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-rw-r--r--source3/lib/bitmap.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/source3/lib/bitmap.c b/source3/lib/bitmap.c
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+++ b/source3/lib/bitmap.c
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+/*
+ Unix SMB/Netbios implementation.
+ Version 1.9.
+ 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 repitition */
+
+
+/****************************************************************************
+allocate a bitmap of the specified size
+****************************************************************************/
+struct bitmap *bitmap_allocate(int n)
+{
+ struct bitmap *bm;
+
+ bm = (struct bitmap *)malloc(sizeof(*bm));
+ bm->n = n;
+
+ if (!bm) return NULL;
+
+ bm->b = (uint32 *)malloc(sizeof(bm->b[0])*(n+31)/32);
+ if (!bm->b) {
+ free(bm);
+ return NULL;
+ }
+
+ memset(bm->b, 0, sizeof(bm->b[0])*bm->n);
+
+ return bm;
+}
+
+/****************************************************************************
+free a bitmap structure
+****************************************************************************/
+void bitmap_free(struct bitmap *bm)
+{
+ free(bm->b);
+ bm->b = NULL;
+ free(bm);
+}
+
+
+/****************************************************************************
+set a bit in a bitmap
+****************************************************************************/
+BOOL bitmap_set(struct bitmap *bm, unsigned i)
+{
+ if (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)
+{
+ 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;
+}