refactor: Use manual size calculation instead of trusting the tar header size

cmd/stbak/cmd/recovery_index.go

@@ -5,6 +5,7 @@ import (
 	"bufio"
 	"context"
 	"io"
+	"io/ioutil"
 	"math"
 	"os"
 
@@ -139,7 +140,16 @@ func index(
 				return err
 			}
 
-			nextTotalBlocks := math.Ceil(float64((curr + hdr.Size)) / float64(controllers.BlockSize))
+			if _, err := io.Copy(ioutil.Discard, tr); err != nil {
+				return err
+			}
+
+			currAndSize, err := f.Seek(0, io.SeekCurrent)
+			if err != nil {
+				return err
+			}
+
+			nextTotalBlocks := math.Ceil(float64(curr+(currAndSize-curr)) / float64(controllers.BlockSize))
 			record = int64(nextTotalBlocks) / int64(recordSize)
 			block = int64(nextTotalBlocks) - (record * int64(recordSize))
 
@@ -200,7 +210,13 @@ func index(
 
 			curr = int64(counter.BytesRead)
 
-			nextTotalBlocks := math.Ceil(float64((curr + hdr.Size)) / float64(controllers.BlockSize))
+			if _, err := io.Copy(ioutil.Discard, tr); err != nil {
+				return err
+			}
+
+			currAndSize := int64(counter.BytesRead)
+
+			nextTotalBlocks := math.Ceil(float64(curr+(currAndSize-curr)) / float64(controllers.BlockSize))
 			record = int64(nextTotalBlocks) / int64(recordSize)
 			block = int64(nextTotalBlocks) - (record * int64(recordSize))
 

cmd/stbak/cmd/recovery_query.go

@@ -4,6 +4,7 @@ import (
 	"archive/tar"
 	"bufio"
 	"io"
+	"io/ioutil"
 	"math"
 
 	"github.com/pojntfx/stfs/pkg/controllers"
@@ -100,7 +101,16 @@ var recoveryQueryCmd = &cobra.Command{
 					return err
 				}
 
-				nextTotalBlocks := math.Ceil(float64((curr + hdr.Size)) / float64(controllers.BlockSize))
+				if _, err := io.Copy(ioutil.Discard, tr); err != nil {
+					return err
+				}
+
+				currAndSize, err := f.Seek(0, io.SeekCurrent)
+				if err != nil {
+					return err
+				}
+
+				nextTotalBlocks := math.Ceil(float64(curr+(currAndSize-curr)) / float64(controllers.BlockSize))
 				record = int64(nextTotalBlocks) / int64(viper.GetInt(recordSizeFlag))
 				block = int64(nextTotalBlocks) - (record * int64(viper.GetInt(recordSizeFlag)))
 
@@ -165,9 +175,13 @@ var recoveryQueryCmd = &cobra.Command{
 					return err
 				}
 
-				curr = int64(counter.BytesRead)
+				if _, err := io.Copy(ioutil.Discard, tr); err != nil {
+					return err
+				}
 
-				nextTotalBlocks := math.Ceil(float64((curr + hdr.Size)) / float64(controllers.BlockSize))
+				currAndSize := int64(counter.BytesRead)
+
+				nextTotalBlocks := math.Ceil(float64(curr+(currAndSize-curr)) / float64(controllers.BlockSize))
 				record = int64(nextTotalBlocks) / int64(viper.GetInt(recordSizeFlag))
 				block = int64(nextTotalBlocks) - (record * int64(viper.GetInt(recordSizeFlag)))