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Better octal and hex-entity decode #640

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merged 4 commits into from
Sep 26, 2023
Merged

Better octal and hex-entity decode #640

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e19bc69
Better octal and hex-entity decode
GreyWyvern Sep 19, 2023
78abd45
Use #2D to ensure we're capturing hex letters
GreyWyvern Sep 19, 2023
4271583
Change order of special string replacement
GreyWyvern Sep 19, 2023
9ef1c50
Apply suggestions from code review
GreyWyvern Sep 21, 2023
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35 changes: 16 additions & 19 deletions src/Smalot/PdfParser/Font.php
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Original file line number Diff line number Diff line change
Expand Up @@ -349,16 +349,20 @@ public static function decodeHexadecimal(string $hexa, bool $add_braces = false)
*/
public static function decodeOctal(string $text): string
{
$parts = preg_split('/(?<!\\\\)(\\\\[0-7]{1,3})/s', $text, -1, \PREG_SPLIT_NO_EMPTY | \PREG_SPLIT_DELIM_CAPTURE);
$text = '';
// Replace all double backslashes \\ with a special string
$text = strtr($text, ['\\\\' => '[**pdfparserdblslsh**]']);

foreach ($parts as $part) {
if (preg_match('/^\\\\[0-7]{1,3}$/', $part)) {
$text .= \chr(octdec(trim($part, '\\')));
} else {
$text .= str_replace(['\\\\', '\\(', '\\)'], ['\\', '(', ')'], $part);
}
}
// Now we can replace all octal codes without worrying about
// escaped backslashes
$text = preg_replace_callback('/\\\\([0-7]{1,3})/', function ($m) {
return \chr(octdec($m[1]));
}, $text);

// Unescape any parentheses
$text = str_replace(['\\(', '\\)'], ['(', ')'], $text);

// Replace instances of the special string with a single backslash
$text = str_replace('[**pdfparserdblslsh**]', '\\', $text);

return $text;
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}
Expand All @@ -368,16 +372,9 @@ public static function decodeOctal(string $text): string
*/
public static function decodeEntities(string $text): string
{
$parts = preg_split('/(#\d{2})/s', $text, -1, \PREG_SPLIT_NO_EMPTY | \PREG_SPLIT_DELIM_CAPTURE);
$text = '';

foreach ($parts as $part) {
if (preg_match('/^#\d{2}$/', $part)) {
$text .= \chr(hexdec(trim($part, '#')));
} else {
$text .= $part;
}
}
$text = preg_replace_callback('/#([0-9a-f]{2})/i', function ($m) {
return \chr(hexdec($m[1]));
}, $text);

return $text;
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}
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17 changes: 17 additions & 0 deletions tests/PHPUnit/Integration/FontTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -281,12 +281,29 @@ public function testDecodeOctal(): void
$this->assertEquals('AB C', Font::decodeOctal('\\101\\102\\040\\103'));
$this->assertEquals('AB CD', Font::decodeOctal('\\101\\102\\040\\103D'));
$this->assertEquals('AB \199', Font::decodeOctal('\\101\\102\\040\\\\199'));

// Test that series of backslashes of arbitrary length are decoded properly
$this->assertEquals('-', Font::decodeOctal('\\055')); // \055
$this->assertEquals('\\055', Font::decodeOctal('\\\\055')); // \\055
$this->assertEquals('\\-', Font::decodeOctal('\\\\\\055')); // \\\055
$this->assertEquals('\\\\055', Font::decodeOctal('\\\\\\\\055')); // \\\\055
$this->assertEquals('\\\\-', Font::decodeOctal('\\\\\\\\\\055')); // \\\\\055
$this->assertEquals('\\\\\\055', Font::decodeOctal('\\\\\\\\\\\\055')); // \\\\\\055
$this->assertEquals('\\\\\\-', Font::decodeOctal('\\\\\\\\\\\\\\055')); // \\\\\\\055

// Make sure we're unescaping ( and ) before returning the escaped
// backslashes to the string
$this->assertEquals('\\(', Font::decodeOctal('\\\\(')); // \\( - nothing to unescape
$this->assertEquals('\\(', Font::decodeOctal('\\\\\\(')); // \\\( - parenthesis unescaped
$this->assertEquals('\\\\(', Font::decodeOctal('\\\\\\\\(')); // \\\\( - nothing to unescape
$this->assertEquals('\\\\(', Font::decodeOctal('\\\\\\\\\\(')); // \\\\\( - parenthesis unescaped
}

public function testDecodeEntities(): void
{
$this->assertEquals('File Type', Font::decodeEntities('File#20Type'));
$this->assertEquals('File# Ty#pe', Font::decodeEntities('File##20Ty#pe'));
$this->assertEquals('Fi#le#-Ty#p#e ', Font::decodeEntities('Fi#23le##2DTy#p#e '));
}

public function testDecodeUnicode(): void
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