write_hex_file: new parameter byte_count

intelhex/__init__.py

@@ -544,7 +544,7 @@ def _get_eol_textfile(eolstyle, platform):
             raise ValueError("wrong eolstyle %s" % repr(eolstyle))
     _get_eol_textfile = staticmethod(_get_eol_textfile)
 
-    def write_hex_file(self, f, write_start_addr=True, eolstyle='native'):
+    def write_hex_file(self, f, write_start_addr=True, eolstyle='native', byte_count=16):
         """Write data to file f in HEX format.
 
         @param  f                   filename or file-like object for writing
@@ -555,7 +555,10 @@ def write_hex_file(self, f, write_start_addr=True, eolstyle='native'):
         @param  eolstyle            can be used to force CRLF line-endings
                                     for output file on different platforms.
                                     Supported eol styles: 'native', 'CRLF'.
+        @param byte_count           number of bytes in the data field
         """
+        if byte_count > 255 or byte_count < 1:
+            raise ValueError("wrong byte_count " + str(byte_count))
         fwrite = getattr(f, "write", None)
         if fwrite:
             fobj = f
@@ -656,7 +659,7 @@ def write_hex_file(self, f, write_start_addr=True, eolstyle='native'):
                     # produce one record
                     low_addr = cur_addr & 0x0FFFF
                     # chain_len off by 1
-                    chain_len = min(15, 65535-low_addr, maxaddr-cur_addr)
+                    chain_len = min(byte_count - 1, 65535-low_addr, maxaddr-cur_addr)
 
                     # search continuous chain
                     stop_addr = cur_addr + chain_len

intelhex/test.py

@@ -1659,6 +1659,77 @@ def test_sripts_hexdiff_version(self):
     def test_sripts_hexmerge_version(self):
         self.versionChecker('%s scripts/hexmerge.py --version')
 
+
+class TestWriteHexFileByteCount(unittest.TestCase):
+
+    def setUp(self):
+        self.f = StringIO(hex8)
+
+    def tearDown(self):
+        self.f.close()
+        del self.f
+
+    def test_write_hex_file_bad_byte_count(self):
+        ih = intelhex.IntelHex(self.f)
+        sio = StringIO()
+        with self.assertRaises(ValueError):
+            ih.write_hex_file(sio, byte_count=0)
+        with self.assertRaises(ValueError):
+            ih.write_hex_file(sio, byte_count=-1)
+        with self.assertRaises(ValueError):
+            ih.write_hex_file(sio, byte_count=256)
+
+    def test_write_hex_file_byte_count_1(self):
+        ih = intelhex.IntelHex(self.f)
+        sio = StringIO()
+        ih.write_hex_file(sio, byte_count=1)
+        s = sio.getvalue()
+        # control written hex first line to check that byte count is 1
+        sio.seek(0)
+        self.assertEqual(sio.readline(), ':0100000002FD\n',
+                         "Written hex is not in byte count 1")
+        sio.close()
+
+        fin = StringIO(s)
+        ih2 = intelhex.IntelHex(fin)
+
+        self.assertEqual(ih.tobinstr(), ih2.tobinstr(),
+                         "Written hex file does not equal with original")
+
+    def test_write_hex_file_byte_count_13(self):
+        ih = intelhex.IntelHex(self.f)
+        sio = StringIO()
+        ih.write_hex_file(sio, byte_count=13)
+        s = sio.getvalue()
+        # control written hex first line to check that byte count is 13
+        sio.seek(0)
+        self.assertEqual(sio.readline(), ':0D0000000205A2E576246AF8E6057622786E\n',
+                         "Written hex is not in byte count 1")
+        sio.close()
+
+        fin = StringIO(s)
+        ih2 = intelhex.IntelHex(fin)
+
+        self.assertEqual(ih.tobinstr(), ih2.tobinstr(),
+                         "Written hex file does not equal with original")
+
+    def test_write_hex_file_byte_count_255(self):
+        ih = intelhex.IntelHex(self.f)
+        sio = StringIO()
+        ih.write_hex_file(sio, byte_count=255)
+        s = sio.getvalue()
+        # control written hex first line to check that byte count is 255
+        sio.seek(0)
+        self.assertEqual(sio.readline(), ':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\n',
+                         "Written hex is not in byte count 1")
+        sio.close()
+
+        fin = StringIO(s)
+        ih2 = intelhex.IntelHex(fin)
+
+        self.assertEqual(ih.tobinstr(), ih2.tobinstr(),
+                         "Written hex file does not equal with original")
+
 ##
 # MAIN
 if __name__ == '__main__':