lib/common/debug.h

/* ******************************************************************
   debug
   Part of FSE library
   Copyright (C) 2013-present, Yann Collet.

   BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are
   met:

       * Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
       * Redistributions in binary form must reproduce the above
   copyright notice, this list of conditions and the following disclaimer
   in the documentation and/or other materials provided with the
   distribution.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

   You can contact the author at :
   - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
****************************************************************** */


/*
 * The purpose of this header is to enable debug functions.
 * They regroup assert(), DEBUGLOG() and RAWLOG().
 *
 * By default, DEBUGLEVEL==0, which means debug is disabled.
 *
 * Level 1 enables assert() only.
 * Starting level 2, traces can be generated and pushed to stderr.
 * The higher the level, the more verbose the traces.
 *
 * It's possible to dynamically adjust level using variable g_debug_level,
 * which is only declared if DEBUGLEVEL>=2,
 * and is a global variable, not multi-thread protected (use with care)
 */

#ifndef DEBUG_H_12987983217
#define DEBUG_H_12987983217

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


/* static assert is triggered at compile time, leaving no runtime artefact,
 * but can only work with compile-time constants */
#define DEBUG_STATIC_ASSERT(c) { enum { DEBUG_static_assert = 1/(int)(!!(c)) }; }


/* DEBUGLEVEL is expected to be defined externally,
 * typically through compiler command line.
 * Value must be a number. */
#ifndef DEBUGLEVEL
#  define DEBUGLEVEL 0
#endif

/* recommended values for DEBUGLEVEL :
 * 0 : no debug, all functions disabled (except DEBUG_STATIC_ASSERT)
 * 1 : no display, enables assert() only
 * 2 : reserved, for currently active debug path
 * 3 : events once per object lifetime (CCtx, CDict, etc.)
 * 4 : events once per frame
 * 5 : events once per block
 * 6 : events once per sequence (verbose)
 * 7+: events at every position (*very* verbose)
 *
 * It's generally inconvenient to output traces > 5.
 * In which case, it's possible to selectively enable higher verbosity levels
 * by modifying g_debug_level.
 */

#if (DEBUGLEVEL>=1)
#  include <assert.h>
#else
#  ifndef assert   /* assert may be already defined, due to prior #include <assert.h> */
#    define assert(condition) ((void)0)   /* disable assert (default) */
#  endif
#endif

#if (DEBUGLEVEL>=2)
#  include <stdio.h>
extern int g_debug_level; /* here, this variable is only declared,
                           it actually lives in debug.c,
                           and is shared by the whole process.
                           It's typically used to enable very verbose levels
                           on selective conditions (such as position in src) */

#  define RAWLOG(l, ...) {                                      \
                if (l<=g_debug_level) {                         \
                    fprintf(stderr, __VA_ARGS__);               \
            }   }
#  define DEBUGLOG(l, ...) {                                    \
                if (l<=g_debug_level) {                         \
                    fprintf(stderr, __FILE__ ": " __VA_ARGS__); \
                    fprintf(stderr, " \n");                     \
            }   }
#else
#  define RAWLOG(l, ...)      {}    /* disabled */
#  define DEBUGLOG(l, ...)    {}    /* disabled */
#endif


#if defined (__cplusplus)
}
#endif

#endif /* DEBUG_H_12987983217 */