windows-xp/Source/XPSP1/NT/inetsrv/iis/svcs/infocomm/spuddrv/tracelog.h

/*++

Copyright (c) 1998  Microsoft Corporation

Module Name:

    tracelog.h

Abstract:

    This module contains public declarations and definitions for creating
    trace logs.

    A trace log is a fast, in-memory, thread safe activity log useful
    for debugging certain classes of problems. They are especially useful
    when debugging reference count bugs.

    Note that the creator of the log has the option of adding "extra"
    bytes to the log header. This can be useful if the creator wants to
    create a set of global logs, each on a linked list.

Author:

    Keith Moore (keithmo)       30-Apr-1997

Revision History:

--*/


#ifndef _TRACELOG_H_
#define _TRACELOG_H_


#if defined(__cplusplus)
extern "C" {
#endif  // __cplusplus


typedef struct _TRACE_LOG {

    //
    // Signature.
    //

    LONG Signature;

    //
    // The total number of entries available in the log.
    //

    LONG LogSize;

    //
    // The index of the next entry to use.
    //

    LONG NextEntry;

    //
    // The byte size of each entry.
    //

    LONG EntrySize;

    //
    // Pointer to the start of the circular buffer.
    //

    PUCHAR LogBuffer;

    //
    // Filler to keep the log entries aligned on a 16-byte boundary.
    // (Makes it much easier to interpret the log from within a debugger.)
    //

    LONG Filler[3];

    //
    // The extra header bytes and actual log entries go here.
    //
    // BYTE ExtraHeaderBytes[ExtraBytesInHeader];
    // BYTE Entries[LogSize][EntrySize];
    //

} TRACE_LOG, *PTRACE_LOG;


//
// Log header signature.
//

#define TRACE_LOG_SIGNATURE   ((ULONG)'gOlT')
#define TRACE_LOG_SIGNATURE_X ((ULONG)'golX')


//
// This macro maps a TRACE_LOG pointer to a pointer to the 'extra'
// data associated with the log.
//

#define TRACE_LOG_TO_EXTRA_DATA(log)    (PVOID)( (log) + 1 )


//
// Manipulators.
//

PTRACE_LOG
CreateTraceLog(
    IN LONG LogSize,
    IN LONG ExtraBytesInHeader,
    IN LONG EntrySize
    );

VOID
DestroyTraceLog(
    IN PTRACE_LOG Log
    );

VOID
WriteTraceLog(
    IN PTRACE_LOG Log,
    IN PVOID Entry
    );

VOID
ResetTraceLog(
    IN PTRACE_LOG Log
    );


#if defined(__cplusplus)
}   // extern "C"
#endif  // __cplusplus


#endif  // _TRACELOG_H_