/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011  Cyan Worlds, Inc.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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Additional permissions under GNU GPL version 3 section 7

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*==LICENSE==*/

#ifndef hsBitVector_inc
#define hsBitVector_inc

#include "HeadSpin.h"

template <class T> class hsTArray;
class hsStream;

class hsBitVector {

protected:
    uint32_t*                 fBitVectors;
    uint32_t                  fNumBitVectors;

    void        IGrow(uint32_t newNumBitVectors);

    friend      class hsBitIterator;
public:
    hsBitVector(const hsBitVector& other);
    hsBitVector(uint32_t which) : fBitVectors(nil), fNumBitVectors(0) { SetBit(which); }
    hsBitVector(int b, ...); // list of one or more integer bits to set. -1 (or any negative) terminates the list (e.g. hsBitVector(0,1,4,-1);
    hsBitVector(const hsTArray<int16_t>& list); // sets bit for each int in list
    hsBitVector() : fBitVectors(nil), fNumBitVectors(0) {}
    virtual ~hsBitVector() { Reset(); }

    hsBitVector& Reset() { delete [] fBitVectors; fBitVectors = nil; fNumBitVectors = 0; return *this; }
    hsBitVector& Clear(); // everyone clear, but no dealloc
    hsBitVector& Set(int upToBit=-1); // WARNING - see comments at function

    int operator==(const hsBitVector& other) const; // unset (ie uninitialized) bits are clear, 
    int operator!=(const hsBitVector& other) const { return !(*this == other); }
    hsBitVector& operator=(const hsBitVector& other); // will wind up identical

    hsBool ClearBit(uint32_t which) { return SetBit(which, 0); } // returns previous state
    hsBool SetBit(uint32_t which, hsBool on = true); // returns previous state
    hsBool IsBitSet(uint32_t which) const; // returns current state
    hsBool ToggleBit(uint32_t which); // returns previous state
    hsBitVector& RemoveBit(uint32_t which); // removes bit, sliding higher bits down to fill the gap.

    friend inline int Overlap(const hsBitVector& lhs, const hsBitVector& rhs) { return lhs.Overlap(rhs); }
    hsBool Overlap(const hsBitVector& other) const;
    hsBool Empty() const;

    hsBool operator[](uint32_t which) const { return IsBitSet(which); }

    friend inline hsBitVector operator&(const hsBitVector& lhs, const hsBitVector& rhs); // See Overlap()
    friend inline hsBitVector operator|(const hsBitVector& lhs, const hsBitVector& rhs);
    friend inline hsBitVector operator^(const hsBitVector& lhs, const hsBitVector& rhs);
    friend inline hsBitVector operator-(const hsBitVector& lhs, const hsBitVector& rhs); // return lhs w/ rhs's bits turned off

    hsBitVector& operator&=(const hsBitVector& other); // See Overlap()
    hsBitVector& operator|=(const hsBitVector& other);
    hsBitVector& operator^=(const hsBitVector& other);
    hsBitVector& operator-=(const hsBitVector& other); // return me w/ other's bits turned off

    hsBitVector& Compact();
    hsBitVector& SetSize(uint32_t numBits) { ClearBit(numBits+1); return *this; }
    uint32_t GetSize() { return fNumBitVectors << 5; }

    // integer level access
    uint32_t GetNumBitVectors() const { return fNumBitVectors; }
    uint32_t GetBitVector(int i) const { return fBitVectors[i]; }
    void SetNumBitVectors(uint32_t n) { Reset(); fNumBitVectors=n; fBitVectors = new uint32_t[n]; }
    void SetBitVector(int i, uint32_t val) { fBitVectors[i]=val; }

    // Do dst.SetCount(0), then add each set bit's index into dst, returning dst.
    hsTArray<int16_t>& Enumerate(hsTArray<int16_t>& dst) const;
    // this->Clear(), then set all bits listed in src, returning *this.
    hsBitVector& FromList(const hsTArray<int16_t>& src);

    void Read(hsStream* s);
    void Write(hsStream* s) const;
};

inline hsBitVector::hsBitVector(const hsBitVector& other)
{
    if( 0 != (fNumBitVectors = other.fNumBitVectors) )
    {       
        fBitVectors = new uint32_t[fNumBitVectors];
        int i;
        for( i = 0; i < fNumBitVectors; i++ )
            fBitVectors[i] = other.fBitVectors[i];
    }
    else
        fBitVectors = nil;
}

inline hsBool hsBitVector::Empty() const
{
    int i;
    for( i = 0; i < fNumBitVectors; i++ )
    {
        if( fBitVectors[i] )
            return false;
    }
    return true;
}

inline hsBool hsBitVector::Overlap(const hsBitVector& other) const
{
    if( fNumBitVectors > other.fNumBitVectors )
        return other.Overlap(*this);

    int i;
    for( i = 0; i < fNumBitVectors; i++ )
    {
        if( fBitVectors[i] & other.fBitVectors[i] )
            return true;
    }
    return false;
}

inline hsBitVector& hsBitVector::operator=(const hsBitVector& other)
{
    if( this != &other )
    {
        if( fNumBitVectors < other.fNumBitVectors )
        {
            Reset();
            fNumBitVectors = other.fNumBitVectors;
            fBitVectors = new uint32_t[fNumBitVectors];
        }
        else
        {
            Clear();
        }

        int i;
        for( i = 0; i < other.fNumBitVectors; i++ )
            fBitVectors[i] = other.fBitVectors[i];
    }
    return *this;
}

inline int hsBitVector::operator==(const hsBitVector& other) const
{
    if( fNumBitVectors < other.fNumBitVectors )
        return other.operator==(*this);
    int i;
    for( i = 0; i < other.fNumBitVectors; i++ )
        if( fBitVectors[i] ^ other.fBitVectors[i] )
            return false;
    for( ; i < fNumBitVectors; i++ )
        if( fBitVectors[i] )
            return false;
    return true;
}

inline hsBitVector& hsBitVector::operator&=(const hsBitVector& other)
{
    if( this == &other )
        return *this;

    if( fNumBitVectors > other.fNumBitVectors )
    {
        fNumBitVectors = other.fNumBitVectors;
    }
    int i;
    for( i = 0; i < fNumBitVectors; i++ )
        fBitVectors[i] &= other.fBitVectors[i];
    return *this;
}

inline hsBitVector& hsBitVector::operator|=(const hsBitVector& other)
{
    if( this == &other )
        return *this;

    if( fNumBitVectors < other.fNumBitVectors )
    {
        IGrow(other.fNumBitVectors);
    }
    int i;
    for( i = 0; i < other.fNumBitVectors; i++ )
        fBitVectors[i] |= other.fBitVectors[i];
    return *this;
}

inline hsBitVector& hsBitVector::operator^=(const hsBitVector& other)
{
    if( this == &other )
    {
        Clear();
        return *this;
    }

    if( fNumBitVectors < other.fNumBitVectors )
    {
        IGrow(other.fNumBitVectors);
    }
    int i;
    for( i = 0; i < other.fNumBitVectors; i++ )
        fBitVectors[i] ^= other.fBitVectors[i];
    return *this;
}

inline hsBitVector& hsBitVector::operator-=(const hsBitVector& other)
{
    if( this == &other )
    {
        Clear();
        return *this;
    }

    int minNum = fNumBitVectors < other.fNumBitVectors ? fNumBitVectors : other.fNumBitVectors;
    int i;
    for( i = 0; i < minNum; i++ )
        fBitVectors[i] &= ~other.fBitVectors[i];
    return *this;
}

inline hsBitVector operator&(const hsBitVector& rhs, const hsBitVector& lhs)
{
    hsBitVector ret(rhs);
    return ret &= lhs;
}

inline hsBitVector operator|(const hsBitVector& rhs, const hsBitVector& lhs)
{
    hsBitVector ret(rhs);
    return ret |= lhs;
}

inline hsBitVector operator^(const hsBitVector& rhs, const hsBitVector& lhs)
{
    hsBitVector ret(rhs);
    return ret ^= lhs;
}

inline hsBitVector operator-(const hsBitVector& rhs, const hsBitVector& lhs)
{
    hsBitVector ret(rhs);
    return ret -= lhs;
}

inline hsBitVector& hsBitVector::Clear()
{
    int i;
    for( i = 0; i < fNumBitVectors; i++ )
        fBitVectors[i] = 0;
    return *this;
}

// WARNING - since the bitvector is conceptually infinitely long,
// we can't actually set all the bits. If you pass in a non-negative
// upToBit, this sets all bits up to and including that one, otherwise
// it just sets however many bits are currently allocated. You can
// assure this is as many as you want by first calling SetSize, but
// if there are more bits than the requested size, these will also
// get set. Calling Set with a non-negative upToBit will only set
// the bits from 0 to upToBit, but won't clear any higher bits.
inline hsBitVector& hsBitVector::Set(int upToBit)
{
    if( upToBit >= 0 )
    {
        uint32_t major = upToBit >> 5;
        uint32_t minor = 1 << (upToBit & 0x1f);
        if( major >= fNumBitVectors )
            IGrow(major+1);

        uint32_t i;
        for( i = 0; i < major; i++ )
            fBitVectors[i] = 0xffffffff;
        for( i = 1; i <= minor && i > 0; i <<= 1 )
            fBitVectors[major] |= i;
    }
    else
    {
        int i;
        for( i = 0; i < fNumBitVectors; i++ )
            fBitVectors[i] = 0xffffffff;
    }
    return *this;
}

inline hsBool hsBitVector::IsBitSet(uint32_t which) const
{
    uint32_t major = which >> 5;
    return 
        (major < fNumBitVectors)
        && (0 != (fBitVectors[major] & 1 << (which & 0x1f)));
}

inline hsBool hsBitVector::SetBit(uint32_t which, hsBool on)
{
    uint32_t major = which >> 5;
    uint32_t minor = 1 << (which & 0x1f);
    if( major >= fNumBitVectors )
        IGrow(major+1);
    hsBool ret = 0 != (fBitVectors[major] & minor);
    if( ret != on )
    {
        if( on )
            fBitVectors[major] |= minor;
        else
            fBitVectors[major] &= ~minor;
    }

    return ret;
}

inline hsBool hsBitVector::ToggleBit(uint32_t which)
{
    uint32_t major = which >> 5;
    uint32_t minor = 1 << (which & 0x1f);
    if( major >= fNumBitVectors )
        IGrow(major);
    hsBool ret = 0 != (fBitVectors[major] & minor);
    if( ret )
        fBitVectors[major] &= ~minor;
    else
        fBitVectors[major] |= minor;
    return ret;
}

inline hsBitVector& hsBitVector::RemoveBit(uint32_t which)
{
    uint32_t major = which >> 5;
    if( major >= fNumBitVectors )
        return *this;
    uint32_t minor = 1 << (which & 0x1f);
    uint32_t lowMask = minor-1;
    uint32_t hiMask = ~(lowMask);

    fBitVectors[major] = (fBitVectors[major] & lowMask)
        | ((fBitVectors[major] >> 1) & hiMask);

    while( major < fNumBitVectors-1 )
    {
        if( fBitVectors[major+1] & 0x1 )
            fBitVectors[major] |= 0x80000000;
        else
            fBitVectors[major] &= ~0x80000000;

        major++;

        fBitVectors[major] >>= 1;
    }
    fBitVectors[major] &= ~0x80000000;

    return *this;
}

class hsBitIterator
{
protected:
    const hsBitVector&  fBits;

    int                 fCurrent;

    int                 fCurrVec;
    int                 fCurrBit;

    int         IAdvanceBit();
    int         IAdvanceVec();

public:
    // Must call begin after instanciating.
    hsBitIterator(const hsBitVector& bits) : fBits(bits) {}

    int         Begin();
    int                 Current() const { return fCurrent; }
    int         Advance();
    int                 End() const { return fCurrVec < 0; }
};


#endif // hsBitVector_inc
