HEADERS = $(TOP_INCDIR)/afs/opr.h \
$(TOP_INCDIR)/afs/opr_assert.h \
$(TOP_INCDIR)/opr/dict.h \
+ $(TOP_INCDIR)/opr/ffs.h \
$(TOP_INCDIR)/opr/fmt.h \
$(TOP_INCDIR)/opr/jhash.h \
$(TOP_INCDIR)/opr/lock.h \
$(TOP_INCDIR)/opr/dict.h: ${srcdir}/dict.h
$(INSTALL_DATA) $? $@
+$(TOP_INCDIR)/opr/ffs.h: ${srcdir}/ffs.h
+ $(INSTALL_DATA) $? $@
+
$(TOP_INCDIR)/opr/fmt.h: ${srcdir}/fmt.h
$(INSTALL_DATA) $? $@
--- /dev/null
+/*
+ * Copyright (C) 2014 by the Massachusetts Institute of Technology.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This contains portable implementations of the BSD ffs() suite of functions,
+ * which locate the first or last bit set in a bit string.
+ */
+
+#ifndef OPENAFS_OPR_FFS_H
+#define OPENAFS_OPR_FFS_H
+
+static_inline int
+opr_ffs(int value)
+{
+ afs_int32 i;
+ afs_uint32 tmp = value;
+
+ if (tmp == 0)
+ return 0;
+ /* This loop must terminate because tmp is nonzero and thus has at least
+ * one bit set. */
+ for (i = 1;; ++i) {
+ if (tmp & 1u)
+ return i;
+ else
+ tmp >>= 1;
+ }
+ /* NOTREACHED */
+}
+
+static_inline int
+opr_ffsll(long long value)
+{
+ afs_int32 i;
+ afs_uint64 tmp = value;
+
+ if (tmp == 0)
+ return 0;
+ /* This loop must terminate because tmp is nonzero and thus has at least
+ * one bit set. */
+ for (i = 1;; ++i) {
+ if (tmp & 1ull)
+ return i;
+ else
+ tmp >>= 1;
+ }
+ /* NOTREACHED */
+}
+
+static_inline int
+opr_fls(int value)
+{
+ afs_int32 i;
+ /* tmp must be unsigned to avoid undefined behavior. */
+ afs_uint32 tmp = value;
+
+ if (tmp == 0)
+ return 0;
+ /* This loop must terminate because tmp is nonzero and thus has at least
+ * one bit set. */
+ for (i = 32;; --i) {
+ if (tmp & 0x80000000u)
+ return i;
+ else
+ tmp <<= 1;
+ }
+ /* NOTREACHED */
+}
+
+static_inline int
+opr_flsll(long long value)
+{
+ afs_int32 i;
+ /* tmp must be unsigned to avoid undefined behavior. */
+ afs_uint64 tmp = value;
+
+ if (tmp == 0)
+ return 0;
+ /* This loop must terminate because tmp is nonzero and thus has at least
+ * one bit set. */
+ for (i = 64;; --i) {
+ if (tmp & 0x8000000000000000ull)
+ return i;
+ else
+ tmp <<= 1;
+ }
+ /* NOTREACHED */
+}
+
+#endif /* OPENAFS_OPR_FFS_H */