diff options
| -rw-r--r-- | serial_link/protocol/byte_stuffer.c | 26 | ||||
| -rw-r--r-- | serial_link/tests/byte_stuffer_tests.c | 92 |
2 files changed, 112 insertions, 6 deletions
diff --git a/serial_link/protocol/byte_stuffer.c b/serial_link/protocol/byte_stuffer.c index e578f88dc1..cc7afe97ae 100644 --- a/serial_link/protocol/byte_stuffer.c +++ b/serial_link/protocol/byte_stuffer.c @@ -24,26 +24,35 @@ SOFTWARE. #include "protocol/byte_stuffer.h" #include "protocol/frame_validator.h" +#include <stdio.h> // This implements the "Consistent overhead byte stuffing protocol" // https://en.wikipedia.org/wiki/Consistent_Overhead_Byte_Stuffing // http://www.stuartcheshire.org/papers/COBSforToN.pdf +#define MAX_FRAME_SIZE 1024 + typedef struct byte_stuffer_state { uint16_t next_zero; uint16_t data_pos; - uint8_t data[256]; + bool long_frame; + 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 void start_frame(byte_stuffer_state_t* state, uint8_t data) { } void recv_byte(byte_stuffer_state_t* state, 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; return; } @@ -56,15 +65,20 @@ void recv_byte(byte_stuffer_state_t* state, uint8_t data) { } else { // The frame is invalid, so reset - state->next_zero = 0; - state->data_pos = 0; + init_byte_stuffer_state(state); } } else { if (state->next_zero == 0) { - // Special case for zeroes - state->next_zero = data; - state->data[state->data_pos++] = 0; + if (state->long_frame) { + state->next_zero = data; + state->long_frame = data == 0xFF; + } + else { + // Special case for zeroes + state->next_zero = data; + state->data[state->data_pos++] = 0; + } } else { state->data[state->data_pos++] = data; diff --git a/serial_link/tests/byte_stuffer_tests.c b/serial_link/tests/byte_stuffer_tests.c index 74a349b1f3..a28c361938 100644 --- a/serial_link/tests/byte_stuffer_tests.c +++ b/serial_link/tests/byte_stuffer_tests.c @@ -154,3 +154,95 @@ Ensure(ByteStuffer, receives_valid_frame_after_unexpected_non_zero) { recv_byte(&state, 7); recv_byte(&state, 0); } + +Ensure(ByteStuffer, receives_a_valid_frame_with_over254_non_zeroes_and_then_end_of_frame) { + uint8_t expected[254]; + int i; + for (i=0;i<254;i++) { + expected[i] = i + 1; + } + expect(recv_frame, + when(size, is_equal_to(254)), + when(data, is_equal_to_contents_of(expected, 254)) + ); + recv_byte(&state, 0xFF); + for (i=0;i<254;i++) { + recv_byte(&state, i+1); + } + recv_byte(&state, 0); +} + +Ensure(ByteStuffer, receives_a_valid_frame_with_over254_non_zeroes_next_byte_is_non_zero) { + uint8_t expected[255]; + int i; + for (i=0;i<254;i++) { + expected[i] = i + 1; + } + expected[254] = 7; + expect(recv_frame, + when(size, is_equal_to(255)), + when(data, is_equal_to_contents_of(expected, 255)) + ); + recv_byte(&state, 0xFF); + for (i=0;i<254;i++) { + recv_byte(&state, i+1); + } + recv_byte(&state, 2); + recv_byte(&state, 7); + recv_byte(&state, 0); +} + +Ensure(ByteStuffer, receives_a_valid_frame_with_over254_non_zeroes_next_byte_is_zero) { + uint8_t expected[255]; + int i; + for (i=0;i<254;i++) { + expected[i] = i + 1; + } + expected[254] = 0; + expect(recv_frame, + when(size, is_equal_to(255)), + when(data, is_equal_to_contents_of(expected, 255)) + ); + recv_byte(&state, 0xFF); + for (i=0;i<254;i++) { + recv_byte(&state, i+1); + } + recv_byte(&state, 1); + recv_byte(&state, 1); + recv_byte(&state, 0); +} + +Ensure(ByteStuffer, receives_two_long_frames_and_some_more) { + uint8_t expected[515]; + int i; + int j; + for (j=0;j<2;j++) { + for (i=0;i<254;i++) { + expected[i+254*j] = i + 1; + } + } + for (i=0;i<7;i++) { + expected[254*2+i] = i + 1; + } + expect(recv_frame, + when(size, is_equal_to(515)), + when(data, is_equal_to_contents_of(expected, 510)) + ); + recv_byte(&state, 0xFF); + for (i=0;i<254;i++) { + recv_byte(&state, i+1); + } + recv_byte(&state, 0xFF); + for (i=0;i<254;i++) { + recv_byte(&state, 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); +} |