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Rename Gillham conversion function

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ICAO documents refer to AC13 for altitude encoding and ID13 for squawk
wncoding. Rename decodeGillhamField to decodeID13Field to better
represent this.
This commit is contained in:
Malcolm Robb 2013-04-30 18:07:16 +01:00
parent 9783b4786a
commit 539faaaf27
1 changed files with 18 additions and 18 deletions

36
dump1090.c
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@ -1258,22 +1258,22 @@ int ICAOAddressWasRecentlySeen(uint32_t addr) {
//
// For more info: http://en.wikipedia.org/wiki/Gillham_code
//
int decodeGillhamField(int rawGillham) {
int decodeID13Field(int ID13Field) {
int hexGillham = 0;
if (rawGillham & 0x1000) {hexGillham |= 0x0010;} // Bit 12 = C1
if (rawGillham & 0x0800) {hexGillham |= 0x1000;} // Bit 11 = A1
if (rawGillham & 0x0400) {hexGillham |= 0x0020;} // Bit 10 = C2
if (rawGillham & 0x0200) {hexGillham |= 0x2000;} // Bit 9 = A2
if (rawGillham & 0x0100) {hexGillham |= 0x0040;} // Bit 8 = C4
if (rawGillham & 0x0080) {hexGillham |= 0x4000;} // Bit 7 = A4
//if (rawGillham & 0x0040) {hexGillham |= 0x0800;} // Bit 6 = X or Q
if (rawGillham & 0x0020) {hexGillham |= 0x0100;} // Bit 5 = B1
if (rawGillham & 0x0010) {hexGillham |= 0x0001;} // Bit 4 = D1
if (rawGillham & 0x0008) {hexGillham |= 0x0200;} // Bit 3 = B2
if (rawGillham & 0x0004) {hexGillham |= 0x0002;} // Bit 2 = D2
if (rawGillham & 0x0002) {hexGillham |= 0x0400;} // Bit 1 = B4
if (rawGillham & 0x0001) {hexGillham |= 0x0004;} // Bit 0 = D4
if (ID13Field & 0x1000) {hexGillham |= 0x0010;} // Bit 12 = C1
if (ID13Field & 0x0800) {hexGillham |= 0x1000;} // Bit 11 = A1
if (ID13Field & 0x0400) {hexGillham |= 0x0020;} // Bit 10 = C2
if (ID13Field & 0x0200) {hexGillham |= 0x2000;} // Bit 9 = A2
if (ID13Field & 0x0100) {hexGillham |= 0x0040;} // Bit 8 = C4
if (ID13Field & 0x0080) {hexGillham |= 0x4000;} // Bit 7 = A4
//if (ID13Field & 0x0040) {hexGillham |= 0x0800;} // Bit 6 = X or Q
if (ID13Field & 0x0020) {hexGillham |= 0x0100;} // Bit 5 = B1
if (ID13Field & 0x0010) {hexGillham |= 0x0001;} // Bit 4 = D1
if (ID13Field & 0x0008) {hexGillham |= 0x0200;} // Bit 3 = B2
if (ID13Field & 0x0004) {hexGillham |= 0x0002;} // Bit 2 = D2
if (ID13Field & 0x0002) {hexGillham |= 0x0400;} // Bit 1 = B4
if (ID13Field & 0x0001) {hexGillham |= 0x0004;} // Bit 0 = D4
return (hexGillham);
}
@ -1297,7 +1297,7 @@ int decodeAC13Field(int AC13Field, int *unit) {
return ((n * 25) - 1000);
} else {
// N is an 11 bit Gillham coded altitude
int n = ModeAToModeC(decodeGillhamField(AC13Field));
int n = ModeAToModeC(decodeID13Field(AC13Field));
if (n < -12) {n = 0;}
return (100 * n);
@ -1324,7 +1324,7 @@ int decodeAC12Field(int AC12Field, int *unit) {
return ((n * 25) - 1000);
} else {
// N is an 11 bit Gillham coded altitude
int n = n = ModeAToModeC(decodeGillhamField(AC12Field));
int n = n = ModeAToModeC(decodeID13Field(AC12Field));
if (n < -12) {n = 0;}
return (100 * n);
@ -1459,9 +1459,9 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
mm->dr = (msg[1] >> 3) & 0x1F; // Request extraction of downlink request
mm->um = ((msg[1] & 7) << 3) | (msg[2] >> 5); // Request extraction of downlink request
// Fields for DF5,21 = Gillham encoded Squawk
// Fields for DF5, DF21 = Gillham encoded Squawk
if (mm->msgtype == 5 || mm->msgtype == 21) {
mm->modeA = decodeGillhamField((msg[2] << 8) | msg[3]);
mm->modeA = decodeID13Field((msg[2] << 8) | msg[3]);
}
// Fields for DF0, DF4, DF16, DF20 13 bit altitude