C++ SdBaseFile::open方法代码示例

/** Change a volume's working directory
 *
 * Changes the volume working directory to the \a path subdirectory.
 * Optionally set the current working directory to the volume's
 * working directory.
 *
 * Example: If the volume's working directory is "/DIR", chdir("SUB")
 * will change the volume's working directory from "/DIR" to "/DIR/SUB".
 *
 * If path is "/", the volume's working directory will be changed to the
 * root directory
 *
 * \param[in] path The name of the subdirectory.
 *
 * \param[in] set_cwd Set the current working directory to this volume's
 *  working directory if true.
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 */
bool SdFat::chdir(const char *path, bool set_cwd) {
    SdBaseFile dir;
    if (path[0] == '/' && path[1] == '\0') return chdir(set_cwd);
    if (!dir.open(&m_vwd, path, O_READ)) goto fail;
    if (!dir.isDir()) goto fail;
    m_vwd = dir;
    if (set_cwd) SdBaseFile::setCwd(&m_vwd);
    return true;

fail:
    return false;
}

void CardReader::chdir(const char* relpath) {
  SdBaseFile newfile;
  SdBaseFile* parent = &root;
  if (workDir.isOpen()) parent = &workDir;
  if (!newfile.open(parent, relpath, O_READ)) {
    ECHO_LMT(DB, SERIAL_SD_CANT_ENTER_SUBDIR, relpath);
  }
  else {
    if (workDirDepth < SD_MAX_FOLDER_DEPTH) {
      ++workDirDepth;
      for (int d = workDirDepth; d--;) workDirParents[d + 1] = workDirParents[d];
      workDirParents[0] = *parent;
    }
    workDir = newfile;
  }
}

void SDCard::JSONFileInfo(const char* filename) {
    SdBaseFile targetFile;
    GCodeFileInfo *info,tmpInfo;
    if (strlen(filename) == 0)  {
        targetFile = file;
        info = &fileInfo;
    } else {
        if (!targetFile.open(fat.vwd(), filename, O_READ) || targetFile.isDir()) {
            Com::printF(Com::tJSONErrorStart);
            Com::printF(Com::tFileOpenFailed);
            Com::printFLN(Com::tJSONErrorEnd);
            return;
        }
        info = &tmpInfo;
        info->init(targetFile);
    }
    if (!targetFile.isOpen()) {
        Com::printF(Com::tJSONErrorStart);
        Com::printF(Com::tNotSDPrinting);
        Com::printFLN(Com::tJSONErrorEnd);
        return;
    }

    // {"err":0,"size":457574,"height":4.00,"layerHeight":0.25,"filament":[6556.3],"generatedBy":"Slic3r 1.1.7 on 2014-11-09 at 17:11:32"}
    Com::printF(Com::tJSONFileInfoStart);
    Com::print(info->fileSize);
    Com::printF(Com::tJSONFileInfoHeight);
    Com::print(info->objectHeight);
    Com::printF(Com::tJSONFileInfoLayerHeight);
    Com::print(info->layerHeight);
    Com::printF(Com::tJSONFileInfoFilament);
    Com::print(info->filamentNeeded);
    Com::printF(Com::tJSONFileInfoGeneratedBy);
    Com::print(info->generatedBy);
    Com::print('"');
    if (strlen(filename) == 0) {
        Com::printF(Com::tJSONFileInfoName);
        file.printName();
        Com::print('"');
    }
    Com::print('}');
    Com::println();
};

void SDCard::lsJSON(const char *filename)
{
    SdBaseFile dir;
    fat.chdir();
    if (*filename == 0) {
        dir.openRoot(fat.vol());
    } else {
        if (!dir.open(fat.vwd(), filename, O_READ) || !dir.isDir()) {
            Com::printF(Com::tJSONErrorStart);
            Com::printF(Com::tFileOpenFailed);
            Com::printFLN(Com::tJSONErrorEnd);
            return;
        }
    }

    Com::printF(Com::tJSONDir);
    SDCard::printEscapeChars(filename);
    Com::printF(Com::tJSONFiles);
    dir.lsJSON();
    Com::printFLN(Com::tJSONArrayEnd);
}

/** 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] path A path with a valid 8.3 DOS name for the 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 SdFat::truncate(const char* path, uint32_t length) {
    SdBaseFile file;
    if (!file.open(path, O_WRITE)) return false;
    return file.truncate(length);
}

/** Remove a subdirectory from the volume's working directory.
 *
 * \param[in] path A path with a valid 8.3 DOS name for the subdirectory.
 *
 * The subdirectory file will be removed only if it is empty.
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 */
bool SdFat::rmdir(const char* path) {
    SdBaseFile sub;
    if (!sub.open(path, O_READ)) return false;
    return sub.rmdir();
}

/** Rename a file or subdirectory.
 *
 * \param[in] oldPath Path name to the file or subdirectory to be renamed.
 *
 * \param[in] newPath New path name of the file or subdirectory.
 *
 * The \a newPath object must not exist before the rename call.
 *
 * The file to be renamed must not be open.  The directory entry may be
 * moved and file system corruption could occur if the file is accessed by
 * a file object that was opened before the rename() call.
 *
 * \return The value one, true, is returned for success and
 * the value zero, false, is returned for failure.
 */
bool SdFat::rename(const char *oldPath, const char *newPath) {
    SdBaseFile file;
    if (!file.open(oldPath, O_READ)) return false;
    return file.rename(&m_vwd, newPath);
}