init

main.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"crypto"
+	"flag"
+	"io"
+	"log"
+	"os"
+)
+
+func main() {
+	flag.Parse()
+
+	hdrBuff := make([]byte, BlockSize)
+
+	for _, arg := range flag.Args() {
+		func() {
+			// Open the tar archive
+			fh, err := os.Open(arg)
+			if err != nil {
+				log.Fatal(err)
+			}
+			defer fh.Close()
+
+			// prep our buffer
+			buf := hdrBuff[:]
+			copy(buf, zeroBlock)
+
+			if _, err := io.ReadFull(fh, buf); err != nil {
+				log.Fatal(err)
+			}
+		}()
+	}
+}
+
+const BlockSize = 512
+
+var (
+	zeroBlock = make([]byte, BlockSize)
+
+	flOutputJson = flag.String("o", "", "output json of the tar archives")
+)
+
+type (
+	// for a whole tar archive
+	TarInfo struct {
+		Name    string
+		Entries []Entry
+
+		// TODO(vbatts) would be nice to satisfy the Reader interface, so that this could be passed directly to tar.Reader
+	}
+
+	// each file from the tar archive has it's header copied exactly,
+	//and payload of it's file Checksummed if the file size is greater than 0
+	Entry struct {
+		Pos      int64
+		Header   []byte
+		Size     int64
+		Checksum []byte
+		Hash     crypto.Hash
+
+		// TODO(vbatts) perhaps have info to find the file on disk, to provide an io.Reader
+	}
+)