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-rw-r--r--src/basic/bitmap.c208
-rw-r--r--src/basic/bitmap.h50
-rw-r--r--src/test/test-bitmap.c96
3 files changed, 354 insertions, 0 deletions
diff --git a/src/basic/bitmap.c b/src/basic/bitmap.c
new file mode 100644
index 0000000000..d865e2fc6e
--- /dev/null
+++ b/src/basic/bitmap.c
@@ -0,0 +1,208 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2015 Tom Gundersen
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "util.h"
+
+#include "bitmap.h"
+
+struct Bitmap {
+ long long unsigned *bitmaps;
+ size_t n_bitmaps;
+ size_t bitmaps_allocated;
+ unsigned next_entry;
+};
+
+/* Bitmaps are only meant to store relatively small numbers
+ * (corresponding to, say, an enum), so it is ok to limit
+ * the max entry. 64k should be plenty. */
+#define BITMAPS_MAX_ENTRY 0xffff
+
+/* This indicates that we reached the end of the bitmap */
+#define BITMAP_END ((unsigned) -1)
+
+#define BITMAP_NUM_TO_OFFSET(n) ((n) / (sizeof(long long unsigned) * 8))
+#define BITMAP_NUM_TO_REM(n) ((n) % (sizeof(long long unsigned) * 8))
+#define BITMAP_OFFSET_TO_NUM(offset, rem) ((offset) * sizeof(long long unsigned) * 8 + (rem))
+
+Bitmap *bitmap_new(void) {
+ return new0(Bitmap, 1);
+}
+
+void bitmap_free(Bitmap *b) {
+ if (!b)
+ return;
+
+ free(b->bitmaps);
+ free(b);
+}
+
+int bitmap_ensure_allocated(Bitmap **b) {
+ Bitmap *a;
+
+ if (*b)
+ return 0;
+
+ a = bitmap_new();
+ if (!a)
+ return -ENOMEM;
+
+ *b = a;
+
+ return 0;
+}
+
+int bitmap_set(Bitmap *b, unsigned n) {
+ long long bitmask;
+ unsigned offset;
+
+ assert(b);
+
+ /* we refuse to allocate huge bitmaps */
+ if (n > BITMAPS_MAX_ENTRY)
+ return -ERANGE;
+
+ offset = BITMAP_NUM_TO_OFFSET(n);
+
+ if (offset >= b->n_bitmaps) {
+ if (!GREEDY_REALLOC0(b->bitmaps, b->bitmaps_allocated, offset + 1))
+ return -ENOMEM;
+
+ b->n_bitmaps = offset + 1;
+ }
+
+ bitmask = 1 << BITMAP_NUM_TO_REM(n);
+
+ b->bitmaps[offset] |= bitmask;
+
+ return 0;
+}
+
+void bitmap_unset(Bitmap *b, unsigned n) {
+ long long bitmask;
+ unsigned offset;
+
+ assert(b);
+
+ offset = BITMAP_NUM_TO_OFFSET(n);
+
+ if (offset >= b->n_bitmaps)
+ return;
+
+ bitmask = 1 << BITMAP_NUM_TO_REM(n);
+
+ b->bitmaps[offset] &= ~bitmask;
+}
+
+bool bitmap_isset(Bitmap *b, unsigned n) {
+ long long bitmask;
+ unsigned offset;
+
+ if (!b || !b->bitmaps)
+ return false;
+
+ offset = BITMAP_NUM_TO_OFFSET(n);
+
+ if (offset >= b->n_bitmaps)
+ return false;
+
+ bitmask = 1 << BITMAP_NUM_TO_REM(n);
+
+ return !!(b->bitmaps[offset] & bitmask);
+}
+
+bool bitmap_isclear(Bitmap *b) {
+ unsigned i;
+
+ assert(b);
+
+ for (i = 0; i < b->n_bitmaps; i++)
+ if (b->bitmaps[i])
+ return false;
+
+ return true;
+}
+
+void bitmap_clear(Bitmap *b) {
+ unsigned i;
+
+ assert(b);
+
+ for (i = 0; i < b->n_bitmaps; i++)
+ b->bitmaps[i] = 0;
+}
+
+void bitmap_rewind(Bitmap *b) {
+ if (!b)
+ return;
+
+ b->next_entry = 0;
+}
+
+bool bitmap_next(Bitmap *b, unsigned *n) {
+ long long bitmask;
+ unsigned offset, rem;
+
+ if (!b && b->next_entry == BITMAP_END)
+ return false;
+
+ offset = BITMAP_NUM_TO_OFFSET(b->next_entry);
+ rem = BITMAP_NUM_TO_REM(b->next_entry);
+ bitmask = 1 << rem;
+
+ for (; offset < b->n_bitmaps; offset ++) {
+ if (b->bitmaps[offset]) {
+ for (; bitmask; bitmask <<= 1, rem ++) {
+ if (b->bitmaps[offset] & bitmask) {
+ *n = BITMAP_OFFSET_TO_NUM(offset, rem);
+ b->next_entry = *n + 1;
+
+ return true;
+ }
+ }
+ }
+
+ rem = 0;
+ bitmask = 1;
+ }
+
+ b->next_entry = BITMAP_END;
+
+ return false;
+}
+
+bool bitmap_equal(Bitmap *a, Bitmap *b) {
+ unsigned i;
+
+ if (!a ^ !b)
+ return false;
+
+ if (!a)
+ return true;
+
+ if (a->n_bitmaps != b->n_bitmaps)
+ return false;
+
+ for (i = 0; i < a->n_bitmaps; i++)
+ if (a->bitmaps[i] != b->bitmaps[i])
+ return false;
+
+ return true;
+}
diff --git a/src/basic/bitmap.h b/src/basic/bitmap.h
new file mode 100644
index 0000000000..92bee51a2c
--- /dev/null
+++ b/src/basic/bitmap.h
@@ -0,0 +1,50 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+ This file is part of systemd.
+
+ Copyright 2015 Tom Gundersen
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "macro.h"
+
+typedef struct Bitmap Bitmap;
+
+Bitmap *bitmap_new(void);
+
+void bitmap_free(Bitmap *b);
+
+int bitmap_ensure_allocated(Bitmap **b);
+
+int bitmap_set(Bitmap *b, unsigned n);
+void bitmap_unset(Bitmap *b, unsigned n);
+bool bitmap_isset(Bitmap *b, unsigned n);
+bool bitmap_isclear(Bitmap *b);
+void bitmap_clear(Bitmap *b);
+
+void bitmap_rewind(Bitmap *b);
+bool bitmap_next(Bitmap *b, unsigned *n);
+
+bool bitmap_equal(Bitmap *a, Bitmap *b);
+
+#define BITMAP_FOREACH(n, b) \
+ for (bitmap_rewind(b); bitmap_next((b), &(n)); )
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(Bitmap*, bitmap_free);
+
+#define _cleanup_bitmap_free_ _cleanup_(bitmap_freep)
diff --git a/src/test/test-bitmap.c b/src/test/test-bitmap.c
new file mode 100644
index 0000000000..304888beb9
--- /dev/null
+++ b/src/test/test-bitmap.c
@@ -0,0 +1,96 @@
+/***
+ This file is part of systemd
+
+ Copyright 2015 Tom Gundersen
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "bitmap.h"
+
+int main(int argc, const char *argv[]) {
+ _cleanup_bitmap_free_ Bitmap *b = NULL;
+ unsigned n = (unsigned) -1, i = 0;
+
+ b = bitmap_new();
+ assert_se(b);
+
+ assert_se(bitmap_ensure_allocated(&b) == 0);
+ bitmap_free(b);
+ b = NULL;
+ assert_se(bitmap_ensure_allocated(&b) == 0);
+
+ assert_se(bitmap_isset(b, 0) == false);
+ assert_se(bitmap_isset(b, 1) == false);
+ assert_se(bitmap_isset(b, 256) == false);
+ assert_se(bitmap_isclear(b) == true);
+
+ assert_se(bitmap_set(b, 0) == 0);
+ assert_se(bitmap_isset(b, 0) == true);
+ assert_se(bitmap_isclear(b) == false);
+ bitmap_unset(b, 0);
+ assert_se(bitmap_isset(b, 0) == false);
+ assert_se(bitmap_isclear(b) == true);
+
+ assert_se(bitmap_set(b, 1) == 0);
+ assert_se(bitmap_isset(b, 1) == true);
+ assert_se(bitmap_isclear(b) == false);
+ bitmap_unset(b, 1);
+ assert_se(bitmap_isset(b, 1) == false);
+ assert_se(bitmap_isclear(b) == true);
+
+ assert_se(bitmap_set(b, 256) == 0);
+ assert_se(bitmap_isset(b, 256) == true);
+ assert_se(bitmap_isclear(b) == false);
+ bitmap_unset(b, 256);
+ assert_se(bitmap_isset(b, 256) == false);
+ assert_se(bitmap_isclear(b) == true);
+
+ assert_se(bitmap_set(b, 0) == 0);
+ assert_se(bitmap_set(b, 1) == 0);
+ assert_se(bitmap_set(b, 256) == 0);
+
+ BITMAP_FOREACH(n, b) {
+ assert_se(n == i);
+ if (i == 0)
+ i = 1;
+ else if (i == 1)
+ i = 256;
+ else if (i == 256)
+ i = (unsigned) -1;
+ }
+
+ assert_se(i == (unsigned) -1);
+
+ i = 0;
+
+ BITMAP_FOREACH(n, b) {
+ assert_se(n == i);
+ if (i == 0)
+ i = 1;
+ else if (i == 1)
+ i = 256;
+ else if (i == 256)
+ i = (unsigned) -1;
+ }
+
+ assert_se(i == (unsigned) -1);
+
+ bitmap_clear(b);
+ assert_se(bitmap_isclear(b) == true);
+
+ assert_se(bitmap_set(b, (unsigned) -1) == -ERANGE);
+
+ return 0;
+}
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