/* IBM_PROLOG_BEGIN_TAG                                                   */
/* This is an automatically generated prolog.                             */
/*                                                                        */
/* $Source: src/usr/trace/bufferpage.H $                                  */
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/* IBM CONFIDENTIAL                                                       */
/*                                                                        */
/* COPYRIGHT International Business Machines Corp. 2012                   */
/*                                                                        */
/* p1                                                                     */
/*                                                                        */
/* Object Code Only (OCO) source materials                                */
/* Licensed Internal Code Source Materials                                */
/* IBM HostBoot Licensed Internal Code                                    */
/*                                                                        */
/* The source code for this program is not published or otherwise         */
/* divested of its trade secrets, irrespective of what has been           */
/* deposited with the U.S. Copyright Office.                              */
/*                                                                        */
/* Origin: 30                                                             */
/*                                                                        */
/* IBM_PROLOG_END_TAG                                                     */
#ifndef __TRACE_BUFFERPAGE_H
#define __TRACE_BUFFERPAGE_H

#include <trace/interface.H>

namespace TRACE
{
    class Entry;

    /** @struct BufferPage
     *
     *  A structure which can be overlaid onto a page of memory to allocate
     *  entries within the page.
     */
    struct BufferPage
    {
        BufferPage* next;       //< Linked-list 'next' ptr.
        BufferPage* prev;       //< Linked-list 'prev' ptr.

        uint32_t commonPage;    //< Status used by daemon pages.
        uint32_t usedSize;      //< Size already allocated for entries.

        char data[0];           //< Data for entries.

        /** @brief Lockless-ly claim an entry from the page.
         *
         *  @param[in] i_size - Size in bytes.
         *
         *  @return Entry* or NULL, if not enough space.
         */
        Entry* claimEntry(size_t i_size);

        /** @brief Utility function to allocate a page.
         *
         *  @param[in] i_common - Page is "common" from a daemon perspective.
         *
         *  @return Pointer to page.
         */
        static BufferPage* allocate(bool i_common = false);

        /** @brief Utility function to free a page.
         *
         *  @param[in] i_page - Page to deallocate.
         */
        static void deallocate(BufferPage* i_page);

    };
}

#endif