/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: t; c-basic-offset: 4 -*- */
/* librevenge

   Original source: POLE - Portable C++ library to access OLE Storage
   Copyright (C) 2002-2005 Ariya Hidayat <ariya@kde.org>

   Performance optimization: Dmitry Fedorov
   Copyright 2009 <www.bioimage.ucsb.edu> <www.dimin.net>

   Fix for more than 236 mbat block entries : Michel Boudinot
   Copyright 2010 <Michel.Boudinot@inaf.cnrs-gif.fr>

   Version: 0.4

   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.
*/

/*
 This file taken from librevenge RVNGOLEStream.cpp
*/

#include <string.h>
#include <ctype.h>

#include <cassert>
#include <sstream>
#include <iostream>
#include <list>
#include <locale>
#include <set>
#include <string>
#include <vector>

#include <librevenge-stream/librevenge-stream.h>

#include "libwps_internal.h"

#include "WPSStringStream.h"

#include "WPSOLEStream.h"

namespace libwps_OLE
{

class IStorage;
class IStream;

enum { Avail = 0xffffffff, Eof = 0xfffffffe, Bat = 0xfffffffd, MetaBat = 0xfffffffc, NotFound=0xfffffff0 };

static inline unsigned short readU16(const unsigned char *ptr)
{
	return static_cast<unsigned short>(ptr[0]+(ptr[1]<<8));
}

static inline unsigned readU32(const unsigned char *ptr)
{
	return unsigned(ptr[0]+(ptr[1]<<8)+(ptr[2]<<16)+(ptr[3]<<24));
}

static inline void writeU16(unsigned char *ptr, unsigned long data)
{
	ptr[0] = static_cast<unsigned char>(data & 0xff);
	ptr[1] = static_cast<unsigned char>((data >> 8) & 0xff);
}

static inline void writeU32(unsigned char *ptr, unsigned long data)
{
	ptr[0] = static_cast<unsigned char>(data & 0xff);
	ptr[1] = static_cast<unsigned char>((data >> 8) & 0xff);
	ptr[2] = static_cast<unsigned char>((data >> 16) & 0xff);
	ptr[3] = static_cast<unsigned char>((data >> 24) & 0xff);
}

static unsigned long getLength(librevenge::RVNGInputStream *const input)
{
	assert(input);

	const long pos = input->tell();
	if (0 > pos)
		return 0;

	long end = 0;

	if (0 == input->seek(0, librevenge::RVNG_SEEK_END))
		end = input->tell();
	if ((0 != input->seek(pos, librevenge::RVNG_SEEK_SET)) || (0 > end))
		return 0;

	assert(pos <= end);

	return static_cast<unsigned long>(end);
}

class Header
{
public:
	unsigned char m_magic[8];       // signature, or magic identifier
	unsigned m_revision;         // the file revision
	unsigned m_num_bat;          // blocks allocated for big bat
	unsigned m_start_dirent;     // starting block for directory info
	unsigned m_threshold;        // switch from small to big file (usually 4K)
	unsigned m_start_sbat;       // starting block index to store small bat
	unsigned m_num_sbat;         // blocks allocated for small bat
	unsigned m_shift_sbat;          // sbat->blockSize = 1 << m_shift_sbat
	unsigned m_size_sbat;		// the small block size, default 0x40
	unsigned m_shift_bbat;          // bbat->blockSize = 1 << m_shift_bbat
	unsigned m_size_bbat;		// the big block size, default 0x200
	unsigned m_start_mbat;       // starting block to store meta bat
	unsigned m_num_mbat;         // blocks allocated for meta bat
	unsigned long m_blocks_bbat[109];

	Header();
	void compute_block_size()
	{
		assert(m_shift_bbat < 31);
		assert(m_shift_sbat < 31);
		m_size_bbat = 1 << m_shift_bbat;
		m_size_sbat = 1 << m_shift_sbat;
	}
	bool valid_signature() const
	{
		for (unsigned i = 0; i < 8; i++)
			if (m_magic[i] != s_ole_magic[i]) return false;
		return true;
	}
	bool valid(unsigned long fileSize) const;
	void load(const unsigned char *buffer, unsigned long size);
	void save(unsigned char *buffer);
protected:
	static const unsigned char s_ole_magic[];
};

const unsigned char Header::s_ole_magic[] =
{ 0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1, 0x1a, 0xe1 };

class AllocTable
{
public:
	unsigned m_blockSize;
	AllocTable() : m_blockSize(4096), m_data()
	{
		resize(128); // initial size
	}
	void clear();
	unsigned long count() const
	{
		return static_cast<unsigned long>(m_data.size());
	}
	void resize(unsigned long newsize)
	{
		m_data.resize(size_t(newsize), Avail);
	}
	void set(unsigned long index, unsigned long val)
	{
		if (index >= count())
			resize(index+1);
		m_data[size_t(index)] = val;
	}
	std::vector<unsigned long> follow(unsigned long start) const;
	unsigned long operator[](unsigned long index) const
	{
		return m_data[size_t(index)];
	}
	void load(const unsigned char *buffer, unsigned len)
	{
		resize(len / 4);
		for (unsigned i = 0; i < count(); i++)
			set(i, readU32(buffer + i*4));
	}

	// write part
	void setChain(std::vector<unsigned long> chain, unsigned end);
	void save(unsigned char *buffer) const
	{
		auto cnt=unsigned(count());
		unsigned i = 0;
		for (i = 0; i < cnt; i++)
			writeU32(buffer + i*4, m_data[i]);
		unsigned lastFree = 128-(cnt%128);
		if (lastFree==128) return;
		for (i = 0; i < lastFree; i++)
			writeU32(buffer + (cnt+i)*4, Avail);
	}
	// return space required to save the allocation table
	unsigned saveSize() const
	{
		auto cnt=unsigned(((count()+127)/128)*128);
		return cnt * 4;
	}
private:
	std::vector<unsigned long> m_data;
	AllocTable(const AllocTable &);
	AllocTable &operator=(const AllocTable &);
};

class DirInfo
{
public:
	//! constructor
	DirInfo()
	{
		int i = 0;
		for (i=0; i < 4; i++)
			m_time[i]=0;
		for (i=0; i < 4; i++)
			m_clsid[i]=0;
	}
	//! returns true if the clsid field is filed
	bool hasCLSId() const
	{
		for (unsigned int i : m_clsid)
			if (i) return true;
		return false;
	}
	/** four uint32_t : the first two used for creation, the last for modification time */
	unsigned m_time[4];
	/** four uint32_t: the clsid data */
	unsigned m_clsid[4];
};

class DirEntry
{
public:
	enum { End= 0xffffffff };
	//! constructor
	DirEntry() : m_valid(false), m_macRootEntry(false), m_type(0), m_colour(0), m_size(0), m_start(0),
		m_right(End), m_left(End), m_child(End), m_info(), m_name("")
	{
	}
	//! returns true for a directory
	bool is_dir() const
	{
		return m_type==1 || m_type==5;
	}
	//! returns the simplified file name
	std::string name() const
	{
		if (m_name.length() && m_name[0]<32)
			return m_name.substr(1);
		return m_name;
	}
	/** returns the string which was store inside the file.

	\note: either name() or a index (unknown) followed by name() */
	std::string const &filename() const
	{
		return m_name;
	}
	/** sets the file name */
	void setName(std::string const &nm)
	{
		m_name=nm;
	}
	/** reads a entry content in buffer */
	void load(unsigned char *buffer, unsigned len);
	//! saves a entry content in buffer */
	void save(unsigned char *buffer) const;
	//! returns space required to save a dir entry
	static unsigned saveSize()
	{
		return 128;
	}

	bool m_valid;            /** false if invalid (should be skipped) */
	bool m_macRootEntry;      /** true if this is a classic mac directory entry */
	unsigned m_type;         /** the type */
	unsigned m_colour;       /** the red/black color: 0 means red */
	unsigned long m_size;    /** size (not valid if directory) */
	unsigned long m_start;   /** starting block */
	unsigned m_right;        /** previous sibling */
	unsigned m_left;         /** next sibling */
	unsigned m_child;        /** first child */

	DirInfo m_info; //! the file information
protected:
	std::string m_name;      /** the name, not in unicode anymore */
};

class DirTree
{
public:
	/** constructor */
	DirTree() : m_entries()
	{
		clear();
	}
	/** clear all entries, leaving only a root entries */
	void clear();
	/** set the root to a mac/pc root */
	void setRootType(bool pc=true);
	/** returns true if it is a pc file */
	bool hasRootTypePc() const
	{
		return !m_entries.size() || !m_entries[0].m_macRootEntry;
	}
	/** returns the number of entries */
	unsigned count() const
	{
		return unsigned(m_entries.size());
	}
	/** returns the entry with a given index */
	DirEntry const *entry(unsigned ind) const
	{
		if (ind >= count()) return nullptr;
		return &m_entries[ size_t(ind) ];
	}
	/** returns the entry with a given index */
	DirEntry *entry(unsigned ind)
	{
		if (ind >= count()) return  nullptr;
		return &m_entries[ size_t(ind) ];
	}
	/** returns the entry with a given name */
	DirEntry *entry(const std::string &name)
	{
		return entry(index(name));
	}
	/** given a fullname (e.g "/ObjectPool/_1020961869"), find the entry */
	unsigned index(const std::string &name, bool create=false);
	/** tries to find a child of ind with a given name */
	unsigned find_child(unsigned ind, const std::string &name) const
	{
		DirEntry const *p = entry(ind);
		if (!p || !p->m_valid) return 0;
		std::vector<unsigned> siblingsList = get_siblings(p->m_child);
		for (unsigned s : siblingsList)
		{
			p  = entry(s);
			if (!p) continue;
			if (p->name()==name)
				return s;
		}
		return 0;
	}
	/** returns the list of ind substream */
	std::vector<std::string> getSubStreamList(unsigned ind=0, bool retrieveAll=false)
	{
		std::vector<std::string> res;
		std::set<unsigned> seens;
		getSubStreamList(ind, retrieveAll, "", res, seens, true);
		return res;
	}
	/** tries to read the different entries */
	void load(unsigned char *buffer, unsigned len);

	// write part:
	//! check/update so that the sibling are store with a red black tree
	void setInRedBlackTreeForm()
	{
		std::set<unsigned> seens;
		setInRedBlackTreeForm(0, seens);
	}
	//! return space required to save a dir entry
	unsigned saveSize() const
	{
		unsigned cnt = count();
		cnt = 4*((cnt+3)/4);
		return cnt*DirEntry::saveSize();
	}
	//! save the list of direntry in buffer
	void save(unsigned char *buffer) const
	{
		unsigned entrySize=DirEntry::saveSize();
		size_t cnt = count();
		for (size_t i = 0; i < cnt; i++)
			m_entries[i].save(buffer+entrySize*i);
		if ((cnt%4)==0) return;
		DirEntry empty;
		while (cnt%4)
			empty.save(buffer+entrySize*cnt++);
	}
protected:
	//! returns a list of siblings corresponding to a node
	std::vector<unsigned> get_siblings(unsigned ind) const
	{
		std::set<unsigned> seens;
		get_siblings(ind, seens);
		std::vector<unsigned> retVal;
		for (unsigned seen : seens)
			retVal.push_back(seen);
		return retVal;
	}
	//! constructs the list of siblings ( by filling the seens set )
	void get_siblings(unsigned ind, std::set<unsigned> &seens) const
	{
		if (seens.find(ind) != seens.end())
			return;
		seens.insert(ind);
		DirEntry const *e = entry(ind);
		if (!e) return;
		unsigned cnt = count();
		if (e->m_left>0&& e->m_left < cnt)
			get_siblings(e->m_left, seens);
		if (e->m_right>0 && e->m_right < cnt)
			get_siblings(e->m_right, seens);
	}
	/** returns a substream list */
	void getSubStreamList(unsigned ind, bool all, const std::string &prefix,
	                      std::vector<std::string> &res, std::set<unsigned> &seen,
	                      bool isRoot=false) const;

	/** check that the subtrees of index is a red black tree, if not rebuild it */
	void setInRedBlackTreeForm(unsigned id, std::set<unsigned> &seen);
	/** rebuild all the childs m_left, m_right index as a red black
		tree, returns the root index.

		\note: this function supposes that the childs list is already sorted
	*/
	unsigned setInRBTForm(std::vector<unsigned> const &childList,
	                      unsigned firstInd, unsigned lastInd,
	                      unsigned height);

	/** a comparaison funcion of DirTree used to sort the entry by name */
	struct CompareEntryName
	{
		//! constructor
		explicit CompareEntryName(DirTree &tree) : m_tree(tree)
		{
		}
		//! comparaison function
		bool operator()(unsigned ind1, unsigned ind2) const
		{
			DirEntry const *e1=m_tree.entry(ind1);
			DirEntry const *e2=m_tree.entry(ind2);
			if (!e1 && !e2) return false;
			if (!e1) return true;
			if (!e2) return false;
			std::string name1(e1->name()), name2(e2->name());
			size_t len1=name1.length();
			size_t len2=name2.length();
			if (len1 != len2) return len1 < len2;
			for (size_t c=0; c < len1; c++)
			{
				if (tolower(name1[c]) != tolower(name2[c]))
					return tolower(name1[c]) < tolower(name2[c]);
			}
			return ind1 < ind2;
		}

		//! the main tree
		DirTree &m_tree;
	};

private:
	std::vector<DirEntry> m_entries;
	DirTree(const DirTree &);
	DirTree &operator=(const DirTree &);
};

class IStorage
{
public:
	// for m_result
	enum Result { Ok, OpenFailed, NotOLE, BadOLE, UnknownError };

	librevenge::RVNGInputStream *m_input;
	Result m_result;               // result of operation

	Header m_header;           // storage header
	DirTree m_dirtree;         // directory tree
	AllocTable m_bbat;         // allocation table for big blocks
	AllocTable m_sbat;         // allocation table for small blocks

	std::vector<unsigned long> m_sb_blocks; // blocks for "small" files

	explicit IStorage(librevenge::RVNGInputStream *is);
	~IStorage() {}

	//! returns a directory entry corresponding to a index
	DirEntry *entry(unsigned ind)
	{
		load();
		return m_dirtree.entry(ind);
	}
	//! returns a directory entry corresponding to a name
	DirEntry *entry(const std::string &name)
	{
		if (!name.length()) return nullptr;
		load();
		return m_dirtree.entry(name);
	}
	//! returns a directory entry corresponding to a index
	unsigned index(const std::string &name)
	{
		if (!name.length()) return NotFound;
		load();
		return m_dirtree.index(name);
	}
	/** returns the OLE revision */
	unsigned revision() const
	{
		return m_header.m_revision;
	}
	/** returns true if it is a pc file */
	bool hasRootTypePc() const
	{
		return m_dirtree.hasRootTypePc();
	}
	//! returns true if the entry exists in the OLE, if so fills isDir
	bool isSubStream(const std::string &name, bool &isDir);
	//! returns the list of subStream given a dirEntry index
	std::vector<std::string> getSubStreamList(unsigned ind=0, bool retrieveAll=false)
	{
		load();
		return m_dirtree.getSubStreamList(ind, retrieveAll);
	}

	bool isStructured();
	std::vector<std::string> getSubStreamNamesList();
	void load();

	bool use_big_block_for(unsigned long size) const
	{
		return size >= m_header.m_threshold;
	}
	unsigned long loadBigBlocks(std::vector<unsigned long> const &blocks, unsigned char *buffer, unsigned long maxlen) const;

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

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

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

protected:
	bool m_isLoad;
private:
	// no copy or assign
	IStorage(const IStorage &);
	IStorage &operator=(const IStorage &);

};

class OStorage
{
public:
	//! constructor
	explicit OStorage(unsigned long minSize=0) : m_header(), m_dirtree(), m_bbat(), m_num_bbat(0), m_sbat(), m_num_sbat(0), m_sb_blocks(), m_data()
	{
		// update data to contain at least, header
		m_data.resize(minSize>512 ? minSize : 512);
	}
	//! destructor
	~OStorage() { }

	//! function to retrieve the list of actual direntry
	std::vector<std::string> getSubStreamList(unsigned ind=0, bool all=false)
	{
		return m_dirtree.getSubStreamList(ind, all);
	}
	/** set the OLE revision */
	void setRevision(unsigned rev)
	{
		m_header.m_revision=rev;
	}
	//! set the root to a mac/pc root */
	void setRootType(bool pc)
	{
		m_dirtree.setRootType(pc);
	}
	//! add a new stream knowing its data
	bool addStream(std::string const &name, unsigned char const *buffer, unsigned long len);
	//! add a new directory (usefull to create empty leaf dir )
	bool addDirectory(std::string const &dir);
	//! set a node information
	void setInformation(std::string const &name, DirInfo const &info)
	{
		DirEntry *e = m_dirtree.entry(name);
		if (!e)
		{
			WPS_DEBUG_MSG(("librevengeOLE::OStorage::setInformation: can not find entry %s!!!\n", name.c_str()));
			return;
		}
		e->m_info = info;
	}
	//! try to return in data the contain of the file
	bool getFileData(std::vector<unsigned char> &data)
	{
		try
		{
			if (!updateToSave())
				return false;
			data = m_data;
		}
		catch (...)
		{
			return false;
		}
		return true;
	}

protected:
	//! add stream data in a file, returns the first index
	unsigned insertData(unsigned char const *buffer, unsigned long len, bool useBigBlock, unsigned end=Eof);

	//! return true if we need to use big block
	bool useBigBlockFor(unsigned long size) const
	{
		return size >= m_header.m_threshold;
	}
	//! returns the maximum size of a big/small block
	static unsigned long getMaximumSize(bool isBig)
	{
		return isBig ? 512 : 64;
	}
	//! returns the address of a big/small block
	size_t getDataAddress(unsigned block, bool isBig) const
	{
		if (isBig) return size_t((block+1)*512);
		auto bId=size_t(block/8);
		if (bId >= m_sb_blocks.size()) throw libwps::GenericException();
		return size_t((m_sb_blocks[bId]+1)*512+64*(block%8));
	}

	//! create a new big block, resize m_data; ... and return is identifier
	unsigned newBBlock()
	{
		unsigned res = m_num_bbat++;
		if (m_data.size() < (res+2)*512) m_data.resize((res+2)*512, 0);
		m_bbat.resize(res+1);
		return res;
	}
	//! create a new small block, ... and returns is identifier
	unsigned newSBlock()
	{
		unsigned res = m_num_sbat++;
		if ((res%8)==0)
			m_sb_blocks.push_back(newBBlock());
		m_sbat.resize(res+1);
		return res;
	}

	//! return a new dir entry, if it does not exists
	DirEntry *createEntry(std::string const &name)
	{
		if (name.length()==0)
		{
			WPS_DEBUG_MSG(("librevengeOLE::OStorage::createEntry: called with no name\n"));
			return nullptr;
		}
		if (m_dirtree.index(name)!=NotFound)
		{
			WPS_DEBUG_MSG(("librevengeOLE::OStorage::createEntry: entry %s already exists\n", name.c_str()));
			return nullptr;
		}
		unsigned index = m_dirtree.index(name,true);
		if (index == NotFound) return nullptr;

		return m_dirtree.entry(index);
	}

	//! finish to update the file ( note: it is better to call this function only one time )
	bool updateToSave();

	Header m_header;           // storage header
	DirTree m_dirtree;         // directory tree
	AllocTable m_bbat;         // allocation table for big blocks
	unsigned m_num_bbat;       // the number of bbat
	AllocTable m_sbat;         // allocation table for small blocks
	unsigned m_num_sbat;       // the number of sbat

	std::vector<unsigned long> m_sb_blocks; // blocks for "small" files

	std::vector<unsigned char> m_data;
private:
	// no copy or assign
	OStorage(const OStorage &);
	OStorage &operator=(const OStorage &);
};

class IStream
{
public:
	IStorage *m_iStorage;
	//! the stream size
	unsigned long m_size;
	std::string m_name;

	IStream(IStorage *io, std::string const &name);
	~IStream()
	{
	}
	unsigned long size() const
	{
		return m_size;
	}
	unsigned long tell() const
	{
		return m_pos;
	}
	unsigned long read(unsigned char *data, unsigned long maxlen)
	{
		if (!m_size)
			return 0;
		unsigned long bytes;
		if (m_data.size())
			bytes = readData(tell(), data, maxlen);
		else
			bytes = readUsingStorage(tell(), data, maxlen);
		m_pos += bytes;
		return bytes;
	}

protected:
	//! create the data corresponding to a directory
	bool createOleFromDirectory(IStorage *io, std::string const &name);
	//! try to read maxlen data using m_iStorage
	unsigned long readUsingStorage(unsigned long pos, unsigned char *data, unsigned long maxlen);
	//! try to read maxlen data using m_data
	unsigned long readData(unsigned long pos, unsigned char *data, unsigned long maxlen);

private:
	std::vector<unsigned long> m_blocks;

	// no copy or assign
	IStream(const IStream &);
	IStream &operator=(const IStream &);

	// pointer for read
	unsigned long m_pos;

	// a copy of the data when the entry came for OStorage
	std::vector<unsigned char> m_data;
};

} // namespace librevenge
// =========== Header ==========

libwps_OLE::Header::Header() :
	m_revision(0x3e), m_num_bat(0), m_start_dirent(0), m_threshold(4096),
	m_start_sbat(Eof), m_num_sbat(0), m_shift_sbat(6), m_size_sbat(0),
	m_shift_bbat(9), m_size_bbat(0),
	m_start_mbat(Eof), m_num_mbat(0)
{
	for (unsigned i = 0; i < 8; i++)
		m_magic[i] = s_ole_magic[i];
	for (unsigned long &j : m_blocks_bbat)
		j = Avail;
	compute_block_size();
}

bool libwps_OLE::Header::valid(const unsigned long fileSize) const
{
	if (m_threshold != 4096) return false;
	// there must be at least the header, one bat sector and one dirent sector in the file
	if ((fileSize / m_size_bbat) < 3) return false;
	// sectors must fit into the file
	if ((fileSize / m_size_bbat) < m_num_mbat) return false;
	if (m_num_bat == 0) return false;
	if ((m_num_bat > 109) && (m_num_bat > (m_num_mbat * (m_size_bbat/4-1)) + 109)) return false;
	if ((m_num_bat < 109) && (m_num_mbat != 0)) return false;
	if (m_shift_sbat > m_shift_bbat) return false;
	if (m_shift_bbat <= 6) return false;
	if (m_shift_bbat >=31) return false;
	return true;
}

void libwps_OLE::Header::load(const unsigned char *buffer, unsigned long size)
{
	if (size < 512)
		return;
	m_revision = unsigned(readU16(buffer+0x18));
	m_shift_bbat      =static_cast<unsigned int>(readU16(buffer + 0x1e));
	if (m_shift_bbat > 31)
		m_shift_bbat = 31;
	m_shift_sbat      =static_cast<unsigned int>(readU16(buffer + 0x20));
	if (m_shift_sbat > 31)
		m_shift_sbat = 31;
	m_num_bat      =static_cast<unsigned int>(readU32(buffer + 0x2c));
	m_start_dirent =static_cast<unsigned int>(readU32(buffer + 0x30));
	m_threshold    =static_cast<unsigned int>(readU32(buffer + 0x38));
	m_start_sbat   =static_cast<unsigned int>(readU32(buffer + 0x3c));
	m_num_sbat     =static_cast<unsigned int>(readU32(buffer + 0x40));
	m_start_mbat   =static_cast<unsigned int>(readU32(buffer + 0x44));
	m_num_mbat     =static_cast<unsigned int>(readU32(buffer + 0x48));

	for (unsigned i = 0; i < 8; i++)
		m_magic[i] = buffer[i];
	for (unsigned j=0; j<109; j++)
		m_blocks_bbat[j] = readU32(buffer + 0x4C+j*4);
}

void libwps_OLE::Header::save(unsigned char *buffer)
{
	memcpy(buffer, s_ole_magic, 8);          // ole signature
	memset(buffer + 8, 0, 0x4c - 8);
	writeU32(buffer + 8, 0);                // unknown
	writeU32(buffer + 12, 0);               // unknown
	writeU32(buffer + 16, 0);               // unknown
	writeU16(buffer + 24, m_revision);
	writeU16(buffer + 26, 3);               // version ?
	writeU16(buffer + 28, 0xfffe);          // unknown
	writeU16(buffer + 0x1e, m_shift_bbat);
	writeU16(buffer + 0x20, m_shift_sbat);
	writeU32(buffer + 0x2c, m_num_bat);
	writeU32(buffer + 0x30, m_start_dirent);
	writeU32(buffer + 0x38, m_threshold);
	writeU32(buffer + 0x3c, m_start_sbat);
	writeU32(buffer + 0x40, m_num_sbat);
	writeU32(buffer + 0x44, m_start_mbat);
	writeU32(buffer + 0x48, m_num_mbat);

	for (unsigned i=0; i<109; i++)
		writeU32(buffer + 0x4C+i*4, m_blocks_bbat[i]);
}


// =========== AllocTable ==========

std::vector<unsigned long> libwps_OLE::AllocTable::follow(unsigned long start) const
{
	std::vector<unsigned long> chain;
	if (start >= count()) return chain;

	std::set<unsigned long> seens;
	unsigned long p = start;
	while (p < count())
	{
		if (p == Eof || p == Bat || p == MetaBat) break;
		if (seens.find(p) != seens.end()) break;
		seens.insert(p);
		chain.push_back(p);
		p = m_data[ p ];
	}

	return chain;
}

void libwps_OLE::AllocTable::setChain(std::vector<unsigned long> chain, unsigned end)
{
	if (!chain.size()) return;

	for (unsigned i=0; i<chain.size()-1; i++)
		set(chain[i], chain[i+1]);
	set(chain[ chain.size()-1 ], end);
}

// =========== DirEntry ==========
void libwps_OLE::DirEntry::load(unsigned char *buffer, unsigned len)
{
	if (len != 128)
	{
		WPS_DEBUG_MSG(("DirEntry::load: unexpected len for DirEntry::load\n"));
		*this=DirEntry();
		return;
	}
	// 2 = file (aka stream), 1 = directory (aka storage), 5 = root
	m_type = buffer[ 0x42];
	m_colour = buffer[0x43];

	// parse name of this entry, which stored as Unicode 16-bit
	m_name=std::string("");
	auto name_len = unsigned(readU16(buffer + 0x40));
	if (name_len > 64) name_len = 64;
	if (name_len==2 && m_type==5 && readU16(buffer)==0x5200)
	{
		// find in some mswork mac 4.0 file
		m_name="R";
		m_macRootEntry=true;
	}
	else
	{
		for (unsigned j=0; (j < name_len) && buffer[j]; j+= 2)
			m_name.append(1, char(buffer[j]));
	}

	int i = 0;
	for (i = 0; i < 4; i++)
		m_info.m_clsid[i]=unsigned(readU32(buffer + 0x50 + 4*i));
	for (i = 0; i < 4; i++)
		m_info.m_time[i]=unsigned(readU32(buffer + 0x64 + 4*i));

	m_valid = true;
	m_start =static_cast<unsigned int>(readU32(buffer + 0x74));
	m_size =static_cast<unsigned int>(readU32(buffer + 0x78));
	m_left =static_cast<unsigned int>(readU32(buffer + 0x44));
	m_right =static_cast<unsigned int>(readU32(buffer + 0x48));
	m_child =static_cast<unsigned int>(readU32(buffer + 0x4C));

	// sanity checks
	if ((m_type != 2) && (m_type != 1) && (m_type != 5)) m_valid = false;
	if (name_len < 1) m_valid = false;
}

void libwps_OLE::DirEntry::save(unsigned char *buffer) const
{
	int i = 0;
	for (i = 0; i < 128; i++) buffer[i]=0;

	auto name_len = unsigned(m_name.length());
	if (name_len>31) name_len = 31;
	if (name_len==2 && m_macRootEntry && m_type==5)
		buffer[1]='R';
	else
	{
		for (size_t j = 0; j < name_len; j++)
			writeU16(buffer+2*j, unsigned(m_name[j]));
	}
	writeU16(buffer+0x40, 2*name_len+2);

	buffer[0x42]=static_cast<unsigned char>(m_type);
	buffer[0x43]=static_cast<unsigned char>(m_colour);
	for (i = 0; i < 4; i++)
		writeU32(buffer + 0x50+4*i, m_info.m_clsid[i]);
	for (i = 0; i < 4; i++)
		writeU32(buffer + 0x64+4*i, m_info.m_time[i]);
	writeU32(buffer + 0x74, m_start);
	writeU32(buffer + 0x78, m_size);
	writeU32(buffer + 0x44, m_left);
	writeU32(buffer + 0x48, m_right);
	writeU32(buffer + 0x4C, m_child);
}
// =========== DirTree ==========

void libwps_OLE::DirTree::clear()
{
	m_entries.resize(0);
	setRootType(true);
}

void libwps_OLE::DirTree::setRootType(bool pc)
{
	if (!m_entries.size())
	{
		m_entries.resize(1);
		m_entries[0]=DirEntry();
		m_entries[0].m_valid = true;
		m_entries[0].setName("Root Entry");
		m_entries[0].m_type = 5;
	}
	if (pc)
		m_entries[0].setName("Root Entry");
	else
	{
		m_entries[0].setName("R");
		m_entries[0].m_macRootEntry = true;
	}
}

unsigned libwps_OLE::DirTree::index(const std::string &name, bool create)
{

	if (name.length()==0) return NotFound;

	// quick check for "/" (that's root)
	if (name == "/") return 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
	unsigned ind = 0 ;

	// trace one by one
	std::list<std::string>::const_iterator it;
	size_t depth = 0;

	for (it = names.begin(); it != names.end(); ++it, ++depth)
	{
		std::string childName(*it);
		if (childName.length() && childName[0]<32)
			childName= it->substr(1);

		unsigned child = find_child(ind, childName);
		// traverse to the child
		if (child > 0)
		{
			ind = child;
			continue;
		}
		else if (!create) return NotFound;

		// create a new entry
		unsigned parent = ind;
		m_entries.push_back(DirEntry());
		ind = count()-1;
		DirEntry *e = entry(ind);
		e->m_valid = true;
		e->setName(*it);
		e->m_type = depth+1==names.size() ? 2 : 1;
		// e->m_start = Eof; CHECKME
		e->m_left = entry(parent)->m_child;
		entry(parent)->m_child = ind;
	}

	return ind;
}

void libwps_OLE::DirTree::load(unsigned char *buffer, unsigned size)
{
	m_entries.clear();

	for (unsigned i = 0; i < size/128; i++)
	{
		DirEntry e;
		e.load(buffer+i*128, 128);
		m_entries.push_back(e);
	}
}

void libwps_OLE::DirTree::getSubStreamList(unsigned ind, bool all, const std::string &prefix,
                                           std::vector<std::string> &res,
                                           std::set<unsigned> &seen,
                                           bool isRoot) const
{
	if (seen.find(ind) != seen.end())
		return;
	seen.insert(ind);
	unsigned cnt = count();
	DirEntry const *p = entry(ind);
	if (!p || !p->m_valid)
		return;
	std::string name(prefix);
	if (ind && !isRoot)
	{
		if (p->filename().length())
			name+= p->filename();
		else
			return;
	}
	if (!p->is_dir())
	{
		res.push_back(name);
		return;
	}
	if (ind)
		name += "/";
	if (all)
	{
		if (ind)
			res.push_back(name);
		else
			res.push_back("/");
	}
	if (p->m_child >= cnt)
		return;
	std::vector<unsigned> siblings=get_siblings(p->m_child);
	for (unsigned sibling : siblings)
		getSubStreamList(sibling, all, name, res, seen);
}

void libwps_OLE::DirTree::setInRedBlackTreeForm(unsigned ind, std::set<unsigned> &seen)
{
	if (seen.find(ind) != seen.end())
		return;
	seen.insert(ind);

	DirEntry *p = entry(ind);
	if (!p || !p->m_valid)
		return;

	p->m_colour=1; // set all nodes blacks
	std::vector<unsigned> childs=get_siblings(p->m_child);
	size_t numChild=childs.size();
	for (size_t s=0; s < numChild; s++)
		setInRedBlackTreeForm(childs[s], seen);
	if (numChild <= 1)
		return;
	CompareEntryName compare(*this);
	std::set<unsigned,CompareEntryName> set(childs.begin(),childs.end(),compare);
	std::vector<unsigned> sortedChildren;
	for (unsigned iter : set)
		sortedChildren.push_back(iter);
	if (sortedChildren.size() != numChild)
	{
		WPS_DEBUG_MSG(("DirTree::setInRedBlackTreeForm: OOPS pb with numChild\n"));
		return;
	}
	unsigned h=1;
	unsigned hNumChild=1;
	while (2*hNumChild+1<=numChild)
	{
		hNumChild=2*hNumChild+1;
		h++;
	}
	p->m_child=setInRBTForm(sortedChildren, 0, unsigned(numChild-1), h);
}

unsigned libwps_OLE::DirTree::setInRBTForm(std::vector<unsigned> const &childs,
                                           unsigned firstInd, unsigned lastInd,
                                           unsigned height)
{
	unsigned middle = (firstInd+lastInd)/2;
	unsigned ind=childs[middle];
	DirEntry *p = entry(ind);
	if (!p)
	{
		WPS_DEBUG_MSG(("DirTree::setInRedBlackTreeForm: OOPS can not find tree to modified\n"));
		throw libwps::GenericException();
	}
	unsigned newH = height==0 ? 0 : height-1;
	if (height==0)
	{
		p->m_colour = 0;
		if (firstInd!=middle || lastInd!=middle)
		{
			WPS_DEBUG_MSG(("DirTree::setInRedBlackTreeForm: OOPS problem setting RedBlack colour\n"));
		}
	}
	if (firstInd!=middle)
		p->m_left=setInRBTForm(childs, firstInd,unsigned(middle-1),newH);
	else
		p->m_left=DirEntry::End;
	if (lastInd!=middle)
		p->m_right=setInRBTForm(childs, unsigned(middle+1),lastInd,newH);
	else
		p->m_right=DirEntry::End;
	return ind;
}


// =========== IStorage ==========

libwps_OLE::IStorage::IStorage(librevenge::RVNGInputStream *is) :
	m_input(is),
	m_result(libwps_OLE::IStorage::Ok),
	m_header(), m_dirtree(),
	m_bbat(), m_sbat(), m_sb_blocks(),
	m_isLoad(false)
{
	m_bbat.m_blockSize = m_header.m_size_bbat;
	m_sbat.m_blockSize = m_header.m_size_sbat;
}

bool libwps_OLE::IStorage::isStructured()
{
	load();
	return (m_result == libwps_OLE::IStorage::Ok);
}

std::vector<std::string> libwps_OLE::IStorage::getSubStreamNamesList()
{
	load();
	if (m_result != Ok)
		return std::vector<std::string>();
	return m_dirtree.getSubStreamList(0, true);
}

bool libwps_OLE::IStorage::isSubStream(const std::string &name, bool &isDir)
{
	if (!name.length()) return false;
	load();
	// search in the entries
	DirEntry *e = m_dirtree.entry(name);
	if (!e) return false;
	isDir = e->is_dir();
	return true;
}

void libwps_OLE::IStorage::load()
{
	if (m_isLoad)
		return;
	m_isLoad = true;
	m_result = NotOLE;
	if (!m_input)
		return;

	std::vector<unsigned long> blocks;

	// load header
	unsigned long numBytesRead = 0;
	m_input->seek(0, librevenge::RVNG_SEEK_SET);
	const unsigned char *buf = m_input->read(512, numBytesRead);

	if (numBytesRead < 512)
		return;

	m_header.load(buf, numBytesRead);

	// check OLE magic id
	if (!m_header.valid_signature())
		return;

	// important block size
	m_header.compute_block_size();
	m_bbat.m_blockSize = m_header.m_size_bbat;
	m_sbat.m_blockSize = m_header.m_size_sbat;

	// sanity checks
	m_result = BadOLE;
	if (!m_header.valid(getLength(m_input))) return;
	if (m_header.m_threshold != 4096) return;

	// find blocks allocated to store big bat
	// the first 109 blocks are in header, the rest in meta bat
	blocks.clear();
	blocks.resize(m_header.m_num_bat);
	for (unsigned j = 0; j < 109; j++)
		if (j >= m_header.m_num_bat) break;
		else blocks[j] = m_header.m_blocks_bbat[j];
	if ((m_header.m_num_bat > 109) && (m_header.m_num_mbat > 0))
	{
		std::vector<unsigned char> buffer2(m_bbat.m_blockSize);
		unsigned k = 109;
		unsigned long sector;
		for (unsigned r = 0; r < m_header.m_num_mbat && k > 0; r++)
		{
			if (r == 0) // 1st meta bat location is in file header.
				sector = m_header.m_start_mbat;
			else      // next meta bat location is the last current block value.
				sector = blocks[--k];
			unsigned long readData=loadBigBlock(sector, &buffer2[0], m_bbat.m_blockSize);
			for (unsigned s=0; s < m_bbat.m_blockSize; s+=4)
			{
				// check that for maximum block and that the data are correctly read
				if (k >= m_header.m_num_bat || s>=readData) break;
				else  blocks[k++] = readU32(&buffer2[s]);
			}
		}
	}

	// load big bat
	if (blocks.size()*m_bbat.m_blockSize > 0)
	{
		std::vector<unsigned char> buffer(blocks.size()*m_bbat.m_blockSize);
		unsigned long readData=loadBigBlocks(blocks, &buffer[0], buffer.size());
		m_bbat.load(&buffer[0], unsigned(readData));
	}

	// load small bat
	blocks.clear();
	blocks = m_bbat.follow(m_header.m_start_sbat);
	if (blocks.size()*m_bbat.m_blockSize > 0)
	{
		std::vector<unsigned char> buffer(blocks.size()*m_bbat.m_blockSize);
		unsigned long readData=loadBigBlocks(blocks, &buffer[0], buffer.size());
		m_sbat.load(&buffer[0], unsigned(readData));
	}

	// load directory tree
	blocks.clear();
	blocks = m_bbat.follow(m_header.m_start_dirent);
	if (blocks.size()*m_bbat.m_blockSize > 0)
	{
		std::vector<unsigned char> buffer(blocks.size()*m_bbat.m_blockSize);
		unsigned long readData=loadBigBlocks(blocks, &buffer[0], buffer.size());
		m_dirtree.load(&buffer[0], unsigned(readData));
		if (readData >= 0x74 + 4)
		{
			unsigned sb_start = readU32(&buffer[0x74]);

			// fetch block chain as data for small-files
			m_sb_blocks = m_bbat.follow(sb_start);   // small files

			// so far so good
			m_result = libwps_OLE::IStorage::Ok;
		}
	}
}

unsigned long libwps_OLE::IStorage::loadBigBlocks(std::vector<unsigned long> const &blocks,
                                                  unsigned char *data, unsigned long maxlen) const
{
	// sentinel
	if (!data) 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 =  m_bbat.m_blockSize * (block+1);
		unsigned long p = (m_bbat.m_blockSize < maxlen-bytes) ? m_bbat.m_blockSize : maxlen-bytes;

		if (m_input->seek(long(pos), librevenge::RVNG_SEEK_SET)!=0)
			continue;
		unsigned long numBytesRead = 0;
		const unsigned char *buf = m_input->read(p, numBytesRead);
		memcpy(data+bytes, buf, numBytesRead);
		bytes += numBytesRead;
	}

	return bytes;
}

unsigned long libwps_OLE::IStorage::loadBigBlock(unsigned long block,
                                                 unsigned char *data, unsigned long maxlen) const
{
	// sentinel
	if (!data) 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 libwps_OLE::IStorage::loadSmallBlocks(std::vector<unsigned long> const &blocks,
                                                    unsigned char *data, unsigned long maxlen)
{
	// sentinel
	if (!data  || blocks.size() < 1 ||  maxlen == 0) return 0;

	// our own local buffer
	std::vector<unsigned char> tmpBuf(m_bbat.m_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 * m_sbat.m_blockSize;
		unsigned long bbindex = pos / m_bbat.m_blockSize;
		if (bbindex >= m_sb_blocks.size()) break;

		unsigned long readData=loadBigBlock(m_sb_blocks[ bbindex ], &tmpBuf[0], m_bbat.m_blockSize);

		// copy the data
		unsigned long offset = pos % m_bbat.m_blockSize;
		unsigned long p = (maxlen-bytes < m_bbat.m_blockSize-offset) ? maxlen-bytes :  m_bbat.m_blockSize-offset;
		// sanety check
		if (m_sbat.m_blockSize<p) p=m_sbat.m_blockSize;
		if (readData < p) p = readData;
		memcpy(data + bytes, &tmpBuf[offset], p);
		bytes += p;
	}

	return bytes;
}

unsigned long libwps_OLE::IStorage::loadSmallBlock(unsigned long block,
                                                   unsigned char *data, unsigned long maxlen)
{
	// sentinel
	if (!data) return 0;

	// wraps call for loadSmallBlocks
	std::vector<unsigned long> blocks;
	blocks.resize(1);
	blocks.assign(1, block);

	return loadSmallBlocks(blocks, data, maxlen);
}

// =========== OStorage ==========
bool libwps_OLE::OStorage::addDirectory(std::string const &dir)
{
	DirEntry *e=createEntry(dir);
	if (!e) return false;

	e->m_type=1;
	return true;
}

bool libwps_OLE::OStorage::addStream(std::string const &name, unsigned char const *buffer, unsigned long len)
{
	DirEntry *e=createEntry(name);
	if (!e) return false;

	if (!len)
	{
		WPS_DEBUG_MSG(("librevengeOLE::OStorage::addStream: call to create an empty file!!!\n"));
		return true;
	}
	e->m_start = insertData(buffer, len, useBigBlockFor(len));
	e->m_size = len;
	return true;
}

bool libwps_OLE::OStorage::updateToSave()
{
	unsigned long dirSize = m_dirtree.saveSize();
	DirEntry *rEntry = m_dirtree.entry(0);
	if (!dirSize || !rEntry)
	{
		WPS_DEBUG_MSG(("librevengeOLE::OStorage::updateToSave: can not find dir tree size!!!\n"));
		return false;
	}
	m_dirtree.setInRedBlackTreeForm();

	std::vector<unsigned char> buffer;
	// first add the small block allocation table
	unsigned long sbatSize = m_sbat.saveSize();
	if (!sbatSize)
		m_header.m_start_sbat = Bat;
	else
	{
		// FIXME: set m_header.m_start_sbat
		buffer.resize(sbatSize);
		m_sbat.save(&buffer[0]);
		m_header.m_num_sbat = unsigned(sbatSize+511)/512;
		m_header.m_start_sbat = insertData(&buffer[0], sbatSize, true, unsigned(Eof));
		if (m_sb_blocks.size())
		{
			rEntry->m_start = unsigned(m_sb_blocks[0]);
			m_bbat.setChain(m_sb_blocks, unsigned(Eof));
		}
		rEntry->m_size = 64*m_num_sbat;
	}
	// then add dirtree
	buffer.resize(dirSize);
	m_dirtree.save(&buffer[0]);
	m_header.m_start_dirent=insertData(&buffer[0], dirSize, true, unsigned(Eof));

	// now update the big alloc table to add size for self and for the meta data
	unsigned numBBlock = m_num_bbat;
	if (numBBlock==0)
	{
		WPS_DEBUG_MSG(("librevengeOLE::OStorage::updateToSave: can not find any big block!!!\n"));
		return false;
	}
	unsigned numBAlloc = (numBBlock+127)/128;
	unsigned numMAlloc = (numBAlloc+17)/127; // ie. 109->0, 110->1, ...
	while (numBBlock+numBAlloc+numMAlloc > numBAlloc*128)
	{
		numBAlloc++;
		numMAlloc = (numBAlloc+17)/127;
	}

	std::vector<unsigned long> mainBlocks(numBAlloc);
	unsigned b = 0;
	for (b = 0; b < numBAlloc; b++)
	{
		mainBlocks[b]=numBBlock+b;
		m_bbat.set(mainBlocks[b], unsigned(Bat));
	}
	if (numMAlloc)
	{
		for (b = 0; b < numMAlloc; b++)
			m_bbat.set(numBBlock+numBAlloc+b, unsigned(MetaBat));
	}

	// now add the small block allocation table
	unsigned long bbatSize = m_bbat.saveSize();
	if (bbatSize)
	{
		buffer.resize(bbatSize);
		m_bbat.save(&buffer[0]);
		insertData(&buffer[0], bbatSize, true, unsigned(Bat));
	}

	for (b = 0; b < numBAlloc; b++)
	{
		if (b >= 109)
			break;
		m_header.m_blocks_bbat[b]=mainBlocks[b];
	}
	if (numMAlloc)
	{
		buffer.resize(numMAlloc*512,0);
		size_t wPos=0;
		for (b=109; b < numBAlloc; b++)
		{
			if ((wPos%512)==508)
			{
				writeU32(&buffer[wPos],numBBlock+numBAlloc+(wPos+4)/512);
				wPos+=4;
			}
			writeU32(&buffer[wPos],mainBlocks[b]);
			wPos+=4;
		}
		while (wPos%512)
		{
			writeU32(&buffer[wPos], Avail);
			wPos+=4;
		}
		m_header.m_start_mbat = insertData(reinterpret_cast<unsigned char const *>(buffer.data()), 512*numMAlloc, true, unsigned(Eof));
		m_header.m_start_mbat = numBBlock+numBAlloc;
	}
	m_header.m_num_bat = (m_num_bbat+127)/128;
	m_header.m_num_mbat = numMAlloc;

	m_data.resize((m_num_bbat+1)*512,0);
	// save the header
	m_header.save(&m_data[0]);
	return true;
}

unsigned libwps_OLE::OStorage::insertData(unsigned char const *buffer, unsigned long len, bool useBigBlock, unsigned end)
{
	if (buffer==nullptr || len == 0)
	{
		WPS_DEBUG_MSG(("librevengeOLE::OStorage::insertData: call with no data\n"));
		return 0;
	}

	unsigned long bSize = getMaximumSize(useBigBlock);
	size_t nBlock = ((len+bSize-1)/bSize);
	std::vector<unsigned long> chain;
	for (size_t b=0; b < nBlock; b++)
	{
		unsigned block=useBigBlock ? newBBlock() : newSBlock();
		chain.push_back(block);
		size_t wPos = getDataAddress(block, useBigBlock);
		unsigned long wSize = len > bSize ? bSize : len;
		memcpy(&m_data[wPos], &buffer[0], wSize);
		buffer += bSize;
		len -= wSize;
	}
	if (useBigBlock)
		m_bbat.setChain(chain, end);
	else
		m_sbat.setChain(chain, end);
	return unsigned(chain[0]);
}

// =========== IStream ==========

libwps_OLE::IStream::IStream(libwps_OLE::IStorage *s, std::string const &name) :
	m_iStorage(s),
	m_size(0),
	m_name(name),
	m_blocks(),
	m_pos(0),
	m_data()
{
	if (!name.length() || !m_iStorage) return;
	m_iStorage->load();
	DirEntry *entry = m_iStorage->entry(name);
	if (!entry)
		return;
	if (entry->is_dir())
	{
		createOleFromDirectory(s, name);
		return;
	}

	m_size = entry->m_size;

	unsigned blockSize = 0;

	if (m_iStorage->use_big_block_for(entry->m_size))
	{
		m_blocks = m_iStorage->m_bbat.follow(entry->m_start);
		blockSize = m_iStorage->m_bbat.m_blockSize;
	}
	else
	{
		m_blocks = m_iStorage->m_sbat.follow(entry->m_start);
		blockSize = m_iStorage->m_sbat.m_blockSize;
	}

	// sanity check of stream size
	const auto maxSize = unsigned(blockSize * m_blocks.size());
	if (m_size > maxSize)
	{
		WPS_DEBUG_MSG(("libwps_OLE::IStream::IStream: size %lu is wrong, using an approximated value %u\n", m_size, maxSize));
		m_size = maxSize;
		entry->m_size = m_size;
	}
}

unsigned long libwps_OLE::IStream::readData(unsigned long pos, unsigned char *data, unsigned long maxlen)
{
	// sanity checks
	if (!data || (maxlen == 0) || static_cast<unsigned long>(m_data.size()) != m_size || !m_size)
		return 0;

	if (pos >= m_size)
		return 0;
	unsigned long count = m_size - pos;
	if (count > maxlen) count = maxlen;
	memcpy(data, &m_data[size_t(pos)], count);
	return count;
}

unsigned long libwps_OLE::IStream::readUsingStorage(unsigned long pos, unsigned char *data, unsigned long maxlen)
{
	// sanity checks
	if (!data || (maxlen == 0) || !m_iStorage || !m_size) return 0;

	unsigned long totalbytes = 0;

	if (!m_iStorage->use_big_block_for(size()))
	{
		// small file
		unsigned sBlockSize = m_iStorage->m_sbat.m_blockSize;
		unsigned long index = pos / sBlockSize;

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

		std::vector<unsigned char> buf(sBlockSize);
		unsigned long offset = pos % sBlockSize;
		while (totalbytes < maxlen)
		{
			if (index >= m_blocks.size()) break;
			m_iStorage->loadSmallBlock(m_blocks[index], &buf[0], m_iStorage->m_bbat.m_blockSize);
			unsigned long count = sBlockSize - offset;
			if (count > maxlen-totalbytes) count = maxlen-totalbytes;
			memcpy(data+totalbytes, &buf[offset], count);
			totalbytes += count;
			offset = 0;
			index++;
		}
	}
	else
	{
		// big file
		unsigned bBlockSize = m_iStorage->m_bbat.m_blockSize;
		unsigned long index = pos / bBlockSize;

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

		std::vector<unsigned char> buf(bBlockSize);
		unsigned long offset = pos % bBlockSize;
		while (totalbytes < maxlen)
		{
			if (index >= m_blocks.size()) break;
			m_iStorage->loadBigBlock(m_blocks[index], &buf[0], bBlockSize);
			unsigned long count = bBlockSize - offset;
			if (count > maxlen-totalbytes) count = maxlen-totalbytes;
			memcpy(data+totalbytes, &buf[offset], count);
			totalbytes += count;
			index++;
			offset = 0;
		}
	}

	return totalbytes;
}

bool libwps_OLE::IStream::createOleFromDirectory(IStorage *io, std::string const &name)
{
	// sanety check
	if (!name.length() || !io) return false;
	m_iStorage->load();
	DirEntry *entry = io->entry(name);
	if (!entry || !entry->is_dir()) return false;

	unsigned index = io->index(name);
	if (index==libwps_OLE::NotFound)  return false;
	std::vector<std::string> nodes=io->getSubStreamList(index, true);
	if (nodes.size() <= 1)
	{
		WPS_DEBUG_MSG(("libwps_OLE::IStream::createOleFromDirectory: can not find any child for %s\n", name.c_str()));
		return false;
	}
	try
	{
		std::string dir(name);
		size_t len=dir.length();
		if (len && dir[len-1]=='/') dir.resize(len-1);
		std::vector<unsigned char> buffer;

		// try to compute a minimum data size
		unsigned long minimalSize = 0;
		size_t l=0;
		for (l=0; l < nodes.size(); l++)
		{
			std::string fullName=dir+nodes[l];
			entry=io->entry(fullName);
			if (!entry || !entry->m_valid)
				continue;
			minimalSize += 128; // DirEntry
			if (!entry->is_dir() && entry->m_size < 50000000)
				minimalSize+=((entry->m_size+63)/64)*64;
		}

		libwps_OLE::OStorage storage(minimalSize);
		storage.setRevision(io->revision());
		if (!io->hasRootTypePc())
			storage.setRootType(false);
		for (l=0; l < nodes.size(); l++)
		{
			std::string fullName=dir+nodes[l];
			entry=io->entry(fullName);
			if (!entry)
			{
				WPS_DEBUG_MSG(("libwps_OLE::IStream::createOleFromDirectory: can not find child for %s\n", fullName.c_str()));
				continue;
			}
			if (entry->is_dir())
			{
				if (entry->m_child == libwps_OLE::DirEntry::End)
					storage.addDirectory(nodes[l]);
				continue;
			}
			libwps_OLE::IStream leafStream(io,fullName);
			unsigned long sz=leafStream.size();
			bool ok = true;
			if (sz)
			{
				// a test because empty file are rare but seems to exists
				buffer.resize(sz);
				ok = leafStream.read(&buffer[0], sz) == sz;
				if (ok)
					ok=storage.addStream(nodes[l], &buffer[0], sz);
			}
			else
			{
				ok=storage.addStream(nodes[l], nullptr, 0);
			}
			if (!ok)
			{
				WPS_DEBUG_MSG(("libwps_OLE::IStream::createOleFromDirectory: can not read %s\n", fullName.c_str()));
				return false;
			}
		}
		// finally try to update the storage info
		std::vector<std::string> resNodes=storage.getSubStreamList(0, true);
		for (l=0; l < resNodes.size(); l++)
		{
			std::string fullName=dir+resNodes[l];
			entry=io->entry(fullName);
			if (!entry) continue;
			if (resNodes[l].length())
				storage.setInformation(resNodes[l], entry->m_info);
		}

		// retrieve the data
		if (!storage.getFileData(m_data))
		{
			m_data.resize(0);
			return false;
		}
		// ok, we can update size
		m_size = static_cast<unsigned long>(m_data.size());
		return true;
	}
	catch (...)
	{
	}
	return false;
}

namespace libwps_OLE
{
//////////////////////////////////////////////////
/** internal class used to create a RVNGInputStream from an OLE file */
class WPSOLEStream final: public librevenge::RVNGInputStream
{
public:
	//! constructor
	explicit WPSOLEStream(RVNGInputStreamPtr &input)
		: m_input(input)
		, m_streamNameList()
	{
		if (!m_input) return;
		IStorage storage(m_input.get());
		if (storage.isStructured())
		{
			m_streamNameList=storage.getSubStreamNamesList();
			// time to do some cleaning ( remove ^A, ^B, ... )
			for (auto &re : m_streamNameList)
			{
				std::string str=re, finalStr("");
				for (char s : str)
					if (s>=32)
						finalStr+=s;
				re=finalStr;
			}
		}
	}
	//! destructor
	~WPSOLEStream() final
	{
	}
	/**! reads numbytes data.

	 * \return a pointer to the read elements
	 */
	const unsigned char *read(unsigned long, unsigned long &) final
	{
		return nullptr;
	}
	//! returns actual offset position
	long tell() final
	{
		return 0;
	}
	/*! \brief seeks to a offset position, from actual, beginning or ending position
	 * \return 0 if ok
	 */
	int seek(long, librevenge::RVNG_SEEK_TYPE) final
	{
		return 1;
	}
	//! returns true if we are at the end of the section/file
	bool isEnd() final
	{
		return true;
	}

	/** returns true if the stream is ole*/
	bool isStructured() final
	{
		return !m_streamNameList.empty();
	}
	/** returns the number of sub streams.*/
	unsigned subStreamCount() final
	{
		return unsigned(m_streamNameList.size());
	}
	/** returns the ith sub streams name*/
	const char *subStreamName(unsigned id) final
	{
		if (id>=unsigned(m_streamNameList.size()))
			return nullptr;
		return m_streamNameList[size_t(id)].c_str();
	}
	/** returns true if a substream with name exists*/
	bool existsSubStream(const char *name) final
	{
		for (const auto &i : m_streamNameList)
		{
			if (i == name)
				return true;
		}
		return false;
	}
	/** return a new stream for a ole zone */
	librevenge::RVNGInputStream *getSubStreamByName(const char *name) final;
	/** return a new stream for a ole zone */
	librevenge::RVNGInputStream *getSubStreamById(unsigned id) final
	{
		return getSubStreamByName(subStreamName(id));
	}

protected:
	//! the main input
	RVNGInputStreamPtr m_input;
	//! return the name list
	std::vector<std::string> m_streamNameList;
private:
	WPSOLEStream(const WPSOLEStream &) = delete; // copy is not allowed
	WPSOLEStream &operator=(const WPSOLEStream &) = delete; // assignment is not allowed
};

librevenge::RVNGInputStream *WPSOLEStream::getSubStreamByName(const char *name)
{
	if (!isStructured())
		return nullptr;

	IStorage storage(m_input.get());
	IStream tmpStream(&storage, name);
	if (storage.m_result != storage.Ok  || !tmpStream.size())
		return nullptr;

	std::vector<unsigned char> buf(tmpStream.size());
	unsigned long tmpLength;
	tmpLength = tmpStream.read(&buf[0], tmpStream.size());

	// sanity check
	if (tmpLength != tmpStream.size())
		/* something went wrong here and we do not trust the
		   resulting buffer */
		return nullptr;

	return new WPSStringStream(&buf[0], unsigned(tmpLength));
}

RVNGInputStreamPtr getOLEInputStream(RVNGInputStreamPtr input)
{
	RVNGInputStreamPtr ole=std::make_shared<WPSOLEStream>(input);
	if (!ole->isStructured())
		return RVNGInputStreamPtr();
	return ole;
}

}
/* vim:set shiftwidth=4 softtabstop=4 noexpandtab: */
