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[oscilloscope] Use enums instead of strcmp
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Faster and safer than string comparisons
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@kubark42
kubark42 committed Aug 22, 2023
1 parent 67fec0f commit bcf0873
Showing 1 changed file with 80 additions and 23 deletions.
103 changes: 80 additions & 23 deletions oscilloscope.h
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Original file line number Diff line number Diff line change
Expand Up @@ -56,21 +56,31 @@
STOPPED - set by oscReader
*/

enum ReadType {
RT_DIGITAL,
RT_ANALOG,
};

enum TimeUnit {
TU_US,
TU_MS,
};

struct oscSharedMemory { // data structure to be shared among oscilloscope tasks
// basic data
WebSocket *webSocket; // open webSocket for communication with javascript client
bool clientIsBigEndian; // true if javascript client is big endian machine
// sampling sharedMemory
char readType [8]; // analog or digital
ReadType readType; // analog or digital
bool analog; // true if readType is analog, false if digital (digitalRead)
int gpio1; // gpio where ESP32 is taking samples from (digitalRead)
adc1_channel_t adcchannel1; // channel mapped from gpio ESP32 is taking samples from (adc1_get_raw instead of analogRead)
adc1_channel_t adcchannel2; // channel mapped from gpio ESP32 is taking samples from (adc1_get_raw instead of analogRead)
int gpio2; // 2nd gpio if requested
int samplingTime; // time between samples in ms or us
char samplingTimeUnit [3]; // ms or us
TimeUnit samplingTimeUnit; // ms or us
int screenWidthTime; // oscilloscope screen width in ms or us
char screenWidthTimeUnit [3]; // ms or us
TimeUnit screenWidthTimeUnit; // ms or us
bool positiveTrigger; // true if posotive slope trigger is set
int positiveTriggerTreshold; // positive slope trigger treshold value
bool negativeTrigger; // true if negative slope trigger is set
Expand All @@ -85,8 +95,8 @@
// oscilloscope reader read samples to read-buffer of shared memory - it will be copied to send buffer when it is ready to be sent

void oscReader (void *sharedMemory) {
bool doAnalogRead = !strcmp (((oscSharedMemory *) sharedMemory)->readType, "analog");
bool unitIsMicroSeconds = !strcmp (((oscSharedMemory *) sharedMemory)->samplingTimeUnit, "us");
bool doAnalogRead = ((oscSharedMemory *) sharedMemory)->readType == RT_ANALOG;
bool unitIsMicroSeconds = ((oscSharedMemory *) sharedMemory)->samplingTimeUnit == TU_US;
int samplingTime = ((oscSharedMemory *) sharedMemory)->samplingTime;
bool positiveTrigger = ((oscSharedMemory *) sharedMemory)->positiveTrigger;
bool negativeTrigger = ((oscSharedMemory *) sharedMemory)->negativeTrigger;
Expand Down Expand Up @@ -439,15 +449,28 @@
}
// parse 1st part
sharedMemory.gpio1 = sharedMemory.gpio2 = 255; // invalid GPIO
if (sscanf (cmdPart1, "start %7s sampling on GPIO %2i, %2i", sharedMemory.readType, &sharedMemory.gpio1, &sharedMemory.gpio2) < 2) {
char tmpReadTypeString[8];
if (sscanf (cmdPart1, "start %7s sampling on GPIO %2i, %2i", tmpReadTypeString, &sharedMemory.gpio1, &sharedMemory.gpio2) < 2) {
#ifdef __DMESG__
dmesg ("[oscilloscope] oscilloscope protocol syntax error.");
#endif
webSocket->sendString ("[oscilloscope] oscilloscope protocol syntax error."); // send error also to javascript client
return;
}

// Parse the read type string
if (!strncmp(tmpReadTypeString, sizeof(tmpReadTypeString), "analog")) {
sharedMemory.readType = RT_ANALOG;
} else if (!strncmp(tmpReadTypeString, sizeof(tmpReadTypeString), "digital")) {
sharedMemory.readType = RT_DIGITAL;
} else {
#ifdef __DMESG__
dmesg ("[oscilloscope] oscilloscope protocol syntax error. Received `%s`, but only `analog` and `digital` are valid inputs for the read type.", tmpReadTypeString);
#endif
}

// use adc1_get_raw instead of analogRead
if (!strcmp (sharedMemory.readType, "analog")) {
if (sharedMemory.readType == RT_ANALOG) {
switch (sharedMemory.gpio1) {
// ADC1
case 36: sharedMemory.adcchannel1 = ADC1_CHANNEL_0; break;
Expand Down Expand Up @@ -490,13 +513,55 @@
webSocket->sendString ("[oscilloscope] oscilloscope protocol syntax error."); // send error also to javascript client
return;
}
if (sscanf (cmdPart2, "every %i %2s screen width = %i %2s", &sharedMemory.samplingTime, sharedMemory.samplingTimeUnit, &sharedMemory.screenWidthTime, sharedMemory.screenWidthTimeUnit) != 4) {

char tmpSamplingTimeUnitString[3];
char tmpScreenWidthTimeUnitString[3];
if (sscanf (cmdPart2, "every %i %2s screen width = %i %2s", &sharedMemory.samplingTime, tmpSamplingTimeUnitString, &sharedMemory.screenWidthTime, tmpScreenWidthTimeUnitString) != 4) {
#ifdef __DMESG__
dmesg ("[oscilloscope] oscilloscope protocol syntax error.");
#endif
webSocket->sendString ("[oscilloscope] oscilloscope protocol syntax error."); // send error also to javascript client
return;
}

if (!strncmp(tmpSamplingTimeUnitString, "us", 2)) {
sharedMemory.samplingTimeUnit = TU_US;
} else if (!strncmp(tmpSamplingTimeUnitString, "ms", 2)) {
sharedMemory.samplingTimeUnit = TU_MS;
} else {
char errorMsg_sampleTimeUnit[200];
snprintf(errorMsg_sampleTimeUnit, sizeof(errorMsg_sampleTimeUnit), "[oscilloscope] wrong samplingTimeUnit: %s. Sampling time unit can only be ms or us.", tmpSamplingTimeUnitString);
#ifdef __DMESG__
dmesg (errorMsg_sampleTimeUnit);
#endif
webSocket->sendString (errorMsg_sampleTimeUnit); // send error also to javascript client
return;
}

if (!strncmp(tmpScreenWidthTimeUnitString, "us", 2)) {
sharedMemory.screenWidthTimeUnit = TU_US;
} else if (!strncmp(tmpScreenWidthTimeUnitString, "ms", 2)) {
sharedMemory.screenWidthTimeUnit = TU_MS;
} else {
char errorMsg_screenWidthTimeUnit[200];
snprintf(errorMsg_screenWidthTimeUnit, sizeof(errorMsg_screenWidthTimeUnit), "[oscilloscope] wrong samplingTimeUnit: %s. Sampling time unit can only be ms or us.", tmpSamplingTimeUnitString);
#ifdef __DMESG__
dmesg (errorMsg_screenWidthTimeUnit);
#endif
webSocket->sendString (errorMsg_screenWidthTimeUnit); // send error also to javascript client
return;
}

if (sharedMemory.screenWidthTimeUnit != sharedMemory.samplingTimeUnit) {
char errMsg[200];
snprintf(errMsg, sizeof(errMsg), "[oscilloscope] screenWidthTimeUnit must be the same as samplingTimeUnit. The former is %s and the latter is %s", tmpScreenWidthTimeUnitString, tmpSamplingTimeUnitString);
#ifdef __DMESG__
dmesg (errMsg);
#endif
webSocket->sendString(errMsg); // send error also to javascript client
return;
}


// parse 3rd part
if (cmdPart3) {
Expand Down Expand Up @@ -532,10 +597,10 @@
}
}

// DEBUG: Serial.printf ("[oscilloscope] parsing command: samplingTime = %i %s, screenWidth = %i %s\n", sharedMemory.samplingTime, sharedMemory.samplingTimeUnit, sharedMemory.screenWidthTime, sharedMemory.screenWidthTimeUnit);
// DEBUG: Serial.printf ("[oscilloscope] parsing command: samplingTime = %i %s, screenWidth = %i %s\n", sharedMemory.samplingTime, (sharedMemory.samplingTimeUnit == TU_US ? "us" : "ms"), sharedMemory.screenWidthTime, (sharedMemory.screenWidthTimeUnit == TU_US ? "us" : "ms"));

// check the values and calculate derived values
if (!(!strcmp (sharedMemory.readType, "analog") || !strcmp (sharedMemory.readType, "digital"))) {
if (sharedMemory.readType != RT_ANALOG && sharedMemory.readType != RT_DIGITAL) {
#ifdef __DMESG__
dmesg ("[oscilloscope] wrong readType. Read type can only be analog or digital.");
#endif
Expand All @@ -556,7 +621,7 @@
webSocket->sendString ("[oscilloscope] invalid sampling time. Sampling time must be between 1 and 25000."); // send error also to javascript client
return;
}
if (strcmp (sharedMemory.samplingTimeUnit, "ms") && strcmp (sharedMemory.samplingTimeUnit, "us")) {
if (sharedMemory.samplingTimeUnit != TU_US && sharedMemory.samplingTimeUnit != TU_MS) {
#ifdef __DMESG__
dmesg ("[oscilloscope] wrong samplingTimeUnit. Sampling time unit can only be ms or us.");
#endif
Expand All @@ -571,18 +636,10 @@
return;
}

if (strcmp (sharedMemory.screenWidthTimeUnit, sharedMemory.samplingTimeUnit)) {
#ifdef __DMESG__
dmesg ("[oscilloscope] screenWidthTimeUnit must be the same as samplingTimeUnit.");
#endif
webSocket->sendString ("[oscilloscope] screenWidthTimeUnit must be the same as samplingTimeUnit."); // send error also to javascript client
return;
}

// DEBUG: Serial.printf ("[oscilloscope] parsing4 command: samplingTime = %i %s, screenWidth = %i %s\n", sharedMemory.samplingTime, sharedMemory.samplingTimeUnit, sharedMemory.screenWidthTime, sharedMemory.screenWidthTimeUnit);
// DEBUG: Serial.printf ("[oscilloscope] parsing4 command: samplingTime = %i %s, screenWidth = %i %s\n", sharedMemory.samplingTime, (sharedMemory.samplingTimeUnit == TU_US ? "us" : "ms"), sharedMemory.screenWidthTime, (sharedMemory.screenWidthTimeUnit == TU_US ? "us" : "ms"));

if (sharedMemory.positiveTrigger) {
if (sharedMemory.positiveTriggerTreshold > 0 && sharedMemory.positiveTriggerTreshold <= (strcmp (sharedMemory.readType, "analog") ? 1 : 4095)) {
if (sharedMemory.positiveTriggerTreshold > 0 && sharedMemory.positiveTriggerTreshold <= (sharedMemory.readType == RT_ANALOG ? 4095 : 1)) {
;// Serial.printf ("[oscilloscope] positive slope trigger treshold = %i\n", sharedMemory.positiveTriggerTreshold);
} else {
#ifdef __DMESG__
Expand All @@ -593,7 +650,7 @@
}
}
if (sharedMemory.negativeTrigger) {
if (sharedMemory.negativeTriggerTreshold >= 0 && sharedMemory.negativeTriggerTreshold < (strcmp (sharedMemory.readType, "analog") ? 1 : 4095)) {
if (sharedMemory.negativeTriggerTreshold >= 0 && sharedMemory.negativeTriggerTreshold < (sharedMemory.readType == RT_ANALOG ? 4095 : 1)) {
;//Serial.printf ("[oscilloscope] negative slope trigger treshold = %i\n", sharedMemory.negativeTriggerTreshold);
} else {
#ifdef __DMESG__
Expand All @@ -604,7 +661,7 @@
}
}

// DEBUG: Serial.printf ("[oscilloscope] parsing5 command: samplingTime = %i %s, screenWidth = %i %s\n", sharedMemory.samplingTime, sharedMemory.samplingTimeUnit, sharedMemory.screenWidthTime, sharedMemory.screenWidthTimeUnit);
// DEBUG: Serial.printf ("[oscilloscope] parsing5 command: samplingTime = %i %s, screenWidth = %i %s\n", sharedMemory.samplingTime, (sharedMemory.samplingTimeUnit == TU_US ? "us" : "ms"), sharedMemory.screenWidthTime, (sharedMemory.screenWidthTimeUnit == TU_US ? "us" : "ms"));

sharedMemory.oscReaderState = INITIAL;

Expand Down

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