3 files changed, 91 insertions, 82 deletions
diff --git a/sw/cal/dbc.go b/sw/cal/dbc.go
new file mode 100644
index 0000000..53ca852
--- /dev/null
+++ b/sw/cal/dbc.go
@@ -0,0 +1,81 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"slices"
+
+	"go.einride.tech/can/pkg/dbc"
+)
+
+// Extract signals from the DBC file.
+func parseSignals(filename string, names []string) ([]dbc.SignalDef, error) {
+	// Parse DBC file
+	msgDefs, err := parseDbcFile(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	// Search for signals
+	sigPtrs := make([]*dbc.SignalDef, len(names))
+	for _, msg := range msgDefs {
+		for i := range names {
+			j := slices.IndexFunc(msg.Signals, func(sig dbc.SignalDef) bool { return sig.Name == dbc.Identifier(names[i]) })
+			if j < 0 {
+				continue
+			}
+			if sigPtrs[i] != nil {
+				return nil, ErrDupSig{msg.Signals[j]}
+			}
+			sigPtrs[i] = &msg.Signals[j]
+		}
+	}
+
+	// Check all signals are present
+	if i := slices.IndexFunc(sigPtrs, func(sp *dbc.SignalDef) bool { return sp == nil }); i >= 0 {
+		return nil, ErrNoSig{filename, names[i]}
+	}
+
+	// Dereference
+	signals := make([]dbc.SignalDef, len(sigPtrs))
+	for i := range sigPtrs {
+		signals[i] = *sigPtrs[i]
+	}
+
+	return signals, nil
+}
+
+func parseDbcFile(filename string) ([]*dbc.MessageDef, error) {
+	// Read file
+	buf, err := os.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	// Parse file
+	parser := dbc.NewParser(filename, buf)
+	if err := parser.Parse(); err != nil {
+		return nil, err
+	}
+
+	// Filter message definitions
+	defs := parser.Defs()
+	msgDefs := make([]*dbc.MessageDef, 0, len(defs))
+	for _, def := range defs {
+		if msg, ok := def.(*dbc.MessageDef); ok {
+			msgDefs = append(msgDefs, msg)
+		}
+	}
+	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
+
+}
diff --git a/sw/cal/err.go b/sw/cal/err.go
index 951ac12..452e5f0 100644
--- a/sw/cal/err.go
+++ b/sw/cal/err.go
@@ -2,10 +2,20 @@ package main
 
 import (
 	"fmt"
+	"os"
 
 	"go.einride.tech/can/pkg/dbc"
 )
 
+func eprintf(format string, a ...any) {
+	weprintf(format, a...)
+	os.Exit(1)
+}
+
+func weprintf(format string, a ...any) {
+	fmt.Fprintf(os.Stderr, format, a...)
+}
+
 type ErrDupSig struct {
 	sig dbc.SignalDef
 }
diff --git a/sw/cal/main.go b/sw/cal/main.go
index e3794f4..3758a07 100644
--- a/sw/cal/main.go
+++ b/sw/cal/main.go
@@ -4,7 +4,6 @@ import (
 	"flag"
 	"fmt"
 	"os"
-	"slices"
 
 	"go.einride.tech/can/pkg/dbc"
 )
@@ -67,84 +66,3 @@ func nonEmpty(ss ...string) []string {
 	}
 	return r
 }
-
-// Extract signals from the DBC file.
-func parseSignals(filename string, names []string) ([]dbc.SignalDef, error) {
-	// Parse DBC file
-	msgDefs, err := parseDbcFile(filename)
-	if err != nil {
-		return nil, err
-	}
-
-	// Search for signals
-	sigPtrs := make([]*dbc.SignalDef, len(names))
-	for _, msg := range msgDefs {
-		for i := range names {
-			j := slices.IndexFunc(msg.Signals, func(sig dbc.SignalDef) bool { return sig.Name == dbc.Identifier(names[i]) })
-			if j < 0 {
-				continue
-			}
-			if sigPtrs[i] != nil {
-				return nil, ErrDupSig{msg.Signals[j]}
-			}
-			sigPtrs[i] = &msg.Signals[j]
-		}
-	}
-
-	// Check all signals are present
-	if i := slices.IndexFunc(sigPtrs, func(sp *dbc.SignalDef) bool { return sp == nil }); i >= 0 {
-		return nil, ErrNoSig{filename, names[i]}
-	}
-
-	// Dereference
-	signals := make([]dbc.SignalDef, len(sigPtrs))
-	for i := range sigPtrs {
-		signals[i] = *sigPtrs[i]
-	}
-
-	return signals, nil
-}
-
-func parseDbcFile(filename string) ([]*dbc.MessageDef, error) {
-	// Read file
-	buf, err := os.ReadFile(filename)
-	if err != nil {
-		return nil, err
-	}
-
-	// Parse file
-	parser := dbc.NewParser(filename, buf)
-	if err := parser.Parse(); err != nil {
-		return nil, err
-	}
-
-	// Filter message definitions
-	defs := parser.Defs()
-	msgDefs := make([]*dbc.MessageDef, 0, len(defs))
-	for _, def := range defs {
-		if msg, ok := def.(*dbc.MessageDef); ok {
-			msgDefs = append(msgDefs, msg)
-		}
-	}
-	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)
-}
-
-func weprintf(format string, a ...any) {
-	fmt.Fprintf(os.Stderr, format, a...)
-}