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

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

/** Print a demangled stack backtrace of the caller function to FILE* out. */
inline static 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_