1 files changed, 89 insertions, 0 deletions
diff --git a/preload-zstd.inc b/preload-zstd.inc
new file mode 100644
index 0000000..de8abd0
--- /dev/null
+++ b/preload-zstd.inc
@@ -0,0 +1,89 @@
+<?php
+/** 
+ * ZSTD compressor using FFI and libzstd
+ * PoC, only for documentation purpose
+ *
+ * Copyright (c) 2019 Remi Collet
+ * License: CC-BY-SA
+ * http://creativecommons.org/licenses/by-sa/4.0/
+ */
+namespace Remi;
+
+class Zstd {
+	static private $ffi = null;
+
+	public static function init() {
+		if (self::$ffi) {
+			return;
+		}
+		// Try if preloaded
+		try {
+			self::$ffi = \FFI::scope("_REMI_ZSTD_");
+		} catch (\FFI\Exception $e) {
+			// Try direct load
+			if (PHP_SAPI === 'cli' || (int)ini_get("ffi.enable")) {
+				self::$ffi = \FFI::load(__DIR__ . '/preload-zstd.h');
+			} else {
+				throw $e;
+			}
+		}
+		if (!self::$ffi) {
+			throw new \RuntimeException("FFI parse fails");
+		}
+	}
+
+	public static function compress($in, $out) {
+		self::init();
+
+		$ret = [];
+		$src = file_get_contents($in);
+		if ($src === false) {
+			throw new \RuntimeException("Read fails");
+		}
+		$len = strlen($src);
+		$ret['in_len'] = $len;
+
+		$max = self::$ffi->ZSTD_compressBound($len);
+		$ret['max_len'] = $max;
+
+		$comp = str_repeat(' ', $max);
+		$clen = self::$ffi->ZSTD_compress($comp, $max, $src, $len, 6);
+		if (self::$ffi->ZSTD_isError($clen)) {
+			throw new \RuntimeException("Compression fails");
+		}
+		$ret['out_len'] = $clen;
+		if (file_put_contents($out, substr($comp, 0, $clen)) !== $clen) {
+			throw new \RuntimeException("Save fails");
+		}
+
+		return $ret;
+	}
+
+	public static function decompress($in, $out) {
+		self::init();
+
+		$ret = [];
+		$comp = file_get_contents($in);
+		if ($comp === false) {
+			throw new \RuntimeException("Read fails");
+		}
+		$clen = strlen($comp);
+		$ret['in_len'] = $clen;
+
+		$max = self::$ffi->ZSTD_decompressBound($comp, $clen);
+		$ret['max_len'] = $max;
+
+		$unco = str_repeat(' ', $max);
+		$ulen = self::$ffi->ZSTD_decompress($unco, $max, $comp, $clen);
+		if (self::$ffi->ZSTD_isError($clen)) {
+			throw new \RuntimeException("Compression fails");
+		}
+		$ret['out_len'] = $ulen;
+		if (file_put_contents($out, substr($unco, 0, $ulen)) !== $ulen) {
+			throw new \RuntimeException("Save fails");
+		}
+
+		return $ret;
+	}
+}
+