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-rw-r--r--ax25ipd/crc.c141
1 files changed, 73 insertions, 68 deletions
diff --git a/ax25ipd/crc.c b/ax25ipd/crc.c
index ff07195..f6fc565 100644
--- a/ax25ipd/crc.c
+++ b/ax25ipd/crc.c
@@ -30,57 +30,57 @@ typedef unsigned short u16;
* FCS lookup table as calculated by the table generator in section 2.
*/
static u16 fcstab[256] = {
- 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
- 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
- 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
- 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
- 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
- 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
- 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
- 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
- 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
- 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
- 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
- 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
- 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
- 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
- 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
- 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
- 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
- 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
- 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
- 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
- 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
- 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
- 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
- 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
- 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
- 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
- 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
- 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
- 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
- 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
- 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
- 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
+ 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
+ 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
+ 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
+ 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
+ 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
+ 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
+ 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
+ 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
+ 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
+ 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
+ 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
+ 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
+ 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
+ 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
+ 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
+ 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
+ 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
+ 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
+ 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
+ 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
+ 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
+ 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
+ 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
+ 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
+ 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
+ 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
+ 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
+ 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
+ 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
+ 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
+ 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
+ 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};
-#define PPPINITFCS 0xffff /* Initial FCS value */
-#define PPPGOODFCS 0xf0b8 /* Good final FCS value */
+#define PPPINITFCS 0xffff /* Initial FCS value */
+#define PPPGOODFCS 0xf0b8 /* Good final FCS value */
/*
* Calculate a new fcs given the current fcs and the new data.
*/
u16 pppfcs(fcs, cp, len)
- register u16 fcs;
- register unsigned char *cp;
- register int len;
+register u16 fcs;
+register unsigned char *cp;
+register int len;
{
/* ASSERT(sizeof (u16) == 2); */
/* ASSERT(((u16) -1) > 0); */
- while (len--)
- fcs = (fcs >> 8) ^ fcstab[(fcs ^ *cp++) & 0xff];
+ while (len--)
+ fcs = (fcs >> 8) ^ fcstab[(fcs ^ *cp++) & 0xff];
- return (fcs);
+ return (fcs);
}
/*
@@ -94,8 +94,7 @@ u16 pppfcs(fcs, cp, len)
*/
/* Return the computed CRC */
-unsigned short int
-compute_crc(buf, l)
+unsigned short int compute_crc(buf, l)
unsigned char *buf;
int l;
{
@@ -108,8 +107,7 @@ int l;
}
/* Return true if the CRC is correct */
-int
-ok_crc(buf, l)
+int ok_crc(buf, l)
unsigned char *buf;
int l;
{
@@ -127,45 +125,52 @@ int l;
*/
#ifdef TEST
-void
-main()
+void main()
{
unsigned char buf[258];
int l, i;
unsigned short int f;
l = 256;
- for(i=0;i<l;i++){
- buf[i]=i;
+ for (i = 0; i < l; i++) {
+ buf[i] = i;
}
- f = compute_crc(buf,l);
- printf("computed crc=0x%04x\n",f);
+ f = compute_crc(buf, l);
+ printf("computed crc=0x%04x\n", f);
- buf[l]=(f&0xff);
- buf[l+1]=(f>>8);
+ buf[l] = (f & 0xff);
+ buf[l + 1] = (f >> 8);
printf("crc should be good... ");
- i = ok_crc(buf, l+2);
- if(i)printf("CRC declared OK\n");
- else printf("CRC declared bad\n");
-
- buf[l+1]=(f&0xff);
- buf[l]=(f>>8);
+ i = ok_crc(buf, l + 2);
+ if (i)
+ printf("CRC declared OK\n");
+ else
+ printf("CRC declared bad\n");
+
+ buf[l + 1] = (f & 0xff);
+ buf[l] = (f >> 8);
printf("reversed the CRC byte order... CRC should be bad...");
- i = ok_crc(buf, l+2);
- if(i)printf("CRC declared OK\n");
- else printf("CRC declared bad\n");
+ i = ok_crc(buf, l + 2);
+ if (i)
+ printf("CRC declared OK\n");
+ else
+ printf("CRC declared bad\n");
printf("changed the frame length... CRC should be bad...");
- i = ok_crc(buf, l+1);
- if(i)printf("CRC declared OK\n");
- else printf("CRC declared bad\n");
+ i = ok_crc(buf, l + 1);
+ if (i)
+ printf("CRC declared OK\n");
+ else
+ printf("CRC declared bad\n");
- buf[0]-=1;
+ buf[0] -= 1;
printf("corrupted the data... CRC should be bad...");
- i = ok_crc(buf, l+2);
- if(i)printf("CRC declared OK\n");
- else printf("CRC declared bad\n");
+ i = ok_crc(buf, l + 2);
+ if (i)
+ printf("CRC declared OK\n");
+ else
+ printf("CRC declared bad\n");
}
#endif