LXR linux/arch/powerpc/boot/gunzip

   1/*
   2 * Decompression convenience functions
   3 *
   4 * Copyright 2007 David Gibson, IBM Corporation.
   5 *
   6 * This file is licensed under the terms of the GNU General Public
   7 * License version 2.  This program is licensed "as is" without any
   8 * warranty of any kind, whether express or implied.
   9 */
  10#ifndef _PPC_BOOT_GUNZIP_UTIL_H_
  11#define _PPC_BOOT_GUNZIP_UTIL_H_
  12
  13#include "zlib.h"
  14
  15/*
  16 * These functions are designed to make life easy for decompressing
  17 * kernel images, initrd images or any other gzip compressed image,
  18 * particularly if its useful to decompress part of the image (e.g. to
  19 * examine headers) before decompressing the remainder.
  20 *
  21 * To use:
  22 *     - declare a gunzip_state structure
  23 *     - use gunzip_start() to initialize the state, associating it
  24 *       with a stream of compressed data
  25 *     - use gunzip_partial(), gunzip_exactly() and gunzip_discard()
  26 *       in any combination to extract pieces of data from the stream
  27 *     - Finally use gunzip_finish() to extract the tail of the
  28 *       compressed stream and wind up zlib
  29 */
  30
  31/* scratch space for gunzip; 46912 is from zlib_inflate_workspacesize() */
  32#define GUNZIP_SCRATCH_SIZE     46912
  33
  34struct gunzip_state {
  35        z_stream s;
  36        char scratch[46912];
  37};
  38
  39void gunzip_start(struct gunzip_state *state, void *src, int srclen);
  40int gunzip_partial(struct gunzip_state *state, void *dst, int dstlen);
  41void gunzip_exactly(struct gunzip_state *state, void *dst, int len);
  42void gunzip_discard(struct gunzip_state *state, int len);
  43int gunzip_finish(struct gunzip_state *state, void *dst, int len);
  44
  45#endif /* _PPC_BOOT_GUNZIP_UTIL_H_ */
  46