file transfer script cleanup + automatic EOT detection

scripts/transfer.py

@@ -4,10 +4,12 @@ import select
 import signal
 import time
 
+bytes_processed: int  = 0
 
-def print_usage():
-    print('Usage: python serialfile.py -in <serial device> > file', file=sys.stderr)
+def print_usage_and_exit():
+    print('Usage: python serialfile.py -in <serial device> [ > file ]', file=sys.stderr)
     print('Usage: python serialfile.py -out <serial device> < file', file=sys.stderr)
+    exit(1)
 
 
 def get_serial(port: str) -> serial.Serial:
@@ -24,6 +26,44 @@ def get_serial(port: str) -> serial.Serial:
 def data_ready_on_stdin():
     return bool(select.select([sys.stdin], [], [], 0)[0])
 
+def data_ready_on_port(port: serial.Serial):
+    return bool(select.select([port.fileno()], [], [], 0)[0])
+
+
+def handle_inbound_transmission(port: str):
+    global bytes_processed
+
+    with get_serial(port) as s:
+        print('Waiting for data... ', file=sys.stderr, end='', flush=True)
+        while not data_ready_on_port(s):
+            pass
+        print('OK', file=sys.stderr)
+
+        s.timeout = 1
+        while True:
+            data = s.read()
+            if len(data) > 0:
+                sys.stdout.buffer.write(data)
+                bytes_processed += len(data)
+            else:
+                break
+        print('Transmission finished', file=sys.stderr)
+
+
+def handle_outbound_transmission(port: str):
+    global bytes_processed
+
+    if not data_ready_on_stdin():
+        print_usage_and_exit()
+
+    with get_serial(port) as s:
+        data = sys.stdin.buffer.read()
+        while len(data) > 0:
+            s.write(data)
+            bytes_processed += len(data)
+            data = sys.stdin.buffer.read()
+
+
 """
 This utility receives/sends files via selected serial port to the
 Apple-1 Serial Interface card.
@@ -35,28 +75,23 @@ pip3 install pyserial
 if __name__ == "__main__":
 
     if len(sys.argv) != 3:
-        print_usage()
-        exit(1)
+        print_usage_and_exit()
+
+    def print_bytes_processed_and_exit(status: int):
+        print(f'Total bytes processed: {bytes_processed}', file=sys.stderr)
+        exit(status)
+
+    # terminate silently on SIGINT
+    signal.signal(signal.SIGINT, lambda s, fr: print_bytes_processed_and_exit(1))
 
     if sys.argv[1] == '-in':
-        print('Press Ctrl+C after the transmission ends', file=sys.stderr)
-        
-        # terminate silently on SIGINT
-        signal.signal(signal.SIGINT, lambda s, fr: exit(0))
-        with get_serial(sys.argv[2]) as s:
-            while True:
-                sys.stdout.buffer.write(s.read())
+        handle_inbound_transmission(sys.argv[2])
 
     elif sys.argv[1] == '-out':
-        # check if the data is available on stdin
-        if not data_ready_on_stdin():
-            exit(0)
-        with get_serial(sys.argv[2]) as s:
-            data = sys.stdin.buffer.read()
-            while len(data) > 0:
-                s.write(data)
-                data = sys.stdin.buffer.read()
+        handle_outbound_transmission(sys.argv[2])
+
     else:
         print(f'Unknown option: {sys.argv[1]}', file=sys.stderr)
-        print_usage()
-        exit(1)
+        print_usage_and_exit()
+
+    print_bytes_processed_and_exit(0)