Imported reiserfsprogs-3.6.20

libmisc/bitops.c

@@ -0,0 +1,181 @@
+/*
+ * Copyright 1996-2004 by Hans Reiser, licensing governed by 
+ * reiserfsprogs/README
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include "misc/bitops.h"
+#include "misc/types.h"
+
+/* Only le bitops operations are used. */
+inline int misc_set_bit (unsigned long long nr, void * addr) {
+    __u8 * p, mask;
+    int retval;
+
+    p = (__u8 *)addr;
+    p += nr >> 3;
+    mask = 1 << (nr & 0x7);
+    /*cli();*/
+    retval = (mask & *p) != 0;
+    *p |= mask;
+    /*sti();*/
+    return retval;
+}
+
+
+inline int misc_clear_bit (unsigned long long nr, void * addr) {
+    __u8 * p, mask;
+    int retval;
+
+    p = (__u8 *)addr;
+    p += nr >> 3;
+    mask = 1 << (nr & 0x7);
+    /*cli();*/
+    retval = (mask & *p) != 0;
+    *p &= ~mask;
+    /*sti();*/
+    return retval;
+}
+
+inline int misc_test_bit(unsigned long long nr, const void * addr) {
+    __u8 * p, mask;
+
+    p = (__u8 *)addr;
+    p += nr >> 3;
+    mask = 1 << (nr & 0x7);
+    return ((mask & *p) != 0);
+}
+
+inline unsigned long long misc_find_first_zero_bit (const void *vaddr, 
+    unsigned long long size) 
+{
+    const __u8 *p = vaddr, *addr = vaddr;
+    unsigned long long res;
+
+    if (!size)
+        return 0;
+
+    size = (size >> 3) + ((size & 0x7) > 0);
+    while (*p++ == 255) {
+        if (--size == 0)
+            return (unsigned long long)(p - addr) << 3;
+    }
+
+    --p;
+    for (res = 0; res < 8; res++)
+        if (!misc_test_bit (res, p))
+            break;
+    return res + (p - addr) * 8;
+}
+
+
+inline unsigned long long misc_find_next_zero_bit (const void *vaddr, 
+    unsigned long long size, unsigned long long offset) 
+{
+    const __u8 *addr = vaddr;
+    const __u8 *p = addr + (offset >> 3);
+    int bit = offset & 7;
+    unsigned long long res;
+
+    if (offset >= size)
+        return size;
+
+    if (bit) {
+        /* Look for zero in first char */
+        for (res = bit; res < 8; res++)
+            if (!misc_test_bit (res, p))
+                return res + (p - addr) * 8;
+        p++;
+    }
+    /* No zero yet, search remaining full bytes for a zero */
+    res = misc_find_first_zero_bit (p, size - 8 * (p - addr));
+    return res + (p - addr) * 8;
+}
+
+inline unsigned long long misc_find_first_set_bit (const void *vaddr, 
+    unsigned long long size) 
+{
+    const __u8 *p = vaddr, *addr = vaddr;
+    unsigned long long res;
+
+    if (!size)
+        return 0;
+
+    size = (size >> 3) + ((size & 0x7) > 0);
+    while (*p++ == 0) {
+        if (--size == 0)
+            return (unsigned long long)(p - addr) << 3;
+    }
+
+    --p;
+    for (res = 0; res < 8; res++)
+        if (misc_test_bit (res, p))
+            break;
+
+    return res + (p - addr) * 8;
+}
+
+inline unsigned long long misc_find_next_set_bit(const void *vaddr, 
+    unsigned long long size, unsigned long long offset)
+{
+    const __u8 *addr = vaddr;
+    const __u8 *p = addr + (offset >> 3);
+    int bit = offset & 7;
+    unsigned long long res;
+
+    if (offset >= size)
+        return size;
+
+    if (bit) {
+        /* Look for zero in first char */
+        for (res = bit; res < 8; res++)
+            if (misc_test_bit (res, p))
+                return res + (p - addr) * 8;
+        p++;
+    }
+    /* No set bit yet, search remaining full bytes for a 1 */
+    res = misc_find_first_set_bit (p, size - 8 * (p - addr));
+    return res + (p - addr) * 8;
+}
+
+/* there are masks for certain bits  */
+__u16 mask16 (int from, int count)
+{
+    __u16 mask;
+
+
+    mask = (0xffff >> from);
+    mask <<= from;
+    mask <<= (16 - from - count);
+    mask >>= (16 - from - count);
+    return mask;
+}
+
+
+__u32 mask32 (int from, int count)
+{
+    __u32 mask;
+
+
+    mask = (0xffffffff >> from);
+    mask <<= from;
+    mask <<= (32 - from - count);
+    mask >>= (32 - from - count);
+    return mask;
+}
+
+
+__u64 mask64 (int from, int count)
+{
+    __u64 mask;
+
+
+    mask = (0xffffffffffffffffLL >> from);
+    mask <<= from;
+    mask <<= (64 - from - count);
+    mask >>= (64 - from - count);
+    return mask;
+}