SdBaseFile.cpp

changeset 0
2c8ba1964db7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SdBaseFile.cpp	Sat Nov 07 13:23:07 2015 +0100
@@ -0,0 +1,1791 @@
+/* Arduino SdFat Library
+ * Copyright (C) 2009 by William Greiman
+ *
+ * This file is part of the Arduino SdFat Library
+ *
+ * This Library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This Library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with the Arduino SdFat Library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include "Marlin.h"
+#ifdef SDSUPPORT
+
+#include "SdBaseFile.h"
+//------------------------------------------------------------------------------
+// pointer to cwd directory
+SdBaseFile* SdBaseFile::cwd_ = 0;
+// callback function for date/time
+void (*SdBaseFile::dateTime_)(uint16_t* date, uint16_t* time) = 0;
+//------------------------------------------------------------------------------
+// add a cluster to a file
+bool SdBaseFile::addCluster() {
+  if (!vol_->allocContiguous(1, &curCluster_)) goto fail;
+
+  // if first cluster of file link to directory entry
+  if (firstCluster_ == 0) {
+    firstCluster_ = curCluster_;
+    flags_ |= F_FILE_DIR_DIRTY;
+  }
+  return true;
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+// Add a cluster to a directory file and zero the cluster.
+// return with first block of cluster in the cache
+bool SdBaseFile::addDirCluster() {
+  uint32_t block;
+  // max folder size
+  if (fileSize_/sizeof(dir_t) >= 0XFFFF) goto fail;
+
+  if (!addCluster()) goto fail;
+  if (!vol_->cacheFlush()) goto fail;
+
+  block = vol_->clusterStartBlock(curCluster_);
+
+  // set cache to first block of cluster
+  vol_->cacheSetBlockNumber(block, true);
+
+  // zero first block of cluster
+  memset(vol_->cacheBuffer_.data, 0, 512);
+
+  // zero rest of cluster
+  for (uint8_t i = 1; i < vol_->blocksPerCluster_; i++) {
+    if (!vol_->writeBlock(block + i, vol_->cacheBuffer_.data)) goto fail;
+  }
+  // Increase directory file size by cluster size
+  fileSize_ += 512UL << vol_->clusterSizeShift_;
+  return true;
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+// cache a file's directory entry
+// return pointer to cached entry or null for failure
+dir_t* SdBaseFile::cacheDirEntry(uint8_t action) {
+  if (!vol_->cacheRawBlock(dirBlock_, action)) goto fail;
+  return vol_->cache()->dir + dirIndex_;
+
+ fail:
+  return 0;
+}
+//------------------------------------------------------------------------------
+/** Close a file and force cached data and directory information
+ *  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 no file is open or an I/O error.
+ */
+bool SdBaseFile::close() {
+  bool rtn = sync();
+  type_ = FAT_FILE_TYPE_CLOSED;
+  return rtn;
+}
+//------------------------------------------------------------------------------
+/** Check for contiguous file and return its raw block range.
+ *
+ * \param[out] bgnBlock the first block address for the file.
+ * \param[out] endBlock the last  block address 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 not contiguous, file has zero length
+ * or an I/O error occurred.
+ */
+bool SdBaseFile::contiguousRange(uint32_t* bgnBlock, uint32_t* endBlock) {
+  // error if no blocks
+  if (firstCluster_ == 0) goto fail;
+
+  for (uint32_t c = firstCluster_; ; c++) {
+    uint32_t next;
+    if (!vol_->fatGet(c, &next)) goto fail;
+
+    // check for contiguous
+    if (next != (c + 1)) {
+      // error if not end of chain
+      if (!vol_->isEOC(next)) goto fail;
+      *bgnBlock = vol_->clusterStartBlock(firstCluster_);
+      *endBlock = vol_->clusterStartBlock(c)
+                  + vol_->blocksPerCluster_ - 1;
+      return true;
+    }
+  }
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+/** Create and open a new contiguous file of a specified size.
+ *
+ * \note This function only supports short DOS 8.3 names.
+ * See open() for more information.
+ *
+ * \param[in] dirFile The directory where the file will be created.
+ * \param[in] path A path with a valid DOS 8.3 file name.
+ * \param[in] size The desired file size.
+ *
+ * \return The value one, true, is returned for success and
+ * the value zero, false, is returned for failure.
+ * Reasons for failure include \a path contains
+ * an invalid DOS 8.3 file name, the FAT volume has not been initialized,
+ * a file is already open, the file already exists, the root
+ * directory is full or an I/O error.
+ *
+ */
+bool SdBaseFile::createContiguous(SdBaseFile* dirFile,
+        const char* path, uint32_t size) {
+  uint32_t count;
+  // don't allow zero length file
+  if (size == 0) goto fail;
+  if (!open(dirFile, path, O_CREAT | O_EXCL | O_RDWR)) goto fail;
+
+  // calculate number of clusters needed
+  count = ((size - 1) >> (vol_->clusterSizeShift_ + 9)) + 1;
+
+  // allocate clusters
+  if (!vol_->allocContiguous(count, &firstCluster_)) {
+    remove();
+    goto fail;
+  }
+  fileSize_ = size;
+
+  // insure sync() will update dir entry
+  flags_ |= F_FILE_DIR_DIRTY;
+
+  return sync();
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+/** Return a file's directory entry.
+ *
+ * \param[out] dir Location for return of the file's directory entry.
+ *
+ * \return The value one, true, is returned for success and
+ * the value zero, false, is returned for failure.
+ */
+bool SdBaseFile::dirEntry(dir_t* dir) {
+  dir_t* p;
+  // make sure fields on SD are correct
+  if (!sync()) goto fail;
+
+  // read entry
+  p = cacheDirEntry(SdVolume::CACHE_FOR_READ);
+  if (!p) goto fail;
+
+  // copy to caller's struct
+  memcpy(dir, p, sizeof(dir_t));
+  return true;
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+/** Format the name field of \a dir into the 13 byte array
+ * \a name in standard 8.3 short name format.
+ *
+ * \param[in] dir The directory structure containing the name.
+ * \param[out] name A 13 byte char array for the formatted name.
+ */
+void SdBaseFile::dirName(const dir_t& dir, char* name) {
+  uint8_t j = 0;
+  for (uint8_t i = 0; i < 11; i++) {
+    if (dir.name[i] == ' ')continue;
+    if (i == 8) name[j++] = '.';
+    name[j++] = dir.name[i];
+  }
+  name[j] = 0;
+}
+//------------------------------------------------------------------------------
+/** Test for the existence of a file in a directory
+ *
+ * \param[in] name Name of the file to be tested for.
+ *
+ * The calling instance must be an open directory file.
+ *
+ * dirFile.exists("TOFIND.TXT") searches for "TOFIND.TXT" in  the directory
+ * dirFile.
+ *
+ * \return true if the file exists else false.
+ */
+bool SdBaseFile::exists(const char* name) {
+  SdBaseFile file;
+  return file.open(this, name, O_READ);
+}
+//------------------------------------------------------------------------------
+/**
+ * Get a string from a file.
+ *
+ * fgets() reads bytes from a file into the array pointed to by \a str, until
+ * \a num - 1 bytes are read, or a delimiter is read and transferred to \a str,
+ * or end-of-file is encountered. The string is then terminated
+ * with a null byte.
+ *
+ * fgets() deletes CR, '\\r', from the string.  This insures only a '\\n'
+ * terminates the string for Windows text files which use CRLF for newline.
+ *
+ * \param[out] str Pointer to the array where the string is stored.
+ * \param[in] num Maximum number of characters to be read
+ * (including the final null byte). Usually the length
+ * of the array \a str is used.
+ * \param[in] delim Optional set of delimiters. The default is "\n".
+ *
+ * \return For success fgets() returns the length of the string in \a str.
+ * If no data is read, fgets() returns zero for EOF or -1 if an error occurred.
+ **/
+int16_t SdBaseFile::fgets(char* str, int16_t num, char* delim) {
+  char ch;
+  int16_t n = 0;
+  int16_t r = -1;
+  while ((n + 1) < num && (r = read(&ch, 1)) == 1) {
+    // delete CR
+    if (ch == '\r') continue;
+    str[n++] = ch;
+    if (!delim) {
+      if (ch == '\n') break;
+    } else {
+      if (strchr(delim, ch)) break;
+    }
+  }
+  if (r < 0) {
+    // read error
+    return -1;
+  }
+  str[n] = '\0';
+  return n;
+}
+//------------------------------------------------------------------------------
+/** Get a file's name
+ *
+ * \param[out] name An array of 13 characters for the file's name.
+ *
+ * \return The value one, true, is returned for success and
+ * the value zero, false, is returned for failure.
+ */
+bool SdBaseFile::getFilename(char* name) {
+  if (!isOpen()) return false;
+
+  if (isRoot()) {
+    name[0] = '/';
+    name[1] = '\0';
+    return true;
+  }
+  // cache entry
+  dir_t* p = cacheDirEntry(SdVolume::CACHE_FOR_READ);
+  if (!p) return false;
+
+  // format name
+  dirName(*p, name);
+  return true;
+}
+//------------------------------------------------------------------------------
+void SdBaseFile::getpos(fpos_t* pos) {
+  pos->position = curPosition_;
+  pos->cluster = curCluster_;
+}
+
+//------------------------------------------------------------------------------
+/** List directory contents.
+ *
+ * \param[in] pr Print stream for list.
+ *
+ * \param[in] flags The inclusive OR of
+ *
+ * LS_DATE - %Print file modification date
+ *
+ * LS_SIZE - %Print file size.
+ *
+ * LS_R - Recursive list of subdirectories.
+ *
+ * \param[in] indent Amount of space before file name. Used for recursive
+ * list to indicate subdirectory level.
+ */
+void SdBaseFile::ls(uint8_t flags, uint8_t indent) {
+  rewind();
+  int8_t status;
+  while ((status = lsPrintNext( flags, indent))) {
+    if (status > 1 && (flags & LS_R)) {
+      uint16_t index = curPosition()/32 - 1;
+      SdBaseFile s;
+      if (s.open(this, index, O_READ)) s.ls( flags, indent + 2);
+      seekSet(32 * (index + 1));
+    }
+  }
+}
+//------------------------------------------------------------------------------
+// saves 32 bytes on stack for ls recursion
+// return 0 - EOF, 1 - normal file, or 2 - directory
+int8_t SdBaseFile::lsPrintNext( uint8_t flags, uint8_t indent) {
+  dir_t dir;
+  uint8_t w = 0;
+
+  while (1) {
+    if (read(&dir, sizeof(dir)) != sizeof(dir)) return 0;
+    if (dir.name[0] == DIR_NAME_FREE) return 0;
+
+    // skip deleted entry and entries for . and  ..
+    if (dir.name[0] != DIR_NAME_DELETED && dir.name[0] != '.'
+      && DIR_IS_FILE_OR_SUBDIR(&dir)) break;
+  }
+  // indent for dir level
+  for (uint8_t i = 0; i < indent; i++) MYSERIAL.write(' ');
+
+  // print name
+  for (uint8_t i = 0; i < 11; i++) {
+    if (dir.name[i] == ' ')continue;
+    if (i == 8) {
+      MYSERIAL.write('.');
+      w++;
+    }
+    MYSERIAL.write(dir.name[i]);
+    w++;
+  }
+  if (DIR_IS_SUBDIR(&dir)) {
+    MYSERIAL.write('/');
+    w++;
+  }
+  if (flags & (LS_DATE | LS_SIZE)) {
+    while (w++ < 14) MYSERIAL.write(' ');
+  }
+  // print modify date/time if requested
+  if (flags & LS_DATE) {
+    MYSERIAL.write(' ');
+    printFatDate( dir.lastWriteDate);
+    MYSERIAL.write(' ');
+    printFatTime( dir.lastWriteTime);
+  }
+  // print size if requested
+  if (!DIR_IS_SUBDIR(&dir) && (flags & LS_SIZE)) {
+    MYSERIAL.write(' ');
+    MYSERIAL.print(dir.fileSize);
+  }
+  MYSERIAL.println();
+  return DIR_IS_FILE(&dir) ? 1 : 2;
+}
+//------------------------------------------------------------------------------
+// format directory name field from a 8.3 name string
+bool SdBaseFile::make83Name(const char* str, uint8_t* name, const char** ptr) {
+  uint8_t c;
+  uint8_t n = 7;  // max index for part before dot
+  uint8_t i = 0;
+  // blank fill name and extension
+  while (i < 11) name[i++] = ' ';
+  i = 0;
+  while (*str != '\0' && *str != '/') {
+    c = *str++;
+    if (c == '.') {
+      if (n == 10) goto fail;  // only one dot allowed
+      n = 10;  // max index for full 8.3 name
+      i = 8;   // place for extension
+    } else {
+      // illegal FAT characters
+      PGM_P p = PSTR("|<>^+=?/[];,*\"\\");
+      uint8_t b;
+      while ((b = pgm_read_byte(p++))) if (b == c) goto fail;
+      // check size and only allow ASCII printable characters
+      if (i > n || c < 0X21 || c > 0X7E)goto fail;
+      // only upper case allowed in 8.3 names - convert lower to upper
+      name[i++] = c < 'a' || c > 'z' ?  c : c + ('A' - 'a');
+    }
+  }
+  *ptr = str;
+  // must have a file name, extension is optional
+  return name[0] != ' ';
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+/** Make a new directory.
+ *
+ * \param[in] parent An open SdFat instance for the directory that will contain
+ * the new directory.
+ *
+ * \param[in] path A path with a valid 8.3 DOS name for the new directory.
+ *
+ * \param[in] pFlag Create missing parent directories if true.
+ *
+ * \return The value one, true, is returned for success and
+ * the value zero, false, is returned for failure.
+ * Reasons for failure include this file is already open, \a parent is not a
+ * directory, \a path is invalid or already exists in \a parent.
+ */
+bool SdBaseFile::mkdir(SdBaseFile* parent, const char* path, bool pFlag) {
+  uint8_t dname[11];
+  SdBaseFile dir1, dir2;
+  SdBaseFile* sub = &dir1;
+  SdBaseFile* start = parent;
+
+  if (!parent || isOpen()) goto fail;
+
+  if (*path == '/') {
+    while (*path == '/') path++;
+    if (!parent->isRoot()) {
+      if (!dir2.openRoot(parent->vol_)) goto fail;
+      parent = &dir2;
+    }
+  }
+  while (1) {
+    if (!make83Name(path, dname, &path)) goto fail;
+    while (*path == '/') path++;
+    if (!*path) break;
+    if (!sub->open(parent, dname, O_READ)) {
+      if (!pFlag || !sub->mkdir(parent, dname)) {
+        goto fail;
+      }
+    }
+    if (parent != start) parent->close();
+    parent = sub;
+    sub = parent != &dir1 ? &dir1 : &dir2;
+  }
+  return mkdir(parent, dname);
+
+  fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+bool SdBaseFile::mkdir(SdBaseFile* parent, const uint8_t dname[11]) {
+  uint32_t block;
+  dir_t d;
+  dir_t* p;
+
+  if (!parent->isDir()) goto fail;
+
+  // create a normal file
+  if (!open(parent, dname, O_CREAT | O_EXCL | O_RDWR)) goto fail;
+
+  // convert file to directory
+  flags_ = O_READ;
+  type_ = FAT_FILE_TYPE_SUBDIR;
+
+  // allocate and zero first cluster
+  if (!addDirCluster())goto fail;
+
+  // force entry to SD
+  if (!sync()) goto fail;
+
+  // cache entry - should already be in cache due to sync() call
+  p = cacheDirEntry(SdVolume::CACHE_FOR_WRITE);
+  if (!p) goto fail;
+
+  // change directory entry  attribute
+  p->attributes = DIR_ATT_DIRECTORY;
+
+  // make entry for '.'
+  memcpy(&d, p, sizeof(d));
+  d.name[0] = '.';
+  for (uint8_t i = 1; i < 11; i++) d.name[i] = ' ';
+
+  // cache block for '.'  and '..'
+  block = vol_->clusterStartBlock(firstCluster_);
+  if (!vol_->cacheRawBlock(block, SdVolume::CACHE_FOR_WRITE)) goto fail;
+
+  // copy '.' to block
+  memcpy(&vol_->cache()->dir[0], &d, sizeof(d));
+
+  // make entry for '..'
+  d.name[1] = '.';
+  if (parent->isRoot()) {
+    d.firstClusterLow = 0;
+    d.firstClusterHigh = 0;
+  } else {
+    d.firstClusterLow = parent->firstCluster_ & 0XFFFF;
+    d.firstClusterHigh = parent->firstCluster_ >> 16;
+  }
+  // copy '..' to block
+  memcpy(&vol_->cache()->dir[1], &d, sizeof(d));
+
+  // write first block
+  return vol_->cacheFlush();
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+ /** Open a file 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).
+  *
+  * \return The value one, true, is returned for success and
+  * the value zero, false, is returned for failure.
+  */
+  bool SdBaseFile::open(const char* path, uint8_t oflag) {
+    return open(cwd_, path, oflag);
+  }
+//------------------------------------------------------------------------------
+/** Open a file or directory by name.
+ *
+ * \param[in] dirFile An open SdFat instance for the directory containing the
+ * file to be opened.
+ *
+ * \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 flags from the following list
+ *
+ * O_READ - Open for reading.
+ *
+ * O_RDONLY - Same as O_READ.
+ *
+ * O_WRITE - Open for writing.
+ *
+ * O_WRONLY - Same as O_WRITE.
+ *
+ * O_RDWR - Open for reading and writing.
+ *
+ * O_APPEND - If set, the file offset shall be set to the end of the
+ * file prior to each write.
+ *
+ * O_AT_END - Set the initial position at the end of the file.
+ *
+ * O_CREAT - If the file exists, this flag has no effect except as noted
+ * under O_EXCL below. Otherwise, the file shall be created
+ *
+ * O_EXCL - If O_CREAT and O_EXCL are set, open() shall fail if the file exists.
+ *
+ * O_SYNC - Call sync() after each write.  This flag should not be used with
+ * write(uint8_t), write_P(PGM_P), writeln_P(PGM_P), or the Arduino Print class.
+ * These functions do character at a time writes so sync() will be called
+ * after each byte.
+ *
+ * O_TRUNC - If the file exists and is a regular file, and the file is
+ * successfully opened and is not read only, its length shall be truncated to 0.
+ *
+ * WARNING: A given file must not be opened by more than one SdBaseFile object
+ * of file corruption may occur.
+ *
+ * \note Directory files must be opened read only.  Write and truncation is
+ * not allowed for directory files.
+ *
+ * \return The value one, true, is returned for success and
+ * the value zero, false, is returned for failure.
+ * Reasons for failure include this file is already open, \a dirFile is not
+ * a directory, \a path is invalid, the file does not exist
+ * or can't be opened in the access mode specified by oflag.
+ */
+bool SdBaseFile::open(SdBaseFile* dirFile, const char* path, uint8_t oflag) {
+  uint8_t dname[11];
+  SdBaseFile dir1, dir2;
+  SdBaseFile *parent = dirFile;
+  SdBaseFile *sub = &dir1;
+
+  if (!dirFile) goto fail;
+
+  // error if already open
+  if (isOpen()) goto fail;
+
+  if (*path == '/') {
+    while (*path == '/') path++;
+    if (!dirFile->isRoot()) {
+      if (!dir2.openRoot(dirFile->vol_)) goto fail;
+      parent = &dir2;
+    }
+  }
+  while (1) {
+    if (!make83Name(path, dname, &path)) goto fail;
+    while (*path == '/') path++;
+    if (!*path) break;
+    if (!sub->open(parent, dname, O_READ)) goto fail;
+    if (parent != dirFile) parent->close();
+    parent = sub;
+    sub = parent != &dir1 ? &dir1 : &dir2;
+  }
+  return open(parent, dname, oflag);
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+// open with filename in dname
+bool SdBaseFile::open(SdBaseFile* dirFile,
+  const uint8_t dname[11], uint8_t oflag) {
+  bool emptyFound = false;
+  bool fileFound = false;
+  uint8_t index;
+  dir_t* p;
+
+  vol_ = dirFile->vol_;
+
+  dirFile->rewind();
+  // search for file
+
+  while (dirFile->curPosition_ < dirFile->fileSize_) {
+    index = 0XF & (dirFile->curPosition_ >> 5);
+    p = dirFile->readDirCache();
+    if (!p) goto fail;
+
+    if (p->name[0] == DIR_NAME_FREE || p->name[0] == DIR_NAME_DELETED) {
+      // remember first empty slot
+      if (!emptyFound) {
+        dirBlock_ = dirFile->vol_->cacheBlockNumber();
+        dirIndex_ = index;
+        emptyFound = true;
+      }
+      // done if no entries follow
+      if (p->name[0] == DIR_NAME_FREE) break;
+    } else if (!memcmp(dname, p->name, 11)) {
+      fileFound = true;
+      break;
+    }
+  }
+  if (fileFound) {
+    // don't open existing file if O_EXCL
+    if (oflag & O_EXCL) goto fail;
+  } else {
+    // don't create unless O_CREAT and O_WRITE
+    if (!(oflag & O_CREAT) || !(oflag & O_WRITE)) goto fail;
+    if (emptyFound) {
+      index = dirIndex_;
+      p = cacheDirEntry(SdVolume::CACHE_FOR_WRITE);
+      if (!p) goto fail;
+    } else {
+      if (dirFile->type_ == FAT_FILE_TYPE_ROOT_FIXED) goto fail;
+
+      // add and zero cluster for dirFile - first cluster is in cache for write
+      if (!dirFile->addDirCluster()) goto fail;
+
+      // use first entry in cluster
+      p = dirFile->vol_->cache()->dir;
+      index = 0;
+    }
+    // initialize as empty file
+    memset(p, 0, sizeof(dir_t));
+    memcpy(p->name, dname, 11);
+
+    // set timestamps
+    if (dateTime_) {
+      // call user date/time function
+      dateTime_(&p->creationDate, &p->creationTime);
+    } else {
+      // use default date/time
+      p->creationDate = FAT_DEFAULT_DATE;
+      p->creationTime = FAT_DEFAULT_TIME;
+    }
+    p->lastAccessDate = p->creationDate;
+    p->lastWriteDate = p->creationDate;
+    p->lastWriteTime = p->creationTime;
+
+    // write entry to SD
+    if (!dirFile->vol_->cacheFlush()) goto fail;
+  }
+  // open entry in cache
+  return openCachedEntry(index, oflag);
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+/** Open a file by index.
+ *
+ * \param[in] dirFile An open SdFat instance for the directory.
+ *
+ * \param[in] index The \a index of the directory entry for the file to be
+ * opened.  The value for \a index is (directory file position)/32.
+ *
+ * \param[in] oflag Values for \a oflag are constructed by a bitwise-inclusive
+ * OR of flags O_READ, O_WRITE, O_TRUNC, and O_SYNC.
+ *
+ * See open() by path for definition of flags.
+ * \return true for success or false for failure.
+ */
+bool SdBaseFile::open(SdBaseFile* dirFile, uint16_t index, uint8_t oflag) {
+  dir_t* p;
+
+  vol_ = dirFile->vol_;
+
+  // error if already open
+  if (isOpen() || !dirFile) goto fail;
+
+  // don't open existing file if O_EXCL - user call error
+  if (oflag & O_EXCL) goto fail;
+
+  // seek to location of entry
+  if (!dirFile->seekSet(32 * index)) goto fail;
+
+  // read entry into cache
+  p = dirFile->readDirCache();
+  if (!p) goto fail;
+
+  // error if empty slot or '.' or '..'
+  if (p->name[0] == DIR_NAME_FREE ||
+      p->name[0] == DIR_NAME_DELETED || p->name[0] == '.') {
+    goto fail;
+  }
+  // open cached entry
+  return openCachedEntry(index & 0XF, oflag);
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+// open a cached directory entry. Assumes vol_ is initialized
+bool SdBaseFile::openCachedEntry(uint8_t dirIndex, uint8_t oflag) {
+  // location of entry in cache
+  dir_t* p = &vol_->cache()->dir[dirIndex];
+
+  // write or truncate is an error for a directory or read-only file
+  if (p->attributes & (DIR_ATT_READ_ONLY | DIR_ATT_DIRECTORY)) {
+    if (oflag & (O_WRITE | O_TRUNC)) goto fail;
+  }
+  // remember location of directory entry on SD
+  dirBlock_ = vol_->cacheBlockNumber();
+  dirIndex_ = dirIndex;
+
+  // copy first cluster number for directory fields
+  firstCluster_ = (uint32_t)p->firstClusterHigh << 16;
+  firstCluster_ |= p->firstClusterLow;
+
+  // make sure it is a normal file or subdirectory
+  if (DIR_IS_FILE(p)) {
+    fileSize_ = p->fileSize;
+    type_ = FAT_FILE_TYPE_NORMAL;
+  } else if (DIR_IS_SUBDIR(p)) {
+    if (!vol_->chainSize(firstCluster_, &fileSize_)) goto fail;
+    type_ = FAT_FILE_TYPE_SUBDIR;
+  } else {
+    goto fail;
+  }
+  // save open flags for read/write
+  flags_ = oflag & F_OFLAG;
+
+  // set to start of file
+  curCluster_ = 0;
+  curPosition_ = 0;
+  if ((oflag & O_TRUNC) && !truncate(0)) return false;
+  return oflag & O_AT_END ? seekEnd(0) : true;
+
+ fail:
+  type_ = FAT_FILE_TYPE_CLOSED;
+  return false;
+}
+//------------------------------------------------------------------------------
+/** Open the next file or subdirectory in a directory.
+ *
+ * \param[in] dirFile An open SdFat instance for the directory containing the
+ * file to be opened.
+ *
+ * \param[in] oflag Values for \a oflag are constructed by a bitwise-inclusive
+ * OR of flags O_READ, O_WRITE, O_TRUNC, and O_SYNC.
+ *
+ * See open() by path for definition of flags.
+ * \return true for success or false for failure.
+ */
+bool SdBaseFile::openNext(SdBaseFile* dirFile, uint8_t oflag) {
+  dir_t* p;
+  uint8_t index;
+
+  if (!dirFile) goto fail;
+
+  // error if already open
+  if (isOpen()) goto fail;
+
+  vol_ = dirFile->vol_;
+
+  while (1) {
+    index = 0XF & (dirFile->curPosition_ >> 5);
+
+    // read entry into cache
+    p = dirFile->readDirCache();
+    if (!p) goto fail;
+
+    // done if last entry
+    if (p->name[0] == DIR_NAME_FREE) goto fail;
+
+    // skip empty slot or '.' or '..'
+    if (p->name[0] == DIR_NAME_DELETED || p->name[0] == '.') {
+      continue;
+    }
+    // must be file or dir
+    if (DIR_IS_FILE_OR_SUBDIR(p)) {
+      return openCachedEntry(index, oflag);
+    }
+  }
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+/** Open a directory's parent directory.
+ *
+ * \param[in] dir Parent of this directory will be opened.  Must not be root.
+ *
+ * \return The value one, true, is returned for success and
+ * the value zero, false, is returned for failure.
+ */
+bool SdBaseFile::openParent(SdBaseFile* dir) {
+  dir_t entry;
+  dir_t* p;
+  SdBaseFile file;
+  uint32_t c;
+  uint32_t cluster;
+  uint32_t lbn;
+  // error if already open or dir is root or dir is not a directory
+  if (isOpen() || !dir || dir->isRoot() || !dir->isDir()) goto fail;
+  vol_ = dir->vol_;
+  // position to '..'
+  if (!dir->seekSet(32)) goto fail;
+  // read '..' entry
+  if (dir->read(&entry, sizeof(entry)) != 32) goto fail;
+  // verify it is '..'
+  if (entry.name[0] != '.' || entry.name[1] != '.') goto fail;
+  // start cluster for '..'
+  cluster = entry.firstClusterLow;
+  cluster |= (uint32_t)entry.firstClusterHigh << 16;
+  if (cluster == 0) return openRoot(vol_);
+  // start block for '..'
+  lbn = vol_->clusterStartBlock(cluster);
+  // first block of parent dir
+  if (!vol_->cacheRawBlock(lbn, SdVolume::CACHE_FOR_READ)) {
+    goto fail;
+  }
+  p = &vol_->cacheBuffer_.dir[1];
+  // verify name for '../..'
+  if (p->name[0] != '.' || p->name[1] != '.') goto fail;
+  // '..' is pointer to first cluster of parent. open '../..' to find parent
+  if (p->firstClusterHigh == 0 && p->firstClusterLow == 0) {
+    if (!file.openRoot(dir->volume())) goto fail;
+  } else {
+    if (!file.openCachedEntry(1, O_READ)) goto fail;
+  }
+  // search for parent in '../..'
+  do {
+    if (file.readDir(&entry) != 32) goto fail;
+    c = entry.firstClusterLow;
+    c |= (uint32_t)entry.firstClusterHigh << 16;
+  } while (c != cluster);
+  // open parent
+  return open(&file, file.curPosition()/32 - 1, O_READ);
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+/** Open a volume's root directory.
+ *
+ * \param[in] vol The FAT volume containing the root directory to be opened.
+ *
+ * \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 already open, the FAT volume has
+ * not been initialized or it a FAT12 volume.
+ */
+bool SdBaseFile::openRoot(SdVolume* vol) {
+  // error if file is already open
+  if (isOpen()) goto fail;
+
+  if (vol->fatType() == 16 || (FAT12_SUPPORT && vol->fatType() == 12)) {
+    type_ = FAT_FILE_TYPE_ROOT_FIXED;
+    firstCluster_ = 0;
+    fileSize_ = 32 * vol->rootDirEntryCount();
+  } else if (vol->fatType() == 32) {
+    type_ = FAT_FILE_TYPE_ROOT32;
+    firstCluster_ = vol->rootDirStart();
+    if (!vol->chainSize(firstCluster_, &fileSize_)) goto fail;
+  } else {
+    // volume is not initialized, invalid, or FAT12 without support
+    return false;
+  }
+  vol_ = vol;
+  // read only
+  flags_ = O_READ;
+
+  // set to start of file
+  curCluster_ = 0;
+  curPosition_ = 0;
+
+  // root has no directory entry
+  dirBlock_ = 0;
+  dirIndex_ = 0;
+  return true;
+
+ fail:
+  return false;
+}
+//------------------------------------------------------------------------------
+/** Return the next available byte without consuming it.
+ *
+ * \return The byte if no error and not at eof else -1;
+ */
+int SdBaseFile::peek() {
+  fpos_t pos;
+  getpos(&pos);
+  int c = read();
+  if (c >= 0) setpos(&pos);
+  return c;
+}
+
+//------------------------------------------------------------------------------
+/** %Print the name field of a directory entry in 8.3 format.
+ * \param[in] pr Print stream for output.
+ * \param[in] dir The directory structure containing the name.
+ * \param[in] width Blank fill name if length is less than \a width.
+ * \param[in] printSlash Print '/' after directory names if true.
+ */
+void SdBaseFile::printDirName(const dir_t& dir,
+  uint8_t width, bool printSlash) {
+  uint8_t w = 0;
+  for (uint8_t i = 0; i < 11; i++) {
+    if (dir.name[i] == ' ')continue;
+    if (i == 8) {
+      MYSERIAL.write('.');
+      w++;
+    }
+    MYSERIAL.write(dir.name[i]);
+    w++;
+  }
+  if (DIR_IS_SUBDIR(&dir) && printSlash) {
+    MYSERIAL.write('/');
+    w++;
+  }
+  while (w < width) {
+    MYSERIAL.write(' ');
+    w++;
+  }
+}
+//------------------------------------------------------------------------------
+// print uint8_t with width 2
+static void print2u( uint8_t v) {
+  if (v < 10) MYSERIAL.write('0');
+  MYSERIAL.print(v, DEC);
+}
+//------------------------------------------------------------------------------
+/** %Print a directory date field to Serial.
+ *
+ *  Format is yyyy-mm-dd.
+ *
+ * \param[in] fatDate The date field from a directory entry.
+ */
+
+//------------------------------------------------------------------------------
+/** %Print a directory date field.
+ *
+ *  Format is yyyy-mm-dd.
+ *
+ * \param[in] pr Print stream for output.
+ * \param[in] fatDate The date field from a directory entry.
+ */
+void SdBaseFile::printFatDate(uint16_t fatDate) {
+  MYSERIAL.print(FAT_YEAR(fatDate));
+  MYSERIAL.write('-');
+  print2u( FAT_MONTH(fatDate));
+  MYSERIAL.write('-');
+  print2u( FAT_DAY(fatDate));
+}
+
+//------------------------------------------------------------------------------
+/** %Print a directory time field.
+ *
+ * Format is hh:mm:ss.
+ *
+ * \param[in] pr Print stream for output.
+ * \param[in] fatTime The time field from a directory entry.
+ */
+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[13];
+  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 directory entry from a directory file.
+ *
+ * \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) {
+  int16_t n;
+  // if not a directory file or miss-positioned return an error
+  if (!isDir() || (0X1F & curPosition_)) return -1;
+
+  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;
+    // 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

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