cmd/dif-dump: first import

cmd/dif-dump/main.go

+// Copyright 2020 The go-lpc Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Command dif-dump decodes and displays DIF data.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+
+	"github.com/go-lpc/mim/dif"
+	"golang.org/x/xerrors"
+)
+
+func main() {
+	log.SetPrefix("dif-dump: ")
+	log.SetFlags(0)
+
+	flag.Parse()
+	fname := flag.Arg(0)
+
+	f, err := os.Open(fname)
+	if err != nil {
+		log.Fatalf("could not open %q: %+v", fname, err)
+	}
+	defer f.Close()
+
+	dec := dif.NewDecoder(difIDFrom(f), f)
+loop:
+	for {
+		var d dif.DIF
+		err := dec.Decode(&d)
+		if err != nil {
+			if xerrors.Is(err, io.EOF) {
+				break loop
+			}
+			log.Fatalf("could not decode DIF: %+v", err)
+		}
+		fmt.Printf("=== DIF-ID 0x%x ===\n", d.Header.ID)
+		fmt.Printf("DIF trigger: % 10d\n", d.Header.DTC)
+		fmt.Printf("ACQ trigger: % 10d\n", d.Header.ATC)
+		fmt.Printf("Gbl trigger: % 10d\n", d.Header.GTC)
+		fmt.Printf("Abs BCID:    % 10d\n", d.Header.AbsBCID)
+		fmt.Printf("Time DIF:    % 10d\n", d.Header.TimeDIFTC)
+		fmt.Printf("Frames:      % 10d\n", len(d.Frames))
+
+		for _, frame := range d.Frames {
+			fmt.Printf("  hroc=0x%02x BCID=% 8d %x\n",
+				frame.Header, frame.BCID, frame.Data,
+			)
+		}
+	}
+}
+
+func difIDFrom(f io.ReaderAt) uint8 {
+	p := []byte{0}
+	_, err := f.ReadAt(p, 1)
+	if err != nil {
+		panic(err)
+	}
+	return uint8(p[0])
+}