awful C

char *sanitize_name(char *outbuf, const char *input, int length)     {
  char hex[3]                                                        ;
  char temp[strlen(input)*2+1]                                       ;
  char *output = temp                                                ;

  if(!isalpha(*input) && *input != '_')
    *(output++) = '_';
  while(*input)                                                      {
    if(isalnum(*input))
      *(output++) = *input                                           ;
    else if(*input == ' ' || *input == '-')                          {
      *(output++) = '_'                                              ;}
    else                                                             {
      sprintf(hex, "%.2x", *input)                                   ;
      strcpy(output, hex)                                            ;
      output += 2                                                    ;}
    input++                                                          ;}
  *(output) = 0                                                      ;

  strlcpy(outbuf, temp, length)                                      ;
  return outbuf                                                      ;}