SdBaseFile.cpp

void SdBaseFile::printFatTime( uint16_t fatTime) {
  print2u( FAT_HOUR(fatTime));
  MYSERIAL.write(':');
  print2u( FAT_MINUTE(fatTime));
  MYSERIAL.write(':');
  print2u( FAT_SECOND(fatTime));
}
//------------------------------------------------------------------------------
/** Print a file's name to Serial
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 */
bool SdBaseFile::printName() {
  char name[FILENAME_LENGTH];
  if (!getFilename(name)) return false;
  MYSERIAL.print(name);
  return true;
}
//------------------------------------------------------------------------------
/** Read the next byte from a file.
 *
 * \return For success read returns the next byte in the file as an int.
 * If an error occurs or end of file is reached -1 is returned.
 */
int16_t SdBaseFile::read() {
  uint8_t b;
  return read(&b, 1) == 1 ? b : -1;
}
//------------------------------------------------------------------------------
/** Read data from a file starting at the current position.
 *
 * \param[out] buf Pointer to the location that will receive the data.
 *
 * \param[in] nbyte Maximum number of bytes to read.
 *
 * \return For success read() returns the number of bytes read.
 * A value less than \a nbyte, including zero, will be returned
 * if end of file is reached.
 * If an error occurs, read() returns -1.  Possible errors include
 * read() called before a file has been opened, corrupt file system
 * or an I/O error occurred.
 */
int16_t SdBaseFile::read(void* buf, uint16_t nbyte) {
  uint8_t* dst = reinterpret_cast<uint8_t*>(buf);
  uint16_t offset;
  uint16_t toRead;
  uint32_t block;  // raw device block number

  // error if not open or write only
  if (!isOpen() || !(flags_ & O_READ)) goto fail;

  // max bytes left in file
  if (nbyte >= (fileSize_ - curPosition_)) {
    nbyte = fileSize_ - curPosition_;
  }
  // amount left to read
  toRead = nbyte;
  while (toRead > 0) {
    offset = curPosition_ & 0X1FF;  // offset in block
    if (type_ == FAT_FILE_TYPE_ROOT_FIXED) {
      block = vol_->rootDirStart() + (curPosition_ >> 9);
    } else {
      uint8_t blockOfCluster = vol_->blockOfCluster(curPosition_);
      if (offset == 0 && blockOfCluster == 0) {
        // start of new cluster
        if (curPosition_ == 0) {
          // use first cluster in file
          curCluster_ = firstCluster_;
        } else {
          // get next cluster from FAT
          if (!vol_->fatGet(curCluster_, &curCluster_)) goto fail;
        }
      }
      block = vol_->clusterStartBlock(curCluster_) + blockOfCluster;
    }
    uint16_t n = toRead;

    // amount to be read from current block
    if (n > (512 - offset)) n = 512 - offset;

    // no buffering needed if n == 512
    if (n == 512 && block != vol_->cacheBlockNumber()) {
      if (!vol_->readBlock(block, dst)) goto fail;
    } else {
      // read block to cache and copy data to caller
      if (!vol_->cacheRawBlock(block, SdVolume::CACHE_FOR_READ)) goto fail;
      uint8_t* src = vol_->cache()->data + offset;
      memcpy(dst, src, n);
    }
    dst += n;
    curPosition_ += n;
    toRead -= n;
  }
  return nbyte;

 fail:
  return -1;
}

/**
 * Read the next entry in a directory.
 *
 * \param[out] dir The dir_t struct that will receive the data.
 *
 * \return For success readDir() returns the number of bytes read.
 * A value of zero will be returned if end of file is reached.
 * If an error occurs, readDir() returns -1.  Possible errors include
 * readDir() called before a directory has been opened, this is not
 * a directory file or an I/O error occurred.
 */
int8_t SdBaseFile::readDir(dir_t* dir, char* longFilename) {
  int16_t n;
  // if not a directory file or miss-positioned return an error
  if (!isDir() || (0X1F & curPosition_)) return -1;
  
  //If we have a longFilename buffer, mark it as invalid. If we find a long filename it will be filled automaticly.
  if (longFilename != NULL) longFilename[0] = '\0';

  while (1) {

    n = read(dir, sizeof(dir_t));
    if (n != sizeof(dir_t)) return n == 0 ? 0 : -1;

    // last entry if DIR_NAME_FREE
    if (dir->name[0] == DIR_NAME_FREE) return 0;

    // skip empty entries and entry for .  and ..
    if (dir->name[0] == DIR_NAME_DELETED || dir->name[0] == '.') continue;

    // Fill the long filename if we have a long filename entry.
    // Long filename entries are stored before the short filename.
    if (longFilename != NULL && DIR_IS_LONG_NAME(dir)) {
      vfat_t *VFAT = (vfat_t*)dir;
      // Sanity-check the VFAT entry. The first cluster is always set to zero. And the sequence number should be higher than 0
      if (VFAT->firstClusterLow == 0 && (VFAT->sequenceNumber & 0x1F) > 0 && (VFAT->sequenceNumber & 0x1F) <= MAX_VFAT_ENTRIES) {
        // TODO: Store the filename checksum to verify if a none-long filename aware system modified the file table.
        n = ((VFAT->sequenceNumber & 0x1F) - 1) * FILENAME_LENGTH;
        for (uint8_t i=0; i<FILENAME_LENGTH; i++)
          longFilename[n+i] = (i < 5) ? VFAT->name1[i] : (i < 11) ? VFAT->name2[i-5] : VFAT->name3[i-11];
        // If this VFAT entry is the last one, add a NUL terminator at the end of the string
        if (VFAT->sequenceNumber & 0x40) longFilename[n+FILENAME_LENGTH] = '\0';
      }
    }
    // Return if normal file or subdirectory
    if (DIR_IS_FILE_OR_SUBDIR(dir)) return n;
  }
}

//------------------------------------------------------------------------------
// Read next directory entry into the cache
// Assumes file is correctly positioned
dir_t* SdBaseFile::readDirCache() {
  uint8_t i;
  // error if not directory
  if (!isDir()) goto fail;

  // index of entry in cache
  i = (curPosition_ >> 5) & 0XF;

  // use read to locate and cache block
  if (read() < 0) goto fail;

  // advance to next entry
  curPosition_ += 31;

  // return pointer to entry
  return vol_->cache()->dir + i;

 fail:
  return 0;
}
//------------------------------------------------------------------------------
/** Remove a file.
 *
 * The directory entry and all data for the file are deleted.
 *
 * \note This function should not be used to delete the 8.3 version of a
 * file that has a long name. For example if a file has the long name
 * "New Text Document.txt" you should not delete the 8.3 name "NEWTEX~1.TXT".
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 * Reasons for failure include the file read-only, is a directory,
 * or an I/O error occurred.
 */
bool SdBaseFile::remove() {
  dir_t* d;
  // free any clusters - will fail if read-only or directory
  if (!truncate(0)) goto fail;

  // cache directory entry
  d = cacheDirEntry(SdVolume::CACHE_FOR_WRITE);
  if (!d) goto fail;

  // mark entry deleted
  d->name[0] = DIR_NAME_DELETED;

  // set this file closed
  type_ = FAT_FILE_TYPE_CLOSED;

  // write entry to SD
  return vol_->cacheFlush();
  return true;

 fail:
  return false;
}
//------------------------------------------------------------------------------
/** Remove a file.
 *
 * The directory entry and all data for the file are deleted.
 *
 * \param[in] dirFile The directory that contains the file.
 * \param[in] path Path for the file to be removed.
 *
 * \note This function should not be used to delete the 8.3 version of a
 * file that has a long name. For example if a file has the long name
 * "New Text Document.txt" you should not delete the 8.3 name "NEWTEX~1.TXT".
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 * Reasons for failure include the file is a directory, is read only,
 * \a dirFile is not a directory, \a path is not found
 * or an I/O error occurred.
 */
bool SdBaseFile::remove(SdBaseFile* dirFile, const char* path) {
  SdBaseFile file;
  if (!file.open(dirFile, path, O_WRITE)) goto fail;
  return file.remove();

 fail:
  // can't set iostate - static function
  return false;
}
//------------------------------------------------------------------------------
/** Rename a file or subdirectory.
 *
 * \param[in] dirFile Directory for the new path.
 * \param[in] newPath New path name for the file/directory.
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 * Reasons for failure include \a dirFile is not open or is not a directory
 * file, newPath is invalid or already exists, or an I/O error occurs.
 */
bool SdBaseFile::rename(SdBaseFile* dirFile, const char* newPath) {
  dir_t entry;
  uint32_t dirCluster = 0;
  SdBaseFile file;
  dir_t* d;

  // must be an open file or subdirectory
  if (!(isFile() || isSubDir())) goto fail;

  // can't move file
  if (vol_ != dirFile->vol_) goto fail;

  // sync() and cache directory entry
  sync();
  d = cacheDirEntry(SdVolume::CACHE_FOR_WRITE);
  if (!d) goto fail;

  // save directory entry
  memcpy(&entry, d, sizeof(entry));

  // mark entry deleted
  d->name[0] = DIR_NAME_DELETED;

  // make directory entry for new path
  if (isFile()) {
    if (!file.open(dirFile, newPath, O_CREAT | O_EXCL | O_WRITE)) {
      goto restore;
    }
  } else {
    // don't create missing path prefix components
    if (!file.mkdir(dirFile, newPath, false)) {
      goto restore;
    }
    // save cluster containing new dot dot
    dirCluster = file.firstCluster_;
  }
  // change to new directory entry
  dirBlock_ = file.dirBlock_;
  dirIndex_ = file.dirIndex_;

  // mark closed to avoid possible destructor close call
  file.type_ = FAT_FILE_TYPE_CLOSED;

  // cache new directory entry
  d = cacheDirEntry(SdVolume::CACHE_FOR_WRITE);
  if (!d) goto fail;

  // copy all but name field to new directory entry
  memcpy(&d->attributes, &entry.attributes, sizeof(entry) - sizeof(d->name));

  // update dot dot if directory
  if (dirCluster) {
    // get new dot dot
    uint32_t block = vol_->clusterStartBlock(dirCluster);
    if (!vol_->cacheRawBlock(block, SdVolume::CACHE_FOR_READ)) goto fail;
    memcpy(&entry, &vol_->cache()->dir[1], sizeof(entry));

    // free unused cluster
    if (!vol_->freeChain(dirCluster)) goto fail;

    // store new dot dot
    block = vol_->clusterStartBlock(firstCluster_);
    if (!vol_->cacheRawBlock(block, SdVolume::CACHE_FOR_WRITE)) goto fail;
    memcpy(&vol_->cache()->dir[1], &entry, sizeof(entry));
  }
  return vol_->cacheFlush();

 restore:
  d = cacheDirEntry(SdVolume::CACHE_FOR_WRITE);
  if (!d) goto fail;
  // restore entry
  d->name[0] = entry.name[0];
  vol_->cacheFlush();

 fail:
  return false;
}
//------------------------------------------------------------------------------
/** Remove a directory file.
 *
 * The directory file will be removed only if it is empty and is not the
 * root directory.  rmdir() follows DOS and Windows and ignores the
 * read-only attribute for the directory.
 *
 * \note This function should not be used to delete the 8.3 version of a
 * directory that has a long name. For example if a directory has the
 * long name "New folder" you should not delete the 8.3 name "NEWFOL~1".
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 * Reasons for failure include the file is not a directory, is the root
 * directory, is not empty, or an I/O error occurred.
 */
bool SdBaseFile::rmdir() {
  // must be open subdirectory
  if (!isSubDir()) goto fail;

  rewind();

  // make sure directory is empty
  while (curPosition_ < fileSize_) {
    dir_t* p = readDirCache();
    if (!p) goto fail;
    // done if past last used entry
    if (p->name[0] == DIR_NAME_FREE) break;
    // skip empty slot, '.' or '..'
    if (p->name[0] == DIR_NAME_DELETED || p->name[0] == '.') continue;
    // error not empty
    if (DIR_IS_FILE_OR_SUBDIR(p)) goto fail;
  }
  // convert empty directory to normal file for remove
  type_ = FAT_FILE_TYPE_NORMAL;
  flags_ |= O_WRITE;
  return remove();

 fail:
  return false;
}
//------------------------------------------------------------------------------
/** Recursively delete a directory and all contained files.
 *
 * This is like the Unix/Linux 'rm -rf *' if called with the root directory
 * hence the name.
 *
 * Warning - This will remove all contents of the directory including
 * subdirectories.  The directory will then be removed if it is not root.
 * The read-only attribute for files will be ignored.
 *
 * \note This function should not be used to delete the 8.3 version of
 * a directory that has a long name.  See remove() and rmdir().
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 */
bool SdBaseFile::rmRfStar() {
  uint16_t index;
  SdBaseFile f;
  rewind();
  while (curPosition_ < fileSize_) {
    // remember position
    index = curPosition_/32;

    dir_t* p = readDirCache();
    if (!p) goto fail;

    // done if past last entry
    if (p->name[0] == DIR_NAME_FREE) break;

    // skip empty slot or '.' or '..'
    if (p->name[0] == DIR_NAME_DELETED || p->name[0] == '.') continue;

    // skip if part of long file name or volume label in root
    if (!DIR_IS_FILE_OR_SUBDIR(p)) continue;

    if (!f.open(this, index, O_READ)) goto fail;
    if (f.isSubDir()) {
      // recursively delete
      if (!f.rmRfStar()) goto fail;
    } else {
      // ignore read-only
      f.flags_ |= O_WRITE;
      if (!f.remove()) goto fail;
    }
    // position to next entry if required
    if (curPosition_ != (32*(index + 1))) {
      if (!seekSet(32*(index + 1))) goto fail;
    }
  }
  // don't try to delete root
  if (!isRoot()) {
    if (!rmdir()) goto fail;
  }
  return true;

 fail:
  return false;
}
//------------------------------------------------------------------------------
/**  Create a file object and open it in the current working directory.
 *
 * \param[in] path A path with a valid 8.3 DOS name for a file to be opened.
 *
 * \param[in] oflag Values for \a oflag are constructed by a bitwise-inclusive
 * OR of open flags. see SdBaseFile::open(SdBaseFile*, const char*, uint8_t).
 */
SdBaseFile::SdBaseFile(const char* path, uint8_t oflag) {
  type_ = FAT_FILE_TYPE_CLOSED;
  writeError = false;
  open(path, oflag);
}
//------------------------------------------------------------------------------
/** Sets a file's position.
 *
 * \param[in] pos The new position in bytes from the beginning of the file.
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 */
bool SdBaseFile::seekSet(uint32_t pos) {
  uint32_t nCur;
  uint32_t nNew;
  // error if file not open or seek past end of file
  if (!isOpen() || pos > fileSize_) goto fail;

  if (type_ == FAT_FILE_TYPE_ROOT_FIXED) {
    curPosition_ = pos;
    goto done;
  }
  if (pos == 0) {
    // set position to start of file
    curCluster_ = 0;
    curPosition_ = 0;
    goto done;
  }
  // calculate cluster index for cur and new position
  nCur = (curPosition_ - 1) >> (vol_->clusterSizeShift_ + 9);
  nNew = (pos - 1) >> (vol_->clusterSizeShift_ + 9);

  if (nNew < nCur || curPosition_ == 0) {
    // must follow chain from first cluster
    curCluster_ = firstCluster_;
  } else {
    // advance from curPosition
    nNew -= nCur;
  }
  while (nNew--) {
    if (!vol_->fatGet(curCluster_, &curCluster_)) goto fail;
  }
  curPosition_ = pos;

 done:
  return true;

 fail:
  return false;
}
//------------------------------------------------------------------------------
void SdBaseFile::setpos(fpos_t* pos) {
  curPosition_ = pos->position;
  curCluster_ = pos->cluster;
}
//------------------------------------------------------------------------------
/** The sync() call causes all modified data and directory fields
 * to be written to the storage device.
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 * Reasons for failure include a call to sync() before a file has been
 * opened or an I/O error.
 */
bool SdBaseFile::sync() {
  // only allow open files and directories
  if (!isOpen()) goto fail;

  if (flags_ & F_FILE_DIR_DIRTY) {
    dir_t* d = cacheDirEntry(SdVolume::CACHE_FOR_WRITE);
    // check for deleted by another open file object
    if (!d || d->name[0] == DIR_NAME_DELETED) goto fail;

    // do not set filesize for dir files
    if (!isDir()) d->fileSize = fileSize_;

    // update first cluster fields
    d->firstClusterLow = firstCluster_ & 0XFFFF;
    d->firstClusterHigh = firstCluster_ >> 16;

    // set modify time if user supplied a callback date/time function
    if (dateTime_) {
      dateTime_(&d->lastWriteDate, &d->lastWriteTime);
      d->lastAccessDate = d->lastWriteDate;
    }
    // clear directory dirty
    flags_ &= ~F_FILE_DIR_DIRTY;
  }
  return vol_->cacheFlush();

 fail:
  writeError = true;
  return false;
}
//------------------------------------------------------------------------------
/** Copy a file's timestamps
 *
 * \param[in] file File to copy timestamps from.
 *
 * \note
 * Modify and access timestamps may be overwritten if a date time callback
 * function has been set by dateTimeCallback().
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 */
bool SdBaseFile::timestamp(SdBaseFile* file) {
  dir_t* d;
  dir_t dir;

  // get timestamps
  if (!file->dirEntry(&dir)) goto fail;

  // update directory fields
  if (!sync()) goto fail;

  d = cacheDirEntry(SdVolume::CACHE_FOR_WRITE);
  if (!d) goto fail;

  // copy timestamps
  d->lastAccessDate = dir.lastAccessDate;
  d->creationDate = dir.creationDate;
  d->creationTime = dir.creationTime;
  d->creationTimeTenths = dir.creationTimeTenths;
  d->lastWriteDate = dir.lastWriteDate;
  d->lastWriteTime = dir.lastWriteTime;

  // write back entry
  return vol_->cacheFlush();

 fail:
  return false;
}
//------------------------------------------------------------------------------
/** Set a file's timestamps in its directory entry.
 *
 * \param[in] flags Values for \a flags are constructed by a bitwise-inclusive
 * OR of flags from the following list
 *
 * T_ACCESS - Set the file's last access date.
 *
 * T_CREATE - Set the file's creation date and time.
 *
 * T_WRITE - Set the file's last write/modification date and time.
 *
 * \param[in] year Valid range 1980 - 2107 inclusive.
 *
 * \param[in] month Valid range 1 - 12 inclusive.
 *
 * \param[in] day Valid range 1 - 31 inclusive.
 *
 * \param[in] hour Valid range 0 - 23 inclusive.
 *
 * \param[in] minute Valid range 0 - 59 inclusive.
 *
 * \param[in] second Valid range 0 - 59 inclusive
 *
 * \note It is possible to set an invalid date since there is no check for
 * the number of days in a month.
 *
 * \note
 * Modify and access timestamps may be overwritten if a date time callback
 * function has been set by dateTimeCallback().
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 */
bool SdBaseFile::timestamp(uint8_t flags, uint16_t year, uint8_t month,
         uint8_t day, uint8_t hour, uint8_t minute, uint8_t second) {
  uint16_t dirDate;
  uint16_t dirTime;
  dir_t* d;

  if (!isOpen()
    || year < 1980
    || year > 2107
    || month < 1
    || month > 12
    || day < 1
    || day > 31
    || hour > 23
    || minute > 59
    || second > 59) {
      goto fail;
  }
  // update directory entry
  if (!sync()) goto fail;

  d = cacheDirEntry(SdVolume::CACHE_FOR_WRITE);
  if (!d) goto fail;

  dirDate = FAT_DATE(year, month, day);
  dirTime = FAT_TIME(hour, minute, second);
  if (flags & T_ACCESS) {
    d->lastAccessDate = dirDate;
  }
  if (flags & T_CREATE) {
    d->creationDate = dirDate;
    d->creationTime = dirTime;
    // seems to be units of 1/100 second not 1/10 as Microsoft states
    d->creationTimeTenths = second & 1 ? 100 : 0;
  }
  if (flags & T_WRITE) {
    d->lastWriteDate = dirDate;
    d->lastWriteTime = dirTime;
  }
  return vol_->cacheFlush();

 fail:
  return false;
}
//------------------------------------------------------------------------------
/** Truncate a file to a specified length.  The current file position
 * will be maintained if it is less than or equal to \a length otherwise
 * it will be set to end of file.
 *
 * \param[in] length The desired length for the file.
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 * Reasons for failure include file is read only, file is a directory,
 * \a length is greater than the current file size or an I/O error occurs.
 */
bool SdBaseFile::truncate(uint32_t length) {
  uint32_t newPos;
  // error if not a normal file or read-only
  if (!isFile() || !(flags_ & O_WRITE)) goto fail;

  // error if length is greater than current size
  if (length > fileSize_) goto fail;

  // fileSize and length are zero - nothing to do
  if (fileSize_ == 0) return true;

  // remember position for seek after truncation
  newPos = curPosition_ > length ? length : curPosition_;

  // position to last cluster in truncated file
  if (!seekSet(length)) goto fail;

  if (length == 0) {
    // free all clusters
    if (!vol_->freeChain(firstCluster_)) goto fail;
    firstCluster_ = 0;
  } else {
    uint32_t toFree;
    if (!vol_->fatGet(curCluster_, &toFree)) goto fail;

    if (!vol_->isEOC(toFree)) {
      // free extra clusters
      if (!vol_->freeChain(toFree)) goto fail;

      // current cluster is end of chain
      if (!vol_->fatPutEOC(curCluster_)) goto fail;
    }
  }
  fileSize_ = length;

  // need to update directory entry
  flags_ |= F_FILE_DIR_DIRTY;

  if (!sync()) goto fail;

  // set file to correct position
  return seekSet(newPos);

 fail:
  return false;
}
//------------------------------------------------------------------------------
/** Write data to an open file.
 *
 * \note Data is moved to the cache but may not be written to the
 * storage device until sync() is called.
 *
 * \param[in] buf Pointer to the location of the data to be written.
 *
 * \param[in] nbyte Number of bytes to write.
 *
 * \return For success write() returns the number of bytes written, always
 * \a nbyte.  If an error occurs, write() returns -1.  Possible errors
 * include write() is called before a file has been opened, write is called
 * for a read-only file, device is full, a corrupt file system or an I/O error.
 *
 */
int16_t SdBaseFile::write(const void* buf, uint16_t nbyte) {
  // convert void* to uint8_t*  -  must be before goto statements
  const uint8_t* src = reinterpret_cast<const uint8_t*>(buf);

  // number of bytes left to write  -  must be before goto statements
  uint16_t nToWrite = nbyte;

  // error if not a normal file or is read-only
  if (!isFile() || !(flags_ & O_WRITE)) goto fail;

  // seek to end of file if append flag
  if ((flags_ & O_APPEND) && curPosition_ != fileSize_) {
    if (!seekEnd()) goto fail;
  }

  while (nToWrite > 0) {
    uint8_t blockOfCluster = vol_->blockOfCluster(curPosition_);
    uint16_t blockOffset = curPosition_ & 0X1FF;
    if (blockOfCluster == 0 && blockOffset == 0) {
      // start of new cluster
      if (curCluster_ == 0) {
        if (firstCluster_ == 0) {
          // allocate first cluster of file
          if (!addCluster()) goto fail;
        } else {
          curCluster_ = firstCluster_;
        }
      } else {
        uint32_t next;
        if (!vol_->fatGet(curCluster_, &next)) goto fail;
        if (vol_->isEOC(next)) {
          // add cluster if at end of chain
          if (!addCluster()) goto fail;
        } else {
          curCluster_ = next;
        }
      }
    }
    // max space in block
    uint16_t n = 512 - blockOffset;

    // lesser of space and amount to write
    if (n > nToWrite) n = nToWrite;

    // block for data write
    uint32_t block = vol_->clusterStartBlock(curCluster_) + blockOfCluster;
    if (n == 512) {
      // full block - don't need to use cache
      if (vol_->cacheBlockNumber() == block) {
        // invalidate cache if block is in cache
        vol_->cacheSetBlockNumber(0XFFFFFFFF, false);
      }
      if (!vol_->writeBlock(block, src)) goto fail;
    } else {
      if (blockOffset == 0 && curPosition_ >= fileSize_) {
        // start of new block don't need to read into cache
        if (!vol_->cacheFlush()) goto fail;
        // set cache dirty and SD address of block
        vol_->cacheSetBlockNumber(block, true);
      } else {
        // rewrite part of block
        if (!vol_->cacheRawBlock(block, SdVolume::CACHE_FOR_WRITE)) goto fail;
      }
      uint8_t* dst = vol_->cache()->data + blockOffset;
      memcpy(dst, src, n);
    }
    curPosition_ += n;
    src += n;
    nToWrite -= n;
  }
  if (curPosition_ > fileSize_) {
    // update fileSize and insure sync will update dir entry
    fileSize_ = curPosition_;
    flags_ |= F_FILE_DIR_DIRTY;
  } else if (dateTime_ && nbyte) {
    // insure sync will update modified date and time
    flags_ |= F_FILE_DIR_DIRTY;
  }

  if (flags_ & O_SYNC) {
    if (!sync()) goto fail;
  }
  return nbyte;

 fail:
  // return for write error
  writeError = true;
  return -1;
}
//------------------------------------------------------------------------------
// suppress cpplint warnings with NOLINT comment
#if ALLOW_DEPRECATED_FUNCTIONS && !defined(DOXYGEN)
void (*SdBaseFile::oldDateTime_)(uint16_t& date, uint16_t& time) = 0;  // NOLINT
#endif  // ALLOW_DEPRECATED_FUNCTIONS


#endif