Merge pull request #7 from SimonFrings/documentation

Update documentation and examples to match version in early access

.gitignore

@@ -0,0 +1,2 @@
+/composer.lock
+/vendor/

README.md

@@ -2,6 +2,34 @@
 
 Streaming TSV (Tab-Separated Values) parser and encoder for [ReactPHP](https://reactphp.org/).
 
+**Table of contents**
+
+* [Support us](#support-us)
+* [Quickstart example](#quickstart-example)
+* [TSV format](#tsv-format)
+* [Usage](#usage)
+    * [TsvDecoder](#tsvdecoder)
+    * [TsvEncoder](#tsvencoder)
+* [Install](#install)
+* [Tests](#tests)
+* [License](#license)
+* [More](#more)
+
+## Support us
+
+[![A clue·access project](https://raw.githubusercontent.com/clue-access/clue-access/main/clue-access.png)](https://github.com/clue-access/clue-access)
+
+*This project is currently under active development,
+you're looking at a temporary placeholder repository.*
+
+The code is available in early access to my sponsors here: https://github.com/clue-access/reactphp-tsv
+
+Do you sponsor me on GitHub? Thank you for supporting sustainable open-source, you're awesome! ❤️ Have fun with the code! 🎉
+
+Seeing a 404 (Not Found)? Sounds like you're not in the early access group. Consider becoming a [sponsor on GitHub](https://github.com/sponsors/clue) for early access. Check out [clue·access](https://github.com/clue-access/clue-access) for more details.
+
+This way, more people get a chance to take a look at the code before the public release.
+
 ## Quickstart example
 
 TSV (Tab-Separated Values) is a very simple text-based format for storing a
@@ -43,26 +71,293 @@ Carol's birthday is 2006-01-01
 Dave's birthday is 1995-01-01
 ```
 
+## TSV format
+
+TSV (Tab-Separated Values) is a very simple text-based format for storing a
+large number of (uniform) records, such as a list of temparature records or log
+entries.
+
+```
+name    birthday    ip
+Alice   2017-01-01  1.1.1.1
+Carol   2006-01-01  2.1.1.1
+Dave    1995-01-01  3.1.1.1
+```
+
+While this may look somewhat trivial, this simplicity comes at a price. TSV is
+limited to untyped, two-dimensional data, so there's no standard way of storing
+any nested structures or to differentiate a boolean value from a string or
+integer.
+
+While TSV may look somewhat similar to CSV (Comma-Separated Values or less
+commonly Character-Separated Values), it is more than just a small variation.
+
+* TSV always uses a tab stop (`\t`) as a delimiter between fields, CSV uses a
+  comma (`,`) by default, but some applications use variations such as a
+  semicolon (`;`) or other application-dependant characters (this is
+  particularly common for systems in Europe (and elsewhere) that use a comma as
+  decimal separator).
+* TSV always uses field names in the first row, CSV allows for optional field
+  names (which is application-dependant).
+* TSV always uses the same number of fields for all rows, CSV allows for rows
+  with different number of fields (though this is rarely used).
+* CSV requires quoting
+* CSV supports newlines and thus requires more advanced parsing rules
+* MIME type CSV is text/csv and for TSV text/tab-separated-values.
+* TSV is defined in a [simple document](https://www.iana.org/assignments/media-types/text/tab-separated-values),
+  while CSV is defined in a dedicated [RFC 4180](https://tools.ietf.org/html/rfc4180).
+  However many applications started using some CSV-variant long before this
+  standard was defined, so parsing rules differ somewhat between implementations.
+
+TSV files are commonly limited to only ASCII characters for best interoperability.
+However, many legacy TSV files often use ISO 8859-1 encoding or some other
+variant. Newer TSV files are usually best saved as UTF-8 and may thus also
+contain special characters from the Unicode range. The text-encoding is usually
+application-dependant, so your best bet would be to convert to (or assume) UTF-8
+consistently.
+
+Despite its shortcomings, TSV is widely used and this is unlikely to change any
+time soon. In particular, TSV is a very common export format for a lot of tools
+to interface with spreadsheet processors (such as Excel, Calc etc.). This means
+that TSV is often used for historical reasons and using TSV to store structured
+application data is usually not a good idea nowadays – but exporting to TSV for
+known applications continues to be a very reasonable approach.
+
+As an alternative, if you want to process structured data in a more modern
+JSON-based format, you may want to use [clue/reactphp-ndjson](https://github.com/clue/reactphp-ndjson)
+to process newline-delimited JSON (NDJSON) files (`.ndjson` file extension).
+
+```json
+{"name":"Alice","age":30,"comment":"Yes, I like cheese"}
+{"name":"Bob","age":50,"comment":"Hello\nWorld!"}
+```
+
+## Usage
+
+### TsvDecoder
+
+The `TsvDecoder` (parser) class can be used to make sure you only get back
+complete, valid TSV elements when reading from a stream.
+It wraps a given
+[`ReadableStreamInterface`](https://github.com/reactphp/stream#readablestreaminterface)
+and exposes its data through the same interface, but emits the TSV elements
+as parsed values instead of just chunks of strings:
+
+```
+name    age
+Alice   20
+Carol   30
+```
+
+```php
+$stdin = new React\Stream\ReadableResourceStream(STDIN);
+$stream = new Clue\React\Tsv\TsvDecoder($stdin);
+
+$stream->on('data', function ($data) {
+    // data is a parsed element from the TSV stream
+    // line 1: $data = array('name' => 'Alice', 'age' => '20');
+    // line 2: $data = array('name' => 'Carol', 'age' => '30');
+    var_dump($data);
+});
+```
+
+ReactPHP's streams emit chunks of data strings and make no assumption about their lengths.
+These chunks do not necessarily represent complete TSV elements, as an
+element may be broken up into multiple chunks.
+This class reassembles these elements by buffering incomplete ones.
+
+Accordingly, the `TsvDecoder` limits the maximum buffer size (maximum line
+length) to avoid buffer overflows due to malformed user input. Usually, there
+should be no need to change this value, unless you know you're dealing with some
+unreasonably long lines. It accepts an additional argument if you want to change
+this from the default of 64 KiB:
+
+```php
+$stream = new Clue\React\Tsv\TsvDecoder($stdin, 64 * 1024);
+```
+
+If the underlying stream emits an `error` event or the plain stream contains
+any data that does not represent a valid TSV stream,
+it will emit an `error` event and then `close` the input stream:
+
+```php
+$stream->on('error', function (Exception $error) {
+    // an error occured, stream will close next
+});
+```
+
+If the underlying stream emits an `end` event, it will flush any incomplete
+data from the buffer, thus either possibly emitting a final `data` event
+followed by an `end` event on success or an `error` event for
+incomplete/invalid TSV data as above:
+
+```php
+$stream->on('end', function () {
+    // stream successfully ended, stream will close next
+});
+```
+
+If either the underlying stream or the `TsvDecoder` is closed, it will forward
+the `close` event:
+
+```php
+$stream->on('close', function () {
+    // stream closed
+    // possibly after an "end" event or due to an "error" event
+});
+```
+
+The `close(): void` method can be used to explicitly close the `TsvDecoder` and
+its underlying stream:
+
+```php
+$stream->close();
+```
+
+The `pipe(WritableStreamInterface $dest, array $options = array(): WritableStreamInterface`
+method can be used to forward all data to the given destination stream.
+Please note that the `TsvDecoder` emits decoded/parsed data events, while many
+(most?) writable streams expect only data chunks:
+
+```php
+$stream->pipe($logger);
+```
+
+For more details, see ReactPHP's
+[`ReadableStreamInterface`](https://github.com/reactphp/stream#readablestreaminterface).
+
+### TsvEncoder
+
+The `TsvEncoder` (serializer) class can be used to make sure anything you write to
+a stream ends up as valid TSV elements in the resulting TSV stream.
+It wraps a given
+[`WritableStreamInterface`](https://github.com/reactphp/stream#writablestreaminterface)
+and accepts its data through the same interface, but handles any data as complete
+TSV elements instead of just chunks of strings:
+
+```php
+$stdout = new React\Stream\WritableResourceStream(STDOUT);
+$stream = new Clue\React\Tsv\TsvEncoder($stdout);
+
+$stream->write(array('name' => 'Alice', 'age' => '20'));
+$stream->write(array('name' => 'Carol', 'age' => '30'));
+```
+
+```
+name    age
+Alice   20
+Carol   30
+```
+
+If the underlying stream emits an `error` event or the given data contains
+any data that can not be represented as a valid TSV stream,
+it will emit an `error` event and then `close` the input stream:
+
+```php
+$stream->on('error', function (Exception $error) {
+    // an error occured, stream will close next
+});
+```
+
+If either the underlying stream or the `TsvEncoder` is closed, it will forward
+the `close` event:
+
+```php
+$stream->on('close', function () {
+    // stream closed
+    // possibly after an "end" event or due to an "error" event
+});
+```
+
+The `end(mixed $data = null): void` method can be used to optionally emit
+any final data and then soft-close the `TsvEncoder` and its underlying stream:
+
+```php
+$stream->end();
+```
+
+The `close(): void` method can be used to explicitly close the `TsvEncoder` and
+its underlying stream:
+
+```php
+$stream->close();
+```
+
+For more details, see ReactPHP's
+[`WritableStreamInterface`](https://github.com/reactphp/stream#writablestreaminterface).
+
 ## Install
 
-[![A clue·access project](https://raw.githubusercontent.com/clue-access/clue-access/main/clue-access.png)](https://github.com/clue-access/clue-access)
+The recommended way to install this library is [through Composer](https://getcomposer.org/).
+[New to Composer?](https://getcomposer.org/doc/00-intro.md)
 
-*This project is currently under active development,
-you're looking at a temporary placeholder repository.*
+This project does not yet follow [SemVer](https://semver.org/).
+This will install the latest supported version:
 
-The code is available in early access to my sponsors here: https://github.com/clue-access/reactphp-tsv
+While in [early access](#support-us), you first have to manually change your
+`composer.json` to include these lines to access the supporters-only repository:
 
-Do you sponsor me on GitHub? Thank you for supporting sustainable open-source, you're awesome! ❤️ Have fun with the code! 🎉
+```json
+{
+    "repositories": [
+        {
+            "type": "vcs",
+            "url": "https://github.com/clue-access/reactphp-tsv"
+        }
+    ]
+}
+```
 
-Seeing a 404 (Not Found)? Sounds like you're not in the early access group. Consider becoming a [sponsor on GitHub](https://github.com/sponsors/clue) for early access. Check out [clue·access](https://github.com/clue-access/clue-access) for more details.
+Then install this package as usual:
 
-This way, more people get a chance to take a look at the code before the public release.
+```bash
+$ composer require clue/reactphp-tsv:dev-main
+```
+
+This project aims to run on any platform and thus does not require any PHP
+extensions and supports running on legacy PHP 5.3 through current PHP 8+.
+It's *highly recommended to use the latest supported PHP version* for this project.
+
+# Tests
+
+To run the test suite, you first need to clone this repo and then install all
+dependencies [through Composer](https://getcomposer.org/):
+
+```bash
+$ composer install
+```
+
+To run the test suite, go to the project root and run:
 
-Rock on 🤘
+```bash
+$ vendor/bin/phpunit
+```
 
 ## License
 
-This project will be released under the permissive [MIT license](LICENSE).
+This project is released under the permissive [MIT license](LICENSE).
 
 > Did you know that I offer custom development services and issuing invoices for
   sponsorships of releases and for contributions? Contact me (@clue) for details.
+
+## More
+
+* If you want to learn more about processing streams of data, refer to the documentation of
+  the underlying [react/stream](https://github.com/reactphp/stream) component.
+
+* If you want to process a more common text-based format,
+  you may want to use [clue/reactphp-csv](https://github.com/clue/reactphp-csv)
+  to process Comma-Separated Values (CSV) files (`.csv` file extension).
+
+* If you want to process structured data in a more modern JSON-based format,
+  you may want to use [clue/reactphp-ndjson](https://github.com/clue/reactphp-ndjson)
+  to process newline-delimited JSON (NDJSON) files (`.ndjson` file extension).
+
+* If you want to process compressed TSV files (`.tsv.gz` file extension)
+  you may want to use [clue/reactphp-zlib](https://github.com/clue/reactphp-zlib)
+  on the compressed input stream before passing the decompressed stream to the TSV decoder.
+
+* If you want to create compressed TSV files (`.tsv.gz` file extension)
+  you may want to use [clue/reactphp-zlib](https://github.com/clue/reactphp-zlib)
+  on the resulting TSV encoder output stream before passing the compressed
+  stream to the file output stream.

examples/91-benchmark-count.php

@@ -0,0 +1,36 @@
+<?php
+
+// To run the example, execute the following command:
+// $ php examples/91-benchmark-count.php < examples/users.tsv
+//
+// If you want to achieve more convincing result,
+// you can run the same example with some larger TSV files.
+// Take a look at:
+// @link https://datasets.imdbws.com/
+
+use React\EventLoop\Loop;
+
+require __DIR__ . '/../vendor/autoload.php';
+
+if (extension_loaded('xdebug')) {
+    echo 'NOTICE: The "xdebug" extension is loaded, this has a major impact on performance.' . PHP_EOL;
+}
+
+$decoder = new Clue\React\Tsv\TsvDecoder(new React\Stream\ReadableResourceStream(STDIN));
+
+$count = 0;
+$decoder->on('data', function () use (&$count) {
+    ++$count;
+});
+
+$start = microtime(true);
+$report = Loop::addPeriodicTimer(0.05, function () use (&$count, $start) {
+    printf("\r%d records in %0.3fs...", $count, microtime(true) - $start);
+});
+
+$decoder->on('close', function () use (&$count, $report, $start) {
+    $now = microtime(true);
+    Loop::cancelTimer($report);
+
+    printf("\r%d records in %0.3fs => %d records/s\n", $count, $now - $start, $count / ($now - $start));
+});