/**
 * @file debug.h
 * @author Ambroz Bizjak <ambrop7@gmail.com>
 * 
 * @section LICENSE
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of the author nor the
 *    names of its contributors may be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 * 
 * 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 AUTHOR 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.
 * 
 * @section DESCRIPTION
 * 
 * Debugging macros.
 */

/**
 * @def DEBUG
 * 
 * Macro for printing debugging text. Use the same way as printf,
 * but without a newline.
 * Prepends "function_name: " and appends a newline.
 */

/**
 * @def ASSERT_FORCE
 * 
 * Macro for forced assertions.
 * Evaluates the argument and terminates the program abnormally
 * if the result is false.
 */

/**
 * @def ASSERT
 * 
 * Macro for assertions.
 * The argument may or may not be evaluated.
 * If the argument is evaluated, it must not evaluate to false.
 */

/**
 * @def ASSERT_EXECUTE
 * 
 * Macro for always-evaluated assertions.
 * The argument is evaluated.
 * The argument must not evaluate to false.
 */

/**
 * @def DEBUG_ZERO_MEMORY
 * 
 * If debugging is enabled, zeroes the given memory region.
 * First argument is pointer to the memory region, second is
 * number of bytes.
 */

/**
 * @def WARN_UNUSED
 * 
 * Tells the compiler that the result of a function should not be unused.
 * Insert at the end of the declaration of a function before the semicolon.
 */

/**
 * @def B_USE
 * 
 * This can be used to suppress warnings about unused variables. It can
 * be applied to a variable or any expression. It does not evaluate the
 * expression.
 */

#ifndef BADVPN_MISC_DEBUG_H
#define BADVPN_MISC_DEBUG_H

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <assert.h>

#define DEBUG(...) \
    { \
        fprintf(stderr, "%s: ", __FUNCTION__); \
        fprintf(stderr, __VA_ARGS__); \
        fprintf(stderr, "\n"); \
    }

#define ASSERT_FORCE(e) \
    { \
        if (!(e)) { \
            fprintf(stderr, "%s:%d Assertion failed\n", __FILE__, __LINE__); \
            abort(); \
        } \
    }

#ifdef NDEBUG
    #define DEBUG_ZERO_MEMORY(buf, len) {}
    #define ASSERT(e) {}
    #define ASSERT_EXECUTE(e) { (e); }
#else
    #define DEBUG_ZERO_MEMORY(buf, len) { memset((buf), 0, (len)); }
    #ifdef BADVPN_USE_C_ASSERT
        #define ASSERT(e) { assert(e); }
        #define ASSERT_EXECUTE(e) \
            { \
                int _assert_res = !!(e); \
                assert(_assert_res); \
            }
    #else
        #define ASSERT(e) ASSERT_FORCE(e)
        #define ASSERT_EXECUTE(e) ASSERT_FORCE(e)
    #endif
#endif

#ifdef __GNUC__
    #define WARN_UNUSED __attribute__((warn_unused_result))
#else
    #define WARN_UNUSED
#endif

#define B_USE(expr) (void)(sizeof((expr)));

#define B_ASSERT_USE(expr) { ASSERT(expr) B_USE(expr) }

#endif