1 files changed, 123 insertions, 0 deletions
diff --git a/tools/src/minilzlib/xzstream.h b/tools/src/minilzlib/xzstream.h
new file mode 100644
index 0000000..f227879
--- /dev/null
+++ b/tools/src/minilzlib/xzstream.h
@@ -0,0 +1,123 @@
+/*++
+
+Copyright (c) Alex Ionescu.  All rights reserved.
+
+Module Name:
+
+    xzstream.h
+
+Abstract:
+
+    This header file contains C-style data structures and enumerations that map
+    back to the XZ stream and file format standard, including for the decoding
+    of Variable Length Integers (VLI). This includes definitions for the stream
+    header, block header, index and stream footer, and associated check types.
+
+Author:
+
+    Alex Ionescu (@aionescu) 15-Apr-2020 - Initial version
+
+Environment:
+
+    Windows & Linux, user mode and kernel mode.
+
+--*/
+
+#pragma once
+
+//
+// XZ streams encode certain numbers as "variable length integers", with 7 bits
+// for the data, and a high bit to encode that another byte must be consumed.
+//
+typedef uint32_t vli_type;
+#define VLI_BYTES_MAX (sizeof(vli_type) * 8 / 7)
+
+//
+// These are the possible supported types for integrity checking in an XZ file
+//
+typedef enum _XZ_CHECK_TYPES
+{
+    XzCheckTypeNone = 0,
+    XzCheckTypeCrc32 = 1,
+    XzCheckTypeCrc64 = 4,
+    XzCheckTypeSha2 = 10
+} XZ_CHECK_TYPES;
+
+//
+// This describes the first 12 bytes of any XZ container file / stream
+//
+typedef struct _XZ_STREAM_HEADER
+{
+    uint8_t Magic[6];
+    union
+    {
+        struct
+        {
+            uint8_t ReservedFlags;
+            uint8_t CheckType : 4;
+            uint8_t ReservedType : 4;
+        } s;
+        uint16_t Flags;
+    } u;
+    uint32_t Crc32;
+} XZ_STREAM_HEADER, * PXZ_STREAM_HEADER;
+static_assert(sizeof(XZ_STREAM_HEADER) == 12, "Invalid Stream Header Size");
+
+//
+// This describes the last 12 bytes of any XZ container file / stream
+//
+typedef struct _XZ_STREAM_FOOTER
+{
+    uint32_t Crc32;
+    uint32_t BackwardSize;
+    union
+    {
+        struct
+        {
+            uint8_t ReservedFlags;
+            uint8_t CheckType : 4;
+            uint8_t ReservedType : 4;
+        } s;
+        uint16_t Flags;
+    } u;
+    uint16_t Magic;
+} XZ_STREAM_FOOTER, * PXZ_STREAM_FOOTER;
+static_assert(sizeof(XZ_STREAM_FOOTER) == 12, "Invalid Stream Footer Size");
+
+//
+// This describes the beginning of a compressed payload stored in an XZ stream,
+// with hardcoded expectations for an LZMA2-compressed payload that has 0 extra
+// filters (such as BCJ2).
+//
+typedef struct _XZ_BLOCK_HEADER
+{
+    uint8_t Size;
+    union
+    {
+        struct
+        {
+            uint8_t FilterCount : 2;
+            uint8_t Reserved : 4;
+            uint8_t HasCompressedSize : 1;
+            uint8_t HasUncompressedSize : 1;
+        } s;
+        uint8_t Flags;
+    } u;
+    struct
+    {
+        uint8_t Id;
+        uint8_t Size;
+        union
+        {
+            struct
+            {
+                uint8_t DictionarySize : 6;
+                uint8_t Reserved : 2;
+            } s;
+            uint8_t Properties;
+        } u;
+    } LzmaFlags;
+    uint8_t Padding[3];
+    uint32_t Crc32;
+} XZ_BLOCK_HEADER, * PXZ_BLOCK_HEADER;
+static_assert(sizeof(XZ_BLOCK_HEADER) == 12, "Invalid Block Header Size");