/// \file
/// \ingroup qs
/// \brief Internal (package scope) QS/C++ interface.
/// \cond
///***************************************************************************
/// Product: QEP/C++
/// Last updated for version 5.3.0
/// Last updated on  2014-02-27
///
///                    Q u a n t u m     L e a P s
///                    ---------------------------
///                    innovating embedded systems
///
/// Copyright (C) Quantum Leaps, www.state-machine.com.
///
/// This program is open source software: you can redistribute it and/or
/// modify it under the terms of the GNU General Public License as published
/// by the Free Software Foundation, either version 3 of the License, or
/// (at your option) any later version.
///
/// Alternatively, this program may be distributed and modified under the
/// terms of Quantum Leaps commercial licenses, which expressly supersede
/// the GNU General Public License and are specifically designed for
/// licensees interested in retaining the proprietary status of their code.
///
/// This program is distributed in the hope that it will be useful,
/// but WITHOUT ANY WARRANTY; without even the implied warranty of
/// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
/// GNU General Public License for more details.
///
/// You should have received a copy of the GNU General Public License
/// along with this program. If not, see <http://www.gnu.org/licenses/>.
///
/// Contact information:
/// Web:   www.state-machine.com
/// Email: info@state-machine.com
///***************************************************************************
/// \endcond

#ifndef qs_pkg_h
#define qs_pkg_h

//! Internal QS macro to insert an un-escaped byte into the QS buffer
#define QS_INSERT_BYTE(b_) \
    *QS_PTR_AT_(head_) = (b_); \
    ++head_; \
    if (head_ == end_) { \
        head_ = static_cast<QSCtr>(0); \
    }

//! Internal QS macro to insert an escaped byte into the QS buffer
#define QS_INSERT_ESC_BYTE(b_) \
    chksum_ += (b_); \
    if (((b_) != QS_FRAME) && ((b_) != QS_ESC)) { \
        QS_INSERT_BYTE(b_) \
    } \
    else { \
        QS_INSERT_BYTE(QS_ESC) \
        QS_INSERT_BYTE(static_cast<uint8_t>((b_) ^ QS_ESC_XOR)) \
        ++priv_.used; \
    }

//! Internal QS macro to access the QS ring buffer
///
/// \note The QS buffer is allocated by the user and is accessed through the
/// pointer QS_ring_, which violates the MISRA-C 2004 Rule 17.4(req), pointer
/// arithmetic other than array indexing. Encapsulating this violation in a
/// macro allows to selectively suppress this specific deviation.
#define QS_PTR_AT_(i_) (buf_ + (i_))

//! Internal QS macro to increment the given pointer argument \a ptr_
///
/// \note Incrementing a pointer violates the MISRA-C 2004 Rule 17.4(req),
/// pointer arithmetic other than array indexing. Encapsulating this violation
/// in a macro allows to selectively suppress this specific deviation.
#define QS_PTR_INC_(ptr_) (++(ptr_))

//! Internal QS macro to cast enumerated QS record number to uint8_t
///
/// \note Casting from enum to unsigned char violates the MISRA-C++ 2008 rules
/// 5-2-7, 5-2-8 and 5-2-9. Encapsulating this violation in a macro allows to
/// selectively suppress this specific deviation.
#define QS_REC_NUM_(enum_) (static_cast<uint_fast8_t>(enum_))

#ifndef Q_ROM_BYTE
    //! Macro to access a byte allocated in ROM
    ///
    /// Some compilers for Harvard-architecture MCUs, such as gcc for AVR, do
    /// not generate correct code for accessing data allocated in the program
    /// space (ROM). The workaround for such compilers is to explictly add
    /// assembly code to access each data element allocated in the program
    /// space. The macro Q_ROM_BYTE() retrieves a byte from the given ROM
    /// address.
    ///
    /// The Q_ROM_BYTE() macro should be defined for the compilers that
    /// cannot handle correctly data allocated in ROM (such as the gcc).
    /// If the macro is left undefined, the default definition simply returns
    /// the argument and lets the compiler generate the correct code.
    #define Q_ROM_BYTE(x_)   (x_)
#endif

namespace QP {

/// \brief Frame character of the QS output protocol
uint8_t const QS_FRAME = static_cast<uint8_t>(0x7E);

/// \brief Escape character of the QS output protocol
uint8_t const QS_ESC   = static_cast<uint8_t>(0x7D);

/// \brief Escape modifier of the QS output protocol
///
/// The escaped byte is XOR-ed with the escape modifier before it is inserted
/// into the QS buffer.
uint8_t const QS_ESC_XOR = static_cast<uint8_t>(0x20);

} // namespace QP

#endif  // qs_pkg_h