From 79907201ffe2bc45555c7b4caf38860f450fdb07 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Sun, 20 Apr 2025 09:27:05 +0200
Subject: [PATCH 01/11] Add ZStandard compression

---
 src/main/php/io/streams/Compression.class.php |  4 +-
 .../io/streams/compress/ZStandard.class.php   | 34 ++++++++
 .../compress/ZStandardInputStream.class.php   | 82 +++++++++++++++++++
 .../compress/ZStandardOutputStream.class.php  | 65 +++++++++++++++
 .../unittest/CompressionTest.class.php        | 11 ++-
 .../ZStandardInputStreamTest.class.php        | 59 +++++++++++++
 .../ZStandardOutputStreamTest.class.php       | 34 ++++++++
 7 files changed, 283 insertions(+), 6 deletions(-)
 create mode 100755 src/main/php/io/streams/compress/ZStandard.class.php
 create mode 100755 src/main/php/io/streams/compress/ZStandardInputStream.class.php
 create mode 100755 src/main/php/io/streams/compress/ZStandardOutputStream.class.php
 create mode 100755 src/test/php/io/streams/compress/unittest/ZStandardInputStreamTest.class.php
 create mode 100755 src/test/php/io/streams/compress/unittest/ZStandardOutputStreamTest.class.php

diff --git a/src/main/php/io/streams/Compression.class.php b/src/main/php/io/streams/Compression.class.php
index b1534d8..712dd10 100755
--- a/src/main/php/io/streams/Compression.class.php
+++ b/src/main/php/io/streams/Compression.class.php
@@ -1,6 +1,6 @@
 <?php namespace io\streams;
 
-use io\streams\compress\{Algorithm, Algorithms, None, Brotli, Bzip2, Gzip};
+use io\streams\compress\{Algorithm, Algorithms, None, Brotli, Bzip2, Gzip, ZStandard};
 use lang\MethodNotImplementedException;
 
 /**
@@ -22,7 +22,7 @@ static function __static() {
     self::$NONE= new None();
 
     // Register known algorithms included in this library
-    self::$algorithms= (new Algorithms())->add(new Gzip(), new Bzip2(), new Brotli());
+    self::$algorithms= (new Algorithms())->add(new Gzip(), new Bzip2(), new Brotli(), new ZStandard());
   }
 
   /**
diff --git a/src/main/php/io/streams/compress/ZStandard.class.php b/src/main/php/io/streams/compress/ZStandard.class.php
new file mode 100755
index 0000000..e57c6f6
--- /dev/null
+++ b/src/main/php/io/streams/compress/ZStandard.class.php
@@ -0,0 +1,34 @@
+<?php namespace io\streams\compress;
+
+use io\streams\{InputStream, OutputStream, Compression};
+
+class ZStandard extends Algorithm {
+
+  /** Returns whether this algorithm is supported in the current setup */
+  public function supported(): bool { return extension_loaded('zstd'); }
+
+  /** Returns the algorithm's name */
+  public function name(): string { return 'zstandard'; }
+
+  /** Returns the algorithm's HTTP Content-Encoding token */
+  public function token(): string { return 'zstd'; }
+
+  /** Returns the algorithm's common file extension, including a leading "." */
+  public function extension(): string { return '.zstd'; }
+
+  /** Maps fastest, default and strongest levels */
+  public function level(int $select): int {
+    static $levels= [Compression::FASTEST => 1, Compression::DEFAULT => 3, Compression::STRONGEST => 22];
+    return $levels[$select] ?? $select;
+  }
+
+  /** Opens an input stream for reading */
+  public function open(InputStream $in): InputStream {
+    return new ZStandardInputStream($in);
+  }
+
+  /** Opens an output stream for writing */
+  public function create(OutputStream $out, int $level= Compression::DEFAULT): OutputStream {
+    return new ZStandardOutputStream($out, $this->level($level));
+  }
+}
\ No newline at end of file
diff --git a/src/main/php/io/streams/compress/ZStandardInputStream.class.php b/src/main/php/io/streams/compress/ZStandardInputStream.class.php
new file mode 100755
index 0000000..e129737
--- /dev/null
+++ b/src/main/php/io/streams/compress/ZStandardInputStream.class.php
@@ -0,0 +1,82 @@
+<?php namespace io\streams\compress;
+
+use io\IOException;
+use io\streams\InputStream;
+
+/**
+ * ZStandard input stream
+ *
+ * @ext  zstd
+ * @test io.streams.compress.unittest.BrotliInputStreamTest
+ * @see  https://github.com/kjdev/php-ext-zstd
+ */
+class ZStandardInputStream implements InputStream {
+  private $in;
+  private $buffer= null, $position= 0;
+
+  /**
+   * Creates a new compressing output stream
+   *
+   * @param  io.streams.InputStream $in The stream to read from
+   */
+  public function __construct(InputStream $in) {
+    $this->in= $in;
+  }
+
+  /** @see https://github.com/kjdev/php-ext-zstd/issues/64 */
+  private function buffer() {
+    if (null === $this->buffer) {
+      $compressed= '';
+      while ($this->in->available()) {
+        $compressed.= $this->in->read();
+      }
+
+      $this->buffer= zstd_uncompress($compressed);
+      if (false === $this->buffer) {
+        $e= new IOException('Failed to uncompress');
+        \xp::gc(__FILE__);
+        throw $e;
+      }
+    }
+    return $this->buffer;
+  }
+
+  /**
+   * Read a string
+   *
+   * @param   int limit default 8192
+   * @return  string
+   */
+  public function read($limit= 8192) {
+    $chunk= substr($this->buffer(), $this->position, $limit);
+    $this->position+= strlen($chunk);
+    return $chunk;
+  }
+
+  /**
+   * Returns the number of bytes that can be read from this stream 
+   * without blocking.
+   *
+   * @return int
+   */
+  public function available() {
+    return strlen($this->buffer()) - $this->position;
+  }
+
+  /**
+   * Close this buffer.
+   *
+   * @return void
+   */
+  public function close() {
+    $this->buffer= null;
+    $this->in->close();
+  }
+  
+  /**
+   * Destructor. Ensures output stream is closed.
+   */
+  public function __destruct() {
+    $this->close();
+  }
+}
\ No newline at end of file
diff --git a/src/main/php/io/streams/compress/ZStandardOutputStream.class.php b/src/main/php/io/streams/compress/ZStandardOutputStream.class.php
new file mode 100755
index 0000000..a4f480d
--- /dev/null
+++ b/src/main/php/io/streams/compress/ZStandardOutputStream.class.php
@@ -0,0 +1,65 @@
+<?php namespace io\streams\compress;
+
+use io\streams\OutputStream;
+use lang\IllegalArgumentException;
+
+/**
+ * ZStandard output stream
+ *
+ * @ext  zstd
+ * @test io.streams.compress.unittest.ZStandardOutputStreamTest
+ * @see  https://github.com/kjdev/php-ext-zstd
+ */
+class ZStandardOutputStream implements OutputStream {
+  private $out, $level;
+  private $buffer= '';
+
+  /**
+   * Creates a new compressing output stream
+   *
+   * @param  io.streams.OutputStream $out The stream to write to
+   * @param  int $level
+   * @throws lang.IllegalArgumentException
+   */
+  public function __construct(OutputStream $out, $level= ZSTD_COMPRESS_LEVEL_DEFAULT) {
+    if ($level < ZSTD_COMPRESS_LEVEL_MIN || $level > ZSTD_COMPRESS_LEVEL_MAX) {
+      throw new IllegalArgumentException('Level must be between '.ZSTD_COMPRESS_LEVEL_MIN.' and '.ZSTD_COMPRESS_LEVEL_MAX);
+    }
+
+    $this->out= $out;
+    $this->level= $level;
+  }
+
+  /**
+   * Write a string
+   *
+   * @param  var $arg
+   * @return void
+   */
+  public function write($arg) {
+    $this->buffer.= $arg;
+  }
+
+  /**
+   * Flush this buffer
+   *
+   * @return void
+   */
+  public function flush() {
+    // NOOP
+  }
+
+  /**
+   * Closes this object. May be called more than once, which may
+   * not fail - that is, if the object is already closed, this 
+   * method should have no effect.
+   *
+   * @return void
+   */
+  public function close() {
+    if (null !== $this->buffer) {
+      $this->out->write(zstd_compress($this->buffer, $this->level));
+      $this->buffer= null;
+    }
+  }
+}
\ No newline at end of file
diff --git a/src/test/php/io/streams/compress/unittest/CompressionTest.class.php b/src/test/php/io/streams/compress/unittest/CompressionTest.class.php
index 6db0898..1ec0c9b 100755
--- a/src/test/php/io/streams/compress/unittest/CompressionTest.class.php
+++ b/src/test/php/io/streams/compress/unittest/CompressionTest.class.php
@@ -14,14 +14,17 @@ private function names() {
     yield ['gzip', 'gzip'];
     yield ['bzip2', 'bzip2'];
     yield ['brotli', 'brotli'];
+    yield ['zstandard', 'zstandard'];
 
     // File extensions
     yield ['.gz', 'gzip'];
     yield ['.bz2', 'bzip2'];
     yield ['.br', 'brotli'];
+    yield ['.zstd', 'zstandard'];
 
     // HTTP Content-Encoding aliases
     yield ['br', 'brotli'];    
+    yield ['zstd', 'zstandard'];
   }
 
   /** @return iterable */
@@ -38,7 +41,7 @@ public function enumerating_included_algorithms() {
     foreach (Compression::algorithms() as $name => $algorithm) {
       $names[]= $name;
     }
-    Assert::equals(['gzip', 'bzip2', 'brotli'], $names);
+    Assert::equals(['gzip', 'bzip2', 'brotli', 'zstandard'], $names);
   }
 
   #[Test]
@@ -61,17 +64,17 @@ public function algorithms_named($name, $expected) {
     Assert::equals($expected, Compression::algorithms()->named($name)->name());
   }
 
-  #[Test, Values([['gzip', 'zlib'], ['bzip2', 'bzip2'], ['brotli', 'brotli']])]
+  #[Test, Values([['gzip', 'zlib'], ['bzip2', 'bzip2'], ['brotli', 'brotli'], ['zstandard', 'zstd']])]
   public function supported($compression, $extension) {
     Assert::equals(extension_loaded($extension), Compression::algorithms()->named($compression)->supported());
   }
 
-  #[Test, Values([['gzip', 'gzip'], ['bzip2', 'bzip2'], ['brotli', 'br']])]
+  #[Test, Values([['gzip', 'gzip'], ['bzip2', 'bzip2'], ['brotli', 'br'], ['zstandard', 'zstd']])]
   public function token($compression, $expected) {
     Assert::equals($expected, Compression::algorithms()->named($compression)->token());
   }
 
-  #[Test, Values([['gzip', '.gz'], ['bzip2', '.bz2'], ['brotli', '.br']])]
+  #[Test, Values([['gzip', '.gz'], ['bzip2', '.bz2'], ['brotli', '.br'], ['zstandard', '.zstd']])]
   public function extension($compression, $expected) {
     Assert::equals($expected, Compression::algorithms()->named($compression)->extension());
   }
diff --git a/src/test/php/io/streams/compress/unittest/ZStandardInputStreamTest.class.php b/src/test/php/io/streams/compress/unittest/ZStandardInputStreamTest.class.php
new file mode 100755
index 0000000..bd8870c
--- /dev/null
+++ b/src/test/php/io/streams/compress/unittest/ZStandardInputStreamTest.class.php
@@ -0,0 +1,59 @@
+<?php namespace io\streams\compress\unittest;
+
+use io\IOException;
+use io\streams\MemoryInputStream;
+use io\streams\compress\ZStandardInputStream;
+use test\verify\Runtime;
+use test\{Assert, Test, Values};
+
+#[Runtime(extensions: ['zstd'])]
+class ZStandardInputStreamTest {
+
+  /** @return iterable */
+  private function compressable() {
+    foreach ([ZSTD_COMPRESS_LEVEL_MIN, ZSTD_COMPRESS_LEVEL_DEFAULT, ZSTD_COMPRESS_LEVEL_MAX] as $level) {
+      yield [$level, ''];
+      yield [$level, 'Test'];
+      yield [$level, "GIF89a\x14\x12\x77..."];
+    }
+  }
+
+  #[Test]
+  public function can_create() {
+    new ZStandardInputStream(new MemoryInputStream(''));
+  }
+
+  #[Test]
+  public function read_plain() {
+    $in= new ZStandardInputStream(new MemoryInputStream('Test'));
+    Assert::throws(IOException::class, function() use($in) {
+      $in->read();
+    });
+    $in->close();
+  }
+
+  #[Test, Values(from: 'compressable')]
+  public function read_compressed($level, $bytes) {
+    $in= new ZStandardInputStream(new MemoryInputStream(zstd_compress($bytes, $level)));
+    $read= $in->read();
+    $rest= $in->available();
+    $in->close();
+
+    Assert::equals($bytes, $read);
+    Assert::equals(0, $rest);
+  }
+
+  #[Test, Values([1, 8192, 16384])]
+  public function read_all($length) {
+    $bytes= random_bytes($length);
+    $in= new ZStandardInputStream(new MemoryInputStream(zstd_compress($bytes)));
+
+    $read= '';
+    while ($in->available()) {
+      $read.= $in->read();
+    }
+    $in->close();
+
+    Assert::equals($bytes, $read);
+  }
+}
\ No newline at end of file
diff --git a/src/test/php/io/streams/compress/unittest/ZStandardOutputStreamTest.class.php b/src/test/php/io/streams/compress/unittest/ZStandardOutputStreamTest.class.php
new file mode 100755
index 0000000..523878a
--- /dev/null
+++ b/src/test/php/io/streams/compress/unittest/ZStandardOutputStreamTest.class.php
@@ -0,0 +1,34 @@
+<?php namespace io\streams\compress\unittest;
+
+use io\streams\MemoryOutputStream;
+use io\streams\compress\ZStandardOutputStream;
+use lang\IllegalArgumentException;
+use test\verify\Runtime;
+use test\{Assert, Expect, Test, Values};
+
+#[Runtime(extensions: ['zstd'])]
+class ZStandardOutputStreamTest {
+
+  #[Test]
+  public function can_create() {
+    new ZStandardOutputStream(new MemoryOutputStream());
+  }
+
+  #[Test, Expect(IllegalArgumentException::class)]
+  public function using_invalid_compression_level() {
+    new ZStandardOutputStream(new MemoryOutputStream(), -1);
+  }
+
+  #[Test, Values([1, 3, 22])]
+  public function write($level) {
+    $out= new MemoryOutputStream();
+
+    $fixture= new ZStandardOutputStream($out, $level);
+    $fixture->write('Hello');
+    $fixture->write(' ');
+    $fixture->write('World');
+    $fixture->close();
+
+    Assert::equals('Hello World', zstd_uncompress($out->bytes()));
+  }
+}
\ No newline at end of file

From 8d26d9afbe82bd0a3589a1e7106e2ae94e865e08 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Tue, 29 Jul 2025 20:40:14 +0200
Subject: [PATCH 02/11] Use incremental (un)compress APIs added in
 kjdev/php-ext-zstd#79

---
 .../compress/ZStandardInputStream.class.php   | 40 +++++++------------
 .../compress/ZStandardOutputStream.class.php  | 13 +++---
 2 files changed, 20 insertions(+), 33 deletions(-)

diff --git a/src/main/php/io/streams/compress/ZStandardInputStream.class.php b/src/main/php/io/streams/compress/ZStandardInputStream.class.php
index e129737..abe2429 100755
--- a/src/main/php/io/streams/compress/ZStandardInputStream.class.php
+++ b/src/main/php/io/streams/compress/ZStandardInputStream.class.php
@@ -11,8 +11,7 @@
  * @see  https://github.com/kjdev/php-ext-zstd
  */
 class ZStandardInputStream implements InputStream {
-  private $in;
-  private $buffer= null, $position= 0;
+  private $in, $handle;
 
   /**
    * Creates a new compressing output stream
@@ -21,24 +20,7 @@ class ZStandardInputStream implements InputStream {
    */
   public function __construct(InputStream $in) {
     $this->in= $in;
-  }
-
-  /** @see https://github.com/kjdev/php-ext-zstd/issues/64 */
-  private function buffer() {
-    if (null === $this->buffer) {
-      $compressed= '';
-      while ($this->in->available()) {
-        $compressed.= $this->in->read();
-      }
-
-      $this->buffer= zstd_uncompress($compressed);
-      if (false === $this->buffer) {
-        $e= new IOException('Failed to uncompress');
-        \xp::gc(__FILE__);
-        throw $e;
-      }
-    }
-    return $this->buffer;
+    $this->handle= zstd_uncompress_init();
   }
 
   /**
@@ -48,9 +30,13 @@ private function buffer() {
    * @return  string
    */
   public function read($limit= 8192) {
-    $chunk= substr($this->buffer(), $this->position, $limit);
-    $this->position+= strlen($chunk);
-    return $chunk;
+    $bytes= zstd_uncompress_add($this->handle, $this->in->read($limit));
+    if (false === $bytes) {
+      $e= new IOException('Failed to uncompress');
+      \xp::gc(__FILE__);
+      throw $e;
+    }
+    return $bytes;
   }
 
   /**
@@ -60,7 +46,7 @@ public function read($limit= 8192) {
    * @return int
    */
   public function available() {
-    return strlen($this->buffer()) - $this->position;
+    return $this->in->available();
   }
 
   /**
@@ -69,8 +55,10 @@ public function available() {
    * @return void
    */
   public function close() {
-    $this->buffer= null;
-    $this->in->close();
+    if ($this->handle) {
+      $this->handle= null;
+      $this->in->close();
+    }
   }
   
   /**
diff --git a/src/main/php/io/streams/compress/ZStandardOutputStream.class.php b/src/main/php/io/streams/compress/ZStandardOutputStream.class.php
index a4f480d..2321ef1 100755
--- a/src/main/php/io/streams/compress/ZStandardOutputStream.class.php
+++ b/src/main/php/io/streams/compress/ZStandardOutputStream.class.php
@@ -11,8 +11,7 @@
  * @see  https://github.com/kjdev/php-ext-zstd
  */
 class ZStandardOutputStream implements OutputStream {
-  private $out, $level;
-  private $buffer= '';
+  private $out, $handle;
 
   /**
    * Creates a new compressing output stream
@@ -27,7 +26,7 @@ public function __construct(OutputStream $out, $level= ZSTD_COMPRESS_LEVEL_DEFAU
     }
 
     $this->out= $out;
-    $this->level= $level;
+    $this->handle= zstd_compress_init($level);
   }
 
   /**
@@ -37,7 +36,7 @@ public function __construct(OutputStream $out, $level= ZSTD_COMPRESS_LEVEL_DEFAU
    * @return void
    */
   public function write($arg) {
-    $this->buffer.= $arg;
+    $this->out->write(zstd_compress_add($this->handle, $arg, false));
   }
 
   /**
@@ -57,9 +56,9 @@ public function flush() {
    * @return void
    */
   public function close() {
-    if (null !== $this->buffer) {
-      $this->out->write(zstd_compress($this->buffer, $this->level));
-      $this->buffer= null;
+    if (null !== $this->handle) {
+      $this->out->write(zstd_compress_add($this->handle, '', true));
+      $this->handle= null;
     }
   }
 }
\ No newline at end of file

From 399d1e4799802a90e25d6a1d146b2b940e67bdcb Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Tue, 29 Jul 2025 20:42:18 +0200
Subject: [PATCH 03/11] Adjust README [skip ci]

---
 README.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 200aac3..5b41eea 100755
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ Compression streams
 [![Supports PHP 8.0+](https://raw.githubusercontent.com/xp-framework/web/master/static/php-8_0plus.svg)](http://php.net/)
 [![Latest Stable Version](https://poser.pugx.org/xp-forge/compression/version.svg)](https://packagist.org/packages/xp-forge/compression)
 
-Compressing output and decompressing input streams including GZip, BZip2 and Brotli.
+Compressing output and decompressing input streams including GZip, BZip2, ZStandard and Brotli.
 
 Examples
 --------
@@ -44,6 +44,7 @@ Compression algorithms are implemented in C and thus require a specific PHP exte
 * **GZip** - requires PHP's ["zlib" extension](https://www.php.net/zlib)
 * **Bzip2** - requires PHP's ["bzip2" extension](https://www.php.net/bzip2)
 * **Brotli** - requires https://github.com/kjdev/php-ext-brotli
+* **ZStandard** - requires https://github.com/kjdev/php-ext-zstd
 
 Accessing these algorithms can be done via the `Compression` API:
 

From 9961616af1b276f5f403efc6eeee89789aa42097 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Tue, 29 Jul 2025 20:47:54 +0200
Subject: [PATCH 04/11] Include ZStandard in algorithms

---
 README.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/README.md b/README.md
index 5b41eea..741e22d 100755
--- a/README.md
+++ b/README.md
@@ -89,6 +89,7 @@ io.streams.compress.Algorithms@{
   io.streams.compress.Gzip(token: gzip, extension: .gz, supported: true, levels: 1..9)
   io.streams.compress.Bzip2(token: bzip2, extension: .bz2, supported: false, levels: 1..9)
   io.streams.compress.Brotli(token: br, extension: .br, supported: true, levels: 1..11)
+  io.streams.compress.ZStandard(token: zstd, extension: .zstd, supported: true, levels: 1..22)
 }
 ```
 

From 5e3ccb5e1aeba8b58ed10207ee1c6fde28a24392 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Thu, 31 Jul 2025 21:41:06 +0200
Subject: [PATCH 05/11] Implement compress() and decompress()

---
 src/main/php/io/streams/compress/ZStandard.class.php | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/main/php/io/streams/compress/ZStandard.class.php b/src/main/php/io/streams/compress/ZStandard.class.php
index e57c6f6..5b747cf 100755
--- a/src/main/php/io/streams/compress/ZStandard.class.php
+++ b/src/main/php/io/streams/compress/ZStandard.class.php
@@ -22,6 +22,16 @@ public function level(int $select): int {
     return $levels[$select] ?? $select;
   }
 
+  /** Compresses data */
+  public function compress(string $data, int $level= Compression::DEFAULT): string {
+    return zstd_compress($data, $this->level($level));
+  }
+
+  /** Decompresses bytes */
+  public function decompress(string $bytes): string {
+    return zstd_uncompress($bytes);
+  }
+
   /** Opens an input stream for reading */
   public function open(InputStream $in): InputStream {
     return new ZStandardInputStream($in);

From 0b7bdf4c6a60c346605ad96ee6f565c41dec8756 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Thu, 31 Jul 2025 21:43:25 +0200
Subject: [PATCH 06/11] Add test for erroneous ZStandard data

---
 src/main/php/io/streams/compress/ZStandard.class.php      | 8 +++++++-
 .../streams/compress/unittest/CompressionTest.class.php   | 5 +++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/main/php/io/streams/compress/ZStandard.class.php b/src/main/php/io/streams/compress/ZStandard.class.php
index 5b747cf..06cfe46 100755
--- a/src/main/php/io/streams/compress/ZStandard.class.php
+++ b/src/main/php/io/streams/compress/ZStandard.class.php
@@ -1,5 +1,6 @@
 <?php namespace io\streams\compress;
 
+use io\IOException;
 use io\streams\{InputStream, OutputStream, Compression};
 
 class ZStandard extends Algorithm {
@@ -29,7 +30,12 @@ public function compress(string $data, int $level= Compression::DEFAULT): string
 
   /** Decompresses bytes */
   public function decompress(string $bytes): string {
-    return zstd_uncompress($bytes);
+    if (false === ($data= zstd_uncompress($bytes))) {
+      $e= new IOException('Decompression failed');
+      \xp::gc(__FILE__);
+      throw $e;
+    }
+    return $data;
   }
 
   /** Opens an input stream for reading */
diff --git a/src/test/php/io/streams/compress/unittest/CompressionTest.class.php b/src/test/php/io/streams/compress/unittest/CompressionTest.class.php
index 8b6b1fa..2161ae4 100755
--- a/src/test/php/io/streams/compress/unittest/CompressionTest.class.php
+++ b/src/test/php/io/streams/compress/unittest/CompressionTest.class.php
@@ -51,6 +51,11 @@ private function erroneous() {
     if ($bzip2->supported() && PHP_VERSION_ID >= 70400) {
       yield [$bzip2, "BZh61AY&SY\331<Plain data>"];
     }
+
+    $zstd= $algorithms->named('zstd');
+    if ($zstd->supported()) {
+      yield [$zstd, "<Plain data>"];
+    }
   }
 
   #[Test]

From 4769e6bf997284dcd797c23fe53580740ff37245 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Thu, 31 Jul 2025 21:45:11 +0200
Subject: [PATCH 07/11] Add test for erroneous Brotli data

---
 src/main/php/io/streams/compress/Brotli.class.php     |  8 +++++++-
 .../compress/unittest/CompressionTest.class.php       | 11 ++++++++---
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/main/php/io/streams/compress/Brotli.class.php b/src/main/php/io/streams/compress/Brotli.class.php
index 67977e5..b478834 100755
--- a/src/main/php/io/streams/compress/Brotli.class.php
+++ b/src/main/php/io/streams/compress/Brotli.class.php
@@ -1,5 +1,6 @@
 <?php namespace io\streams\compress;
 
+use io\IOException;
 use io\streams\{InputStream, OutputStream, Compression};
 
 class Brotli extends Algorithm {
@@ -29,7 +30,12 @@ public function compress(string $data, int $level= Compression::DEFAULT): string
 
   /** Decompresses bytes */
   public function decompress(string $bytes): string {
-    return brotli_uncompress($bytes);
+    if (false === ($data= brotli_uncompress($bytes))) {
+      $e= new IOException('Decompression failed');
+      \xp::gc(__FILE__);
+      throw $e;
+    }
+    return $data;
   }
 
   /** Opens an input stream for reading */
diff --git a/src/test/php/io/streams/compress/unittest/CompressionTest.class.php b/src/test/php/io/streams/compress/unittest/CompressionTest.class.php
index 2161ae4..28addc9 100755
--- a/src/test/php/io/streams/compress/unittest/CompressionTest.class.php
+++ b/src/test/php/io/streams/compress/unittest/CompressionTest.class.php
@@ -52,9 +52,14 @@ private function erroneous() {
       yield [$bzip2, "BZh61AY&SY\331<Plain data>"];
     }
 
-    $zstd= $algorithms->named('zstd');
-    if ($zstd->supported()) {
-      yield [$zstd, "<Plain data>"];
+    $brotli= $algorithms->named('brotli');
+    if ($brotli->supported()) {
+      yield [$brotli, "<Plain data>"];
+    }
+
+    $zstandard= $algorithms->named('zstandard');
+    if ($zstandard->supported()) {
+      yield [$zstandard, "<Plain data>"];
     }
   }
 

From 69f13cc6cdb1a868e610b8c411356e277d8c5a72 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Thu, 31 Jul 2025 21:49:08 +0200
Subject: [PATCH 08/11] Add ZStandard extension

---
 .github/workflows/ci.yml | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3fd3806..ef2cde8 100755
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -46,14 +46,35 @@ jobs:
         sudo cp brotli.ini /etc/php/${{ matrix.php-versions }}/mods-available/ &&
         sudo phpenmod -v ${{ matrix.php-versions }} brotli
 
+    - name: Add ZStandard extension (Ubuntu)
+      if: runner.os != 'Windows' && matrix.php-versions == '8.4'
+      run: >
+        git clone --recursive --depth=1 https://github.com/kjdev/php-ext-zstd.git &&
+        cd php-ext-zstd &&
+        phpize &&
+        ./configure --enable-zstd &&
+        make -j $(nproc) &&
+        echo "extension=zstd.so" > zstd.ini &&
+        sudo make install &&
+        sudo cp zstd.ini /etc/php/${{ matrix.php-versions }}/mods-available/ &&
+        sudo phpenmod -v ${{ matrix.php-versions }} zstd
+
     - name: Add Brotli extension (Windows)
       if: runner.os == 'Windows' && matrix.php-versions == '8.4'
       run: >
         curl -sSL -o brotli.zip https://github.com/kjdev/php-ext-brotli/releases/download/0.18.0/php_brotli-0.18.0-8.4-nts-vs17-x86_64.zip &&
         unzip brotli.zip &&
-        cp *.dll C:/tools/php/ext/php_brotli.dll &&
+        cp php_brotli*.dll C:/tools/php/ext/php_brotli.dll &&
         echo "extension=brotli" >> C:/tools/php/php.ini
 
+    - name: Add ZStandard extension (Windows)
+      if: runner.os == 'Windows' && matrix.php-versions == '8.4'
+      run: >
+        curl -sSL -o zstd.zip https://github.com/thekid/php-ext-zstd/releases/download/0.15.0/php_zstd-0.15.0-8.4-nts-vs17-x86_64.zip &&
+        unzip zstd.zip &&
+        cp php_zstd*.dll C:/tools/php/ext/php_zstd.dll &&
+        echo "extension=zstd" >> C:/tools/php/php.ini
+
     - name: Validate composer.json and composer.lock
       run: composer validate
 

From 4aa8f3839744e7bd9409193c956f282a015ae1a8 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Thu, 31 Jul 2025 21:56:58 +0200
Subject: [PATCH 09/11] Add ChangeLog entry [skip ci]

---
 ChangeLog.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/ChangeLog.md b/ChangeLog.md
index eaf8bdc..c9b6532 100755
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -3,6 +3,10 @@ Compression streams ChangeLog
 
 ## ?.?.? / ????-??-??
 
+* Merged PR #8: Add ZStandard compression, based on the `zstd` extension
+  from https://github.com/kjdev/php-ext-zstd/ - see issue #7.
+  (@thekid)
+
 ## 1.4.0 / 2025-07-31
 
 * Merged PR #9: Add `Algorithm::compress()` and `Algorithm::decompress()`

From df1d2a48066a4e4417c8404ccb2516b664319882 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Fri, 15 Aug 2025 20:23:44 +0200
Subject: [PATCH 10/11] Adapt to API changes for compression options

---
 src/main/php/io/streams/compress/ZStandard.class.php | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/main/php/io/streams/compress/ZStandard.class.php b/src/main/php/io/streams/compress/ZStandard.class.php
index 06cfe46..8091795 100755
--- a/src/main/php/io/streams/compress/ZStandard.class.php
+++ b/src/main/php/io/streams/compress/ZStandard.class.php
@@ -24,8 +24,8 @@ public function level(int $select): int {
   }
 
   /** Compresses data */
-  public function compress(string $data, int $level= Compression::DEFAULT): string {
-    return zstd_compress($data, $this->level($level));
+  public function compress(string $data, $options= null): string {
+    return zstd_compress($data, $this->level(Options::from($options)->level));
   }
 
   /** Decompresses bytes */
@@ -44,7 +44,7 @@ public function open(InputStream $in): InputStream {
   }
 
   /** Opens an output stream for writing */
-  public function create(OutputStream $out, int $level= Compression::DEFAULT): OutputStream {
-    return new ZStandardOutputStream($out, $this->level($level));
+  public function create(OutputStream $out, $options= null): OutputStream {
+    return new ZStandardOutputStream($out, $this->level(Options::from($options)->level));
   }
 }
\ No newline at end of file

From 16bd7a1b3a17a5ce2572fdd6218900920b125c05 Mon Sep 17 00:00:00 2001
From: Timm Friebe <thekid@thekid.de>
Date: Fri, 15 Aug 2025 20:26:08 +0200
Subject: [PATCH 11/11] Use official php_zstd.dll

---
 .github/workflows/ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7bb54d6..da70ebb 100755
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -70,7 +70,7 @@ jobs:
     - name: Add ZStandard extension (Windows)
       if: runner.os == 'Windows' && matrix.php-versions == '8.4'
       run: >
-        curl -sSL -o zstd.zip https://github.com/thekid/php-ext-zstd/releases/download/0.15.0/php_zstd-0.15.0-8.4-nts-vs17-x86_64.zip &&
+        curl -sSL -o zstd.zip https://github.com/kjdev/php-ext-zstd/releases/download/0.15.0/php_zstd-0.15.0-8.4-nts-vs17-x86_64.zip &&
         unzip zstd.zip &&
         cp php_zstd*.dll C:/tools/php/ext/php_zstd.dll &&
         echo "extension=zstd" >> C:/tools/php/php.ini