diff --git a/SWCompression.xcodeproj/project.pbxproj b/SWCompression.xcodeproj/project.pbxproj
index f6a54dc0..61e89fc7 100644
--- a/SWCompression.xcodeproj/project.pbxproj
+++ b/SWCompression.xcodeproj/project.pbxproj
@@ -164,6 +164,10 @@
 		0651461F1FA8E004007F83F4 /* XZStreamHeader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0651461D1FA8E004007F83F4 /* XZStreamHeader.swift */; };
 		065146201FA8E004007F83F4 /* XZStreamHeader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0651461D1FA8E004007F83F4 /* XZStreamHeader.swift */; };
 		065146211FA8E004007F83F4 /* XZStreamHeader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0651461D1FA8E004007F83F4 /* XZStreamHeader.swift */; };
+		065146231FA8E20C007F83F4 /* XZBlock.swift in Sources */ = {isa = PBXBuildFile; fileRef = 065146221FA8E20C007F83F4 /* XZBlock.swift */; };
+		065146241FA8E20C007F83F4 /* XZBlock.swift in Sources */ = {isa = PBXBuildFile; fileRef = 065146221FA8E20C007F83F4 /* XZBlock.swift */; };
+		065146251FA8E20C007F83F4 /* XZBlock.swift in Sources */ = {isa = PBXBuildFile; fileRef = 065146221FA8E20C007F83F4 /* XZBlock.swift */; };
+		065146261FA8E20C007F83F4 /* XZBlock.swift in Sources */ = {isa = PBXBuildFile; fileRef = 065146221FA8E20C007F83F4 /* XZBlock.swift */; };
 		0651FEC21F8E2E9100C49646 /* ContainerEntryType+Tar.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0651FEC11F8E2E9100C49646 /* ContainerEntryType+Tar.swift */; };
 		0651FEC31F8E2E9100C49646 /* ContainerEntryType+Tar.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0651FEC11F8E2E9100C49646 /* ContainerEntryType+Tar.swift */; };
 		0651FEC41F8E2E9100C49646 /* ContainerEntryType+Tar.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0651FEC11F8E2E9100C49646 /* ContainerEntryType+Tar.swift */; };
@@ -525,6 +529,7 @@
 		064F722E1F1E63D800017297 /* test1.7z */ = {isa = PBXFileReference; lastKnownFileType = file; path = test1.7z; sourceTree = "<group>"; };
 		064F72301F1E63E200017297 /* 7zTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = 7zTests.swift; sourceTree = "<group>"; };
 		0651461D1FA8E004007F83F4 /* XZStreamHeader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XZStreamHeader.swift; sourceTree = "<group>"; };
+		065146221FA8E20C007F83F4 /* XZBlock.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = XZBlock.swift; sourceTree = "<group>"; };
 		0651FEC11F8E2E9100C49646 /* ContainerEntryType+Tar.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "ContainerEntryType+Tar.swift"; sourceTree = "<group>"; };
 		0655693F1DC659FF00A47E66 /* SWCompression.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = SWCompression.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		0655694C1DC65A8000A47E66 /* SWCompression.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = SWCompression.framework; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -815,6 +820,7 @@
 			children = (
 				06E2346B1E068E9600F18798 /* XZArchive.swift */,
 				061C06201F0E89D900832F0C /* XZError.swift */,
+				065146221FA8E20C007F83F4 /* XZBlock.swift */,
 				0651461D1FA8E004007F83F4 /* XZStreamHeader.swift */,
 				06CC3FE11F8AAF3100BD576D /* DataWithPointer+XZ.swift */,
 			);
@@ -1511,6 +1517,7 @@
 				0620F4951F8E21BC001C9B7A /* Permissions.swift in Sources */,
 				06CDFCB31F111DEC00292758 /* LZMA2Error.swift in Sources */,
 				06DDB1721F8190D400035BEF /* BZip2+BlockSize.swift in Sources */,
+				065146241FA8E20C007F83F4 /* XZBlock.swift in Sources */,
 				061C065D1F0E90E600832F0C /* TarEntry.swift in Sources */,
 				064F722A1F1E638A00017297 /* 7zError.swift in Sources */,
 				06CDFCAE1F111DBE00292758 /* LZMAError.swift in Sources */,
@@ -1604,6 +1611,7 @@
 				0620F4961F8E21BC001C9B7A /* Permissions.swift in Sources */,
 				06CDFCB41F111DEC00292758 /* LZMA2Error.swift in Sources */,
 				06DDB1731F8190D400035BEF /* BZip2+BlockSize.swift in Sources */,
+				065146251FA8E20C007F83F4 /* XZBlock.swift in Sources */,
 				061C065E1F0E90E600832F0C /* TarEntry.swift in Sources */,
 				064F722B1F1E638A00017297 /* 7zError.swift in Sources */,
 				06CDFCAF1F111DBE00292758 /* LZMAError.swift in Sources */,
@@ -1697,6 +1705,7 @@
 				0620F4971F8E21BC001C9B7A /* Permissions.swift in Sources */,
 				06CDFCB51F111DEC00292758 /* LZMA2Error.swift in Sources */,
 				06DDB1741F8190D400035BEF /* BZip2+BlockSize.swift in Sources */,
+				065146261FA8E20C007F83F4 /* XZBlock.swift in Sources */,
 				061C065F1F0E90E600832F0C /* TarEntry.swift in Sources */,
 				064F722C1F1E638A00017297 /* 7zError.swift in Sources */,
 				06CDFCB01F111DBE00292758 /* LZMAError.swift in Sources */,
@@ -1790,6 +1799,7 @@
 				0620F4941F8E21BC001C9B7A /* Permissions.swift in Sources */,
 				06CDFCB21F111DEC00292758 /* LZMA2Error.swift in Sources */,
 				06DDB1711F8190D400035BEF /* BZip2+BlockSize.swift in Sources */,
+				065146231FA8E20C007F83F4 /* XZBlock.swift in Sources */,
 				061C065C1F0E90E600832F0C /* TarEntry.swift in Sources */,
 				064F72291F1E638A00017297 /* 7zError.swift in Sources */,
 				06CDFCAD1F111DBE00292758 /* LZMAError.swift in Sources */,
diff --git a/Sources/XZ/XZBlock.swift b/Sources/XZ/XZBlock.swift
new file mode 100644
index 00000000..ffed6796
--- /dev/null
+++ b/Sources/XZ/XZBlock.swift
@@ -0,0 +1,103 @@
+// Copyright (c) 2017 Timofey Solomko
+// Licensed under MIT License
+//
+// See LICENSE for license information
+
+import Foundation
+
+struct XZBlock {
+
+    let bytes: [UInt8]
+    let unpaddedSize: Int
+
+    var uncompressedSize: Int {
+        return bytes.count
+    }
+
+    init(_ blockHeaderSize: Int, _ pointerData: DataWithPointer) throws {
+        let blockHeaderStartIndex = pointerData.index - 1
+        guard blockHeaderSize >= 0x01 && blockHeaderSize <= 0xFF
+            else { throw XZError.wrongFieldValue }
+        let realBlockHeaderSize = (blockHeaderSize + 1) * 4
+
+        let blockFlags = pointerData.byte()
+        /**
+         Bit values 00, 01, 10, 11 indicate filters number from 1 to 4,
+         so we actually need to add 1 to get filters' number.
+         */
+        let filtersCount = blockFlags & 0x03 + 1
+        guard blockFlags & 0x3C == 0
+            else { throw XZError.fieldReservedValue }
+
+        /// Should match size of compressed data.
+        let compressedSize = blockFlags & 0x40 != 0 ? try pointerData.multiByteDecode() : -1
+
+        /// Should match the size of data after decompression.
+        let uncompressedSize = blockFlags & 0x80 != 0 ? try pointerData.multiByteDecode() : -1
+
+        var filters: [(DataWithPointer) throws -> [UInt8]] = []
+        for _ in 0..<filtersCount {
+            let filterID = try pointerData.multiByteDecode()
+            guard UInt64(filterID) < 0x4000000000000000
+                else { throw XZError.wrongFilterID }
+            // Only LZMA2 filter is supported.
+            if filterID == 0x21 {
+                // First, we need to skip byte with the size of filter's properties
+                _ = try pointerData.multiByteDecode()
+                /// In case of LZMA2 filters property is a dicitonary size.
+                let filterPropeties = pointerData.byte()
+                let closure = { (dwp: DataWithPointer) -> [UInt8] in
+                    let decoder = try LZMA2Decoder(pointerData)
+                    try decoder.setDictionarySize(filterPropeties)
+
+                    try decoder.decode()
+                    return decoder.out
+                }
+                filters.append(closure)
+            } else {
+                throw XZError.wrongFilterID
+            }
+        }
+
+        // We need to take into account 4 bytes for CRC32 so thats why "-4".
+        while pointerData.index - blockHeaderStartIndex < realBlockHeaderSize - 4 {
+            let byte = pointerData.byte()
+            guard byte == 0x00
+                else { throw XZError.wrongPadding }
+        }
+
+        let blockHeaderCRC = pointerData.uint32()
+        pointerData.index = blockHeaderStartIndex
+        guard CheckSums.crc32(pointerData.bytes(count: realBlockHeaderSize - 4)) == blockHeaderCRC
+            else { throw XZError.wrongInfoCRC }
+        pointerData.index += 4
+
+        var intResult = pointerData
+        let compressedDataStart = pointerData.index
+        for filterIndex in 0..<filtersCount - 1 {
+            var arrayResult = try filters[filtersCount.toInt() - filterIndex.toInt() - 1](intResult)
+            intResult = DataWithPointer(array: &arrayResult)
+        }
+        guard compressedSize < 0 || compressedSize == pointerData.index - compressedDataStart
+            else { throw XZError.wrongDataSize }
+
+        let out = try filters[filtersCount.toInt() - 1](intResult)
+        guard uncompressedSize < 0 || uncompressedSize == out.count
+            else { throw XZError.wrongDataSize }
+
+        let unpaddedSize = pointerData.index - blockHeaderStartIndex
+
+        if unpaddedSize % 4 != 0 {
+            let paddingSize = 4 - unpaddedSize % 4
+            for _ in 0..<paddingSize {
+                let byte = pointerData.byte()
+                guard byte == 0x00
+                    else { throw XZError.wrongPadding }
+            }
+        }
+
+        self.bytes = out
+        self.unpaddedSize = unpaddedSize
+    }
+
+}