Add deflate_decompress function

Needed to implement decompressors for gzip without headers.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 39 insertions, 0 deletions

diff --git a/lib/decompress_inflate.c b/lib/decompress_inflate.c
index 5c1ebb6850..d5ea01ad56 100644
--- a/lib/decompress_inflate.c
+++ b/lib/decompress_inflate.c
@@ -183,4 +183,43 @@ gunzip_nomem1:
 	return rc; /* returns Z_OK (0) if successful */
 }
 
+int deflate_decompress(struct z_stream_s *stream, const u8 *src, unsigned int slen, u8 *dst,
+		unsigned int *dlen)
+{
+
+	int ret = 0;
+
+	ret = zlib_inflateReset(stream);
+	if (ret != Z_OK) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	stream->next_in = (u8 *)src;
+	stream->avail_in = slen;
+	stream->next_out = (u8 *)dst;
+	stream->avail_out = *dlen;
+
+	ret = zlib_inflate(stream, Z_SYNC_FLUSH);
+	/*
+	 * Work around a bug in zlib, which sometimes wants to taste an extra
+	 * byte when being used in the (undocumented) raw deflate mode.
+	 * (From USAGI).
+	 */
+	if (ret == Z_OK && !stream->avail_in && stream->avail_out) {
+		u8 zerostuff = 0;
+		stream->next_in = &zerostuff;
+		stream->avail_in = 1;
+		ret = zlib_inflate(stream, Z_FINISH);
+	}
+	if (ret != Z_STREAM_END) {
+		ret = -EINVAL;
+		goto out;
+	}
+	ret = 0;
+	*dlen = stream->total_out;
+out:
+	return ret;
+}
+
 #define decompress gunzip