// 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>

/**
 * @brief Print a demangled stack backtrace of the caller function to file
 * descriptor fd.
 */
static inline void print_stacktrace(int fd = STDERR_FILENO, unsigned int max_frames = 63)
{
	model_dprintf(fd, "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) {
		model_dprintf(fd, "  <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
				model_dprintf(fd, "  %s : %s+%s\n",
											symbollist[i], funcname, begin_offset);
			} else {
				// demangling failed. Output function name as a C function with
				// no arguments.
				model_dprintf(fd, "  %s : %s()+%s\n",
											symbollist[i], begin_name, begin_offset);
			}
		} else {
			// couldn't parse the line? print the whole line.
			model_dprintf(fd, "  %s\n", symbollist[i]);
		}
	}

	free(funcname);
	free(symbollist);
}

static inline void print_stacktrace(FILE *out, unsigned int max_frames = 63)
{
	print_stacktrace(fileno(out), max_frames);
}

#endif// __STACKTRACE_H__