patch-2.1.71 linux/fs/ufs/ufs_swab.c

• Lines: 139
• Date: Wed Dec 3 06:18:33 1997
• Orig file: v2.1.70/linux/fs/ufs/ufs_swab.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.70/linux/fs/ufs/ufs_swab.c linux/fs/ufs/ufs_swab.c
@@ -0,0 +1,138 @@
+/*
+ *  linux/fs/ufs/ufs_swab.c
+ *
+ * Copyright (C) 1997
+ * Francois-Rene Rideau <rideau@ens.fr>
+ *
+ */
+
+/*
+ * For inspiration, you might wanna check sys/ufs/ffs/fs.h from whateverBSD
+ *
+ * NOTES
+ * 19970406 - Fare <rideau@ens.fr>
+ *   1) I began from old very preliminary 2.0.x sources,
+ *	but it was underfeatured;
+ *	I later saw that 2.1.1 sources had a *global* UFS byteswap flag.
+ *	EVIL: imagine that a swabbed partition be mounted
+ *	while a non-swabbed partition are active (that sucks!)
+ *	I merged that source tree with mine.
+ *   2) I hope no one is using obNNUUXXIIous byteorder.
+ *	That's the only thing I might have broken,
+ *	though I rather think it's a fix:
+ *	instead of __u64 like BSD,
+ *	the former driver used an explicitly bigendian array of __u32!
+ *   3) I provide a few macros that use GCC C Extensions.
+ *	Port to other compilers would require avoiding them.
+ *	in any case, 64 bit (long long) support is required,
+ *	unless you're ready to workaround
+ *   4) the swab routines below depend on the precise name and order
+ *	of the structure elements. Watch out any modification in ufs_fs.h!!!
+ *   5) putting byteswapping stuff in ufs_swab* seems cleaner to me.
+ *   6) These sources should work with both 2.0 and 2.1 kernels...
+ *
+ * 19971013 - Fare <rideaufr@issy.cnet.fr>
+ *   1) Ported to 2.1.57
+ *   2) instead of byteswapping, use [bl]e_to_cpu:
+ *     it might be that we run on a VAX!
+ *
+ * HOWTO continue adding swab support:
+ *	basically, anywhere metadata is bread() (i.e. mapped to block device),
+ *      data should either be SWAB()ed on the fly,
+ *      or copied to a buffer and globally bswap_ufs_*() there.
+ *
+ */
+
+#include <linux/fs.h>
+#include "ufs_swab.h"
+
+static __inline__ void n_be16_to_cpus(__u16*p,unsigned n) {
+#ifndef __BIG_ENDIAN
+        unsigned i;
+        for(i=0;i<n;i++) {
+		be16_to_cpus(&p[i]);
+        }
+#endif
+}
+static __inline__ void n_be32_to_cpus(__u32*p,unsigned n) {
+#ifndef __BIG_ENDIAN
+        unsigned i;
+        for(i=0;i<n;i++) {
+		be32_to_cpus(&p[i]);
+        }
+#endif
+}
+static __inline__ void n_le16_to_cpus(__u16*p,unsigned n) {
+#ifndef __LITTLE_ENDIAN
+        unsigned i;
+        for(i=0;i<n;i++) {
+		le16_to_cpus(&p[i]);
+        }
+#endif
+}
+static __inline__ void n_le32_to_cpus(__u32*p,unsigned n) {
+#ifndef __LITTLE_ENDIAN
+        unsigned i;
+        for(i=0;i<n;i++) {
+		le32_to_cpus(&p[i]);
+        }
+#endif
+}
+
+#define __length_before(p,member) \
+        ((unsigned)(((char*)&((p)->member))-(char*)(p)))
+#define __length_since(p,member) \
+        ((unsigned)(sizeof(*p)-__length_before(p,member)))
+#define __length_between(p,begin,after_end) \
+        ((unsigned)(__length_before(p,after_end)-__length_before(p,begin)))
+#define be32_to_cpus__between(s,begin,after_end) \
+        n_be32_to_cpus((__u32*)&((s).begin), \
+                __length_between(&s,begin,after_end)/4)
+#define le32_to_cpus__between(s,begin,after_end) \
+        n_le32_to_cpus((__u32*)&((s).begin), \
+                __length_between(&s,begin,after_end)/4)
+#define be32_to_cpus__since(s,begin) \
+	n_be32_to_cpus((__u32*)&((s).begin), \
+                __length_since(&s,begin)/4)
+#define le32_to_cpus__since(s,begin) \
+	n_le32_to_cpus((__u32*)&((s).begin), \
+                __length_since(&s,begin)/4)
+#define be16_to_cpus__between(s,begin,after_end) \
+	n_be16_to_cpus((__u16*)&((s).begin), \
+                __length_between(&s,begin,after_end)/2)
+#define le16_to_cpus__between(s,begin,after_end) \
+	n_le16_to_cpus((__u16*)&((s).begin), \
+                __length_between(&s,begin,after_end)/2)
+
+/*
+ * Here are the whole-structure swabping routines...
+ */
+
+extern void ufs_superblock_be_to_cpus(struct ufs_superblock * usb) {
+#ifndef __BIG_ENDIAN
+	be32_to_cpus__between(*usb,fs_link,fs_fmod);
+        /* XXX - I dunno what to do w/ fs_csp,
+         * but it is unused by the current code, so that's ok for now.
+         */
+	be32_to_cpus(&usb->fs_cpc);
+        be16_to_cpus__between(*usb,fs_opostbl,fs_sparecon);
+        be32_to_cpus__between(*usb,fs_sparecon,fs_qbmask);
+        be64_to_cpus(&usb->fs_qbmask);
+        be64_to_cpus(&usb->fs_qfmask);
+	be32_to_cpus__between(*usb,fs_postblformat,fs_magic);
+#endif
+}
+extern void ufs_superblock_le_to_cpus(struct ufs_superblock * usb) {
+#ifndef __LITTLE_ENDIAN
+	le32_to_cpus__between(*usb,fs_link,fs_fmod);
+        /* XXX - I dunno what to do w/ fs_csp,
+         * but it is unused by the current code, so that's ok for now.
+         */
+	le32_to_cpus(&usb->fs_cpc);
+        le16_to_cpus__between(*usb,fs_opostbl,fs_sparecon);
+        le32_to_cpus__between(*usb,fs_sparecon,fs_qbmask);
+        le64_to_cpus(&usb->fs_qbmask);
+        le64_to_cpus(&usb->fs_qfmask);
+	le32_to_cpus__between(*usb,fs_postblformat,fs_magic);
+#endif
+}