From 4823c4f3a4d48e5979b8e1349c62b47bd6d96c65 Mon Sep 17 00:00:00 2001
From: Eric-Paul Ickhorn <ericp.ickhorn@gmail.com>
Date: Wed, 6 Dec 2023 18:15:32 +0100
Subject: [PATCH] Added bitfield functions (not tested)

---
 core/exports/librr/bitfield.h | 31 +++++++++++++++++++++++++++++++
 core/src-c/bitfield.c         | 29 +++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)
 create mode 100644 core/exports/librr/bitfield.h
 create mode 100644 core/src-c/bitfield.c

diff --git a/core/exports/librr/bitfield.h b/core/exports/librr/bitfield.h
new file mode 100644
index 0000000..41167f2
--- /dev/null
+++ b/core/exports/librr/bitfield.h
@@ -0,0 +1,31 @@
+
+#ifndef RR_BITFIELD_H
+#define RR_BITFIELD_H
+
+#include <librr/types.h>
+
+/// @brief Tests whether a bit of an u64_t at a given index from the least significant bit is set.
+/// @param buffer Buffer of which to test the presence of a bit.
+/// @param index Index of the bit of which to test the presence.
+///   The index starts at 0;0 is the least significant bit.
+/// @return Whether the bit in 'buffer' at 'index' was set.
+inline bool_t rr_is_bit_set(u64_t buffer, usz_t index);
+
+/// @brief Sets a bit at a given index from the least significant bit in an u64_t and returns the new u64_t.
+/// @param buffer The buffer to set the 'index'th bit of.
+/// @param index Index of the bit in the buffer (as counted from the least significant bit) to set a bit of.
+///  The index starts with 0; there will always be a bit set (except if the index is greater than 63).
+/// @return The modified buffer with the bit set.
+inline u64_t rr_set_bit(u64_t buffer, usz_t index);
+
+/// @brief Returns a bitfield with a given number of bits set to 1, beginning with the least significant bit.
+/// @param count Number of bits to set
+/// @return The bitfield of which the bits were set.
+u64_t rr_bitpad_lsb(usz_t count);
+
+/// @brief Returns a bitfield with a given number of bits set to 1, beginning with the most significant bit.
+/// @param count Number of bits to set
+/// @return The bitfield of which the bits were set.
+u64_t rr_bitpad_msb(usz_t count);
+
+#endif // RR_BITFIELD_H
diff --git a/core/src-c/bitfield.c b/core/src-c/bitfield.c
new file mode 100644
index 0000000..623f601
--- /dev/null
+++ b/core/src-c/bitfield.c
@@ -0,0 +1,29 @@
+#include <librr/bitfield.h>
+
+inline bool_t rr_is_bit_set(u64_t buffer, usz_t index)
+{
+    return !!(buffer & (1 << index));
+}
+
+inline u64_t rr_set_bit(u64_t buffer, usz_t index)
+{
+    return buffer | (1 << index);
+}
+
+u64_t rr_bitpad_lsb(usz_t count)
+{
+    u64_t result = 0;
+    for(usz_t index = 0; index < count; ++index)
+    {
+        result |= 1 << index;
+    }
+}
+
+u64_t rr_bitpad_msb(usz_t count)
+{
+    u64_t result = 0;
+    for(usz_t index = 0; index < count; ++index)
+    {
+        result |= (1 << 63) >> index;
+    }
+}