update the verification script

I've extended the script based on suggestions by @prusnak

The script now checks the available RAM, is there is enough to check the file at once it will do so. If not the file is read in chunks.

scripts/verify-checksum-models.py

@@ -1,5 +1,32 @@
 import os
 import hashlib
+import psutil
+
+def sha256sum(file):
+    # Check if system has enough RAM to read the file at once
+    file_size = os.path.getsize(file)
+    total_memory = psutil.virtual_memory().total
+
+    if file_size < total_memory:
+        # Read the file at once
+        with open(file, "rb") as f:
+            file_hash = hashlib.sha256(f.read())
+            
+    else:
+        # Read the file in chunks
+        block_size = 16 * 1024 * 1024  # 16 MB block size
+        b  = bytearray(block_size)
+        file_hash = hashlib.sha256()
+        mv = memoryview(b)
+        with open(file, 'rb', buffering=0) as f: 
+            while True:
+                n = f.readinto(mv)
+                if not n:
+                    break
+                file_hash.update(mv[:n])
+        
+    return file_hash.hexdigest()
+
 
 # Define the path to the llama directory (parent folder of script directory)
 llama_path = os.path.abspath(os.path.join(os.path.dirname(__file__), os.pardir))
@@ -24,7 +51,7 @@ for line in hash_list:
     # Split the line into hash and filename
     hash_value, filename = line.split("  ")
 
-    # Get the full path of the file by joining the models path and the filename
+    # Get the full path of the file by joining the llama path and the filename
     file_path = os.path.join(llama_path, filename)
 
     # Informing user of the progress of the integrity check
@@ -33,8 +60,7 @@ for line in hash_list:
     # Check if the file exists
     if os.path.exists(file_path):
         # Calculate the SHA256 checksum of the file using hashlib
-        with open(file_path, "rb") as f:
-            file_hash = hashlib.sha256(f.read()).hexdigest()
+        file_hash = sha256sum(file_path)
 
         # Compare the file hash with the expected hash
         if file_hash == hash_value: