Function WriteDoubleToBuffer

src/common/base/string_number.cc:231–248

----------------------------------------------------------------- Double to string or buffer. Make sure buffer size >= kMaxDoubleStringSize -----------------------------------------------------------------

// Make sure buffer size >= kMaxDoubleStringSize
// -----------------------------------------------------------------
char* WriteDoubleToBuffer(double value, char* buffer) {
  // DBL_DIG is 15 on almost all platforms.
  // If it's too big, the buffer will overflow
  //     STATIC_ASSERT(DBL_DIG < 20, "DBL_DIG is too big");

  if (value >= numeric_limits<double>::infinity()) {
    strcpy(buffer, "inf");  // NOLINT
    return buffer + 3;
  } else if (value <= -numeric_limits<double>::infinity()) {
    strcpy(buffer, "-inf");  // NOLINT
    return buffer + 4;
  } else if (IsNaN(value)) {
    strcpy(buffer, "nan");  // NOLINT
    return buffer + 3;
  }

  return buffer + snprintf(buffer, kMaxDoubleStringSize, "%.*g", DBL_DIG, value);
}

// -------------------------------------------------------------
// Float to string or buffer.