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Add COBS encoder

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This commit is contained in:
jaseg 2020-11-26 17:42:05 +01:00
parent 9b5625f12a
commit 44548df52f
8 changed files with 439 additions and 3 deletions
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20
prototype/fw/src/crc32_test.c
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@ -1,20 +0,0 @@
#include <stdio.h>
#include "crc32.h"
int main(void) {
crc32_t state = crc32_reset();
do {
char c;
if (fread(&c, 1, 1, stdin) != 1)
break;
state = crc32_update(state, (uint8_t)c);
} while(23);
state = crc32_finalize(state);
printf("%08x\n", state);
return 0;
}

99
prototype/fw/src/microcobs.c Normal file
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@ -0,0 +1,99 @@
#include <stdint.h>
#include "microcobs.h"
#include <stdio.h>
ssize_t cobs_encode_sg(const struct sg_entry input[], uint8_t *output, size_t output_len)
{
size_t idx_pos = 0;
size_t out_pos = 1;
size_t sg_idx = 0;
const struct sg_entry *e = input;
fprintf(stderr, "\nsg_entry %016x %zd\n", e->target, e->size);
while (e->size >= 0) {
if (sg_idx == e->size) {
sg_idx = 0;
e++;
fprintf(stderr, "\nsg_entry %016x %zd\n", e->target, e->size);
continue;
}
if (out_pos >= output_len)
return -1;
uint8_t inbyte = e->target[sg_idx];
fprintf(stderr, "%02x ", inbyte);
sg_idx += 1;
if (out_pos - idx_pos >= 255) {
output[idx_pos] = 255;
idx_pos = out_pos;
out_pos += 1;
if (out_pos >= output_len)
return -1;
}
if (inbyte) {
output[out_pos] = inbyte;
out_pos += 1;
} else {
output[idx_pos] = out_pos - idx_pos;
idx_pos = out_pos;
out_pos += 1;
}
}
if (out_pos >= output_len)
return -1;
output[idx_pos] = out_pos - idx_pos;
output[out_pos] = 0x00;
fprintf(stderr, "\n");
fprintf(stderr, "Finishing %d %d %d\n", idx_pos, out_pos, out_pos - idx_pos);
return out_pos + 1;
}
ssize_t cobs_encode(const uint8_t *input, size_t input_len, uint8_t *output, size_t output_len)
{
size_t idx_pos = 0;
size_t out_pos = 1;
size_t in_pos = 0;
while (in_pos < input_len) {
if (out_pos >= output_len)
return -1;
uint8_t inbyte = input[in_pos];
fprintf(stderr, "%02x ", inbyte);
in_pos += 1;
if (out_pos - idx_pos >= 255) {
output[idx_pos] = 255;
idx_pos = out_pos;
out_pos += 1;
if (out_pos >= output_len)
return -1;
}
if (inbyte) {
output[out_pos] = inbyte;
out_pos += 1;
} else {
output[idx_pos] = out_pos - idx_pos;
idx_pos = out_pos;
out_pos += 1;
}
}
if (out_pos >= output_len)
return -1;
output[idx_pos] = out_pos - idx_pos;
output[out_pos] = 0x00;
fprintf(stderr, "\n");
fprintf(stderr, "Finishing %d %d %d\n", idx_pos, out_pos, out_pos - idx_pos);
return out_pos + 1;
}

15
prototype/fw/src/microcobs.h Normal file
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@ -0,0 +1,15 @@
#ifndef __MICROCOBS_H__
#define __MICROCOBS_H__
#include <stdint.h>
#include <unistd.h>
struct sg_entry {
uint8_t *target;
ssize_t size;
};
ssize_t cobs_encode_sg(const struct sg_entry input[], uint8_t *output, size_t output_len);
ssize_t cobs_encode(const uint8_t *input, size_t input_len, uint8_t *output, size_t output_len);
#endif /* __MICROCOBS_H__ */