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cleanup

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combine preamble searches (thanks @iceman1001)
simplify Em410xDecode
fix bug in removeParity (I made recently)
move Unique TAG ID printout to avoid confusion
This commit is contained in:
marshmellow42 2017-02-23 13:53:40 -05:00
commit e88096ba25
4 changed files with 41 additions and 58 deletions
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2
client/cmddata.c
View file

@ -175,8 +175,8 @@ void printEM410x(uint32_t hi, uint64_t id)
} else{ } else{
//output 40 bit em id //output 40 bit em id
PrintAndLog("\nEM TAG ID : %010llX", id); PrintAndLog("\nEM TAG ID : %010llX", id);
PrintAndLog("Unique TAG ID : %010llX", id2lo);
PrintAndLog("\nPossible de-scramble patterns"); PrintAndLog("\nPossible de-scramble patterns");
PrintAndLog("Unique TAG ID : %010llX", id2lo);
PrintAndLog("HoneyWell IdentKey {"); PrintAndLog("HoneyWell IdentKey {");
PrintAndLog("DEZ 8 : %08lld",id & 0xFFFFFF); PrintAndLog("DEZ 8 : %08lld",id & 0xFFFFFF);
PrintAndLog("DEZ 10 : %010lld",id & 0xFFFFFFFF); PrintAndLog("DEZ 10 : %010lld",id & 0xFFFFFFFF);

8
client/cmdlfem4x.c
View file

@ -540,7 +540,7 @@ bool EM4x05testDemodReadData(uint32_t *word, bool readCmd) {
// sanity check // sanity check
size = (size > DemodBufferLen) ? DemodBufferLen : size; size = (size > DemodBufferLen) ? DemodBufferLen : size;
// test preamble // test preamble
if ( !onePreambleSearch(DemodBuffer, preamble, sizeof(preamble), size, &startIdx) ) { if ( !preambleSearchEx(DemodBuffer, preamble, sizeof(preamble), &size, &startIdx, true) ) {
if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx); if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", startIdx);
return false; return false;
} }
@ -550,13 +550,13 @@ bool EM4x05testDemodReadData(uint32_t *word, bool readCmd) {
if (g_debugMode) PrintAndLog("DEBUG: Error - End Parity check failed"); if (g_debugMode) PrintAndLog("DEBUG: Error - End Parity check failed");
return false; return false;
} }
// test for even parity bits. // test for even parity bits and remove them. (leave out the end row of parities so 36 bits)
if ( removeParity(DemodBuffer, startIdx + sizeof(preamble),9,0,44) == 0 ) { if ( removeParity(DemodBuffer, startIdx + sizeof(preamble),9,0,36) == 0 ) {
if (g_debugMode) PrintAndLog("DEBUG: Error - Parity not detected"); if (g_debugMode) PrintAndLog("DEBUG: Error - Parity not detected");
return false; return false;
} }
setDemodBuf(DemodBuffer, 40, 0); setDemodBuf(DemodBuffer, 32, 0);
*word = bytebits_to_byteLSBF(DemodBuffer, 32); *word = bytebits_to_byteLSBF(DemodBuffer, 32);
} }
return true; return true;

87
common/lfdemod.c
View file

@ -78,7 +78,7 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p
parityWd = (parityWd << 1) | BitStream[startIdx+word+bit]; parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
BitStream[j++] = (BitStream[startIdx+word+bit]); BitStream[j++] = (BitStream[startIdx+word+bit]);
} }
if (word+pLen >= bLen) break; if (word+pLen > bLen) break;
j--; // overwrite parity with next data j--; // overwrite parity with next data
// if parity fails then return 0 // if parity fails then return 0
@ -150,38 +150,28 @@ uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
{ {
// Sanity check. If preamble length is bigger than bitstream length. return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
if ( *size <= pLen ) return 0;
uint8_t foundCnt=0;
for (int idx=0; idx < *size - pLen; idx++){
if (memcmp(BitStream+idx, preamble, pLen) == 0){
//first index found
foundCnt++;
if (foundCnt == 1){
*startIdx = idx;
}
if (foundCnt == 2){
*size = idx - *startIdx;
return 1;
}
}
}
return 0;
} }
// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) // search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone
// does not look for a repeating preamble // fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
// em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
// leave it generic so it could be reused later...
bool onePreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t size, size_t *startIdx) {
// Sanity check. If preamble length is bigger than bitstream length. // Sanity check. If preamble length is bigger than bitstream length.
if ( size <= pLen ) return false; if ( *size <= pLen ) return false;
for (size_t idx = 0; idx < size - pLen; idx++) {
uint8_t foundCnt = 0;
for (size_t idx = 0; idx < *size - pLen; idx++) {
if (memcmp(BitStream+idx, preamble, pLen) == 0) { if (memcmp(BitStream+idx, preamble, pLen) == 0) {
if (g_debugMode) prnt("DEBUG: preamble found at %u", idx); //first index found
*startIdx = idx; foundCnt++;
return true; if (foundCnt == 1) {
if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
*startIdx = idx;
if (findone) return true;
} else if (foundCnt == 2) {
*size = idx - *startIdx;
return true;
}
} }
} }
return false; return false;
@ -217,39 +207,32 @@ size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_
//takes 1s and 0s and searches for EM410x format - output EM ID //takes 1s and 0s and searches for EM410x format - output EM ID
uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo) uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
{ {
//no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future //sanity checks
// otherwise could be a void with no arguments if (*size < 64) return 0;
//set defaults
uint32_t i = 0;
if (BitStream[1]>1) return 0; //allow only 1s and 0s if (BitStream[1]>1) return 0; //allow only 1s and 0s
// 111111111 bit pattern represent start of frame // 111111111 bit pattern represent start of frame
// include 0 in front to help get start pos // include 0 in front to help get start pos
uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1}; uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
uint32_t idx = 0;
uint32_t parityBits = 0;
uint8_t errChk = 0; uint8_t errChk = 0;
uint8_t FmtLen = 10; uint8_t FmtLen = 10; // sets of 4 bits = end data
*startIdx = 0; *startIdx = 0;
errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx); errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
if (errChk == 0 || *size < 64) return 0; if (errChk == 0 || *size < 64) return 0;
if (*size > 64) FmtLen = 22; if (*size == 110) FmtLen = 22; // 22 sets of 4 bits
*startIdx += 1; //get rid of 0 from preamble
idx = *startIdx + 9; //skip last 4bit parity row for simplicity
for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits) *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5); if (*size == 40) { // std em410x format
//check even parity - quit if failed *hi = 0;
if (parityTest(parityBits, 5, 0) == 0) return 0; *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
//set uint64 with ID from BitStream } else if (*size == 88) { // long em format
for (uint8_t ii=0; ii<4; ii++){ *hi = (bytebits_to_byte(BitStream, 24));
*hi = (*hi << 1) | (*lo >> 63); *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
*lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]); } else {
} return 0;
} }
if (errChk != 0) return 1; return 1;
//skip last 5 bit parity test for simplicity.
// *size = 64 | 128;
return 0;
} }
//by marshmellow //by marshmellow

2
common/lfdemod.h
View file

@ -39,7 +39,7 @@ int manrawdecode(uint8_t *BitStream, size_t *size, uint8_t invert);
int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert); int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert);
uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType); uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType);
uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx); uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx);
bool onePreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t size, size_t *startIdx); bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone);
int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert); int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert);
void psk2TOpsk1(uint8_t *BitStream, size_t size); void psk2TOpsk1(uint8_t *BitStream, size_t size);
void psk1TOpsk2(uint8_t *BitStream, size_t size); void psk1TOpsk2(uint8_t *BitStream, size_t size);