bitmap: add a generic bitmap and bitops library

Add most used bitmap and bitops functions into bitmap.c and bitops.c.
Theses functions are mostly copied from Linux kernel source.

Some of these functions are already redefined in the VNC server. Some
of them could be used for some block stuff. The yet yo be submitted
NUMA work also need bitmaps.

bitops_ffsl() and bitops_flsl() are here because bitops/bitmap works
on unsigned long, not int, and we can't use current code because:
* ffs only works on int
* qemu_fls only works on int
* ffsl is a GNU extension

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 222 insertions, 0 deletions

diff --git a/bitmap.h b/bitmap.h
new file mode 100644
index 0000000000..efd5d3a1ed
--- /dev/null
+++ b/bitmap.h
@@ -0,0 +1,222 @@
+/*
+ * Bitmap Module
+ *
+ * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
+ *
+ * Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ */
+
+#ifndef BITMAP_H
+#define BITMAP_H
+
+#include "qemu-common.h"
+#include "bitops.h"
+
+/*
+ * The available bitmap operations and their rough meaning in the
+ * case that the bitmap is a single unsigned long are thus:
+ *
+ * Note that nbits should be always a compile time evaluable constant.
+ * Otherwise many inlines will generate horrible code.
+ *
+ * bitmap_zero(dst, nbits)			*dst = 0UL
+ * bitmap_fill(dst, nbits)			*dst = ~0UL
+ * bitmap_copy(dst, src, nbits)			*dst = *src
+ * bitmap_and(dst, src1, src2, nbits)		*dst = *src1 & *src2
+ * bitmap_or(dst, src1, src2, nbits)		*dst = *src1 | *src2
+ * bitmap_xor(dst, src1, src2, nbits)		*dst = *src1 ^ *src2
+ * bitmap_andnot(dst, src1, src2, nbits)	*dst = *src1 & ~(*src2)
+ * bitmap_complement(dst, src, nbits)		*dst = ~(*src)
+ * bitmap_equal(src1, src2, nbits)		Are *src1 and *src2 equal?
+ * bitmap_intersects(src1, src2, nbits) 	Do *src1 and *src2 overlap?
+ * bitmap_empty(src, nbits)			Are all bits zero in *src?
+ * bitmap_full(src, nbits)			Are all bits set in *src?
+ * bitmap_set(dst, pos, nbits)			Set specified bit area
+ * bitmap_clear(dst, pos, nbits)		Clear specified bit area
+ * bitmap_find_next_zero_area(buf, len, pos, n, mask)	Find bit free area
+ */
+
+/*
+ * Also the following operations apply to bitmaps.
+ *
+ * set_bit(bit, addr)			*addr |= bit
+ * clear_bit(bit, addr)			*addr &= ~bit
+ * change_bit(bit, addr)		*addr ^= bit
+ * test_bit(bit, addr)			Is bit set in *addr?
+ * test_and_set_bit(bit, addr)		Set bit and return old value
+ * test_and_clear_bit(bit, addr)	Clear bit and return old value
+ * test_and_change_bit(bit, addr)	Change bit and return old value
+ * find_first_zero_bit(addr, nbits)	Position first zero bit in *addr
+ * find_first_bit(addr, nbits)		Position first set bit in *addr
+ * find_next_zero_bit(addr, nbits, bit)	Position next zero bit in *addr >= bit
+ * find_next_bit(addr, nbits, bit)	Position next set bit in *addr >= bit
+ */
+
+#define BITMAP_LAST_WORD_MASK(nbits)                                    \
+    (                                                                   \
+        ((nbits) % BITS_PER_LONG) ?                                     \
+        (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL                       \
+        )
+
+#define DECLARE_BITMAP(name,bits)                  \
+	unsigned long name[BITS_TO_LONGS(bits)]
+
+#define small_nbits(nbits)                      \
+	((nbits) <= BITS_PER_LONG)
+
+int slow_bitmap_empty(const unsigned long *bitmap, int bits);
+int slow_bitmap_full(const unsigned long *bitmap, int bits);
+int slow_bitmap_equal(const unsigned long *bitmap1,
+                   const unsigned long *bitmap2, int bits);
+void slow_bitmap_complement(unsigned long *dst, const unsigned long *src,
+                         int bits);
+void slow_bitmap_shift_right(unsigned long *dst,
+                          const unsigned long *src, int shift, int bits);
+void slow_bitmap_shift_left(unsigned long *dst,
+                         const unsigned long *src, int shift, int bits);
+int slow_bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+                 const unsigned long *bitmap2, int bits);
+void slow_bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
+                 const unsigned long *bitmap2, int bits);
+void slow_bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
+                  const unsigned long *bitmap2, int bits);
+int slow_bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+                    const unsigned long *bitmap2, int bits);
+int slow_bitmap_intersects(const unsigned long *bitmap1,
+			const unsigned long *bitmap2, int bits);
+
+static inline unsigned long *bitmap_new(int nbits)
+{
+    int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+    return qemu_mallocz(len);
+}
+
+static inline void bitmap_zero(unsigned long *dst, int nbits)
+{
+    if (small_nbits(nbits)) {
+        *dst = 0UL;
+    } else {
+        int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+        memset(dst, 0, len);
+    }
+}
+
+static inline void bitmap_fill(unsigned long *dst, int nbits)
+{
+    size_t nlongs = BITS_TO_LONGS(nbits);
+    if (!small_nbits(nbits)) {
+        int len = (nlongs - 1) * sizeof(unsigned long);
+        memset(dst, 0xff,  len);
+    }
+    dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
+}
+
+static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
+                               int nbits)
+{
+    if (small_nbits(nbits)) {
+        *dst = *src;
+    } else {
+        int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+        memcpy(dst, src, len);
+    }
+}
+
+static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
+                             const unsigned long *src2, int nbits)
+{
+    if (small_nbits(nbits)) {
+        return (*dst = *src1 & *src2) != 0;
+    }
+    return slow_bitmap_and(dst, src1, src2, nbits);
+}
+
+static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
+			const unsigned long *src2, int nbits)
+{
+    if (small_nbits(nbits)) {
+        *dst = *src1 | *src2;
+    } else {
+        slow_bitmap_or(dst, src1, src2, nbits);
+    }
+}
+
+static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
+			const unsigned long *src2, int nbits)
+{
+    if (small_nbits(nbits)) {
+        *dst = *src1 ^ *src2;
+    } else {
+        slow_bitmap_xor(dst, src1, src2, nbits);
+    }
+}
+
+static inline int bitmap_andnot(unsigned long *dst, const unsigned long *src1,
+			const unsigned long *src2, int nbits)
+{
+    if (small_nbits(nbits)) {
+        return (*dst = *src1 & ~(*src2)) != 0;
+    }
+    return slow_bitmap_andnot(dst, src1, src2, nbits);
+}
+
+static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
+			int nbits)
+{
+    if (small_nbits(nbits)) {
+        *dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
+    } else {
+        slow_bitmap_complement(dst, src, nbits);
+    }
+}
+
+static inline int bitmap_equal(const unsigned long *src1,
+			const unsigned long *src2, int nbits)
+{
+    if (small_nbits(nbits)) {
+        return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
+    } else {
+        return slow_bitmap_equal(src1, src2, nbits);
+    }
+}
+
+static inline int bitmap_empty(const unsigned long *src, int nbits)
+{
+    if (small_nbits(nbits)) {
+        return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
+    } else {
+        return slow_bitmap_empty(src, nbits);
+    }
+}
+
+static inline int bitmap_full(const unsigned long *src, int nbits)
+{
+    if (small_nbits(nbits)) {
+        return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
+    } else {
+        return slow_bitmap_full(src, nbits);
+    }
+}
+
+static inline int bitmap_intersects(const unsigned long *src1,
+			const unsigned long *src2, int nbits)
+{
+    if (small_nbits(nbits)) {
+        return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
+    } else {
+        return slow_bitmap_intersects(src1, src2, nbits);
+    }
+}
+
+void bitmap_set(unsigned long *map, int i, int len);
+void bitmap_clear(unsigned long *map, int start, int nr);
+unsigned long bitmap_find_next_zero_area(unsigned long *map,
+					 unsigned long size,
+					 unsigned long start,
+					 unsigned int nr,
+					 unsigned long align_mask);
+
+#endif /* BITMAP_H */