/* POLE - Portable C++ library to access OLE Storage

   Copyright (C) 2002-2005 Ariya Hidayat <ariya@kde.org>

   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 <fstream>

#include <iostream>

#include <list>

#include <string>

#include <vector>

#include "pole.h"

#include <string.h>

// enable to activate debugging output

// #define POLE_DEBUG

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();

    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();

    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);

    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();

    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);

    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(std::vector<unsigned long> blocks, unsigned char* buffer, unsigned long maxlen);

    unsigned long loadBigBlock(unsigned long block, unsigned char* buffer, unsigned long maxlen);

    unsigned long loadSmallBlocks(std::vector<unsigned long> blocks, 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);

    unsigned long read(unsigned long pos, unsigned char* data, unsigned long maxlen);

private:

    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 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 ptr[0] + (ptr[1] << 8) + (ptr[2] << 16) + (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()

{

    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 >= 31) return false;

    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); // mini stream cutoff size

    num_sbat     = readU32(buffer + 0x40); // first mini fat sector location

    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()

{

    std::cout << std::endl;

    std::cout << "b_shift " << b_shift << std::endl;

    std::cout << "s_shift " << s_shift << std::endl;

    std::cout << "num_bat " << num_bat << std::endl;

    std::cout << "dirent_start " << dirent_start << std::endl;

    std::cout << "threshold " << threshold << std::endl;

    std::cout << "sbat_start " << sbat_start << std::endl;

    std::cout << "num_sbat " << num_sbat << std::endl;

    std::cout << "mbat_start " << mbat_start << std::endl;

    std::cout << "num_mbat " << num_mbat << std::endl;

    unsigned s = (num_bat <= 109) ? num_bat : 109;

    std::cout << "bat blocks: ";

    for (unsigned i = 0; i < s; i++)

        std::cout << bb_blocks[i] << " ";

    std::cout << 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);

}

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)

{

    std::vector<unsigned long> chain;

    if (start >= count()) return chain;

    unsigned long p = start;

    while (p < count()) {

        if (p == (unsigned long)Eof) break;

        if (p == (unsigned long)Bat) break;

        if (p == (unsigned long)MetaBat) break;

        if (p >= count()) break;

        chain.push_back(p);

        if (data[p] >= count()) break;

        p = data[ p ];

    }

    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()

{

    std::cout << "block size " << data.size() << std::endl;

    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;

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->child < entryCount())

            dirtree_find_siblings(this, result, e->child);

    return result;

}

void DirTree::load(unsigned char* buffer, unsigned size)

{

    entries.clear();

    for (unsigned i = 0; i < size / 128; i++) {

        unsigned p = i * 128;

        // would be < 32 if first char in the name isn't printable

        unsigned prefix = 32;

        // parse name of this entry, which stored as Unicode 16-bit

        std::string name;

        int name_len = readU16(buffer + 0x40 + p);

        if (name_len > 64) name_len = 64;

        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) {

            prefix = buffer[0];

            name.erase(0, 1);

        }

        // 2 = file (aka stream), 1 = directory (aka storage), 5 = root

        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 = (type != 2);

        // sanity checks

        if ((type != 2) && (type != 1) && (type != 5)) e.valid = false;

        if (name_len < 1) e.valid = false;

        // CLSID, contains a object class GUI if this entry is a storage or root

        // storage or all zero if not.

#ifdef POLE_DEBUG

        printf("DirTree::load name=%s type=%i prev=%i next=%i child=%i start=%i size=%i clsid=%i.%i.%i.%i\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);

    }

}

// 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[512];

    file.seekg(0);

    file.read((char*)buffer, 512);

    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;

    // sanity checks

    result = Storage::BadOLE;

    if (!header->valid()) return;

    if (header->threshold != 4096) return;

    // important block size

    bbat->blockSize = 1 << header->b_shift;

    sbat->blockSize = 1 << header->s_shift;

    // 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) {

            delete[] buffer;

            return;

        }

        bbat->load(buffer, buflen);

        delete[] buffer;

    }

    // load small bat

    blocks.clear();

    blocks = bbat->follow(header->sbat_start);

    buflen = blocks.size() * bbat->blockSize;

    if (buflen > 0) {

        buffer = new unsigned char[ buflen ];

        unsigned long r = loadBigBlocks(blocks, buffer, buflen);

        if (r != buflen) {

            delete[] buffer;

            return;

        }

        sbat->load(buffer, buflen);

        delete[] buffer;

    }

    // load directory tree

    blocks.clear();

    blocks = bbat->follow(header->dirent_start);

    buflen = blocks.size() * bbat->blockSize;

    buffer = new unsigned char[ buflen ];

    unsigned long r = loadBigBlocks(blocks, buffer, buflen);

    if (r != buflen) {

        delete[] buffer;

        return;

    }

    dirtree->load(buffer, buflen);

    unsigned sb_start = readU32(buffer + 0x74);

    delete[] buffer;

    // fetch block chain as data for small-files

    sb_blocks = bbat->follow(sb_start);   // small files

    // 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()) {

        std::cerr << "Can't create " << filename << std::endl;

        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)

{

    // 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(std::vector<unsigned long> blocks,

                                       unsigned char* data, unsigned long maxlen)

{

    // sentinel

    if (!data) return 0;

    if (!file.good()) return 0;

    if (blocks.size() < 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 < blocks.size()) && (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;

    // wraps call for loadBigBlocks

    std::vector<unsigned long> blocks;

    blocks.resize(1);

    blocks[ 0 ] = block;

    return loadBigBlocks(blocks, data, maxlen);

}

// return number of bytes which has been read

unsigned long StorageIO::loadSmallBlocks(std::vector<unsigned long> blocks,

        unsigned char* data, unsigned long maxlen)

{

    // sentinel

    if (!data) return 0;

    if (!file.good()) return 0;

    if (blocks.size() < 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 < blocks.size()) && (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;

    // wraps call for loadSmallBlocks

    std::vector<unsigned long> blocks;

    blocks.resize(1);

    blocks.assign(1, block);

    return loadSmallBlocks(blocks, 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);

    else

        blocks = io->sbat->follow(entry->start);

    // prepare cache

    cache_pos = 0;

    cache_size = 4096; // optimal ?

    cache_data = new unsigned char[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 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 = new unsigned char[ io->sbat->blockSize ];

        unsigned long offset = pos % io->sbat->blockSize;

        while (totalbytes < maxlen) {

            if (index >= blocks.size()) break;

            io->loadSmallBlock(blocks[index], buf, io->bbat->blockSize);

            unsigned long count = io->sbat->blockSize - offset;

            if (count > maxlen - totalbytes) count = maxlen - totalbytes;

            memcpy(data + totalbytes, buf + offset, count);

            totalbytes += count;

            offset = 0;

            index++;

        }

        delete[] buf;

    } else {

        // big file

        unsigned long index = pos / io->bbat->blockSize;

        if (index >= blocks.size()) return 0;

        unsigned char* buf = new unsigned char[ io->bbat->blockSize ];

        unsigned long offset = pos % io->bbat->blockSize;

        while (totalbytes < maxlen) {

            if (index >= blocks.size()) break;

            unsigned long r = io->loadBigBlock(blocks[index], buf, io->bbat->blockSize);

            if (r != io->bbat->blockSize) {

                delete [] buf;

                return 0;

            }

            unsigned long count = io->bbat->blockSize - offset;

            if (count > maxlen - totalbytes) count = maxlen - totalbytes;

            memcpy(data + totalbytes, buf + offset, count);

            totalbytes += count;

            index++;

            offset = 0;

        }

        delete [] buf;

    }

    return totalbytes;

}

unsigned long StreamIO::read(unsigned char* data, unsigned long maxlen)

{

    unsigned long bytes = read(tell(), data, maxlen);

    m_pos += bytes;

    return bytes;

}

void StreamIO::updateCache()

{

    // sanity check

    if (!cache_data) return;