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authorAnton Tananaev <anton.tananaev@gmail.com>2015-10-06 16:55:31 +1300
committerAnton Tananaev <anton.tananaev@gmail.com>2015-10-06 16:55:31 +1300
commit2b9187ac736feeb661e2814af8fa534a335998d4 (patch)
tree18e89d33116194bc5f2fa90ea48b169608b81a76 /src/org/traccar/helper/Checksum.java
parent6652e4c3e23da63d4277caaca7f91e651793f503 (diff)
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Clean up CRC-16 implementations
Diffstat (limited to 'src/org/traccar/helper/Checksum.java')
-rw-r--r--src/org/traccar/helper/Checksum.java38
1 files changed, 26 insertions, 12 deletions
diff --git a/src/org/traccar/helper/Checksum.java b/src/org/traccar/helper/Checksum.java
index cdf1bbf50..69c9dd499 100644
--- a/src/org/traccar/helper/Checksum.java
+++ b/src/org/traccar/helper/Checksum.java
@@ -91,8 +91,14 @@ public class Checksum {
0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
};
- public static final int CRC16_CCITT = 0xFFFF;
- public static final int CRC16_CCITT_XOROUT = 0xFFFF;
+ // More info: http://reveng.sourceforge.net/crc-catalogue/16.htm
+ public static final String CRC16_X25 = "X-25";
+ public static final String CRC16_CCITT_FALSE = "CCITT-FALSE";
+ public static final String CRC16_KERMIT = "KERMIT";
+ public static final String CRC16_XMODEM = "XMODEM";
+ public static final String CRC16_AUG_CCITT = "AUG-CCITT";
+ public static final String CRC16_GENIBUS = "GENIBUS";
+ public static final String CRC16_MCRF4XX = "MCRF4XX";
private static int crc16Unreflected(ByteBuffer buf, int crc_in, int[] table) {
int crc16 = crc_in;
@@ -110,16 +116,24 @@ public class Checksum {
return crc16 & 0xFFFF;
}
- public static int crc16Ccitt(ByteBuffer buf) {
- return crc16Reflected(buf, 0xFFFF, CRC16_CCITT_TABLE_REVERSE) ^ 0xFFFF;
- }
-
- public static int crc16X25Ccitt(ByteBuffer buf) {
- return crc16Unreflected(buf, 0xFFFF, CRC16_CCITT_TABLE);
- }
-
- public static int crc16Ccitt(ByteBuffer buf, int seed, int xorout) {
- return crc16Reflected(buf, seed, CRC16_CCITT_TABLE_REVERSE) ^ xorout;
+ public static int crc16(String type, ByteBuffer buf) {
+ switch (type) {
+ case CRC16_X25:
+ return crc16Reflected(buf, 0xFFFF, CRC16_CCITT_TABLE_REVERSE) ^ 0xFFFF;
+ case CRC16_CCITT_FALSE:
+ return crc16Unreflected(buf, 0xFFFF, CRC16_CCITT_TABLE);
+ case CRC16_KERMIT:
+ return crc16Reflected(buf, 0, CRC16_CCITT_TABLE_REVERSE);
+ case CRC16_XMODEM:
+ return crc16Unreflected(buf, 0, CRC16_CCITT_TABLE);
+ case CRC16_AUG_CCITT:
+ return crc16Unreflected(buf, 0x1d0f, CRC16_CCITT_TABLE);
+ case CRC16_GENIBUS:
+ return crc16Unreflected(buf, 0xFFFF, CRC16_CCITT_TABLE) ^ 0xFFFF;
+ case CRC16_MCRF4XX:
+ return crc16Reflected(buf, 0xFFFF, CRC16_CCITT_TABLE_REVERSE);
+ }
+ throw new UnsupportedOperationException();
}
public static int crc32(ByteBuffer buf) {