From bf74114d50add6cb24bf50d6a5dbdc60a92c24b6 Mon Sep 17 00:00:00 2001 From: marshmellow42 Date: Sun, 12 Mar 2017 22:57:01 -0400 Subject: [PATCH] refactor detectST a little... + a little more shuffling --- common/lfdemod.c | 109 ++++++++++++++++++++--------------------------- 1 file changed, 47 insertions(+), 62 deletions(-) diff --git a/common/lfdemod.c b/common/lfdemod.c index a6e215c9..721c9d1c 100644 --- a/common/lfdemod.c +++ b/common/lfdemod.c @@ -5,7 +5,8 @@ // at your option, any later version. See the LICENSE.txt file for the text of // the license. //----------------------------------------------------------------------------- -// Low frequency demod/decode commands +// Low frequency demod/decode commands - by marshmellow, holiman, iceman and +// many others who came before // // NOTES: // LF Demod functions are placed here to allow the flexability to use client or @@ -15,6 +16,9 @@ // There are likely many improvements to the code that could be made, please // make suggestions... // +// we tried to include author comments so any questions could be directed to +// the source. +// // There are 4 main sections of code below: // Utilities Section: // for general utilities used by multiple other functions @@ -32,9 +36,10 @@ #include "lfdemod.h" #include +//---------------------------------Utilities Section-------------------------------------------------- + //to allow debug print calls when used not on device void dummy(char *fmt, ...){} - #ifndef ON_DEVICE #include "ui.h" #include "cmdparser.h" @@ -45,10 +50,7 @@ void dummy(char *fmt, ...){} #define prnt dummy #endif -//---------------------------------Utilities Section-------------------------------------------------- - -uint8_t justNoise(uint8_t *BitStream, size_t size) -{ +uint8_t justNoise(uint8_t *BitStream, size_t size) { static const uint8_t THRESHOLD = 123; //test samples are not just noise uint8_t justNoise1 = 1; @@ -60,8 +62,7 @@ uint8_t justNoise(uint8_t *BitStream, size_t size) //by marshmellow //get high and low values of a wave with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise -int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) -{ +int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) { *high=0; *low=255; // get high and low thresholds @@ -78,8 +79,7 @@ int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi // by marshmellow // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType // returns 1 if passed -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 ans = 0; for (uint8_t i = 0; i < bitLen; i++){ ans ^= ((bits >> i) & 1); @@ -91,8 +91,7 @@ uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) // by marshmellow // takes a array of binary values, start position, length of bits per parity (includes parity bit), // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run) -size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) -{ +size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) { uint32_t parityWd = 0; size_t j = 0, bitCnt = 0; for (int word = 0; word < (bLen); word+=pLen) { @@ -121,8 +120,7 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p // takes a array of binary values, length of bits per parity (includes parity bit), // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run) // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added -size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) -{ +size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) { uint32_t parityWd = 0; size_t j = 0, bitCnt = 0; for (int word = 0; word < sourceLen; word+=pLen-1) { @@ -146,8 +144,7 @@ size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t p return bitCnt; } -uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) -{ +uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) { uint32_t num = 0; for(int i = 0 ; i < numbits ; i++) { @@ -158,8 +155,7 @@ uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) } //least significant bit first -uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) -{ +uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) { uint32_t num = 0; for(int i = 0 ; i < numbits ; i++) { @@ -168,13 +164,6 @@ uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) return num; } -//by marshmellow -//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) -{ - return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0; -} - // 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 // fineone does not look for a repeating preamble for em4x05/4x69 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) { @@ -199,6 +188,12 @@ bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t return false; } +//by marshmellow +//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) { + return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0; +} + // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup. size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) { size_t i = 0; @@ -268,6 +263,23 @@ int ManchesterEncode(uint8_t *BitStream, size_t size) { //------------------------------Modulation Demods &/or Decoding Section------------------------------------------------------ +// look for Sequence Terminator - should be pulses of clk*(1 or 2), clk*2, clk*(1.5 or 2), by idx we mean graph position index... +bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, int i) { + for (; i < buffSize - 4; ++i) { + *stStartIdx += lowToLowWaveLen[i]; //caution part of this wave may be data and part may be ST.... to be accounted for in main function for now... + if (lowToLowWaveLen[i] >= clk*1-tol && lowToLowWaveLen[i] <= (clk*2)+tol && highToLowWaveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior + if (lowToLowWaveLen[i+1] >= clk*2-tol && lowToLowWaveLen[i+1] <= clk*2+tol && highToLowWaveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2 + if (lowToLowWaveLen[i+2] >= (clk*3)/2-tol && lowToLowWaveLen[i+2] <= clk*2+tol && highToLowWaveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave + if (lowToLowWaveLen[i+3] >= clk*1-tol && lowToLowWaveLen[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit + *stStopLoc = i + 3; + return true; + } + } + } + } + } + return false; +} //by marshmellow //attempt to identify a Sequence Terminator in ASK modulated raw wave bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) { @@ -277,9 +289,9 @@ bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststa int clk = 0; int tol = 0; int i, j, skip, start, end, low, high, minClk, waveStart; - bool complete = false; - int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured - int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed... + //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow] + int tmpbuff[bufsize / 32]; // low to low wave count //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured + int waveLen[bufsize / 32]; // high to low wave count //if clock is larger then we waste memory in array size that is not needed... size_t testsize = (bufsize < 512) ? bufsize : 512; int phaseoff = 0; high = low = 128; @@ -337,24 +349,9 @@ bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststa } else tol = clk/8; *foundclock = clk; - - // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2) - start = -1; - for (i = 0; i < j - 4; ++i) { - skip += tmpbuff[i]; - if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior - if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2 - if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave - if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit - start = i + 3; - break; - } - } - } - } - } - // first ST not found - ERROR - if (start < 0) { + i=0; + if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, i)) { + // first ST not found - ERROR if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting"); return false; } else { @@ -369,26 +366,14 @@ bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststa skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point // now do it again to find the end + int dummy1 = 0; end = skip; - for (i += 3; i < j - 4; ++i) { - end += tmpbuff[i]; - if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior - if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2 - if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave - if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit - complete = true; - break; - } - } - } - } - } - end -= phaseoff; - //didn't find second ST - ERROR - if (!complete) { + if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, i+3)) { + //didn't find second ST - ERROR if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting"); return false; } + end -= phaseoff; if (g_debugMode==2) prnt("DEBUG STT: start of data: %d end of data: %d, datalen: %d, clk: %d, bits: %d, phaseoff: %d", skip, end, end-skip, clk, (end-skip)/clk, phaseoff); //now begin to trim out ST so we can use normal demod cmds start = skip; -- 2.39.2