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Reformat spacing/comments in src/crc16.c

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This commit is contained in:
Stefan Rueger
2024-08-18 01:54:09 +01:00
parent 6977a3d674
commit 0f1dc19d06
1 changed files with 15 additions and 28 deletions
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43
src/crc16.c
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@@ -1,10 +1,10 @@
/*
* Derived from CRC algorithm for JTAG ICE mkII, published in Atmel
* Appnote AVR067. Converted from C++ to C.
* Derived from CRC algorithm for JTAG ICE mkII, published in Atmel Appnote
* AVR067. Converted from C++ to C.
*/
#include "crc16.h"
/* CRC16 Definitions */
// CRC16 Definitions
static const unsigned short crc_table[256] = {
0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
@@ -40,44 +40,31 @@ static const unsigned short crc_table[256] = {
0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};
/* CRC calculation macros */
// CRC calculation macros
#define CRC_INIT 0xFFFF
#define CRC(crcval,newchar) crcval = (crcval >> 8) ^ \
crc_table[(crcval ^ newchar) & 0x00ff]
#define CRC(crcval, newchar) ((crcval) = (crcval>>8) ^ crc_table[((crcval) ^ (newchar)) & 0x00ff])
unsigned short
crcsum(const unsigned char* message, unsigned long length,
unsigned short crc)
{
unsigned short crcsum(const unsigned char *message, unsigned long length, unsigned short crc) {
unsigned long i;
for(i = 0; i < length; i++)
{
CRC(crc, message[i]);
}
for(i = 0; i < length; i++) {
CRC(crc, message[i]);
}
return crc;
}
int
crcverify(const unsigned char* message, unsigned long length)
{
/*
* Returns true if the last two bytes in a message is the crc of the
* preceding bytes.
*/
// Returns true if the last two bytes in a message is the crc of the preceding bytes
int crcverify(const unsigned char *message, unsigned long length) {
unsigned short expected;
expected = crcsum(message, length - 2, CRC_INIT);
return (expected & 0xff) == message[length - 2] &&
((expected >> 8) & 0xff) == message[length - 1];
return (expected & 0xff) == message[length - 2] && ((expected >> 8) & 0xff) == message[length - 1];
}
void
crcappend(unsigned char* message, unsigned long length)
{
void crcappend(unsigned char *message, unsigned long length) {
unsigned long crc;
crc = crcsum(message, length, CRC_INIT);
message[length] = (unsigned char)(crc & 0xff);
message[length+1] = (unsigned char)((crc >> 8) & 0xff);
message[length] = (unsigned char) (crc & 0xff);
message[length + 1] = (unsigned char) ((crc >> 8) & 0xff);
}