diff --git a/src/libFLAC/bitbuffer.c b/src/libFLAC/bitbuffer.c
index 05902b24..078461b3 100644
--- a/src/libFLAC/bitbuffer.c
+++ b/src/libFLAC/bitbuffer.c
@@ -580,7 +580,7 @@ unsigned FLAC__bitbuffer_get_input_bytes_unconsumed(const FLAC__BitBuffer *bb)
 	return (bb->total_bits - bb->total_consumed_bits) >> 3;
 }
 
-void FLAC__bitbuffer_get_buffer(FLAC__BitBuffer *bb, const FLAC__byte **buffer, unsigned *bytes)
+void FLAC__bitbuffer_get_buffer(FLAC__BitBuffer *bb, const FLAC__byte **buffer, size_t *bytes)
 {
 	FLAC__ASSERT((bb->consumed_bits & 7) == 0 && (bb->bits & 7) == 0);
 #if FLAC__BITS_PER_BLURB == 8
diff --git a/src/libFLAC/include/private/bitbuffer.h b/src/libFLAC/include/private/bitbuffer.h
index a6b8931d..1bb5b652 100644
--- a/src/libFLAC/include/private/bitbuffer.h
+++ b/src/libFLAC/include/private/bitbuffer.h
@@ -84,7 +84,7 @@ unsigned FLAC__bitbuffer_get_input_bytes_unconsumed(const FLAC__BitBuffer *bb);
 /*
  * direct buffer access
  */
-void FLAC__bitbuffer_get_buffer(FLAC__BitBuffer *bb, const FLAC__byte **buffer, unsigned *bytes);
+void FLAC__bitbuffer_get_buffer(FLAC__BitBuffer *bb, const FLAC__byte **buffer, size_t *bytes);
 void FLAC__bitbuffer_release_buffer(FLAC__BitBuffer *bb);
 
 /*
@@ -122,7 +122,7 @@ FLAC__bool FLAC__bitbuffer_zero_pad_to_byte_boundary(FLAC__BitBuffer *bb);
 /*
  * read functions
  */
-typedef FLAC__bool (*FLAC__BitbufferReadCallback)(FLAC__byte buffer[], unsigned *bytes, void *client_data);
+typedef FLAC__bool (*FLAC__BitbufferReadCallback)(FLAC__byte buffer[], size_t *bytes, void *client_data);
 
 FLAC__bool FLAC__bitbuffer_peek_bit(FLAC__BitBuffer *bb, unsigned *val, FLAC__BitbufferReadCallback read_callback, void *client_data);
 FLAC__bool FLAC__bitbuffer_read_bit(FLAC__BitBuffer *bb, unsigned *val, FLAC__BitbufferReadCallback read_callback, void *client_data);