2 files changed, 100 insertions, 15 deletions

diff --git a/sw/cal/err.go b/sw/cal/err.go
new file mode 100644
index 0000000..951ac12
--- /dev/null
+++ b/sw/cal/err.go
@@ -0,0 +1,24 @@
+package main
+
+import (
+	"fmt"
+
+	"go.einride.tech/can/pkg/dbc"
+)
+
+type ErrDupSig struct {
+	sig dbc.SignalDef
+}
+
+func (e ErrDupSig) Error() string {
+	return fmt.Sprintf("%v: duplicate signal '%s'", e.sig.Pos, e.sig.Name)
+}
+
+type ErrNoSig struct {
+	filename string // DBC file
+	signal   string // signal name
+}
+
+func (e ErrNoSig) Error() string {
+	return fmt.Sprintf("%s: no such signal '%s'", e.filename, e.signal)
+}
diff --git a/sw/cal/main.go b/sw/cal/main.go
index 98e021c..9a1d067 100644
--- a/sw/cal/main.go
+++ b/sw/cal/main.go
@@ -18,21 +18,21 @@ type Signals struct {
 var (
 	// DBC file
 	dbcFilenameFlag = "dbc"
-	dbcFilename = flag.String(dbcFilenameFlag, "", "DBC file name")
+	dbcFilename     = flag.String(dbcFilenameFlag, "", "DBC file name")
 
 	// Signal names
-	tachSigFlag = "tachSig"
+	tachSigFlag  = "tachSig"
 	speedSigFlag = "speedSig"
-	an1SigFlag = "an1Sig"
-	an2SigFlag = "an2Sig"
-	an3SigFlag = "an3Sig"
-	an4SigFlag = "an4Sig"
-	tachSig = flag.String(tachSigFlag, "", "tachometer signal name")
-	speedSig = flag.String(speedSigFlag, "", "speedometer signal name")
-	an1Sig = flag.String(an1SigFlag, "", "analog channel 1 signal name")
-	an2Sig = flag.String(an2SigFlag, "", "analog channel 2 signal name")
-	an3Sig = flag.String(an3SigFlag, "", "analog channel 3 signal name")
-	an4Sig = flag.String(an4SigFlag, "", "analog channel 4 signal name")
+	an1SigFlag   = "an1Sig"
+	an2SigFlag   = "an2Sig"
+	an3SigFlag   = "an3Sig"
+	an4SigFlag   = "an4Sig"
+	tachSig      = flag.String(tachSigFlag, "", "tachometer signal name")
+	speedSig     = flag.String(speedSigFlag, "", "speedometer signal name")
+	an1Sig       = flag.String(an1SigFlag, "", "analog channel 1 signal name")
+	an2Sig       = flag.String(an2SigFlag, "", "analog channel 2 signal name")
+	an3Sig       = flag.String(an3SigFlag, "", "analog channel 3 signal name")
+	an4Sig       = flag.String(an4SigFlag, "", "analog channel 4 signal name")
 
 	// Calibration tables
 	// TODO
@@ -47,18 +47,68 @@ func main() {
 		os.Exit(1)
 	}
 
-	// Parse DBC file
-	msgDefs, err := parseDbcFile(*dbcFilename)
+	// Parse signals in DBC file
+	signals, err := parseSignals(*dbcFilename)
 	if err != nil {
 		eprintf("Error parsing %s: %v\n", *dbcFilename, err)
 	}
 
+	fmt.Println(signals)
+}
 
+// Parse signals in the DBC file.
+func parseSignals(filename string) (Signals, error) {
+	msgDefs, err := parseDbcFile(filename)
+	if err != nil {
+		return Signals{}, err
+	}
+
+	// Search for signals in messages
+	var signals Signals
 	for _, msg := range msgDefs {
 		for _, sig := range msg.Signals {
-			fmt.Println(sig)
+			if err := tryAssignSignal(&signals.tach, sig, *tachSig); err != nil {
+				return signals, err
+			}
+			if err := tryAssignSignal(&signals.speed, sig, *speedSig); err != nil {
+				return signals, err
+			}
+			if err := tryAssignSignal(&signals.an1, sig, *an1Sig); err != nil {
+				return signals, err
+			}
+			if err := tryAssignSignal(&signals.an2, sig, *an2Sig); err != nil {
+				return signals, err
+			}
+			if err := tryAssignSignal(&signals.an3, sig, *an3Sig); err != nil {
+				return signals, err
+			}
+			if err := tryAssignSignal(&signals.an4, sig, *an4Sig); err != nil {
+				return signals, err
+			}
 		}
 	}
+
+	// Check all signals provided on command line are present in the DBC file
+	if *tachSig != "" && signals.tach == nil {
+		return signals, ErrNoSig{filename, *tachSig}
+	}
+	if *speedSig != "" && signals.speed == nil {
+		return signals, ErrNoSig{filename, *speedSig}
+	}
+	if *an1Sig != "" && signals.an1 == nil {
+		return signals, ErrNoSig{filename, *an1Sig}
+	}
+	if *an2Sig != "" && signals.an2 == nil {
+		return signals, ErrNoSig{filename, *an2Sig}
+	}
+	if *an3Sig != "" && signals.an3 == nil {
+		return signals, ErrNoSig{filename, *an3Sig}
+	}
+	if *an4Sig != "" && signals.an4 == nil {
+		return signals, ErrNoSig{filename, *an4Sig}
+	}
+
+	return signals, nil
 }
 
 func parseDbcFile(filename string) ([]*dbc.MessageDef, error) {
@@ -85,6 +135,17 @@ func parseDbcFile(filename string) ([]*dbc.MessageDef, error) {
 	return msgDefs, nil
 }
 
+func tryAssignSignal(dst **dbc.SignalDef, sig dbc.SignalDef, targetName string) error {
+	if targetName != "" && string(sig.Name) == targetName {
+		if *dst != nil {
+			return fmt.Errorf("%v: duplicate signal '%s'", sig.Pos, sig.Name)
+		}
+		*dst = &sig
+	}
+	return nil
+
+}
+
 func eprintf(format string, a ...any) {
 	weprintf(format, a...)
 	os.Exit(1)