SoW-2020-0002: Trace Hit Counters: Implement key-addressed counters in shared memory...

[deliverable/lttng-ust.git] / include / lttng / bitmap.h

diff --git a/include/lttng/bitmap.h b/include/lttng/bitmap.h
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+++ b/include/lttng/bitmap.h
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+/*
+ * lttng/bitmap.h
+ *
+ * LTTng Bitmap API
+ *
+ * Copyright (C) 2020 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef _LTTNG_BITMAP_H
+#define _LTTNG_BITMAP_H
+
+#include <urcu/compiler.h>
+#include <urcu/system.h>
+#include <urcu/uatomic.h>
+#include <stdbool.h>
+
+static inline void lttng_bitmap_index(unsigned int index, unsigned int *word,
+               unsigned int *bit)
+{
+       *word = index / CAA_BITS_PER_LONG;
+       *bit = index % CAA_BITS_PER_LONG;
+}
+
+static inline void lttng_bitmap_set_bit(unsigned int index, unsigned long *p)
+{
+       unsigned int word, bit;
+       unsigned long val;
+
+       lttng_bitmap_index(index, &word, &bit);
+       val = 1U << bit;
+       uatomic_or(p + word, val);
+}
+
+static inline void lttng_bitmap_clear_bit(unsigned int index, unsigned long *p)
+{
+       unsigned int word, bit;
+       unsigned long val;
+
+       lttng_bitmap_index(index, &word, &bit);
+       val = ~(1U << bit);
+       uatomic_and(p + word, val);
+}
+
+static inline bool lttng_bitmap_test_bit(unsigned int index, unsigned long *p)
+{
+       unsigned int word, bit;
+
+       lttng_bitmap_index(index, &word, &bit);
+       return (CMM_LOAD_SHARED(p[word]) >> bit) & 0x1;
+}
+
+#endif /* _LTTNG_BITMAP_H */