internal/compress/flate: Add InputConsumed

1 files changed, 13 insertions, 0 deletions

diff --git a/internal/compress/flate/inflate.go b/internal/compress/flate/inflate.go
index 6e90126d..d200d244 100644
--- a/internal/compress/flate/inflate.go
+++ b/internal/compress/flate/inflate.go
@@ -286,6 +286,14 @@ type Reader interface {
 	io.ByteReader
 }
 
+// InputProgress reports compressed input bytes consumed by inflate state.
+//
+// InputConsumed returns bytes that have been consumed by the decompressor's
+// parser and state machine, not bytes merely read ahead from the source.
+type InputProgress interface {
+	InputConsumed() int64
+}
+
 type step uint8
 
 const (
@@ -344,6 +352,11 @@ type decompressor struct {
 	flushMode flushMode
 }
 
+// InputConsumed returns compressed input bytes consumed by receiver.
+func (f *decompressor) InputConsumed() int64 {
+	return f.roffset
+}
+
 func (f *decompressor) nextBlock() {
 	for f.nb < 1+2 {
 		if f.err = f.moreBits(); f.err != nil {