first public release of samba4 code

source/lib/bitmap.c

@@ -0,0 +1,163 @@
+/*
+   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 = (struct bitmap *)malloc(sizeof(*bm));
+
+	if (!bm) return NULL;
+	
+	bm->n = n;
+	bm->b = (uint32 *)malloc(sizeof(bm->b[0])*(n+31)/32);
+	if (!bm->b) {
+		SAFE_FREE(bm);
+		return NULL;
+	}
+
+	memset(bm->b, 0, sizeof(bm->b[0])*(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 = (struct bitmap *)talloc(mem_ctx, sizeof(*bm));
+
+	if (!bm) return NULL;
+	
+	bm->n = n;
+	bm->b = (uint32 *)talloc(mem_ctx, sizeof(bm->b[0])*(n+31)/32);
+	if (!bm->b) {
+		return NULL;
+	}
+
+	memset(bm->b, 0, sizeof(bm->b[0])*(n+31)/32);
+
+	return bm;
+}
+
+/****************************************************************************
+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;
+}