From de3ac20422850ea919a3c737c112eb3ead9b142a Mon Sep 17 00:00:00 2001
From: Eric-Paul Ickhorn <ericp.ickhorn@gmail.com>
Date: Fri, 1 Dec 2023 16:36:36 +0100
Subject: [PATCH] Added memory functions (not tested)

---
 code/exports/librr/memory.h | 41 +++++++++++++++++++++++++++++
 code/src-c/memory.c         | 51 +++++++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+)
 create mode 100644 code/exports/librr/memory.h
 create mode 100644 code/src-c/memory.c

diff --git a/code/exports/librr/memory.h b/code/exports/librr/memory.h
new file mode 100644
index 0000000..5fcbbeb
--- /dev/null
+++ b/code/exports/librr/memory.h
@@ -0,0 +1,41 @@
+
+#ifndef RR_RUNES_H
+#define RR_RUNES_H
+
+#include <librr/types.h>
+
+
+/// @brief Tests if two memory regions overlap partially or completely.
+/// @param block1 Block to check for overlapping with block2.
+//  If the address of this block is higher than that of block2, the blocks will be swapped internally.
+/// @param length1 The length of the first block.
+/// @param block2 The second block to check for overlapping. 
+/// @param length2 
+/// @return Whether the two blocks overlap.
+bool_t rr_mem_overlap(void *block1, usz_t length1, void *block2, usz_t length2);
+
+/// @brief Checks if two memory blocks contain the equal data. 
+/// @param block1 Address of the data to be checked for equality with 'block2'
+/// @param block2 Address of the other memory block. In cases where there is a clear correct version,
+///  this should be the correct data to be checked against.
+/// @param count How many bytes will be checked.
+/// @return 
+bool_t rr_memequ(void *block1, void *block2, usz_t count);
+
+/// @brief Sets all bytes in a memory region all to one byte
+/// @param destination Address to the memory region to fill with one byte
+/// @param count Number of bytes to set; length of 'destination'
+/// @param value Value to write to every bte of 'destination'.
+void rr_memset(void *destination, usz_t count, u8_t value);
+
+/// @brief Repeats a sequence until a number of bytes was filled, potentially only writing a sequence half-way.
+/// @attention The sequence cannot be contained in the destination.
+/// @param destination Address in memory in which the sequence will be repeated.
+/// @param num_bytes How many bytes of the destination should be filled. The last sequence can be partially finished.
+/// @param sequence Sequence of bytes which will be written to destination.
+/// @param len_sequence Length of 'sequence'
+/// @return The number of attempted or partial repetitions which have been performed.
+usz_t rr_memrep(void *destination, usz_t num_bytes, void *sequence, usz_t len_sequence);
+
+
+#endif // LIBRR_RUNES_H
diff --git a/code/src-c/memory.c b/code/src-c/memory.c
new file mode 100644
index 0000000..477aa6a
--- /dev/null
+++ b/code/src-c/memory.c
@@ -0,0 +1,51 @@
+#include <librr/memory.h>
+
+bool_t rr_mem_overlap(void *block1, usz_t length1, void *block2, usz_t length2)
+{
+    // Make block1 always be before block2
+    if(block1 > block2)
+    {
+        void           *block_backup            = block2;
+        usz_t           length_backup           = length2;
+        block2                  = block1;
+        length2                 = length1;
+        block1                  = block_backup;
+        length1                 = length_backup;
+    }
+    usz_t           start1                  = (usz_t) block1;
+    usz_t           start2                  = (usz_t) block2;
+    usz_t           end2                    = start2 + length2;
+
+    if(end2 > start1)
+    {
+        return TRUE;
+    }
+    return FALSE;
+}
+
+bool_t rr_memequ(void *block1, void *block2, usz_t count)
+{
+    u8_t           *block1_8            = block1;
+    u8_t           *block2_8            = block2;
+    for(usz_t index = 0; index < count; ++index)
+        if(block1_8[index] != block2_8[index]) return FALSE;
+    return TRUE;
+}
+
+void  rr_memset(void *destination, usz_t count, u8_t value)
+{
+    u8_t           *destination_8       = destination;
+    for(usz_t index = 0; index < count; ++index)
+        destination_8[index] = value;
+}
+
+usz_t rr_memrep(void *destination, usz_t num_bytes, void *sequence, usz_t len_sequence)
+{
+    if(rr_mem_overlap(destination, num_bytes, sequence, len_sequence)) return 0;
+    u8_t           *destination_8       = destination;
+    u8_t           *sequence_8          = sequence;
+    for(usz_t index = 0; index < num_bytes; ++index)
+        destination_8[index] = sequence_8[index % len_sequence];
+    return (num_bytes / len_sequence)           // How many full repetitions are performed
+        + ((num_bytes % len_sequence) != 0);    // One more if a partial repetiton is done
+}