// stacktrace.h (c) 2008, Timo Bingmann from http://idlebox.net/
// published under the WTFPL v2.0

#ifndef _STACKTRACE_H_
#define _STACKTRACE_H_
#include <stdio.h>
#include <stdlib.h>
#include <execinfo.h>
#include <cxxabi.h>

/** Print a demangled stack backtrace of the caller function to FILE* out. */
static inline void print_stacktrace( FILE *out = stdout, unsigned int max_frames = 3 )
{
	fprintf( out, "stack trace:\n" );

	// storage array for stack trace address data
	void* addrlist[ max_frames + 1 ];

	// retrieve current stack addresses
	int addrlen = backtrace( addrlist, sizeof( addrlist ) / sizeof( void* ) );

	if( addrlen == 0 )
	{
		fprintf( out, "  <empty, possibly corrupt>\n" );
		return;
	}

	// resolve addresses into strings containing "filename(function+address)",
	// this array must be free()-ed
	char** symbollist = backtrace_symbols( addrlist, addrlen );

	// allocate string which will be filled with the demangled function name
	size_t funcnamesize = 256;
	char* funcname = (char*)malloc( funcnamesize );

	// iterate over the returned symbol lines. skip the first, it is the
	// address of this function.
	for( int i = 1; i < addrlen; i++ )
	{
		char *begin_name = 0, *begin_offset = 0, *end_offset = 0;

		// find parentheses and +address offset surrounding the mangled name:
		// ./module(function+0x15c) [0x8048a6d]
		for( char *p = symbollist[ i ]; *p; ++p )
		{
			if( *p == '(' )
				begin_name = p;
			else if( *p == '+' )
				begin_offset = p;
			else if( *p == ')' && begin_offset )
			{
				end_offset = p;
				break;
			}
		}

		if( begin_name && begin_offset && end_offset
			&& begin_name < begin_offset )
		{
			*begin_name++ = '\0';
			*begin_offset++ = '\0';
			*end_offset = '\0';

			// mangled name is now in [begin_name, begin_offset) and caller
			// offset in [begin_offset, end_offset). now apply
			// __cxa_demangle():

			int status;
			char* ret = abi::__cxa_demangle( begin_name,
											 funcname, &funcnamesize, &status );
			if( status == 0 )
			{
				funcname = ret; // use possibly realloc()-ed string
				char line[ 256 ];
				sprintf( line, "  %s : %s+%s\n",
						 symbollist[ i ], funcname, begin_offset );
				int y = 0;
			}
			else
			{
				// demangling failed. Output function name as a C function with
				// no arguments.
				char line[ 256 ];
				sprintf( line, "  %s : %s()+%s\n",
						 symbollist[ i ], begin_name, begin_offset );
				int x = 0;
			}
		}
		else
		{
			// couldn't parse the line? print the whole line.
			char line[ 256 ];
			sprintf( line, "  %s\n", symbollist[ i ] );
			int x = 0;
		}
	}

	free( funcname );
	free( symbollist );
}

#endif // _STACKTRACE_H_