// Copyright 2022 Google LLC. All Rights Reserved. This file and proprietary
// source code may only be used and distributed under the Widevine License
// Agreement.

#include "string_format.h"

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <memory>

namespace wvutil {

bool FormatString(std::string* out, const char* fmt, ...) {
  if (out == nullptr || fmt == nullptr) return false;

  va_list ap1;
  va_start(ap1, fmt);
  const int desired_size = vsnprintf(nullptr, 0, fmt, ap1);
  va_end(ap1);

  if (desired_size < 0) return false;
  const size_t buffer_size =
      static_cast<size_t>(desired_size) + 1;  // +1 for null
  std::unique_ptr<char[]> buffer(new char[buffer_size]);

  va_list ap2;
  va_start(ap2, fmt);
  const int actual_size = vsnprintf(buffer.get(), buffer_size, fmt, ap2);
  va_end(ap2);

  if (actual_size != desired_size) return false;

  out->assign(buffer.get(), actual_size);
  return true;
}

}  // namespace wvutil