bdebug.h

/*
  bdebug.h - v1.0 - public domain debuging utilities

  by Blat Blatnik
  
  NO WARRANTY IMPLIED - USE AT YOUR OWN RISK

  For licence information see end of file.
  
  Do this:
    #define B_DEBUG_IMPLEMENTATION
  before you include this file in *ONE* C or C++ file to create the implementation.
  
  //i.e. it should look something like this:
  #include ...
  #include ...
  #include B_DEBUG_IMPLEMENTATION
  #include "bdebug.h"
  
  This library includes a logging function and an assertion macro.

  debugLog(message, args...)
    Write a format message to the log file.
    If no log file is open, this will try to open the default log file (log.txt). 
    The special string "CLOSE" can be passed as a first argument to close the currently open log file.
    The special string "OPEN" can be passed as a first argument to open a new log file,
    whose filename must be passed as the second argument.
    All log messages are printed to stdout as well.
    
    //examples
    ...
    debugLog("hello")            // opens the default log file and appends "hello"
    debugLog("world")            // appends "world" to the open log file
    debugLog("CLOSE")            // close the log file
    debugLog("again")            // reopens the default log file and appends "again"
    debugLog("OPEN", "log2.txt") // closes the open log file and opens "log2.txt" as the new log file
    ...

  ASSERT(condition, [message, args...])
    Unlike the standard assert from assert.h, this assert will not call abort upon triggering.
    Also, you can pass in a string LITERAL (it has to be a literal) as a format message, and 
    arguments to format it in. If the passed in condition does not hold, the message and args
    are passed to debugLog, and then a debugger breakpoint is triggered.
    If you #define NDEBUG or #define B_DONT_ASSERT before #include -ing this file, 
    ASSERT will be defined as a NO-OP. But if you #define B_ALWAYS_ASSERT before #include -ing
    then NDEBUG and B_DONT_ASSERT are ignored, and ASSERT will NOT be defined as a NO-OP.

    //examples
    ...
    #line 1 "example.c"
    ASSERT(2 == 2);                                        // condition is true, so nothing happens
    ASSERT(2 == 4);                                        // output 1 is generated and a breakpoint is triggered
    ASSERT(2 == 4, "oh no");                               // output 2 is generated and a breakpoint is triggered
    ASSERT(2 == 4, "oh oh, %d != %d, %s", 2, 4, "panic!!") // generates output 3 and triggers a debugger breakpoint
    ...

    output 1:
      ERROR assert failed "2 == 4"
       in file example.c
       on line 2
    
    output 2:
      ERROR assert failed "2 == 4"
       in file example.c
       on line 3
       oh no
    
    output 3:
      ERROR assert failed "2 == 4"
       in file example.c
       on line 4
       oh oh, 2 != 4, panic!!
  
  -------------------
  ----- Options -----
  -------------------

  #define any of these before including this file for them to take effect:

  #define B_TRIGGER_BREAKPOINT() your-trigger-debugger-breakpoint()
  - Use this to cause ASSERT to trigger a breakpoint on failure. You have to define it
    to something like MSVC's __debugbreak().

  #define B_DONT_ASSERT
  #define NDEBUG
  - Both these will cause ASSERT to be disabled for use in release builds.

  #define B_ALWAYS_ASSERT
  - Ignore B_DONT_ASSERT and NDEBUG and have ASSERT work in release builds as well.

  #define B_DEBUG_PREFIX(name) [your-name-prefix] ## name
  #define B_PREFIX(name) [your-name-prefix] ## name
  - Add a prefix to all functions/variables/types declared by this file.
    Useful for avoiding name-conflicts. By default no prefix is added.
*/

#ifndef B_DEBUG_DEFINITION
#define B_DEBUG_DEFINITION

#ifndef B_DEBUG_PREFIX
#   ifdef B_PREFIX
#       define B_DEBUG_PREFIX(name) B_PREFIX(name)
#   else
#       define B_DEBUG_PREFIX(name) name
#   endif
#endif

void B_DEBUG_PREFIX(debugLog)(const char *message, ...);

#define B_STRINGIFY(identifier) #identifier
#define B_STRINGIFY2(identifier) B_STRINGIFY(identifier)

/* Triggers a debugger breakpoint. */
#ifndef B_TRIGGER_BREAKPOINT
#	ifdef _MSC_VER
#		define B_TRIGGER_BREAKPOINT() __debugbreak()
#	else
#		define B_TRIGGER_BREAKPOINT()
#	endif
#endif

#if defined(B_ALWAYS_ASSERT) || (!defined(B_DONT_ASSERT) && !defined(NDEBUG))
#	define ASSERT(condition, ...)\
		do {\
			if (!!!(condition)) {\
				B_DEBUG_PREFIX(debugLog)(\
					"ERROR assert failed \"" #condition "\"\n"\
					" in file " __FILE__ "\n"\
					" on line " B_STRINGIFY2(__LINE__) "\n"\
					" " __VA_ARGS__);\
				B_TRIGGER_BREAKPOINT();\
			}\
		} while (0)
#else
#	define ASSERT(condition, ...) do {} while (0)
#endif

#endif /* !B_DEBUG_DEFINITION */

/*
 * |                |
 * v Implementation v
 * |                |
 */

#ifdef B_DEBUG_IMPLEMENTATION
#ifndef B_DEBUG_IMPLEMENTED
#define B_DEBUG_IMPLEMENTED

#include <stdio.h>  /* FILE, fopen, fclose, fprintf, vfprintf, stdout, fflush */
#include <stdarg.h> /* va_list, va_start, va_end */
#include <string.h> /* strcmp */
#include <time.h>   /* time_t, time, localtime, struct tm, strftime */

static FILE *b__logFile;

void B_DEBUG_PREFIX(debugLog)(const char *message, ...) {

	if (strcmp(message, "CLOSE") == 0) {

		if (b__logFile) {
            B_DEBUG_PREFIX(debugLog)("log closed");
			fclose(b__logFile);
			b__logFile = NULL;
		}
		return;

	} else if (strcmp(message, "OPEN") == 0) {
	
		va_list args;
		va_start(args, message);
		const char *filename = va_arg(args, const char *);
		va_end(args);
	
		if (b__logFile) {
            B_DEBUG_PREFIX(debugLog)("log closed");
			fclose(b__logFile);
		}
		
		b__logFile = fopen(filename, "at");
		if (b__logFile)
            B_DEBUG_PREFIX(debugLog)("log opened");
	
		return;
	}
	
	if (!b__logFile) {
		/* try to open the default log file */
		b__logFile = fopen("log.txt", "at");
		if (!b__logFile) {
			/* can't assert here because assert also calls
			   debugLog so we would enter an infinite loop.. */
			return;
		}
        B_DEBUG_PREFIX(debugLog)("log opened");
	}

	char timestamp[64];
	time_t timeTicks = time(NULL);
	struct tm *t = localtime(&timeTicks);
	strftime(timestamp, sizeof(timestamp), "[%T] ", t);

	fprintf(stdout, timestamp);
	va_list args1;
	va_start(args1, message);
	vfprintf(stdout, message, args1);
	va_end(args1);
	fprintf(stdout, "\n");

	fprintf(b__logFile, timestamp);
	va_list args2;
	va_start(args2, message);
	vfprintf(b__logFile, message, args2);
	va_end(args2);
	fprintf(b__logFile, "\n");

	fflush(b__logFile);
}

#endif /* !B_DEBUG_IMPLEMENTED */
#endif /* B_DEBUG_IMPLEMENTATION */

/*
  ------------------------------------------------------------------------------
  This software is available under 2 licenses - choose whichever you prefer.
  ------------------------------------------------------------------------------
  ALTERNATIVE A - MIT License
  Copyright (c) 2020 Blat Blatnik
  Permission is hereby granted, free of charge, to any person obtaining a copy of
  this software and associated documentation files (the "Software"), to deal in
  the Software without restriction, including without limitation the rights to
  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  of the Software, and to permit persons to whom the Software is furnished to do
  so, subject to the following conditions:
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
  ------------------------------------------------------------------------------
  ALTERNATIVE B - Public Domain (www.unlicense.org)
  This is free and unencumbered software released into the public domain.
  Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
  software, either in source code form or as a compiled binary, for any purpose,
  commercial or non-commercial, and by any means.
  In jurisdictions that recognize copyright laws, the author or authors of this
  software dedicate any and all copyright interest in the software to the public
  domain. We make this dedication for the benefit of the public at large and to
  the detriment of our heirs and successors. We intend this dedication to be an
  overt act of relinquishment in perpetuity of all present and future rights to
  this software under copyright law.
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  ------------------------------------------------------------------------------
*/