| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 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 | |
| 34 | struct gunzip_state { |
| 35 | z_stream s; |
| 36 | char scratch[46912]; |
| 37 | }; |
| 38 | |
| 39 | void gunzip_start(struct gunzip_state *state, void *src, int srclen); |
| 40 | int gunzip_partial(struct gunzip_state *state, void *dst, int dstlen); |
| 41 | void gunzip_exactly(struct gunzip_state *state, void *dst, int len); |
| 42 | void gunzip_discard(struct gunzip_state *state, int len); |
| 43 | int gunzip_finish(struct gunzip_state *state, void *dst, int len); |
| 44 | |
| 45 | #endif /* _PPC_BOOT_GUNZIP_UTIL_H_ */ |