//===-- Flags.h -------------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef liblldb_Flags_h_
#define liblldb_Flags_h_
#if defined(__cplusplus)


#include <stdint.h>
#include <unistd.h>

namespace lldb_private {

//----------------------------------------------------------------------
/// @class Flags Flags.h "lldb/Core/Flags.h"
/// @brief A class to manage flags.
///
/// The Flags class managed flag bits and allows testing and 
/// modification of individual or multiple flag bits.
//----------------------------------------------------------------------
class Flags
{
public:
    //----------------------------------------------------------------------
    /// The value type for flags is a 32 bit unsigned integer type.
    //----------------------------------------------------------------------
    typedef uint32_t ValueType;

    //----------------------------------------------------------------------
    /// Construct with initial flag bit values.
    ///
    /// Constructs this object with \a mask as the initial value for all
    /// of the flags.
    ///
    /// @param[in] mask
    ///     The initial value for all flags.
    //----------------------------------------------------------------------
    Flags (ValueType flags = 0) :
        m_flags (flags)
    {
    }

    //----------------------------------------------------------------------
    /// Copy constructor.
    ///
    /// Construct and copy the flags from \a rhs.
    ///
    /// @param[in] rhs
    ///     A const Flags object reference to copy.
    //----------------------------------------------------------------------
    Flags (const Flags& rhs) :
        m_flags(rhs.m_flags)
    {
    }

    //----------------------------------------------------------------------
    /// Destructor.
    ///
    /// The destructor is virtual in case this class is subclassed.
    //----------------------------------------------------------------------
    virtual
    ~Flags ()
    {
    }

    //----------------------------------------------------------------------
    /// Get accessor for all flags.
    ///
    /// @return
    ///     Returns all of the flags as a Flags::ValueType.
    //----------------------------------------------------------------------
    ValueType
    Get () const
    {
        return m_flags;
    }

    //----------------------------------------------------------------------
    /// Return the number of flags that can be represented in this 
    /// object.
    ///
    /// @return
    ///     The maximum number bits in this flag object.
    //----------------------------------------------------------------------
    size_t
    GetBitSize() const
    {
        return sizeof (ValueType) * 8;
    }

    //----------------------------------------------------------------------
    /// Set accessor for all flags.
    ///
    /// @param[in] flags
    ///     The bits with which to replace all of the current flags.
    //----------------------------------------------------------------------
    void
    Reset (ValueType flags)
    {
        m_flags = flags;
    }

    //----------------------------------------------------------------------
    /// Clear one or more flags.
    ///
    /// @param[in] mask
    ///     A bitfield containing one or more flags.
    ///
    /// @return
    ///     The new flags after clearing all bits from \a mask.
    //----------------------------------------------------------------------
    ValueType
    Clear (ValueType mask = ~(ValueType)0)
    {
        m_flags &= ~mask;
        return m_flags;
    }


    //----------------------------------------------------------------------
    /// Set one or more flags by logical OR'ing \a mask with the current
    /// flags.
    ///
    /// @param[in] mask
    ///     A bitfield containing one or more flags.
    ///
    /// @return
    ///     The new flags after setting all bits from \a mask.
    //----------------------------------------------------------------------
    ValueType
    Set (ValueType mask)
    {
        m_flags |= mask;
        return m_flags;
    }


    //----------------------------------------------------------------------
    /// Test if all bits in \a mask are 1 in the current flags
    ///
    /// @return
    ///     \b true if all flags in \a mask are 1, \b false
    ///     otherwise.
    //----------------------------------------------------------------------
    bool
    AllSet (ValueType mask) const
    {
        return (m_flags & mask) == mask;
    }

    //----------------------------------------------------------------------
    /// Test one or more flags.
    ///
    /// @return
    ///     \b true if any flags in \a mask are 1, \b false
    ///     otherwise.
    //----------------------------------------------------------------------
    bool
    AnySet (ValueType mask) const
    {
        return (m_flags & mask) != 0;
    }

    //----------------------------------------------------------------------
    /// Test a single flag bit.
    ///
    /// @return
    ///     \b true if \a bit is set, \b false otherwise.
    //----------------------------------------------------------------------
    bool
    Test (ValueType bit) const
    {
        return (m_flags & bit) != 0;
    }
    
    //----------------------------------------------------------------------
    /// Test if all bits in \a mask are clear.
    ///
    /// @return
    ///     \b true if \b all flags in \a mask are clear, \b false
    ///     otherwise.
    //----------------------------------------------------------------------
    bool
    AllClear (ValueType mask) const
    {
        return (m_flags & mask) == 0;
    }

    bool
    AnyClear (ValueType mask) const
    {
        return (m_flags & mask) != mask;
    }
    
    //----------------------------------------------------------------------
    /// Test a single flag bit to see if it is clear (zero).
    ///
    /// @return
    ///     \b true if \a bit is 0, \b false otherwise.
    //----------------------------------------------------------------------
    bool
    IsClear (ValueType bit) const
    {
        return (m_flags & bit) == 0;
    }

    //----------------------------------------------------------------------
    /// Get the number of zero bits in \a m_flags.
    ///
    /// @return
    ///     The number of bits that are set to 0 in the current flags.
    //----------------------------------------------------------------------
    size_t
    ClearCount () const
    {
        size_t count = 0;
        for (ValueType shift = 0; shift < sizeof(ValueType)*8; ++shift)
        {
            if ((m_flags & (1u << shift)) == 0)
                ++count;
        }
        return count;
    }

    //----------------------------------------------------------------------
    /// Get the number of one bits in \a m_flags.
    ///
    /// @return
    ///     The number of bits that are set to 1 in the current flags.
    //----------------------------------------------------------------------
    size_t
    SetCount () const
    {
        size_t count = 0;
        for (ValueType mask = m_flags; mask; mask >>= 1)
        {
            if (mask & 1u)
                ++count;
        }
        return count;
    }

protected:
    ValueType   m_flags;    ///< The flags.
};

} // namespace lldb_private

#endif  // #if defined(__cplusplus)
#endif  // liblldb_Flags_h_