/* Length of "Globally Unique ID" field in WIM header. */
#define WIM_GID_LEN 16
-/* Length of the WIM header on disk. */
+/* 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 (WIM_RESHDR_FLAG_PACKED_STREAMS). New as of Windows 8 WIMGAPI; used
- * for the Windows 8 web downloader, but yet not yet properly documented by
- * Microsoft. This WIM format also allows a new compression format (LZMS). */
+ * 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
((u64)'\0' << 48) | \
((u64)'\0' << 54))
-/* On-disk format of the WIM header. */
+/* On-disk format of the WIM header. */
struct wim_header_disk {
- /* +0x00: Magic characters "MSWIM\0\0\0". */
+ /* +0x00: Magic characters WIM_MAGIC or PWM_MAGIC. */
le64 magic;
/* +0x08: Size of the WIM header, in bytes; WIM_HEADER_DISK_SIZE
u32 wim_flags;
/* +0x14: Uncompressed chunk size for compressed resources in the WIM
- * other than packed resources, or 0 if the WIM is uncompressed. */
+ * 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. */
+ * bunch of random bytes. */
u8 guid[WIM_GID_LEN];
/* +0x28: Number of this WIM part in the split WIM file, indexed from 1,
- * or 1 if the WIM is not split. */
+ * or 1 if the WIM is not split. */
u16 part_number;
/* +0x2a: Total number of parts of the split WIM file, or 1 if the WIM
- * is not split. */
+ * is not split. */
u16 total_parts;
- /* +0x2c: Number of images in the WIM. */
+ /* +0x2c: Number of images in the WIM. WIMGAPI requires that this be at
+ * least 1. wimlib allows 0. */
u32 image_count;
/* +0x30: Location and size of the WIM's lookup table. */
struct wim_reshdr integrity_table_reshdr;
};
-/* Flags for the `flags' field of the struct wim_header: */
+/* WIM header flags ('wim_flags' field of 'struct wim_header_disk'): */
-/* Reserved for future use */
+/* Reserved flag. */
#define WIM_HDR_FLAG_RESERVED 0x00000001
-/* Files and metadata in the WIM are compressed. */
+/* The WIM may contain compressed resources --- specifically, resources with
+ * WIM_RESHDR_FLAG_COMPRESSED set in their headers. Exactly one of the more
+ * specific WIM_HDR_FLAG_COMPRESSION_* flags must be set to specify the
+ * compression format used. */
#define WIM_HDR_FLAG_COMPRESSION 0x00000002
-/* WIM is read-only, so modifications should not be allowed even if the WIM is
- * writable at the filesystem level. */
+/* The WIM is read-only, so modifications should not be allowed even if the WIM
+ * is writable at the filesystem level. */
#define WIM_HDR_FLAG_READONLY 0x00000004
-/* Resource data specified by images in this WIM may be contained in a different
- * WIM. Or in other words, this WIM is part of a split WIM. */
+/* The WIM is part of a split WIM. */
#define WIM_HDR_FLAG_SPANNED 0x00000008
-/* The WIM contains resources only; no filesystem metadata. wimlib ignores this
- * flag, as it looks for resources in all the WIMs anyway. */
+/* All streams included in the WIM's lookup table are non-metadata (do not have
+ * WIM_RESHDR_FLAG_METADATA set). wimlib ignores this flag and clears it on new
+ * WIM files it writes. */
#define WIM_HDR_FLAG_RESOURCE_ONLY 0x00000010
-/* The WIM contains metadata only. wimlib ignores this flag. Note that all the
- * metadata resources for a split WIM should be in the first part. */
+/* All streams included in the WIM's lookup table are metadata (have
+ * WIM_RESHDR_FLAG_METADATA set). wimlib ignores this flag and clears it on
+ * new WIM files it writes. */
#define WIM_HDR_FLAG_METADATA_ONLY 0x00000020
/* The WIM is currently being written or appended to. */
#define WIM_HDR_FLAG_WRITE_IN_PROGRESS 0x00000040
-/* Reparse point fixup flag. See docs for --rpfix and --norpfix in imagex, or
- * WIMLIB_ADD_FLAG_{RPFIX,NORPFIX} in wimlib.h. Note that
- * WIM_HDR_FLAG_RP_FIX is a header flag and just sets the default behavior for
- * the WIM; it can still be overridder on a per-image basis. But there is no
- * flag to set the default behavior for a specific image. */
+/* Reparse point fixup flag. See docs for the --rpfix and --norpfix options to
+ * 'wimlib-imagex capture', or the WIMLIB_ADD_FLAG_{RPFIX,NORPFIX} flags in
+ * wimlib.h. Note that WIM_HDR_FLAG_RP_FIX is a header flag and just sets the
+ * default behavior for the WIM; it can still be programatically overridden on a
+ * per-image basis. But there is no flag in the file format to set the default
+ * behavior for a specific image. */
#define WIM_HDR_FLAG_RP_FIX 0x00000080
-/* Unused, reserved flag for another compression type */
+/* Unused, reserved flag for another compression type. */
#define WIM_HDR_FLAG_COMPRESS_RESERVED 0x00010000
-/* Resources within the WIM are compressed using "XPRESS" compression, which is
- * a LZ77-based compression algorithm. */
+/* Resources in the WIM with WIM_RESHDR_FLAG_COMPRESSED set in their headers are
+ * compressed with XPRESS compression. */
#define WIM_HDR_FLAG_COMPRESS_XPRESS 0x00020000
-/* Resources within the WIM are compressed using "LZX" compression. This is also
- * a LZ77-based algorithm. */
+/* Resources in the WIM with WIM_RESHDR_FLAG_COMPRESSED set in their headers are
+ * compressed with LZX compression. */
#define WIM_HDR_FLAG_COMPRESS_LZX 0x00040000
-/* Starting in Windows 8, WIMGAPI can create WIMs using LZMS compression, and
- * this flag is set on such WIMs. However, an additional undocumented flag
- * needs to be provided to WIMCreateFile() to create such WIMs, and the version
- * number in the header of the resulting WIMs is different (3584). None of this
- * is actually documented, and wimlib does not yet support this compression
- * format. */
+/* Resources in the WIM with WIM_RESHDR_FLAG_COMPRESSED set in their headers are
+ * compressed with LZMS compression. Note: this flag is only valid if the WIM
+ * version is WIM_VERSION_PACKED_STREAMS. Also, this flag is only supported in
+ * wimlib v1.6.0 and later and WIMGAPI Windows 8 and later. */
#define WIM_HDR_FLAG_COMPRESS_LZMS 0x00080000
#endif /* _WIMLIB_HEADER_H */
git://wimlib.net / wimlib / blobdiff