Read entire file into stringstream

How much work is being done in the processing. I would stick with what you have, measure the system when it is complete, and the decide if the potential performance gains would be worth it. Of course if memory is tight, this is in an inner loop, or a program that gets called often like once a second , that changes the balance.

Reading the entire file into memory at once will be much faster than separate reads. Tags: file , string. Questions: I wrote a simple program to play around with in-place creation of objects inside standard library containers. Questions: How can I make this simple class movable? Caution: updating the value of the memory mapped variable will update the file, and this characteristic remains when the variable's value is passed, unmodified, to a verb which modifies its own local variables.

There is no single method to do this in Java 6 and below probably because reading an entire file at once could fill up your memory quickly , so to do this you could simply append the contents as you read them into a buffer. One can memory-map the file in Java, but there's little to gain if one is to create a String out of the file:.

Java 7 added java. Files which has two methods for accomplishing this task: Files. In practice, this is probably not very useful. It would be more typical to collect the raw lines into an array of JSON strings.

The built-in function read , when used with a second argument of String, reads the whole file named by its first argument into a string assuming UTF8 encoding.

Alternatively, for files that are too large to read into memory without swapping, there are a variety of ways to memory-map the file, for example as an array of bytes:. The built-in function io:readFile will read the entire content of the file as a string:. You can download it, then drag-and-drop it onto the LabVIEW block diagram from a file browser, and it will appear as runnable, editable code. By default, string objects, which are always Unicode, are created with the assumption that the file contains UTF-8 encoded data.

When reading the data as a bytes object, the unaltered file data is returned. An approximation to file reading can be had by include which reads a file as M4 input. If it's inside a define then the input is captured as a definition. But this is extremely limited since any macro names, parens, commas, quote characters etc in the file will expand and upset the capture. This is from the GNU Make manual. This might be acceptable for files which are a list of words anyway.

We can replace the last line with the one below if we want to return a type string instead of bytes :. This maximum size is available with the variable Sys. On 32 bit machines this size is about 16Mo. To load bigger files several solutions exist, for example create a structure that contains several strings where the contents of the file can be split.

Or another solution that is often used is to use a bigarray of chars instead of a string:. Then the length of the data can be get with Bigarray. Streams are opened on demand and closed when the script finishes. It is possible if you wish to open and close the streams explicitly. FileContents is a list of bytes. The operation does not assume any particular encoding. The GP interpreter's ability to read files is extremely limited; reading an entire file is almost all that it can do.

They can be concatenated to make a single string. Since readstr returns strings without newlines there's no way to tell whether the last line had a newline or not. This is fine for its intended use on text files, but not good for reading binary files.

See TStrignList example of Delphi. For a one-liner from shell, use -0[code]. File::Map has the advantage of not requiring an explicit munmap. Its tie is faster than the tie form of Sys::Mmap too. Using ' till ' is the shortest way:. With explicit selection of encoding:.

However, both return an array of strings which is fine for pipeline use but if a single string is desired the array needs to be joined:. Since PureBasic terminates strings with a NULL and also split the ReadString is encountering new line chars, any file containing these must be treated as a data stream.

This function accepts a file FolderItem object and an optional TextEncoding class. Since it is intended for cross-platform development, REALbasic has a number of built-in tools for working with different text encodings, line terminators, etc.

To open an arbitrary path which might start with " " , you must use File. The library getf. Reading an entire file as a string, can be achieved with the FileHandle. After the association, each reference to the named variable provides as the variable's value the next block or line of data from the corresponding file.

The exact format of the input function parameters tends to vary based on the implementation in use. In this example, the code reads the file in blocks of k bytes or less until the entire file has been read into one long string in memory. It's possible to get the entire content as an array of lines with cat. However, here we want a single string. See fopen and related functions. OpenText method opens an existing UTF-8 encoded text file for reading.

To open a file with some other character encoding, use the StreamReader class constructor, which optionally takes a specific character encoding. Download Run Code. Average rating 4. Vote count: No votes so far! Be the first to rate this post. Primary Primary. Skip to content. Using File. ReadAllText method System. IO The recommended solution to read all the text in the file into a string is to use the File. ReadAllText fileName ;.

WriteLine text ;.