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Merge pull request #20 from clue-labs/multibyte
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Support multi-byte UTF-8 characters and account for cell width
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@clue
clue committed May 17, 2015
2 parents 758d62f + 975dd78 commit 7fdc350
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18 changes: 16 additions & 2 deletions README.md
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
# clue/stdio-react [![Build Status](https://travis-ci.org/clue/php-stdio-react.svg?branch=master)](https://travis-ci.org/clue/php-stdio-react)

Async standard console input & output (STDIN, STDOUT) for React PHP
Async, event-driven and UTF-8 aware standard console input & output (STDIN, STDOUT) for React PHP

> Note: This project is in early beta stage! Feel free to report any issues you encounter.
Expand Down Expand Up @@ -181,14 +181,28 @@ simply pass a boolean `true` like this:
$readline->setMove(true);
```

The `getCursorPosition()` method can be used to access the current cursor position.
The `getCursorPosition()` method can be used to access the current cursor position,
measured in number of characters.
This can be useful if you want to get a substring of the current *user input buffer*.
Simply invoke it like this:

```php
$position = $readline->getCursorPosition();
```

The `getCursorCell()` method can be used to get the current cursor position,
measured in number of monospace cells.
Most *normal* characters (plain ASCII and most multi-byte UTF-8 sequences) take a single monospace cell.
However, there are a number of characters that have no visual representation
(and do not take a cell at all) or characters that do not fit within a single
cell (like some asian glyphs).
This method is mostly useful for calculating the visual cursor position on screen,
but you may also invoke it like this:

```php
$cell = $readline->getCursorCell();
```

The `moveCursorTo($position)` method can be used to set the current cursor position to the given absolute character position.
For example, to move the cursor to the beginning of the *user input buffer*, simply call:

Expand Down
150 changes: 103 additions & 47 deletions src/Readline.php
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Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,35 @@ public function __construct($output)
$this->sequencer->addSequence(self::ESC_SEQUENCE . self::ESC_DEL, array($this, 'onKeyDelete'));
$this->sequencer->addSequence(self::ESC_SEQUENCE . self::ESC_INS, array($this, 'onKeyInsert'));

$this->sequencer->addFallback('', array($this, 'onFallback'));
$expect = 0;
$char = '';
$that = $this;
$this->sequencer->addFallback('', function ($byte) use (&$expect, &$char, $that) {
if ($expect === 0) {
$code = ord($byte);
// count number of bytes expected for this UTF-8 multi-byte character
$expect = 1;
if ($code & 128 && $code & 64) {
++$expect;
if ($code & 32) {
++$expect;
if ($code & 16) {
++$expect;
}
}
}
}
$char .= $byte;
--$expect;

// forward buffered bytes as a single multi byte character once last byte has been read
if ($expect === 0) {
$save = $char;
$char = '';
$that->onFallback($save);
}
});

$this->sequencer->addFallback(self::ESC_SEQUENCE, function ($bytes) {
echo 'unknown sequence: ' . ord($bytes) . PHP_EOL;
});
Expand Down Expand Up @@ -134,12 +162,15 @@ public function setMove($move)
}

/**
* get current cursor position
* Gets current cursor position measured in number of text characters.
*
* cursor position is measured in number of text characters
* Note that the number of text characters doesn't necessarily reflect the
* number of monospace cells occupied by the text characters. If you want
* to know the latter, use `self::getCursorCell()` instead.
*
* @return int
* @see self::moveCursorTo() to move the cursor to a given position
* @see self::getCursorCell() to get the position measured in monospace cells
* @see self::moveCursorTo() to move the cursor to a given character position
* @see self::moveCursorBy() to move the cursor by given number of characters
* @see self::setMove() to toggle whether the user can move the cursor position
*/
Expand All @@ -149,23 +180,68 @@ public function getCursorPosition()
}

/**
* move cursor to right by $n chars (or left if $n is negative)
* Gets current cursor position measured in monospace cells.
*
* Note that the cell position doesn't necessarily reflect the number of
* text characters. If you want to know the latter, use
* `self::getCursorPosition()` instead.
*
* Most "normal" characters occupy a single monospace cell, i.e. the ASCII
* sequence for "A" requires a single cell, as do most UTF-8 sequences
* like "Ä".
*
* However, there are a number of code points that do not require a cell
* (i.e. invisible surrogates) or require two cells (e.g. some asian glyphs).
*
* Also note that this takes the echo mode into account, i.e. the cursor is
* always at position zero if echo is off. If using a custom echo character
* (like asterisk), it will take its width into account instead of the actual
* input characters.
*
* @return int
* @see self::getCursorPosition() to get current cursor position measured in characters
* @see self::moveCursorTo() to move the cursor to a given character position
* @see self::moveCursorBy() to move the cursor by given number of characters
* @see self::setMove() to toggle whether the user can move the cursor position
* @see self::setEcho()
*/
public function getCursorCell()
{
if ($this->echo === false) {
return 0;
}
if ($this->echo !== true) {
return $this->strwidth($this->echo) * $this->linepos;
}
return $this->strwidth($this->substr($this->linebuffer, 0, $this->linepos));
}

/**
* Moves cursor to right by $n chars (or left if $n is negative).
*
* zero or out of range moves are simply ignored
* Zero value or values out of range (exceeding current input buffer) are
* simply ignored.
*
* Will redraw() the readline only if the visible cell position changes,
* see `self::getCursorCell()` for more details.
*
* @param int $n
* @return self
* @uses self::moveCursorTo()
* @uses self::redraw()
*/
public function moveCursorBy($n)
{
return $this->moveCursorTo($this->linepos + $n);
}

/**
* move cursor to given position in current line buffer
* Moves cursor to given position in current line buffer.
*
* Values out of range (exceeding current input buffer) are simply ignored.
*
* out of range (exceeding current input buffer) are simply ignored
* Will redraw() the readline only if the visible cell position changes,
* see `self::getCursorCell()` for more details.
*
* @param int $n
* @return self
Expand All @@ -177,10 +253,11 @@ public function moveCursorTo($n)
return $this;
}

$old = $this->getCursorCell();
$this->linepos = $n;

// only redraw if cursor is actually visible
if ($this->echo) {
// only redraw if visible cell position change (implies cursor is actually visible)
if ($this->getCursorCell() !== $old) {
$this->redraw();
}

Expand Down Expand Up @@ -280,18 +357,13 @@ public function redraw()
$output = "\r\033[K" . $this->prompt;
if ($this->echo !== false) {
if ($this->echo === true) {
$output .= $this->linebuffer;
$buffer = $this->linebuffer;
} else {
$output .= str_repeat($this->echo, $this->strlen($this->linebuffer));
$buffer = str_repeat($this->echo, $this->strlen($this->linebuffer));
}

$len = $this->strlen($this->linebuffer);
if ($this->linepos !== $len) {
$reverse = $len - $this->linepos;

// move back $reverse chars (by sending backspace)
$output .= str_repeat("\x08", $reverse);
}
// write output, then move back $reverse chars (by sending backspace)
$output .= $buffer . str_repeat("\x08", $this->strwidth($buffer) - $this->getCursorCell());
}
$this->write($output);

Expand Down Expand Up @@ -401,16 +473,12 @@ public function onKeyDown()
*/
public function onFallback($chars)
{
$pre = $this->substr($this->linebuffer, 0, $this->linepos); // read everything up until before backspace
// read everything up until before current position
$pre = $this->substr($this->linebuffer, 0, $this->linepos);
$post = $this->substr($this->linebuffer, $this->linepos);

$this->linebuffer = $pre . $chars . $post;

// TODO: fix lineposition for partial multibyte characters
++$this->linepos;
if ($this->linepos >= $this->strlen($this->linebuffer)) {
$this->linepos = $this->strlen($this->linebuffer);
}

$this->redraw();
}
Expand All @@ -429,16 +497,17 @@ public function onFallback($chars)
public function deleteChar($n)
{
$len = $this->strlen($this->linebuffer);
if ($n < 0 || $n > $len) {
if ($n < 0 || $n >= $len) {
return;
}

// TODO: multibyte-characters

$pre = $this->substr($this->linebuffer, 0, $n); // read everything up until before current position
// read everything up until before current position
$pre = $this->substr($this->linebuffer, 0, $n);
$post = $this->substr($this->linebuffer, $n + 1);

$this->linebuffer = $pre . $post;

// move cursor one cell to the left if we're deleting in front of the cursor
if ($n < $this->linepos) {
--$this->linepos;
}
Expand All @@ -465,24 +534,6 @@ protected function processLine()
$this->redraw();
}

protected function readEscape($char)
{
$this->inEscape = false;

if($char === self::ESC_LEFT && $this->move) {
$this->moveCursorBy(-1);
} else if($char === self::ESC_RIGHT && $this->move) {
$this->moveCursorBy(1);
} else if ($char === self::ESC_UP && $this->history !== null) {
$this->history->moveUp();
} else if ($char === self::ESC_DOWN && $this->history !== null) {
$this->history->moveDown();
} else {
$this->write('invalid char');
// ignore unknown escape code
}
}

protected function strlen($str)
{
return mb_strlen($str, $this->encoding);
Expand All @@ -496,6 +547,11 @@ protected function substr($str, $start = 0, $len = null)
return (string)mb_substr($str, $start, $len, $this->encoding);
}

private function strwidth($str)
{
return mb_strwidth($str, $this->encoding);
}

protected function write($data)
{
$this->output->write($data);
Expand Down
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