patches.axfs/axfs-axfs_uncompress.c.patch

From Aaditya.Kumar@ap.sony.com Fri Nov 23 03:47:49 2012
From: Aaditya Kumar <aaditya.kumar@ap.sony.com>
Date: Fri, 23 Nov 2012 17:12:07 +0530
Subject: [PATCH v2 RESEND 11/15] AXFS: axfs_uncompress.c
To: Greg KH <gregkh@linuxfoundation.org>
Cc: "ltsi-dev@lists.linuxfoundation.org" <ltsi-dev@lists.linuxfoundation.org>, tim.bird@am.sony.com, frank.rowand@am.sony.com, takuzo.ohara@ap.sony.com, amit.agarwal@ap.sony.com, kan.iibuchi@jp.sony.com, aaditya.kumar.30@gmail.com
Message-ID: <50AF610F.3000208@ap.sony.com>


From: Jared Hulbert <jaredeh@gmail.com>

AXFS interfaces to the uncompression library

Signed-off-by: Jared Hulbert <jaredeh@gmail.com>
Signed-off-by: Aaditya Kumar <aaditya.kumar@ap.sony.com>
---
 fs/axfs/axfs_uncompress.c |   90 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
  create mode 100644 fs/axfs/axfs_uncompress.c

--- /dev/null
+++ b/fs/axfs/axfs_uncompress.c
@@ -0,0 +1,90 @@
+/*
+ * Advanced XIP File System for Linux - AXFS
+ *   Readonly, compressed, and XIP filesystem for Linux systems big and small
+ *
+ *   Modified in 2006 by Eric Anderson
+ *     from the cramfs sources fs/cramfs/uncompress.c
+ *
+ * (C) Copyright 1999 Linus Torvalds
+ *
+ * axfs_uncompress.c -
+ *  axfs interfaces to the uncompression library. There's really just
+ * three entrypoints:
+ *
+ *  - axfs_uncompress_init() - called to initialize the thing.
+ *  - axfs_uncompress_exit() - tell me when you're done
+ *  - axfs_uncompress_block() - uncompress a block.
+ *
+ * NOTE NOTE NOTE! The uncompression is entirely single-threaded. We
+ * only have one stream, and we'll initialize it only once even if it
+ * then is used by multiple filesystems.
+ *
+ */
+
+#include <linux/errno.h>
+#include <linux/vmalloc.h>
+#include <linux/zlib.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+
+static z_stream stream;
+static DEFINE_MUTEX(axfs_uncmp_mutex);
+
+int axfs_uncompress_block(void *dst, int dstlen, void *src, int srclen)
+{
+	int err;
+	int out;
+
+	mutex_lock(&axfs_uncmp_mutex);
+
+	stream.next_in = src;
+	stream.avail_in = srclen;
+
+	stream.next_out = dst;
+	stream.avail_out = dstlen;
+
+	err = zlib_inflateReset(&stream);
+	if (err != Z_OK) {
+		printk(KERN_ERR "axfs: zlib_inflateReset error %d\n", err);
+		zlib_inflateEnd(&stream);
+		zlib_inflateInit(&stream);
+	}
+
+	err = zlib_inflate(&stream, Z_FINISH);
+	if (err != Z_STREAM_END)
+		goto err;
+
+	out = stream.total_out;
+
+	mutex_unlock(&axfs_uncmp_mutex);
+
+	return out;
+
+err:
+
+	mutex_unlock(&axfs_uncmp_mutex);
+
+	printk(KERN_ERR "axfs: error %d while decompressing!\n", err);
+	printk(KERN_ERR "%p(%d)->%p(%d)\n", src, srclen, dst, dstlen);
+	return 0;
+}
+
+int __init axfs_uncompress_init(void)
+{
+
+	stream.workspace = vmalloc(zlib_inflate_workspacesize());
+	if (!stream.workspace)
+		return -ENOMEM;
+	stream.next_in = NULL;
+	stream.avail_in = 0;
+	zlib_inflateInit(&stream);
+
+	return 0;
+}
+
+int axfs_uncompress_exit(void)
+{
+	zlib_inflateEnd(&stream);
+	vfree(stream.workspace);
+	return 0;
+}