Initial import

[samba] / source / lib / bitmap.c

diff --git a/source/lib/bitmap.c b/source/lib/bitmap.c
new file mode 100644 (file)
index 0000000..f2442d2
--- /dev/null
+++ b/source/lib/bitmap.c
@@ -0,0 +1,177 @@
+/*
+   Unix SMB/CIFS implementation.
+   simple bitmap functions
+   Copyright (C) Andrew Tridgell 1992-1998
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+
+/* these functions provide a simple way to allocate integers from a
+   pool without repetition */
+
+/****************************************************************************
+allocate a bitmap of the specified size
+****************************************************************************/
+struct bitmap *bitmap_allocate(int n)
+{
+       struct bitmap *bm;
+
+       bm = SMB_MALLOC_P(struct bitmap);
+
+       if (!bm) return NULL;
+       
+       bm->n = n;
+       bm->b = SMB_MALLOC_ARRAY(uint32, (n+31)/32);
+       if (!bm->b) {
+               SAFE_FREE(bm);
+               return NULL;
+       }
+
+       memset(bm->b, 0, sizeof(uint32)*((n+31)/32));
+
+       return bm;
+}
+
+/****************************************************************************
+free a bitmap.
+****************************************************************************/
+
+void bitmap_free(struct bitmap *bm)
+{
+       if (!bm)
+               return;
+
+       SAFE_FREE(bm->b);
+       SAFE_FREE(bm);
+}
+
+/****************************************************************************
+talloc a bitmap
+****************************************************************************/
+struct bitmap *bitmap_talloc(TALLOC_CTX *mem_ctx, int n)
+{
+       struct bitmap *bm;
+
+       if (!mem_ctx) return NULL;
+
+       bm = TALLOC_P(mem_ctx, struct bitmap);
+
+       if (!bm) return NULL;
+       
+       bm->n = n;
+       bm->b = TALLOC_ARRAY(mem_ctx, uint32, (n+31)/32);
+       if (!bm->b) {
+               return NULL;
+       }
+
+       memset(bm->b, 0, sizeof(uint32)*((n+31)/32));
+
+       return bm;
+}
+
+/****************************************************************************
+copy as much of the source bitmap as will fit in the destination bitmap.
+****************************************************************************/
+
+int bitmap_copy(struct bitmap * const dst, const struct bitmap * const src)
+{
+        int count = MIN(dst->n, src->n);
+
+        SMB_ASSERT(dst->b != src->b);
+       memcpy(dst->b, src->b, sizeof(uint32)*((count+31)/32));
+
+        return count;
+}
+
+/****************************************************************************
+set a bit in a bitmap
+****************************************************************************/
+BOOL bitmap_set(struct bitmap *bm, unsigned i)
+{
+       if (i >= bm->n) {
+               DEBUG(0,("Setting invalid bitmap entry %d (of %d)\n",
+                     i, bm->n));
+               return False;
+       }
+       bm->b[i/32] |= (1<<(i%32));
+       return True;
+}
+
+/****************************************************************************
+clear a bit in a bitmap
+****************************************************************************/
+BOOL bitmap_clear(struct bitmap *bm, unsigned i)
+{
+       if (i >= bm->n) {
+               DEBUG(0,("clearing invalid bitmap entry %d (of %d)\n",
+                     i, bm->n));
+               return False;
+       }
+       bm->b[i/32] &= ~(1<<(i%32));
+       return True;
+}
+
+/****************************************************************************
+query a bit in a bitmap
+****************************************************************************/
+BOOL bitmap_query(struct bitmap *bm, unsigned i)
+{
+       if (i >= bm->n) return False;
+       if (bm->b[i/32] & (1<<(i%32))) {
+               return True;
+       }
+       return False;
+}
+
+/****************************************************************************
+find a zero bit in a bitmap starting at the specified offset, with
+wraparound
+****************************************************************************/
+int bitmap_find(struct bitmap *bm, unsigned ofs)
+{
+       unsigned int i, j;
+
+       if (ofs > bm->n) ofs = 0;
+
+       i = ofs;
+       while (i < bm->n) {
+               if (~(bm->b[i/32])) {
+                       j = i;
+                       do {
+                               if (!bitmap_query(bm, j)) return j;
+                               j++;
+                       } while (j & 31 && j < bm->n);
+               }
+               i += 32;
+               i &= ~31;
+       }
+
+       i = 0;
+       while (i < ofs) {
+               if (~(bm->b[i/32])) {
+                       j = i;
+                       do {
+                               if (!bitmap_query(bm, j)) return j;
+                               j++;
+                       } while (j & 31 && j < bm->n);
+               }
+               i += 32;
+               i &= ~31;
+       }
+
+       return -1;
+}