 0x38, threshold);
     writeU32(buffer + 0x3c, sbat_start);
     writeU32(buffer + 0x40, num_sbat);
     writeU32(buffer + 0x44, mbat_start);
     writeU32(buffer + 0x48, num_mbat);
 
     for (unsigned i = 0; i < 109; i++)
         writeU32(buffer + 0x4C + i*4, bb_blocks[i]);
 }
 
 void Header::debug()
 {
     qDebug() << Q_FUNC_INFO;
     qDebug() << "b_shift:" << b_shift;
     qDebug() << "s_shift:" << s_shift;
     qDebug() << "num_bat:" << num_bat;
     qDebug() << "dirent_start: 0x" << hex << dirent_start;
     qDebug() << "threshold:" << dec << threshold;
     qDebug() << "sbat_start: 0x" << hex << sbat_start;
     qDebug() << "num_sbat:" << dec << num_sbat;
     qDebug() << "mbat_start: 0x" << hex << mbat_start;
     qDebug() << "num_mbat:" << dec << num_mbat;
 
     unsigned s = (num_bat <= 109) ? num_bat : 109;
     std::cout << "bat blocks:";
     for (unsigned i = 0; i < s; i++) {
         std::cout << "0x" << std::hex << bb_blocks[i] << " ";
     }
     std::cout << std::dec << std::endl;
 }
 
 // =========== AllocTable ==========
 
 const unsigned AllocTable::Avail = 0xffffffff;
 const unsigned AllocTable::Eof = 0xfffffffe;
 const unsigned AllocTable::Bat = 0xfffffffd;
 const unsigned AllocTable::MetaBat = 0xfffffffc;
 
 AllocTable::AllocTable()
 {
     blockSize = 4096;
     // initial size
     resize(128);
 }
 
 bool AllocTable::valid(const unsigned long filesize, const unsigned shift, const bool isFat) const
 {
     unsigned long offset = 0;
     for (unsigned long i = 0; i < data.size(); i++) {
         switch (data[i]) {
         case AllocTable::Avail:
         case AllocTable::Eof:
         case AllocTable::Bat:
         case AllocTable::MetaBat:
             break;
         default:
             offset = data[i] << shift;
             if (isFat) {
                 offset += OLE_HEADER_SIZE;
             }
             if (offset > filesize) {
 #ifdef POLE_DEBUG
                 qDebug() << "Invalid location of sector in the stream!" <<
                     "offset:" << offset << " | filesize:" << filesize;
 #endif
                 return false;
             }
         }
     }
     return true;
 }
 
 unsigned long AllocTable::count()
 {
     return data.size();
 }
 
 void AllocTable::resize(unsigned long newsize)
 {
     unsigned oldsize = data.size();
     data.resize(newsize);
     if (newsize > oldsize)
         for (unsigned i = oldsize; i < newsize; i++)
             data[i] = Avail;
 }
 
 // make sure there're still free blocks
 void AllocTable::preserve(unsigned long n)
 {
     std::vector<unsigned long> pre;
     for (unsigned i = 0; i < n; i++)
         pre.push_back(unused());
 }
 
 unsigned long AllocTable::operator[](unsigned long index)
 {
     unsigned long result;
     result = data[index];
     return result;
 }
 
 void AllocTable::set(unsigned long index, unsigned long value)
 {
     if (index >= count()) resize(index + 1);
     data[ index ] = value;
 }
 
 void AllocTable::setChain(std::vector<unsigned long> chain)
 {
     if (chain.size()) {
         for (unsigned i = 0; i < chain.size() - 1; i++)
             set(chain[i], chain[i+1]);
         set(chain[ chain.size()-1 ], AllocTable::Eof);
     }
 }
 
 // follow
 std::vector<unsigned long> AllocTable::follow(unsigned long start, bool& fail)
 {
     std::vector<unsigned long> chain;
 
     if (start >= count()) {
 #ifdef POLE_DEBUG
         qDebug() << Q_FUNC_INFO << "start >= count()!";
 #endif
         fail = true;
         return chain;
     }
 
     unsigned long p = start;
     while (p < count()) {
         if (p == (unsigned long)Eof) {
 #ifdef POLE_DEBUG
             qDebug() << Q_FUNC_INFO << "Eof detected!";
 #endif
             break;
         }
         if (p == (unsigned long)Bat) {
 #ifdef POLE_DEBUG
             qDebug() << Q_FUNC_INFO << "Bat detected!";
 #endif
             break;
         }
         if (p == (unsigned long)MetaBat) {
 #ifdef POLE_DEBUG
             qDebug() << Q_FUNC_INFO << "MetaBat detected!";
 #endif
             break;
         }
         if (p >= count()) {
 #ifdef POLE_DEBUG
             qDebug() << Q_FUNC_INFO << "Invalid index detected!";
 #endif
             fail = true;
             break;
         }
         chain.push_back(p);
 
         // break if the chain is longer than the total sector count
         if (chain.size() > count()) {
 #ifdef POLE_DEBUG
             qDebug() << Q_FUNC_INFO << "Probably a loop detected!";
 #endif
             fail = true;
             break;
         }
         p = data[ p ];
     }
     if (p != (unsigned long)AllocTable::Eof) {
 #ifdef POLE_DEBUG
         qDebug() << Q_FUNC_INFO << "Last chain entry MUST be 0x" << hex << AllocTable::Eof <<
             ", detected: 0x" << hex << p;
 #endif
         fail = true;
     }
 
     return chain;
 }
 
 unsigned AllocTable::unused()
 {
     // find first available block
     for (unsigned i = 0; i < data.size(); i++)
         if (data[i] == Avail)
             return i;
 
     // completely full, so enlarge the table
     unsigned block = data.size();
     resize(data.size() + 10);
     return block;
 }
 
 void AllocTable::load(const unsigned char* buffer, unsigned len)
 {
     resize(len / 4);
     for (unsigned i = 0; i < count(); i++)
         set(i, readU32(buffer + i*4));
 }
 
 // return space required to save this dirtree
 unsigned AllocTable::size()
 {
     return count() * 4;
 }
 
 void AllocTable::save(unsigned char* buffer)
 {
     for (unsigned i = 0; i < count(); i++)
         writeU32(buffer + i*4, data[i]);
 }
 
 void AllocTable::debug()
 {
     qDebug() << "block size " << data.size();
     for (unsigned i = 0; i < data.size(); i++) {
         if (data[i] == Avail) continue;
         std::cout << i << ": ";
         if (data[i] == Eof) std::cout << "[eof]";
         else if (data[i] == Bat) std::cout << "[bat]";
         else if (data[i] == MetaBat) std::cout << "[metabat]";
         else std::cout << data[i];
         std::cout << std::endl;
     }
 }
 
 // =========== DirTree ==========
 
 const unsigned DirTree::End = 0xffffffff;
 
 /*
  * Compare DirEntry names according to the spec.
  */
 int ename_cmp(QString& str1, QString& str2)
 {
     str1 = str1.toUpper();
     str2 = str2.toUpper();
     if (str1.size() < str2.size()) return -1;
     else if (str1.size() > str2.size()) return 1;
     else return str1.compare(str2);
 }
 
 /*
  * Check if DirEntry elements at this level have unique names.
  */
 bool valid_enames(DirTree* dirtree, unsigned index)
 {
     std::vector<unsigned> chi = dirtree->children(index);
     QList<std::string> names;
     DirEntry* e = 0;
 
 #ifdef POLE_DEBUG
     if (chi.size()) {
         qDebug() << "---------------------";
         qDebug() << Q_FUNC_INFO;
         qDebug() << "[KIDS]:";
     }
     for (unsigned i = 0; i < chi.size(); i++) {
         e = dirtree->entry(chi[i]);
         if (!e->valid) std::cout << "[INVALID] ";
         printf("DirEntry: name=%s prev=%i next=%i child=%i start=%lu size=%lu dir=%i\n",
                e->name.c_str(), e->prev, e->next, e->child, e->start, e->size, e->dir);
     }
     if (chi.size()) {
         qDebug() << "---------------------";
     }
 #endif
 
     for (unsigned i = 0; i < chi.size(); i++) {
         e = dirtree->entry(chi[i]);
         if (e->valid) {
             if (names.contains(e->name)) {
                 return false;
             } else {
                 names.append(e->name);
             }
         }
     }
     return true;
 }
 
 bool DirTree::valid() const
 {
     const DirEntry* e;
     QString str1, str2;
 
 #ifdef POLE_DEBUG
         qDebug() << Q_FUNC_INFO;
 #endif
     for (unsigned i = 0; i < entries.size(); i++) {
         e = &entries[i];
 
 #ifdef POLE_DEBUG
         if (!e->valid) std::cout << "[INVALID] ";
         printf("DirEntry: name=%s prev=%i next=%i child=%i start=%lu size=%lu dir=%i\n",
                e->name.c_str(), e->prev, e->next, e->child, e->start, e->size, e->dir);
 #endif
 #ifdef POLE_FAIL_ON_NEMPTY_NVALID_OBJS
         if (!e->valid && e->size) {
 #ifdef POLE_DEBUG
             qDebug() << "Invalid DirEntry detected!";
 #endif
             return false;
         }
 #endif
         //Looking for invalid stream objects.
 #ifdef POLE_FAIL_ON_NVALID_STREAM_OBJS
         if (!e->valid && !e->dir) {
 #ifdef POLE_DEBUG
             qDebug() << "Invalid DirEntry (stream object) detected!";
 #endif
             return false;
         }
 #endif
         //Looking for invalid storage objects.
         if (!e->valid && e->dir) {
 #ifdef POLE_DEBUG
             qDebug() << "Invalid DirEntry (storage object) detected!";
 #endif
             return false;
         }
 
     //A root storage: size = size of the mini stream, start = first sector
     //of the mini stream, if the mini stream exists
     //
     //A storage object MAY have e->child set - [MS-CFB].
 #ifdef POLE_CHECK_STORAGE_OBJS
         if ((e->valid && e->dir) && (i > 0) &&
             ((e->start != 0) || (e->size != 0)))
         {
 #ifdef POLE_DEBUG
             qDebug() << "Invalid DirEntry (storage object) detected!";
 #endif
             return false;
         }
 #endif
         //Looking for duplicate DirEntries in the storage object.
         if (e->valid && e->dir) {
             if (!valid_enames(const_cast<DirTree*>(this), i)) {
 #ifdef POLE_DEBUG
                 qDebug() << "Invalid DirEntry (storage object) detected!";
 #endif
                 return false;
             }
         }
 
         //Check the name of the left/right DirEntry.
 #ifdef POLE_CHECK_SIBLINGS
         if (e->prev != End) {
             str1 = QString(entries[e->prev].name.data());
         }
         if (e->next != End) {
             str2 = QString(entries[e->next].name.data());
         }
         if (!str1.isEmpty() && !str2.isEmpty()) {
             if (ename_cmp(str1, str2) > 0) {
 #ifdef POLE_DEBUG
                 qDebug() << "DirEntry: [name, position] mismatch!";
 #endif
                 return false;
             }
         }
 #endif
     }
     return true;
 }
 
 DirTree::DirTree()
 {
     clear();
 }
 
 void DirTree::clear()
 {
     // leave only root entry
     entries.resize(1);
     entries[0].valid = true;
     entries[0].name = "Root Entry";
     entries[0].dir = true;
     entries[0].size = 0;
     entries[0].start = End;
     entries[0].prev = End;
     entries[0].next = End;
     entries[0].child = End;
 }
 
 unsigned DirTree::entryCount()
 {
     return entries.size();
 }
 
 DirEntry* DirTree::entry(unsigned index)
 {
     if (index >= entryCount()) return (DirEntry*) 0;
     return &entries[ index ];
 }
 
 int DirTree::indexOf(DirEntry* e)
 {
     for (unsigned i = 0; i < entryCount(); i++)
         if (entry(i) == e) return i;
 
     return -1;
 }
 
 int DirTree::parent(unsigned index)
 {
     // brute-force, basically we iterate for each entries, find its children
     // and check if one of the children is 'index'
     for (unsigned j = 0; j < entryCount(); j++) {
         std::vector<unsigned> chi = children(j);
         for (unsigned i = 0; i < chi.size(); i++)
             if (chi[i] == index)
                 return j;
     }
 
     return -1;
 }
 
 std::string DirTree::fullName(unsigned index)
 {
     // don't use root name ("Root Entry"), just give "/"
     if (index == 0) return "/";
 
     std::string result = entry(index)->name;
     result.insert(0,  "/");
     int p = parent(index);
     DirEntry * _entry = 0;
     while (p > 0) {
         _entry = entry(p);
         if (_entry->dir && _entry->valid) {
             result.insert(0,  _entry->name);
             result.insert(0,  "/");
         }
         --p;
         index = p;
         if (index <= 0) break;
     }
     return result;
 }
 
 // given a fullname (e.g "/ObjectPool/_1020961869"), find the entry
 // if not found and create is false, return 0
 // if create is true, a new entry is returned
 DirEntry* DirTree::entry(const std::string& name, bool create)
 {
     if (!name.length()) return (DirEntry*)0;
 
     // quick check for "/" (that's root)
     if (name == "/") return entry(0);
 
     // split the names, e.g  "/ObjectPool/_1020961869" will become:
     // "ObjectPool" and "_1020961869"
     std::list<std::string> names;
     std::string::size_type start = 0, end = 0;
     if (name[0] == '/') start++;
     while (start < name.length()) {
         end = name.find_first_of('/', start);
         if (end == std::string::npos) end = name.length();
         names.push_back(name.substr(start, end - start));
         start = end + 1;
     }
 
     // start from root
     int index = 0 ;
 
     // trace one by one
     std::list<std::string>::iterator it;
 
     for (it = names.begin(); it != names.end(); ++it) {
         // find among the children of index
         std::vector<unsigned> chi = children(index);
         unsigned child = 0;
         for (unsigned i = 0; i < chi.size(); i++) {
             DirEntry* ce = entry(chi[i]);
             if (ce)
                 if (ce->valid && (ce->name.length() > 1))
                     if (ce->name == *it)
                         child = chi[i];
         }
 
         // traverse to the child
         if (child > 0) index = child;
         else {
             // not found among children
             if (!create) return (DirEntry*)0;
 
             // create a new entry
             unsigned parent = index;
             entries.push_back(DirEntry());
             index = entryCount() - 1;
             DirEntry* e = entry(index);
             e->valid = true;
             e->name = *it;
             e->dir = false;
             e->size = 0;
             e->start = 0;
             e->child = End;
             e->prev = End;
             e->next = entry(parent)->child;
             entry(parent)->child = index;
         }
     }
 
     return entry(index);
 }
 
 // helper function: recursively find siblings of index
 void dirtree_find_siblings(DirTree* dirtree, std::vector<unsigned>& result,
                            unsigned index)
 {
     DirEntry* e = dirtree->entry(index);
     if (!e) return;
 //     if (!e->valid) return;
 
     // prevent infinite loop
     for (unsigned i = 0; i < result.size(); i++) {
         if (result[i] == index) return;
     }
     // add myself
     result.push_back(index);
 
     // visit previous sibling, don't go infinitely
     unsigned prev = e->prev;
     if ((prev > 0) && (prev < dirtree->entryCount())) {
         for (unsigned i = 0; i < result.size(); i++)
             if (result[i] == prev) prev = 0;
         if (prev) dirtree_find_siblings(dirtree, result, prev);
     }
 
     // visit next sibling, don't go infinitely
     unsigned next = e->next;
     if ((next > 0) && (next < dirtree->entryCount())) {
         for (unsigned i = 0; i < result.size(); i++)
             if (result[i] == next) next = 0;
         if (next) dirtree_find_siblings(dirtree, result, next);
     }
 }
 
 std::vector<unsigned> DirTree::children(unsigned index)
 {
     std::vector<unsigned> result;
 
     DirEntry* e = entry(index);
     if (e) {
         if (e->valid && e->dir) {
             dirtree_find_siblings(this, result, e->child);
         }
     }
     return result;
 }
 
 void DirTree::load(unsigned char* buffer, unsigned size, const unsigned threshold,
                    const unsigned max_sbat, const unsigned max_bbat)
 {
 #ifdef POLE_DEBUG
     qDebug() << "-------------------------------";
     qDebug() << Q_FUNC_INFO;
 #endif
 
     entries.clear();
     unsigned n = (size / 128); //num. of directory entries
 
     for (unsigned i = 0; i < (size / 128); i++) {
         unsigned p = i * 128;
 
 
         // parse name of this entry, which stored as Unicode 16-bit
         int name_len = readU16(buffer + 0x40 + p);
         if (name_len > 64) {
             name_len = 64;
 #ifdef POLE_DEBUG
             qDebug() << "DirEntry: Invalid length of name!";
 #endif
         }
         std::string name;
         for (int j = 0; (buffer[j+p]) && (j < name_len); j += 2) {
             name.append(1, buffer[j+p]);
         }
 
         // first char isn't printable ? remove it...
         if (buffer[p] < 32) {
             name.erase(0, 1);
         }
 
         // [MS-CFB] — v20110318
         // 0x00 = Unknown or unallocated, 0x01 = directory (Storage Object),
         // 0x02 = file (Stream Object), 0x05 = Root Storage Object
         unsigned type = buffer[ 0x42 + p];
 
         DirEntry e;
         e.valid = true;
         e.name = name;
         e.start = readU32(buffer + 0x74 + p);
         e.size = readU32(buffer + 0x78 + p);
         e.prev = readU32(buffer + 0x44 + p);
         e.next = readU32(buffer + 0x48 + p);
         e.child = readU32(buffer + 0x4C + p);
         e.dir = false;
 
         if ((type == 1) || (type == 5)) {
             e.dir = true;
         }
 
         // sanity checks
         if ((type != 0) && (type != 1) && (type != 2) && (type != 5)) {
             e.valid = false;
 #ifdef POLE_DEBUG
             qDebug() << "DirEntry: invalid type!";
 #endif
         }
         if ((type != 0) && (name_len < 1)) {
             e.valid = false;
 #ifdef POLE_DEBUG
             qDebug() << "DirEntry: invalid (type,name) pair!";
 #endif
         }
         // unknown object
         if (type == 0) {
             if ((e.child != End) || (e.prev != End) || (e.next != End)) {
                 e.valid = false;
 #ifdef POLE_DEBUG
                 qDebug() << "DirEntry: reference to prev/next/child != NOSTREAM";
 #endif
             }
             if ((e.start != 0) || (e.size != 0)) {
                 e.valid = false;
 #ifdef POLE_DEBUG
                 qDebug() << "DirEntry: start/size != ZERO";
 #endif
             }
         }
         // storage objects
         if (type == 1) {
             if (((e.prev != End) && (e.prev >= n)) ||
                 ((e.next != End) && (e.next >= n)) ||
                 ((e.child != End) && (e.child >= n))) {
                 e.valid = false;
 #ifdef POLE_DEBUG
                 qDebug() << "DirEntry: reference to prev/next/child > object num. (" << n << ")";
 #endif
             }
         }
         // stream object
         if (type == 2) {
             //check stream position
             if ((e.size >= threshold) && (e.start >= max_bbat)) {
                 e.valid = false;
 #ifdef POLE_DEBUG
                 qDebug() << "DirEntry: (e.start >= max_bbat)";
 #endif
             }
             else if (e.start >= max_sbat) {
                 e.valid = false;
 #ifdef POLE_DEBUG
                 qDebug() << "DirEntry: (e.start >= max_sbat)";
 #endif
             }
             //check stream object
             if (e.child != End) {
                 e.valid = false;
 #ifdef POLE_DEBUG
                 qDebug() << "DirEntry: (e.child != End)";
 #endif
             }
             //NOTE: Disabled because of too many false positives.
 //             if ((e->prev != End) || (e->next != End)) {
 //                 e.valid = false;
 //             }
         }
 
         // CLSID contains an object class GUID (globally unique identifier) if
         // this entry is a storage or root storage.  In a stream object, this
         // field MUST be set to all zeroes.
 #ifdef POLE_DEBUG
         if (!e.valid) {
             std::cout << "[INVALID] ";
         }
         printf("DirEntry: name=%s type=%i prev=%i next=%i child=%i start=%lu size=%lu clsid=%lu.%lu.%lu.%lu\n",
                name.c_str(), type, e.prev, e.next, e.child, e.start, e.size, readU32(buffer + 0x50 + p),
                readU32(buffer + 0x54 + p), readU32(buffer + 0x58 + p), readU32(buffer + 0x5C + p));
 #endif
         entries.push_back(e);
     }
 #ifdef POLE_DEBUG
     qDebug() << "-------------------------------";
 #endif
 }
 
 // return space required to save this dirtree
 unsigned DirTree::size()
 {
     return entryCount() * 128;
 }
 
 void DirTree::save(unsigned char* buffer)
 {
     memset(buffer, 0, size());
 
     // root is fixed as "Root Entry"
     DirEntry* root = entry(0);
     std::string name = "Root Entry";
     for (unsigned j = 0; j < name.length(); j++)
         buffer[ j*2 ] = name[j];
     writeU16(buffer + 0x40, name.length()*2 + 2);
     writeU32(buffer + 0x74, 0xffffffff);
     writeU32(buffer + 0x78, 0);
     writeU32(buffer + 0x44, 0xffffffff);
     writeU32(buffer + 0x48, 0xffffffff);
     writeU32(buffer + 0x4c, root->child);
     buffer[ 0x42 ] = 5;
     buffer[ 0x43 ] = 1;
 
     for (unsigned i = 1; i < entryCount(); i++) {
         DirEntry* e = entry(i);
         if (!e) continue;
         if (e->dir) {
             e->start = 0xffffffff;
             e->size = 0;
         }
 
         // max length for name is 32 chars
         std::string name = e->name;
         if (name.length() > 32)
             name.erase(32, name.length());
 
         // write name as Unicode 16-bit
         for (unsigned j = 0; j < name.length(); j++)
             buffer[ i*128 + j*2 ] = name[j];
 
         writeU16(buffer + i*128 + 0x40, name.length()*2 + 2);
         writeU32(buffer + i*128 + 0x74, e->start);
         writeU32(buffer + i*128 + 0x78, e->size);
         writeU32(buffer + i*128 + 0x44, e->prev);
         writeU32(buffer + i*128 + 0x48, e->next);
         writeU32(buffer + i*128 + 0x4c, e->child);
         buffer[ i*128 + 0x42 ] = e->dir ? 1 : 2;
         buffer[ i*128 + 0x43 ] = 1; // always black
     }
 }
 
 void DirTree::debug()
 {
     for (unsigned i = 0; i < entryCount(); i++) {
         DirEntry* e = entry(i);
         if (!e) continue;
         std::cout << i << ": ";
         if (!e->valid) std::cout << "INVALID ";
         std::cout << e->name << " ";
         if (e->dir) std::cout << "(Dir) ";
         else std::cout << "(File) ";
         std::cout << e->size << " ";
         std::cout << "s:" << e->start << " ";
         std::cout << "(";
         if (e->child == End) std::cout << "-"; else std::cout << e->child;
         std::cout << " ";
         if (e->prev == End) std::cout << "-"; else std::cout << e->prev;
         std::cout << ":";
         if (e->next == End) std::cout << "-"; else std::cout << e->next;
         std::cout << ")";
         std::cout << std::endl;
     }
 }
 
 // =========== StorageIO ==========
 
 StorageIO::StorageIO(Storage* st, const char* fname)
 {
     storage = st;
     filename = fname;
     result = Storage::Ok;
     opened = false;
 
     header = new Header();
     dirtree = new DirTree();
     bbat = new AllocTable();
     sbat = new AllocTable();
 
     filesize = 0;
     bbat->blockSize = 1 << header->b_shift;
     sbat->blockSize = 1 << header->s_shift;
 }
 
 StorageIO::~StorageIO()
 {
     if (opened) close();
     delete sbat;
     delete bbat;
     delete dirtree;
     delete header;
 }
 
 bool StorageIO::open()
 {
     // already opened ? close first
     if (opened) close();
 
     load();
 
     return result == Storage::Ok;
 }
 
 void StorageIO::load()
 {
     unsigned char* buffer = 0;
     unsigned long buflen = 0;
     std::vector<unsigned long> blocks;
 
     // open the file, check for error
     result = Storage::OpenFailed;
     file.open(filename.c_str(), std::ios::binary | std::ios::in);
     if (!file.good()) return;
 
     // find size of input file
     file.seekg(0, std::ios::end);
     filesize = file.tellg();
 
     // load header
     buffer = new unsigned char[OLE_HEADER_SIZE];
     file.seekg(0);
     file.read((char*)buffer, OLE_HEADER_SIZE);
     if (!file.good()) {
         delete[] buffer;
         return;
     }
     header->load(buffer);
     delete[] buffer;
 
     // check OLE magic id
     result = Storage::NotOLE;
     for (unsigned i = 0; i < 8; i++)
         if (header->id[i] != pole_magic[i])
             return;
 
     // important block size
     bbat->blockSize = 1 << header->b_shift;
     sbat->blockSize = 1 << header->s_shift;
     const unsigned max_bbat_block = (filesize - OLE_HEADER_SIZE) / bbat->blockSize;
     const unsigned max_sbat_block = (filesize - OLE_HEADER_SIZE) / sbat->blockSize;
 
     // sanity checks
     result = Storage::BadOLE;
     if (!header->valid(max_sbat_block, max_bbat_block)) {
         return;
     }
 
     // find blocks allocated to store big bat
     // the first 109 blocks are in header, the rest in meta bat
     blocks.clear();
     blocks.resize(header->num_bat);
     for (unsigned i = 0; i < 109; i++) {
         if (i >= header->num_bat) break;
         else blocks[i] = header->bb_blocks[i];
     }
     if ((header->num_bat > 109) && (header->num_mbat > 0)) {
         unsigned char* buffer2 = new unsigned char[ bbat->blockSize ];
         unsigned k = 109;
         unsigned mblock = header->mbat_start;
         for (unsigned r = 0; r < header->num_mbat; r++) {
             unsigned long rr = loadBigBlock(mblock, buffer2, bbat->blockSize);
             if (rr != bbat->blockSize) {
                 delete[] buffer2;
                 return;
             }
             for (unsigned s = 0; s < bbat->blockSize - 4; s += 4) {
                 if (k >= header->num_bat) break;
                 else  blocks[k++] = readU32(buffer2 + s);
             }
             mblock = readU32(buffer2 + bbat->blockSize - 4);
         }
         delete[] buffer2;
     }
 
     // load big bat
     buflen = blocks.size() * bbat->blockSize;
     if (buflen > 0) {
         buffer = new unsigned char[ buflen ];
         unsigned long r = loadBigBlocks(blocks, buffer, buflen);
         if (r != buflen) {
             qCritical() << Q_FUNC_INFO << "SAT construction failed!";
             delete[] buffer;
             return;
         }
         bbat->load(buffer, buflen);
         delete[] buffer;
 
         if (!bbat->valid(filesize, header->b_shift, true)) {
             return;
         }
     }
     //TODO: make fail affect the result value
     bool fail = false;
 
     // load small bat
     blocks.clear();
     blocks = bbat->follow(header->sbat_start, fail);
     buflen = blocks.size() * bbat->blockSize;
     if (buflen > 0) {
         buffer = new unsigned char[ buflen ];
         unsigned long r = loadBigBlocks(blocks, buffer, buflen);
         if (r != buflen) {
             qCritical() << Q_FUNC_INFO << "SSAT construction failed!";
             delete[] buffer;
             return;
         }
         sbat->load(buffer, buflen);
         delete[] buffer;
 
         if (!sbat->valid(filesize, header->s_shift, false)) {
             return;
         }
     }
 
     // load directory tree
     blocks.clear();
     blocks = bbat->follow(header->dirent_start, fail);
     buflen = blocks.size() * bbat->blockSize;
     buffer = new unsigned char[ buflen ];
     unsigned long r = loadBigBlocks(blocks, buffer, buflen);
     if (r != buflen) {
         qCritical() << Q_FUNC_INFO << "DirTree construction failed!";
         delete[] buffer;
         return;
     }
     dirtree->load(buffer, buflen, header->threshold, max_sbat_block, max_bbat_block);
     unsigned sb_start = readU32(buffer + 0x74);
     delete[] buffer;
     if (!dirtree->valid()) {
         qCritical() << Q_FUNC_INFO << "Invalid DirTree!";
         return;
     }
 
     // fetch block chain as data for small-files
     sb_blocks = bbat->follow(sb_start, fail);
 
     // for troubleshooting, just enable this block
 #ifdef POLE_DEBUG
     header->debug();
     sbat->debug();
     bbat->debug();
     dirtree->debug();
 #endif
 
     // so far so good
     result = Storage::Ok;
     opened = true;
 }
 
 void StorageIO::create()
 {
     // std::cout << "Creating " << filename << std::endl;
 
     file.open(filename.c_str(), std::ios::out | std::ios::binary);
     if (!file.good()) {
         qCritical() << Q_FUNC_INFO << "Can't create file:" << filename.c_str();
         result = Storage::OpenFailed;
         return;
     }
 
     // so far so good
     opened = true;
     result = Storage::Ok;
 }
 
 void StorageIO::flush()
 {
     /* Note on Microsoft implementation:
        - directory entries are stored in the last block(s)
        - BATs are as second to the last
        - Meta BATs are third to the last
     */
 }
 
 void StorageIO::close()
 {
     if (!opened) return;
 
     file.close();
     opened = false;
 
     std::list<Stream*>::iterator it;
     for (it = streams.begin(); it != streams.end(); ++it)
         delete *it;
 }
 
 StreamIO* StorageIO::streamIO(const std::string& name)
 {
 #ifdef POLE_DEBUG
     qDebug() << Q_FUNC_INFO << "preparing stream:" << name.c_str();
 #endif
     // sanity check
     if (!name.length()) return (StreamIO*)0;
 
     // search in the entries
     DirEntry* entry = dirtree->entry(name);
     //if( entry) std::cout << "FOUND\n";
     if (!entry) return (StreamIO*)0;
     //if( !entry->dir ) std::cout << "  NOT DIR\n";
     if (entry->dir) return (StreamIO*)0;
 
     StreamIO* result = new StreamIO(this, entry);
     result->fullName = name;
 
     return result;
 }
 
 unsigned long StorageIO::loadBigBlocks(const std::vector<unsigned long>& blocks,
                                        unsigned char* data, unsigned long maxlen)
 {
     return loadBigBlocks(&blocks[0], blocks.size(), data, maxlen);
 }
 
 unsigned long StorageIO::loadBigBlocks(const unsigned long *blocks, unsigned blockCount,
                                        unsigned char *data, unsigned long maxlen)
 {
     // sentinel
     if (!data) return 0;
     if (!file.good()) return 0;
     if (!blocks) return 0;
     if (blockCount < 1) return 0;
     if (maxlen == 0) return 0;
 
     // read block one by one, seems fast enough
     unsigned long bytes = 0;
     for (unsigned long i = 0; (i < blockCount) && (bytes < maxlen); i++) {
         unsigned long block = blocks[i];
         unsigned long pos =  bbat->blockSize * (block + 1);
         unsigned long p = (bbat->blockSize < maxlen - bytes) ? bbat->blockSize : maxlen - bytes;
         if (pos + p > filesize) p = filesize - pos;
         file.seekg(pos);
         file.read((char*)data + bytes, p);
         if (!file.good()) return 0;
         bytes += p;
     }
 
     return bytes;
 }
 
 unsigned long StorageIO::loadBigBlock(unsigned long block,
                                       unsigned char* data, unsigned long maxlen)
 {
     // sentinel
     if (!data) return 0;
     if (!file.good()) return 0;
 
     return loadBigBlocks(&block, 1, data, maxlen);
 }
 
 // return number of bytes which has been read
 unsigned long StorageIO::loadSmallBlocks(const std::vector<unsigned long>& blocks,
         unsigned char* data, unsigned long maxlen)
 {
     return loadSmallBlocks(&blocks[0], blocks.size(), data, maxlen);
 }
 
 unsigned long StorageIO::loadSmallBlocks(const unsigned long *blocks, unsigned blockCount,
                                          unsigned char *data, unsigned long maxlen)
 {
     // sentinel
     if (!data) return 0;
     if (!file.good()) return 0;
     if (!blocks) return 0;
     if (blockCount < 1) return 0;
     if (maxlen == 0) return 0;
 
     // our own local buffer
     unsigned char* buf = new unsigned char[ bbat->blockSize ];
 
     // read small block one by one
     unsigned long bytes = 0;
     for (unsigned long i = 0; (i < blockCount) && (bytes < maxlen); i++) {
         unsigned long block = blocks[i];
 
         // find where the small-block exactly is
         unsigned long pos = block * sbat->blockSize;
         unsigned long bbindex = pos / bbat->blockSize;
         if (bbindex >= sb_blocks.size()) break;
 
         unsigned long r = loadBigBlock(sb_blocks[ bbindex ], buf, bbat->blockSize);
         if (r != bbat->blockSize) {
             delete[] buf;
             return 0;
         }
 
         // copy the data
         unsigned offset = pos % bbat->blockSize;
         unsigned long p = (maxlen - bytes < bbat->blockSize - offset) ? maxlen - bytes :  bbat->blockSize - offset;
         p = (sbat->blockSize < p) ? sbat->blockSize : p;
         memcpy(data + bytes, buf + offset, p);
         bytes += p;
     }
 
     delete[] buf;
 
     return bytes;
 }
 
 unsigned long StorageIO::loadSmallBlock(unsigned long block,
                                         unsigned char* data, unsigned long maxlen)
 {
     // sentinel
     if (!data) return 0;
     if (!file.good()) return 0;
 
     return loadSmallBlocks(&block, 1, data, maxlen);
 }
 
 // =========== StreamIO ==========
 
 StreamIO::StreamIO(StorageIO* s, DirEntry* e)
 {
     io = s;
     entry = e;
     eof = false;
     fail = false;
 
     m_pos = 0;
 
     if (entry->size >= io->header->threshold) {
         blocks = io->bbat->follow(entry->start, fail);
     } else {
         blocks = io->sbat->follow(entry->start, fail);
     }
 
     // prepare cache
     cache_pos = 0;
     base_cache_size = cache_size = 4096; // optimal ?
     cache_data = new unsigned char[base_cache_size];
     updateCache();
 }
 
 // FIXME tell parent we're gone
 StreamIO::~StreamIO()
 {
     delete[] cache_data;
 }
 
 void StreamIO::seek(unsigned long pos)
 {
     m_pos = pos;
 }
 
 unsigned long StreamIO::tell()
 {
     return m_pos;
 }
 
 int StreamIO::getch()
 {
     // past end-of-file ?
     if (m_pos > entry->size) return -1;
 
     // need to update cache ?
     if (!cache_size || (m_pos < cache_pos) ||
             (m_pos >= cache_pos + cache_size))
         updateCache();
 
     // something bad if we don't get good cache
     if (!cache_size) return -1;
 
     int data = cache_data[m_pos - cache_pos];
     m_pos++;
 
     return data;
 }
 
 unsigned long StreamIO::read(unsigned char *data, unsigned long maxlen)
 {
     // sanity checks
     if (!data) return 0;
     if (maxlen == 0) return 0;
 
     unsigned long totalbytes = 0;
 
     while (totalbytes < maxlen) {
         // need to update cache ?
         if (!cache_size || (m_pos < cache_pos) ||
                 (m_pos >= cache_pos + cache_size))
             updateCache();
         if (!cache_size) break;
 
         const unsigned long remaining = cache_size - (m_pos - cache_pos);
         const unsigned long count = std::min(remaining, maxlen - totalbytes);
         memcpy(data + totalbytes, &cache_data[m_pos - cache_pos], count);
         totalbytes += count;
         m_pos += count;
     }
     return totalbytes;
 }
 
 unsigned long StreamIO::readInternal(unsigned long pos, unsigned char* data, unsigned long maxlen)
 {
     // sanity checks
     if (!data) return 0;
     if (maxlen == 0) return 0;
 
     unsigned long totalbytes = 0;
 
     if (entry->size < io->header->threshold) {
         // small file
         unsigned long index = pos / io->sbat->blockSize;
 
         if (index >= blocks.size()) return 0;
 
         unsigned char buf[4096];
         unsigned long offset = pos % io->sbat->blockSize;
         while (totalbytes < maxlen) {
             if (index >= blocks.size()) break;
             io->loadSmallBlock(blocks[index], &buf[0], io->bbat->blockSize);
             unsigned long count = io->sbat->blockSize - offset;
             if (count > maxlen - totalbytes) count = maxlen - totalbytes;
             memcpy(data + totalbytes, &buf[0] + offset, count);
             totalbytes += count;
             offset = 0;
             index++;
         }
 
     } else {
         // big file
         unsigned long index = pos / io->bbat->blockSize;
 
         if (index >= blocks.size()) return 0;
 
         unsigned char buf[4096];
         unsigned long offset = pos % io->bbat->blockSize;
         while (totalbytes < maxlen) {
             if (index >= blocks.size()) break;
             unsigned long r = io->loadBigBlock(blocks[index], &buf[0], io->bbat->blockSize);
             if (r != io->bbat->blockSize) {
                 return 0;
             }
             unsigned long count = io->bbat->blockSize - offset;
             if (count > maxlen - totalbytes) count = maxlen - totalbytes;
             memcpy(data + totalbytes, &buf[0] + offset, count);
             totalbytes += count;
             index++;
             offset = 0;
         }
 
     }
 
     return totalbytes;
 }
 
 unsigned long StreamIO::readInternal(unsigned char* data, unsigned long maxlen)
 {
     unsigned long bytes = readInternal(tell(), data, maxlen);
     m_pos += bytes;
     return bytes;
 }
 
 void StreamIO::updateCache()
 {
     // sanity check
     if (!cache_data) return;
 
     cache_pos = m_pos - (m_pos % base_cache_size);
     unsigned long bytes = base_cache_size;
     if (cache_pos + bytes > entry->size) bytes = entry->size - cache_pos;
     if (cache_pos + bytes <= m_pos) {
         cache_size = 0;
     } else {
         cache_size = readInternal(cache_pos, cache_data, bytes);
     }
 }
 
 
 // =========== Storage ==========
 
 Storage::Storage(const char* filename)
 {
     io = new StorageIO(this, filename);
 }
 
 Storage::~Storage()
 {
     delete io;
 }
 
 int Storage::result()
 {
     return io->result;
 }
 
 bool Storage::open()
 {
     return io->open();
 }
 
 void Storage::close()
 {
     io->close();
 }
 
 std::list<std::string> Storage::entries(const std::string& path)
 {
     std::list<std::string> result;
     DirTree* dt = io->dirtree;
     DirEntry* e = dt->entry(path, false);
     if (e) {
         if (e->dir) {
             unsigned parent = dt->indexOf(e);
             std::vector<unsigned> children = dt->children(parent);
             for (unsigned i = 0; i < children.size(); i++)
                 result.push_back(dt->entry(children[i])->name);
         }
     }
     return result;
 }
 
 bool Storage::isDirectory(const std::string& name)
 {
     DirEntry* e = io->dirtree->entry(name, false);
     return e ? e->dir : false;
 }
 
 // =========== Stream ==========
 
 Stream::Stream(Storage* storage, const std::string& name)
 {
     io = storage->io->streamIO(name);
 }
 
 // FIXME tell parent we're gone
 Stream::~Stream()
 {
     delete io;
 }
 
 std::string Stream::fullName()
 {
     return io ? io->fullName : std::string();
 }
 
 unsigned long Stream::tell()
 {
     return io ? io->tell() : 0;
 }
 
 void Stream::seek(unsigned long newpos)
 {
     if (io) io->seek(newpos);
 }
 
 unsigned long Stream::size()
 {
     return io ? io->entry->size : 0;
 }
 
 int Stream::getch()
 {
     return io ? io->getch() : 0;
 }
 
 unsigned long Stream::read(unsigned char* data, unsigned long maxlen)
 {
     return io ? io->read(data, maxlen) : 0;
 }
 
 bool Stream::eof()
 {
     return io ? io->eof : false;
 }
 
 bool Stream::fail()
 {
     return io ? io->fail : true;
 }