-/* Length of the WIM header on disk. */
-#define WIM_HEADER_DISK_SIZE (148 + WIM_UNUSED_LEN)
-
-/* Compressed resources in the WIM are divided into separated compressed chunks
- * of this size. */
-#define WIM_CHUNK_SIZE 32768
-
-/* Version of the WIM file. There is an older version, but we don't support it
- * yet. The differences between the versions are undocumented. */
-#define WIM_VERSION 0x10d00
-
-/* Header at the very beginning of the WIM file. */
-struct wim_header {
- /* Identifies the file as WIM file. Must be exactly
- * {'M', 'S', 'W', 'I', 'M', 0, 0, 0} */
- //u8 magic[WIM_MAGIC_LEN];
-
- /* size of WIM header in bytes. */
- //u32 hdr_size;
-
- /* Version of the WIM file. Microsoft provides no documentation about
- * exactly what this field affects about the file format, other than the
- * fact that more recent versions have a higher value. */
- //u32 version;
-
- /* Bitwise OR of one or more of the WIM_HDR_FLAG_* defined below. */
- u32 flags;
-
- /* The size of the pieces that the uncompressed files were split up into
- * when they were compressed. This should be the same as
- * WIM_CHUNK_SIZE. Microsoft incorrectly documents this as "the size of
- * the compressed .wim file in bytes".*/
- //u32 chunk_size;
-
- /* A unique identifier for the WIM file. */
+/* Length of the WIM header on disk. wimlib currently requires that the header
+ * be exactly this size. */
+#define WIM_HEADER_DISK_SIZE 208
+
+/* Default WIM version number. Streams are always compressed independently. */
+#define WIM_VERSION_DEFAULT 0x10d00
+
+/* Version number used for WIMs that allow multiple streams packed into one
+ * resource ("solid blocks", marked by WIM_RESHDR_FLAG_PACKED_STREAMS) and also
+ * a new compression format (LZMS). This version is new as of Windows 8
+ * WIMGAPI. Although it is used by Windows 8 web downloader, it is not yet
+ * properly documented by Microsoft. */
+#define WIM_VERSION_PACKED_STREAMS 0xe00
+
+/* Note: there is another WIM version from Vista pre-releases, but it is not
+ * supported by wimlib. */
+
+/* WIM magic characters, translated to a single 64-bit number. */
+#define WIM_MAGIC \
+ (((u64)'M' << 0) | \
+ ((u64)'S' << 8) | \
+ ((u64)'W' << 16) | \
+ ((u64)'I' << 24) | \
+ ((u64)'M' << 32) | \
+ ((u64)'\0' << 40) | \
+ ((u64)'\0' << 48) | \
+ ((u64)'\0' << 54))
+
+/* wimlib pipable WIM magic characters, translated to a single 64-bit number.
+ * */
+#define PWM_MAGIC \
+ (((u64)'W' << 0) | \
+ ((u64)'L' << 8) | \
+ ((u64)'P' << 16) | \
+ ((u64)'W' << 24) | \
+ ((u64)'M' << 32) | \
+ ((u64)'\0' << 40) | \
+ ((u64)'\0' << 48) | \
+ ((u64)'\0' << 54))
+
+/* On-disk format of the WIM header. */
+struct wim_header_disk {
+
+ /* +0x00: Magic characters WIM_MAGIC or PWM_MAGIC. */
+ le64 magic;
+
+ /* +0x08: Size of the WIM header, in bytes; WIM_HEADER_DISK_SIZE
+ * expected (currently the only supported value). */
+ u32 hdr_size;
+
+ /* +0x0c: Version of the WIM file. Recognized values are the
+ * WIM_VERSION_* constants from above. */
+ u32 wim_version;
+
+ /* +0x10: Flags for the WIM file (WIM_HDR_FLAG_*). */
+ u32 wim_flags;
+
+ /* +0x14: Uncompressed chunk size for compressed resources in the WIM
+ * other than packed resources, or 0 if the WIM is uncompressed.
+ * (However wimlib will currently accept any value here if the WIM is
+ * uncompressed.) */
+ u32 chunk_size;
+
+ /* +0x18: Globally unique identifier for the WIM file. Basically a
+ * bunch of random bytes. */