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压缩输出流和解压缩输入流，包括 GZip、BZip2 和 Brotli。

示例

读取 GZIP 压缩文件

use io\streams\FileInputStream;
use io\streams\compress\GzipInputStream;

$in= new GzipInputStream(new FileInputStream('message.txt.gz'));
while ($in->available()) {
  echo $in->read();
}
$in->close();

写入文件，使用 BZIP2 在线压缩数据

use io\streams\FileOutputStream;
use io\streams\compress\Bzip2OutputStream;

$out= new Bzip2OutputStream(new FileOutputStream('message.txt.bz2'));
$out->write('Hello World!');
$out->write("\n");
$out->close();

依赖项

压缩算法是用 C 实现的，因此需要特定的 PHP 扩展

• GZip - 需要 PHP 的 "zlib" 扩展
• Bzip2 - 需要 PHP 的 "bzip2" 扩展
• Brotli - 需要 https://github.com/kjdev/php-ext-brotli

可以通过 Compression API 访问这些算法

use io\streams\{Compression, FileInputStream, FileOutputStream};

// Returns an algorithm instance. Raises a lang.MethodNotImplementedException
// if the required "bzip2" extension is not loaded
$compressed= Compression::named('bzip2');

// Read
$bytes= '';
$in= $compressed->open(new FileInputStream($file));
while ($in->available()) {
  $bytes.= $in->read();
}
$in->close();

// Write using strongest compression (other predefined values are FASTEST
// and DEFAULT; alternatively, the level can be passed directly).
$out= $compressed->create(new FileOutputStream($file), Compression::STRONGEST);
$out->write($bytes);
$out->close();

可以使用 Compression API 来发现支持的算法

use io\streams\Compression;

echo "Supported algorithms:\n";
foreach (Compression::algorithms()->supported() as $compression) {
  echo '✓ ', $compression->name(), "\n";
}

...或者作为一条单行 shell 命令

$ xp -w '\io\streams\Compression::algorithms()'
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)
}

高级示例

使用 HTTP Accept-Encoding 和 Content-Encoding 获取给定的 URL

use io\streams\Compression;
use peer\http\HttpConnection;

// Compile list of supported compression algorithms, e.g. "gzip, br"
$accept= Compression::algorithms()->accept();
echo "== Sending {$accept} ==\n";

// Make request, sending supported content encodings via Accept-Encoding
$conn= new HttpConnection($argv[1]);
$res= $conn->get(null, ['Accept-Encoding' => $accept]);

// Handle Content-Encoding header
if ($encoding= $res->header('Content-Encoding')) {
  $compression= Compression::named($encoding[0]);

  echo "== Using ", $compression->name(), " ==\n";
  $in= $compression->open($res->in());
} else {
  echo "== Uncompressed ==\n";
  $in= $res->in();
}

// Write contents to output
while ($in->available()) {
  echo $in->read();
}
$in->close();