Add byte stuffing send support for large frames
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2f3ea76428
commit
6956c177da
2 changed files with 72 additions and 5 deletions
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@ -25,6 +25,7 @@ SOFTWARE.
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#include "protocol/byte_stuffer.h"
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#include "protocol/frame_validator.h"
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#include "protocol/physical.h"
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#include <stdio.h>
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// This implements the "Consistent overhead byte stuffing protocol"
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// https://en.wikipedia.org/wiki/Consistent_Overhead_Byte_Stuffing
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@ -103,19 +104,29 @@ static void send_block(uint8_t* start, uint8_t* end, uint8_t num_non_zero) {
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void send_frame(uint8_t* data, uint16_t size) {
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const uint8_t zero = 0;
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if (size > 0) {
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uint8_t num_non_zero = 1;
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uint16_t num_non_zero = 1;
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uint8_t* end = data + size;
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uint8_t* start = data;
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while (data < end) {
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if (*data == 0) {
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if (num_non_zero == 0xFF) {
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// There's more data after big non-zero block
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// So send it, and start a new block
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send_block(start, data, num_non_zero);
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start = data + 1;
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start = data;
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num_non_zero = 1;
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}
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else {
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num_non_zero++;
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if (*data == 0) {
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// A zero encountered, so send the block
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send_block(start, data, num_non_zero);
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start = data + 1;
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num_non_zero = 1;
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}
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else {
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num_non_zero++;
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}
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++data;
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}
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++data;
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}
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send_block(start, data, num_non_zero);
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send_data(&zero, 1);
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@ -372,3 +372,59 @@ Ensure(ByteStuffer, sends_three_byte_frame_with_all_zeroes) {
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assert_that(sent_data_size, is_equal_to(sizeof(expected)));
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assert_that(sent_data, is_equal_to_contents_of(expected, sizeof(expected)));
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}
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Ensure(ByteStuffer, sends_frame_with_254_non_zeroes) {
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uint8_t data[254];
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int i;
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for(i=0;i<254;i++) {
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data[i] = i + 1;
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}
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send_frame(data, 254);
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uint8_t expected[256];
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expected[0] = 0xFF;
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for(i=1;i<255;i++) {
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expected[i] = i;
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}
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expected[255] = 0;
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assert_that(sent_data_size, is_equal_to(sizeof(expected)));
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assert_that(sent_data, is_equal_to_contents_of(expected, sizeof(expected)));
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}
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Ensure(ByteStuffer, sends_frame_with_255_non_zeroes) {
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uint8_t data[255];
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int i;
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for(i=0;i<255;i++) {
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data[i] = i + 1;
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}
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send_frame(data, 255);
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uint8_t expected[258];
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expected[0] = 0xFF;
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for(i=1;i<255;i++) {
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expected[i] = i;
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}
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expected[255] = 2;
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expected[256] = 255;
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expected[257] = 0;
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assert_that(sent_data_size, is_equal_to(sizeof(expected)));
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assert_that(sent_data, is_equal_to_contents_of(expected, sizeof(expected)));
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}
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Ensure(ByteStuffer, sends_frame_with_254_non_zeroes_followed_by_zero) {
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uint8_t data[255];
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int i;
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for(i=0;i<254;i++) {
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data[i] = i + 1;
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}
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data[255] = 0;
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send_frame(data, 255);
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uint8_t expected[258];
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expected[0] = 0xFF;
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for(i=1;i<255;i++) {
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expected[i] = i;
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}
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expected[255] = 1;
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expected[256] = 1;
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expected[257] = 0;
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assert_that(sent_data_size, is_equal_to(sizeof(expected)));
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assert_that(sent_data, is_equal_to_contents_of(expected, sizeof(expected)));
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}
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