Add xz_dec_catrun() to support concatenated .xz files.

1 files changed, 79 insertions, 1 deletions

diff --git a/linux/lib/xz/xz_dec_stream.c b/linux/lib/xz/xz_dec_stream.c
index f69581b..e4aab73 100644
--- a/linux/lib/xz/xz_dec_stream.c
+++ b/linux/lib/xz/xz_dec_stream.c
@@ -35,7 +35,8 @@ struct xz_dec {
 		SEQ_INDEX,
 		SEQ_INDEX_PADDING,
 		SEQ_INDEX_CRC32,
-		SEQ_STREAM_FOOTER
+		SEQ_STREAM_FOOTER,
+		SEQ_STREAM_PADDING
 	} sequence;
 
 	/* Position in variable-length integers and Check fields */
@@ -742,6 +743,10 @@ static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
 				return XZ_OK;
 
 			return dec_stream_footer(s);
+
+		case SEQ_STREAM_PADDING:
+			/* Never reached, only silencing a warning */
+			break;
 		}
 	}
 
@@ -809,6 +814,79 @@ XZ_EXTERN enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b)
 	return ret;
 }
 
+#ifdef XZ_DEC_CONCATENATED
+XZ_EXTERN enum xz_ret xz_dec_catrun(struct xz_dec *s, struct xz_buf *b,
+				    int finish)
+{
+	enum xz_ret ret;
+
+	if (DEC_IS_SINGLE(s->mode)) {
+		xz_dec_reset(s);
+		finish = true;
+	}
+
+	while (true) {
+		if (s->sequence == SEQ_STREAM_PADDING) {
+			/*
+			 * Skip Stream Padding. Its size must be a multiple
+			 * of four bytes which is tracked with s->pos.
+			 */
+			while (true) {
+				if (b->in_pos == b->in_size) {
+					/*
+					 * Note that if we are repeatedly
+					 * given no input and finish is false,
+					 * we will keep returning XZ_OK even
+					 * though no progress is being made.
+					 * The lack of XZ_BUF_ERROR support
+					 * isn't a problem here because a
+					 * reasonable caller will eventually
+					 * provide more input or set finish
+					 * to true.
+					 */
+					if (!finish)
+						return XZ_OK;
+
+					if (s->pos != 0)
+						return XZ_DATA_ERROR;
+
+					return XZ_STREAM_END;
+				}
+
+				if (b->in[b->in_pos] != 0x00) {
+					if (s->pos != 0)
+						return XZ_DATA_ERROR;
+
+					break;
+				}
+
+				++b->in_pos;
+				s->pos = (s->pos + 1) & 3;
+			}
+
+			/*
+			 * More input remains. It should be a new Stream.
+			 *
+			 * In single-call mode xz_dec_run() will always call
+			 * xz_dec_reset(). Thus, we need to do it here only
+			 * in multi-call mode.
+			 */
+			if (DEC_IS_MULTI(s->mode))
+				xz_dec_reset(s);
+		}
+
+		ret = xz_dec_run(s, b);
+
+		if (ret != XZ_STREAM_END)
+			break;
+
+		s->sequence = SEQ_STREAM_PADDING;
+	}
+
+	return ret;
+}
+#endif
+
 XZ_EXTERN struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max)
 {
 	struct xz_dec *s = kmalloc(sizeof(*s), GFP_KERNEL);