1 files changed, 45 insertions, 0 deletions
diff --git a/arch/powerpc/boot/gunzip_util.h b/arch/powerpc/boot/gunzip_util.h
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+++ b/arch/powerpc/boot/gunzip_util.h
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+/*
+ * Decompression convenience functions
+ *
+ * Copyright 2007 David Gibson, IBM Corporation.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#ifndef _PPC_BOOT_GUNZIP_UTIL_H_
+#define _PPC_BOOT_GUNZIP_UTIL_H_
+
+#include "zlib.h"
+
+/*
+ * These functions are designed to make life easy for decompressing
+ * kernel images, initrd images or any other gzip compressed image,
+ * particularly if its useful to decompress part of the image (e.g. to
+ * examine headers) before decompressing the remainder.
+ *
+ * To use:
+ *     - declare a gunzip_state structure
+ *     - use gunzip_start() to initialize the state, associating it
+ *       with a stream of compressed data
+ *     - use gunzip_partial(), gunzip_exactly() and gunzip_discard()
+ *       in any combination to extract pieces of data from the stream
+ *     - Finally use gunzip_finish() to extract the tail of the
+ *       compressed stream and wind up zlib
+ */
+
+/* scratch space for gunzip; 46912 is from zlib_inflate_workspacesize() */
+#define GUNZIP_SCRATCH_SIZE	46912
+
+struct gunzip_state {
+	z_stream s;
+	char scratch[46912];
+};
+
+void gunzip_start(struct gunzip_state *state, void *src, int srclen);
+int gunzip_partial(struct gunzip_state *state, void *dst, int dstlen);
+void gunzip_exactly(struct gunzip_state *state, void *dst, int len);
+void gunzip_discard(struct gunzip_state *state, int len);
+int gunzip_finish(struct gunzip_state *state, void *dst, int len);
+
+#endif /* _PPC_BOOT_GUNZIP_UTIL_H_ */