#include <fb/CRTSafeAPIs.h>
#include <memory.h>
#include <string.h>
#include<cstdlib>

int vsnprintf_safe(char *str, size_t str_len, const char *format, va_list args)
{
  if (str == nullptr || str_len <= 0) {
     return -1;
  }
  
  char *buffer = nullptr;
  int result = vasprintf(&buffer, format, args);
  
  if (buffer == nullptr) {
    return -1;
  }
  
  if (result < 0) {
    std::free(buffer);
    return -1;
  }
  
  size_t buffer_len = strlen(buffer);
 
  if (str_len > buffer_len) {
     memcpy(str, buffer, buffer_len + 1);
  } else {
     memcpy(str, buffer, str_len - 1);
     str[str_len - 1] = 0;
  }
  
  std::free(buffer);
  return buffer_len;
}