Delphi ioutils

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Delphi ioutils

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Two methods are provided in each case, one that uses the platform default encoding and the other which allows you to specify an encoding. You are encouraged to always specify an encoding because relying on the platform default can lead to unexpected results, for example when moving from development to production. All the methods in this class that read a stream are buffered internally.

The default buffer size of 4K has been shown to be efficient in tests. Applications can re-use buffers by using the underlying methods directly. This may improve performance for applications that need to do a lot of copying. Wherever possible, the methods in this class do not flush or close the stream.

This is to avoid making non-portable assumptions about the streams' origin and further use. Thus the caller is still responsible for closing streams after use. Origin of code: Excalibur. As of 2. Please use the try-with-resources statement or handle suppressed exceptions manually.

Since: 2. Parameters: conn - the connection to close. Closes an Reader unconditionally. Equivalent to Reader. This is typically used in finally blocks.

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Closes an Writer unconditionally. Equivalent to Writer. Closes an InputStream unconditionally. Equivalent to InputStream. Closes an OutputStream unconditionally. Equivalent to OutputStream. Closes a Closeable unconditionally. Equivalent to Closeable.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. In IOUtils. For example IOUtils. In Embarcadero's code, CreateDirectory just raises an error. I can't use any of the functions in IOUtils. For example: My program needs to process some data in a folder and put the result back there and errors can appear quite often because of accidental wrong permissions on that folder.

The program has a lot of processing to do so it would be unreasonable for its user to let it work over night and find it in the morning stuck at 0. A log will show the failed operation. Other application is a console app.

delphi ioutils

Again, it needs to move on in case of an error. A simple writeln would be sufficient to display the message. I have my full blown library that does what IOUtils does but when possible without raising errors. Just think at it as a GUI-less application or an application that runs unsupervised so nobody would care what is the reason for which it failed one possible example would be a Service. So, is my design wrong?

Why did Embarcadero choose to raise errors instead of using Boolean returning functions? Isn't this wrong? How are they sure that the path was invalid?

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What if the path was correct but the drive was disconnected, or took fire? Or the folder is locked? Or other possible reasons I could came up with? The library still has old For example TDirectory. Learn more.

delphi ioutils

Asked 6 years, 1 month ago. Active 6 years, 1 month ago. Viewed times. A log will show the failed operation Other application is a console app. Update This is how Embarcadero proposes to use their unit: procedure TForm1. Delete edSourcePath. Update 2: The library still has old And GetCreationTime still does not work with some files. Migrate2Lazarus see my profile. Migrate2Lazarus see my profile Migrate2Lazarus see my profile Delphi IOUtils.

Accessing and changing Directories and Files in Delphi. Lots of procedures and functions available to use. IOUtils, System. Types; TDirectory - Any directory related operation 1. Create a new Diretory TDirectory. Delete an existing directory TDirectory. Check if Directory exists TDirectory. Copy a Directory from One folder to another TDirectory.

Move a Directory from One folder to another TDirectory. Find create time, last opened time and last modified time TDirectory. Get list of in a Directory procedure TForm1. Add strFiles[i] ; end; 7. Get list of Folder in Directory procedure TForm1. Add strFiles[i] ; end; 8.

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Get list of logical drives in our system procedure TForm1. Add strFiles[i] ; end; 9. TXT' ; 3. TXT' ; 4. TXT' ; 5. TXT' ; 6. TXT' ; 7. Write some data to file.Commons-IO contains utility classesendian classesline iteratorfile filtersfile comparators and stream implementations.

For a more detailed descriptions, take a look at the javadocs. IOUtils contains utility methods dealing with reading, writing and copying. As an example, consider the task of reading bytes from a URL, and printing them. This would typically done like this:. In certain application domains, such IO operations are common, and this class can save a great deal of time.

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And you can rely on well-tested code. For utility code such as this, flexibility and speed are of primary importance. However you should also understand the limitations of this approach.

Using the above technique to read a 1GB file would result in an attempt to create a 1GB String object! The FileUtils class contains utility methods for working with File objects. These include reading, writing, copying and comparing files. The FilenameUtils class contains utility methods for working with filenames without using File objects.

The class aims to be consistent between Unix and Windows, to aid transitions between these environments such as moving from development to production. The FileSystemUtils class contains utility methods for working with the file system to access functionality not supported by the JDK. Currently, the only method is to get the free space on a drive. Note that this uses the command line, not native code. Different computer architectures adopt different conventions for byte ordering.

In so-called "Little Endian" architectures eg Intelthe low-order byte is stored in memory at the lowest address, and subsequent bytes at higher addresses.

delphi ioutils

For "Big Endian" architectures eg Motorolathe situation is reversed. The org. LineIterator class provides a flexible way for working with a line-based file. The recommended usage pattern is:. FileFilter and java. Besides that the package offers a series of ready-to-use implementations of the IOFileFilter interface including implementation that allow you to combine other such filters. These filters can be used to list files or in FileDialog, for example.

See the filefilter package javadoc for more details.File instanced into array representation. Since: 2. Parameters: directory - the parent directory names - the name elements Returns: the file Since: 2.

delphi ioutils

Parameters: names - the name elements Returns: the file Since: 2. Returns: the path to the system temporary directory. Returns: the system temporary directory.

Returns: the path to the user's home directory.

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Returns: the user's home directory. At the end of the method either the stream will be successfully opened, or an exception will have been thrown. An exception is thrown if the file does not exist. An exception is thrown if the file object exists but is a directory. An exception is thrown if the file exists but cannot be read. The parent directory will be created if it does not exist. The file will be created if it does not exist.

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An exception is thrown if the file exists but cannot be written to. An exception is thrown if the parent directory cannot be created. Parameters: file - the file to open for output, must not be null Returns: a new FileOutputStream for the specified file Throws: IOException - if the file object is a directory IOException - if the file cannot be written to IOException - if a parent directory needs creating but that fails Since: 1.

Parameters: file - the file to open for output, must not be null append - if truethen bytes will be added to the end of the file rather than overwriting Returns: a new FileOutputStream for the specified file Throws: IOException - if the file object is a directory IOException - if the file cannot be written to IOException - if a parent directory needs creating but that fails Since: 2.

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If the size is over 1GB, the size is returned as the number of whole GB, i. NOTE: As from v1. Also, as from v1. This is to account for the difference between File. Parameters: files - a Collection containing java. File instances Returns: an array of java.You seem to have CSS turned off.

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Categories Subversion. Calibre is a cross-platform open-source suite of e-book software. Calibre supports organizing existing e-books into virtual libraries, displaying, editing, creating and converting e-books, as well as syncing e-books with a variety of e-readers. Learn More. User Ratings 5.Class methods in records are used to group different methods into a common namespace. Thus you can have similar named methods for different purposes.

For an example in IOUtils. The older approach was to have distinct function names for FileExists and DirectoryExists which the implementations actually call. While class methods inside classes can be used in the same way, they can in addition have another goal: they can be virtual. Called from a class variable this can lead to different implementations depending on the current content of that variable. This is not possible for records. As a consequence class methods in records are always static.

I just started to play with the new unit in Delphi IOUtils. Is there any benefits of doing that inside records instead of classes? In both cases there's no need for any variables or instance, but I'm not sure if there any real benefits regarding memory consuming or performance improvement.

I would say that the first question to ask is "Why put such functions inside either a record or a class? The use of record methods as in IOUtils is in many cases largely arbitrary in Delphi and in part reflects a fetish with following conventions in other languages that are not directly relevant in Delphi. In some languages Java and. That is, procedures and functions cannot exist independently of any container class.

Hence in those languages if you have functions and procedures they must be contained in a class. If they do not operate on member data then obviously they are declared as class methods to avoid having to construct an instance merely to call what is in fact a classLESS function. Exists s and TFile. Exists s are syntactic alternatives to DirectoryExists s and FileExists s.

In Delphi first class functions are supported and there is therefore no real reason to use classes or records to discriminate between functions, except as a way of facilitating ease of reference for a developer when writing code and using IDE assistance to browse for available methods. With a container record, you only have to know that there is a type TDirectoryand the IDE via code completion suggestions can then present all of the "methods" available for TDirectory operations.


However, in Delphi there is an alternative made possible by the support for first class functions. Rather than using arbitrary and artificial "containers", you or rather the authors of IOUtils could instead have chosen to use the existing container - a Delphi "unit":. This still enjoys the benefits of IDE support in the form of code completion suggestions and also provides the namespace separation required to support identical function names operating on different things.

The downside of this approach and it is a big one is that where a unit uses both IOUtils. File and IOUtils. Directoryit must qualify one or other function name to avoid confusion, but this qualification could be omitted, which is why it is so dangerous:. Directory and need not qualify and repeat that fact anywhere other than in the uses clause. Filethen this could easily lead to scoping errors on any unqualified references.

For those reasons, the design choice in IOUtils at least is understandable and arguably a good one, tho ymmv. The unit that the functions must reside in may itself provide all the grouping behaviour you need.


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