Merge pull request #2 from asymmetric-research/marctrem/custom-error-line-too-long

Introduce ErrLineTruncated

Author: marctrem

io/linereader/err_line_truncated.go

@@ -0,0 +1,11 @@
+package linereader
+
+import "fmt"
+
+type ErrLineTruncated struct {
+	Discarded int
+}
+
+func (e *ErrLineTruncated) Error() string {
+	return fmt.Sprintf("line truncated (discarded %d bytes)", e.Discarded)
+}

io/linereader/linereader.go

@@ -2,7 +2,6 @@ package linereader
 
 import (
 	"bytes"
-	"errors"
 	"io"
 
 	armath "github.com/asymmetric-research/go-commons/math"
@@ -32,7 +31,7 @@ func NewInto(dst *T, reader io.Reader, blockSize uint) {
 func (lr *T) Read(dst []byte) (n int, err error) {
 	n, discarded, err := lr.ReadExtra(dst)
 	if discarded != 0 {
-		return n, errors.New("line too long")
+		return n, &ErrLineTruncated{Discarded: discarded}
 	}
 	return n, err
 }