From 419908e5ef15481bd22dcd4173a25562f6153a5a Mon Sep 17 00:00:00 2001
From: Fred Sundvik <fsundvik@gmail.com>
Date: Wed, 17 Feb 2016 09:07:38 +0200
Subject: [PATCH] Hide the byte stuffer state inside it

---
 serial_link/protocol/byte_stuffer.c    |  52 ++++----
 serial_link/protocol/byte_stuffer.h    |   5 +-
 serial_link/tests/byte_stuffer_tests.c | 177 ++++++++++++-------------
 3 files changed, 117 insertions(+), 117 deletions(-)

diff --git a/serial_link/protocol/byte_stuffer.c b/serial_link/protocol/byte_stuffer.c
index f9aa02a3f..e5a26c2c2 100644
--- a/serial_link/protocol/byte_stuffer.c
+++ b/serial_link/protocol/byte_stuffer.c
@@ -40,56 +40,58 @@ typedef struct byte_stuffer_state {
     uint8_t data[MAX_FRAME_SIZE];
 }byte_stuffer_state_t;
 
-void init_byte_stuffer_state(byte_stuffer_state_t* state) {
-    state->next_zero = 0;
-    state->data_pos = 0;
-    state->long_frame = false;
+static byte_stuffer_state_t state;
+
+void init_byte_stuffer(void) {
+    state.next_zero = 0;
+    state.data_pos = 0;
+    state.long_frame = false;
 }
 
-void recv_byte(byte_stuffer_state_t* state, uint8_t data) {
+void recv_byte(uint8_t data) {
     // Start of a new frame
-    if (state->next_zero == 0) {
-        state->next_zero = data;
-        state->long_frame = data == 0xFF;
-        state->data_pos = 0;
+    if (state.next_zero == 0) {
+        state.next_zero = data;
+        state.long_frame = data == 0xFF;
+        state.data_pos = 0;
         return;
     }
 
-    state->next_zero--;
+    state.next_zero--;
     if (data == 0) {
-        if (state->next_zero == 0) {
+        if (state.next_zero == 0) {
             // The frame is completed
-            if (state->data_pos > 0) {
-                validator_recv_frame(state->data, state->data_pos);
+            if (state.data_pos > 0) {
+                validator_recv_frame(state.data, state.data_pos);
             }
         }
         else {
             // The frame is invalid, so reset
-            init_byte_stuffer_state(state);
+            init_byte_stuffer();
         }
     }
     else {
-        if (state->data_pos == MAX_FRAME_SIZE) {
+        if (state.data_pos == MAX_FRAME_SIZE) {
             // We exceeded our maximum frame size
             // therefore there's nothing else to do than reset to a new frame
-            state->next_zero = data;
-            state->long_frame = data == 0xFF;
-            state->data_pos = 0;
+            state.next_zero = data;
+            state.long_frame = data == 0xFF;
+            state.data_pos = 0;
         }
-        else if (state->next_zero == 0) {
-            if (state->long_frame) {
+        else if (state.next_zero == 0) {
+            if (state.long_frame) {
                 // This is part of a long frame, so continue
-                state->next_zero = data;
-                state->long_frame = data == 0xFF;
+                state.next_zero = data;
+                state.long_frame = data == 0xFF;
             }
             else {
                 // Special case for zeroes
-                state->next_zero = data;
-                state->data[state->data_pos++] = 0;
+                state.next_zero = data;
+                state.data[state.data_pos++] = 0;
             }
         }
         else {
-            state->data[state->data_pos++] = data;
+            state.data[state.data_pos++] = data;
         }
     }
 }
diff --git a/serial_link/protocol/byte_stuffer.h b/serial_link/protocol/byte_stuffer.h
index ea6b8451d..4dcdd24c1 100644
--- a/serial_link/protocol/byte_stuffer.h
+++ b/serial_link/protocol/byte_stuffer.h
@@ -22,7 +22,6 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 */
 
-typedef struct byte_stuffer_state byte_stuffer_state_t;
-void init_byte_stuffer_state(byte_stuffer_state_t* state);
-void recv_byte(byte_stuffer_state_t* state, uint8_t data);
+void init_byte_stuffer(void);
+void recv_byte(uint8_t data);
 void send_frame(uint8_t* data, uint16_t size);
diff --git a/serial_link/tests/byte_stuffer_tests.c b/serial_link/tests/byte_stuffer_tests.c
index 78bcbb473..f29cc1299 100644
--- a/serial_link/tests/byte_stuffer_tests.c
+++ b/serial_link/tests/byte_stuffer_tests.c
@@ -29,13 +29,12 @@ SOFTWARE.
 #include "protocol/frame_validator.h"
 #include "protocol/physical.h"
 
-static byte_stuffer_state_t state;
 static uint8_t sent_data[MAX_FRAME_SIZE*2];
 static uint16_t sent_data_size;
 
 Describe(ByteStuffer);
 BeforeEach(ByteStuffer) {
-    init_byte_stuffer_state(&state);
+    init_byte_stuffer();
     sent_data_size = 0;
 }
 AfterEach(ByteStuffer) {}
@@ -51,23 +50,23 @@ void send_data(const uint8_t* data, uint16_t size) {
 
 Ensure(ByteStuffer, receives_no_frame_for_a_single_zero_byte) {
     never_expect(validator_recv_frame);
-    recv_byte(&state, 0);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_no_frame_for_a_single_FF_byte) {
     never_expect(validator_recv_frame);
-    recv_byte(&state, 0xFF);
+    recv_byte(0xFF);
 }
 
 Ensure(ByteStuffer, receives_no_frame_for_a_single_random_byte) {
     never_expect(validator_recv_frame);
-    recv_byte(&state, 0x4A);
+    recv_byte(0x4A);
 }
 
 Ensure(ByteStuffer, receives_no_frame_for_a_zero_length_frame) {
     never_expect(validator_recv_frame);
-    recv_byte(&state, 1);
-    recv_byte(&state, 0);
+    recv_byte(1);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_single_byte_valid_frame) {
@@ -76,9 +75,9 @@ Ensure(ByteStuffer, receives_single_byte_valid_frame) {
         when(size, is_equal_to(1)),
         when(data, is_equal_to_contents_of(expected, 1))
     );
-    recv_byte(&state, 2);
-    recv_byte(&state, 0x37);
-    recv_byte(&state, 0);
+    recv_byte(2);
+    recv_byte(0x37);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_three_bytes_valid_frame) {
@@ -87,11 +86,11 @@ Ensure(ByteStuffer, receives_three_bytes_valid_frame) {
         when(size, is_equal_to(3)),
         when(data, is_equal_to_contents_of(expected, 3))
     );
-    recv_byte(&state, 4);
-    recv_byte(&state, 0x37);
-    recv_byte(&state, 0x99);
-    recv_byte(&state, 0xFF);
-    recv_byte(&state, 0);
+    recv_byte(4);
+    recv_byte(0x37);
+    recv_byte(0x99);
+    recv_byte(0xFF);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_single_zero_valid_frame) {
@@ -100,9 +99,9 @@ Ensure(ByteStuffer, receives_single_zero_valid_frame) {
         when(size, is_equal_to(1)),
         when(data, is_equal_to_contents_of(expected, 1))
     );
-    recv_byte(&state, 1);
-    recv_byte(&state, 1);
-    recv_byte(&state, 0);
+    recv_byte(1);
+    recv_byte(1);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_valid_frame_with_zeroes) {
@@ -111,12 +110,12 @@ Ensure(ByteStuffer, receives_valid_frame_with_zeroes) {
         when(size, is_equal_to(4)),
         when(data, is_equal_to_contents_of(expected, 4))
     );
-    recv_byte(&state, 2);
-    recv_byte(&state, 5);
-    recv_byte(&state, 2);
-    recv_byte(&state, 3);
-    recv_byte(&state, 1);
-    recv_byte(&state, 0);
+    recv_byte(2);
+    recv_byte(5);
+    recv_byte(2);
+    recv_byte(3);
+    recv_byte(1);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_two_valid_frames) {
@@ -130,13 +129,13 @@ Ensure(ByteStuffer, receives_two_valid_frames) {
         when(size, is_equal_to(1)),
         when(data, is_equal_to_contents_of(expected2, 1))
     );
-    recv_byte(&state, 2);
-    recv_byte(&state, 5);
-    recv_byte(&state, 1);
-    recv_byte(&state, 0);
-    recv_byte(&state, 2);
-    recv_byte(&state, 3);
-    recv_byte(&state, 0);
+    recv_byte(2);
+    recv_byte(5);
+    recv_byte(1);
+    recv_byte(0);
+    recv_byte(2);
+    recv_byte(3);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_valid_frame_after_unexpected_zero) {
@@ -145,13 +144,13 @@ Ensure(ByteStuffer, receives_valid_frame_after_unexpected_zero) {
         when(size, is_equal_to(2)),
         when(data, is_equal_to_contents_of(expected, 2))
     );
-    recv_byte(&state, 3);
-    recv_byte(&state, 1);
-    recv_byte(&state, 0);
-    recv_byte(&state, 3);
-    recv_byte(&state, 5);
-    recv_byte(&state, 7);
-    recv_byte(&state, 0);
+    recv_byte(3);
+    recv_byte(1);
+    recv_byte(0);
+    recv_byte(3);
+    recv_byte(5);
+    recv_byte(7);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_valid_frame_after_unexpected_non_zero) {
@@ -160,14 +159,14 @@ Ensure(ByteStuffer, receives_valid_frame_after_unexpected_non_zero) {
         when(size, is_equal_to(2)),
         when(data, is_equal_to_contents_of(expected, 2))
     );
-    recv_byte(&state, 2);
-    recv_byte(&state, 9);
-    recv_byte(&state, 4); // This should have been zero
-    recv_byte(&state, 0);
-    recv_byte(&state, 3);
-    recv_byte(&state, 5);
-    recv_byte(&state, 7);
-    recv_byte(&state, 0);
+    recv_byte(2);
+    recv_byte(9);
+    recv_byte(4); // This should have been zero
+    recv_byte(0);
+    recv_byte(3);
+    recv_byte(5);
+    recv_byte(7);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_a_valid_frame_with_over254_non_zeroes_and_then_end_of_frame) {
@@ -180,11 +179,11 @@ Ensure(ByteStuffer, receives_a_valid_frame_with_over254_non_zeroes_and_then_end_
         when(size, is_equal_to(254)),
         when(data, is_equal_to_contents_of(expected, 254))
     );
-    recv_byte(&state, 0xFF);
+    recv_byte(0xFF);
     for (i=0;i<254;i++) {
-        recv_byte(&state, i+1);
+        recv_byte(i+1);
     }
-    recv_byte(&state, 0);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_a_valid_frame_with_over254_non_zeroes_next_byte_is_non_zero) {
@@ -198,13 +197,13 @@ Ensure(ByteStuffer, receives_a_valid_frame_with_over254_non_zeroes_next_byte_is_
         when(size, is_equal_to(255)),
         when(data, is_equal_to_contents_of(expected, 255))
     );
-    recv_byte(&state, 0xFF);
+    recv_byte(0xFF);
     for (i=0;i<254;i++) {
-        recv_byte(&state, i+1);
+        recv_byte(i+1);
     }
-    recv_byte(&state, 2);
-    recv_byte(&state, 7);
-    recv_byte(&state, 0);
+    recv_byte(2);
+    recv_byte(7);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_a_valid_frame_with_over254_non_zeroes_next_byte_is_zero) {
@@ -218,13 +217,13 @@ Ensure(ByteStuffer, receives_a_valid_frame_with_over254_non_zeroes_next_byte_is_
         when(size, is_equal_to(255)),
         when(data, is_equal_to_contents_of(expected, 255))
     );
-    recv_byte(&state, 0xFF);
+    recv_byte(0xFF);
     for (i=0;i<254;i++) {
-        recv_byte(&state, i+1);
+        recv_byte(i+1);
     }
-    recv_byte(&state, 1);
-    recv_byte(&state, 1);
-    recv_byte(&state, 0);
+    recv_byte(1);
+    recv_byte(1);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_two_long_frames_and_some_more) {
@@ -243,23 +242,23 @@ Ensure(ByteStuffer, receives_two_long_frames_and_some_more) {
         when(size, is_equal_to(515)),
         when(data, is_equal_to_contents_of(expected, 510))
     );
-    recv_byte(&state, 0xFF);
+    recv_byte(0xFF);
     for (i=0;i<254;i++) {
-        recv_byte(&state, i+1);
+        recv_byte(i+1);
     }
-    recv_byte(&state, 0xFF);
+    recv_byte(0xFF);
     for (i=0;i<254;i++) {
-        recv_byte(&state, i+1);
+        recv_byte(i+1);
     }
-    recv_byte(&state, 8);
-    recv_byte(&state, 1);
-    recv_byte(&state, 2);
-    recv_byte(&state, 3);
-    recv_byte(&state, 4);
-    recv_byte(&state, 5);
-    recv_byte(&state, 6);
-    recv_byte(&state, 7);
-    recv_byte(&state, 0);
+    recv_byte(8);
+    recv_byte(1);
+    recv_byte(2);
+    recv_byte(3);
+    recv_byte(4);
+    recv_byte(5);
+    recv_byte(6);
+    recv_byte(7);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, receives_an_all_zeros_frame_that_is_maximum_size) {
@@ -269,23 +268,23 @@ Ensure(ByteStuffer, receives_an_all_zeros_frame_that_is_maximum_size) {
         when(data, is_equal_to_contents_of(expected, MAX_FRAME_SIZE))
     );
     int i;
-    recv_byte(&state, 1);
+    recv_byte(1);
     for(i=0;i<MAX_FRAME_SIZE;i++) {
-       recv_byte(&state, 1);
+       recv_byte(1);
     }
-    recv_byte(&state, 0);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, doesnt_recv_a_frame_thats_too_long_all_zeroes) {
     uint8_t expected[1] = {0};
     never_expect(validator_recv_frame);
     int i;
-    recv_byte(&state, 1);
+    recv_byte(1);
     for(i=0;i<MAX_FRAME_SIZE;i++) {
-       recv_byte(&state, 1);
+       recv_byte(1);
     }
-    recv_byte(&state, 1);
-    recv_byte(&state, 0);
+    recv_byte(1);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, received_frame_is_aborted_when_its_too_long) {
@@ -295,13 +294,13 @@ Ensure(ByteStuffer, received_frame_is_aborted_when_its_too_long) {
         when(data, is_equal_to_contents_of(expected, 1))
     );
     int i;
-    recv_byte(&state, 1);
+    recv_byte(1);
     for(i=0;i<MAX_FRAME_SIZE;i++) {
-       recv_byte(&state, 1);
+       recv_byte(1);
     }
-    recv_byte(&state, 2);
-    recv_byte(&state, 1);
-    recv_byte(&state, 0);
+    recv_byte(2);
+    recv_byte(1);
+    recv_byte(0);
 }
 
 Ensure(ByteStuffer, does_nothing_when_sending_zero_size_frame) {
@@ -438,7 +437,7 @@ Ensure(ByteStuffer, sends_and_receives_full_roundtrip_small_packet) {
     );
     int i;
     for(i=0;i<sent_data_size;i++) {
-       recv_byte(&state, sent_data[i]);
+       recv_byte(sent_data[i]);
     }
 }
 
@@ -451,7 +450,7 @@ Ensure(ByteStuffer, sends_and_receives_full_roundtrip_small_packet_with_zeros) {
     );
     int i;
     for(i=0;i<sent_data_size;i++) {
-       recv_byte(&state, sent_data[i]);
+       recv_byte(sent_data[i]);
     }
 }
 
@@ -467,7 +466,7 @@ Ensure(ByteStuffer, sends_and_receives_full_roundtrip_254_bytes) {
         when(data, is_equal_to_contents_of(original_data, sizeof(original_data)))
     );
     for(i=0;i<sent_data_size;i++) {
-       recv_byte(&state, sent_data[i]);
+       recv_byte(sent_data[i]);
     }
 }
 
@@ -485,7 +484,7 @@ Ensure(ByteStuffer, sends_and_receives_full_roundtrip_256_bytes) {
         when(data, is_equal_to_contents_of(original_data, sizeof(original_data)))
     );
     for(i=0;i<sent_data_size;i++) {
-       recv_byte(&state, sent_data[i]);
+       recv_byte(sent_data[i]);
     }
 }
 
@@ -502,6 +501,6 @@ Ensure(ByteStuffer, sends_and_receives_full_roundtrip_254_bytes_and_then_zero) {
         when(data, is_equal_to_contents_of(original_data, sizeof(original_data)))
     );
     for(i=0;i<sent_data_size;i++) {
-       recv_byte(&state, sent_data[i]);
+       recv_byte(sent_data[i]);
     }
 }