From: Andrei Emeltchenko <andrei.emeltchenko@xxxxxxxxx>
For small unique id generation we may use bitfield since it is very fast
and memory efficient. If we need to generate id from 1 to 64 helper
functions are added to utils.
---
src/shared/util.c | 24 ++++++++++++++++++++++++
src/shared/util.h | 3 +++
2 files changed, 27 insertions(+)
diff --git a/src/shared/util.c b/src/shared/util.c
index 74ffb08..3ae6b9e 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -106,3 +106,27 @@ unsigned char util_get_dt(const char *parent, const char *name)
return DT_UNKNOWN;
}
+
+/* Helpers for bitfield operations */
+/* Find unique id from 1 to max */
+uint8_t util_get_bitmap64_uid(uint64_t *bitmap, uint8_t max)
+{
+ uint64_t temp = *bitmap >> 1;
+ uint64_t id = 1;
+
+ for (; temp & 0x01; temp >>= 1)
+ id++;
+
+ if (id > max)
+ return 0;
+
+ *bitmap |= 0x01l << id;
+
+ return id;
+}
+
+/* Clear id bit in bitmap */
+void util_clear_bitmap64(uint64_t *bitmap, uint8_t id)
+{
+ *bitmap &= ~(0x01l << id);
+}
diff --git a/src/shared/util.h b/src/shared/util.h
index 8437662..8f28c24 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -93,6 +93,9 @@ void util_hexdump(const char dir, const unsigned char *buf, size_t len,
unsigned char util_get_dt(const char *parent, const char *name);
+uint8_t util_get_bitmap64_uid(uint64_t *bitmap, uint8_t max);
+void util_clear_bitmap64(uint64_t *bitmap, uint8_t id);
+
static inline void bswap_128(const void *src, void *dst)
{
const uint8_t *s = src;
--
2.1.0
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