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This commit is contained in:
iceman1001
2025-07-10 11:52:39 +02:00
parent cb8bb8d520
commit 2597c7576e
50 changed files with 135 additions and 99 deletions
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47
common/crc16.c
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@@ -27,12 +27,14 @@ static CrcType_t current_crc_type = CRC_NONE;
void init_table(CrcType_t crctype) {
// same crc algo, and initialised already
if (crctype == current_crc_type && crc_table_init)
if (crctype == current_crc_type && crc_table_init) {
return;
}
// not the same crc algo. reset table.
if (crctype != current_crc_type)
if (crctype != current_crc_type) {
reset_table();
}
current_crc_type = crctype;
@@ -68,23 +70,29 @@ void init_table(CrcType_t crctype) {
void generate_table(uint16_t polynomial, bool refin) {
for (uint16_t i = 0; i < 256; i++) {
uint16_t c, crc = 0;
if (refin)
if (refin) {
c = reflect8(i) << 8;
else
} else {
c = i << 8;
}
for (uint16_t j = 0; j < 8; j++) {
if ((crc ^ c) & 0x8000)
if ((crc ^ c) & 0x8000) {
crc = (crc << 1) ^ polynomial;
else
} else {
crc = crc << 1;
}
c = c << 1;
}
if (refin)
if (refin) {
crc = reflect16(crc);
}
crc_table[i] = crc;
}
@@ -102,21 +110,25 @@ uint16_t crc16_fast(uint8_t const *d, size_t n, uint16_t initval, bool refin, bo
// fast lookup table algorithm without augmented zero bytes, e.g. used in pkzip.
// only usable with polynom orders of 8, 16, 24 or 32.
if (n == 0)
if (n == 0) {
return (~initval);
}
uint16_t crc = initval;
if (refin)
if (refin) {
crc = reflect16(crc);
}
if (!refin)
if (refin == false) {
while (n--) crc = (crc << 8) ^ crc_table[((crc >> 8) ^ *d++) & 0xFF ];
else
} else {
while (n--) crc = (crc >> 8) ^ crc_table[(crc & 0xFF) ^ *d++];
}
if (refout ^ refin)
if (refout ^ refin) {
crc = reflect16(crc);
}
return crc;
}
@@ -143,8 +155,9 @@ uint16_t update_crc16(uint16_t crc, uint8_t c) {
// two ways. msb or lsb loop.
uint16_t Crc16(uint8_t const *d, size_t bitlength, uint16_t remainder, uint16_t polynomial, bool refin, bool refout) {
if (bitlength == 0)
if (bitlength == 0) {
return (~remainder);
}
uint8_t offset = 8 - (bitlength % 8);
// front padding with 0s won't change the CRC result
@@ -153,7 +166,9 @@ uint16_t Crc16(uint8_t const *d, size_t bitlength, uint16_t remainder, uint16_t
uint8_t c = prebits | d[i] >> offset;
prebits = d[i] << (8 - offset);
if (refin) c = reflect8(c);
if (refin) {
c = reflect8(c);
}
// xor in at msb
remainder ^= (c << 8);
@@ -167,8 +182,10 @@ uint16_t Crc16(uint8_t const *d, size_t bitlength, uint16_t remainder, uint16_t
}
}
}
if (refout)
if (refout) {
remainder = reflect16(remainder);
}
return remainder;
}