From 3fda01066706245df9cf9878ed60889e4748e75d Mon Sep 17 00:00:00 2001
From: Alexandre Paillier <alexandre.paillier@ledger.fr>
Date: Mon, 2 May 2022 14:41:00 +0200
Subject: [PATCH] Add memory functions

---
 src_features/signMessageEIP712/mem.c | 58 ++++++++++++++++++++++++++++
 src_features/signMessageEIP712/mem.h | 13 +++++++
 2 files changed, 71 insertions(+)
 create mode 100644 src_features/signMessageEIP712/mem.c
 create mode 100644 src_features/signMessageEIP712/mem.h

diff --git a/src_features/signMessageEIP712/mem.c b/src_features/signMessageEIP712/mem.c
new file mode 100644
index 0000000..0677783
--- /dev/null
+++ b/src_features/signMessageEIP712/mem.c
@@ -0,0 +1,58 @@
+#include <stdint.h>
+#include "mem.h"
+
+static uint8_t  mem_buffer[SIZE_MEM_BUFFER];
+static size_t   mem_idx;
+
+/**
+ * Initializes the memory buffer index
+ */
+void    mem_init(void)
+{
+    mem_idx = 0;
+}
+
+/**
+ * Resets the memory buffer index
+ */
+void    mem_reset(void)
+{
+    mem_init();
+}
+
+/**
+ * Allocates a chunk of the memory buffer of a given size.
+ * Checks to see if there are enough space left in the memory buffer, returns
+ * the current location in the memory buffer and moves the index accordingly.
+ *
+ * @param[in] size Requested allocation size in bytes
+ *
+ * @return Allocated memory pointer; \ref NULL if not enough space left.
+ */
+void    *mem_alloc(size_t size)
+{
+    if ((mem_idx + size) > SIZE_MEM_BUFFER) // Buffer exceeded
+    {
+        return NULL;
+    }
+    mem_idx += size;
+    return &mem_buffer[mem_idx - size];
+}
+
+
+/**
+ * De-allocates a chunk of memory buffer by a given size.
+ *
+ * @param[in] size Requested deallocation size in bytes
+ */
+void    mem_dealloc(size_t size)
+{
+    if (size > mem_idx) // More than is already allocated
+    {
+        mem_idx = 0;
+    }
+    else
+    {
+        mem_idx -= size;
+    }
+}
diff --git a/src_features/signMessageEIP712/mem.h b/src_features/signMessageEIP712/mem.h
new file mode 100644
index 0000000..2a7b179
--- /dev/null
+++ b/src_features/signMessageEIP712/mem.h
@@ -0,0 +1,13 @@
+#ifndef MEM_H_
+#define MEM_H_
+
+#include <stdlib.h>
+
+#define SIZE_MEM_BUFFER 1024
+
+void    mem_init(void);
+void    mem_reset(void);
+void    *mem_alloc(size_t size);
+void    mem_dealloc(size_t size);
+
+#endif // MEM_H_