1 /*
2 * uncompress.c
3 *
4 * (C) Copyright 1999 Linus Torvalds
5 *
6 * cramfs interfaces to the uncompression library. There's really just
7 * three entrypoints:
8 *
9 * - cramfs_uncompress_init() - called to initialize the thing.
10 * - cramfs_uncompress_exit() - tell me when you're done
11 * - cramfs_uncompress_block() - uncompress a block.
12 *
13 * NOTE NOTE NOTE! The uncompression is entirely single-threaded. We
14 * only have one stream, and we'll initialize it only once even if it
15 * then is used by multiple filesystems.
16 */
17
18 #include <linux/kernel.h>
19
20 #include "inflate/zlib.h"
21
22 static z_stream stream;
23 static int initialized;
24
25 /* Returns length of decompressed data. */
26 int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen)
27 {
28 int err;
29
30 stream.next_in = src;
31 stream.avail_in = srclen;
32
33 stream.next_out = dst;
34 stream.avail_out = dstlen;
35
36 err = cramfs_inflateReset(&stream);
37 if (err != Z_OK) {
38 printk("cramfs_inflateReset error %d\n", err);
39 cramfs_inflateEnd(&stream);
40 cramfs_inflateInit(&stream);
41 }
42
43 err = cramfs_inflate(&stream, Z_FINISH);
44 if (err != Z_STREAM_END)
45 goto err;
46 return stream.total_out;
47
48 err:
49 printk("Error %d while decompressing!\n", err);
50 printk("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen);
51 return 0;
52 }
53
54 int cramfs_uncompress_init(void)
55 {
56 if (!initialized++) {
57 stream.next_in = NULL;
58 stream.avail_in = 0;
59 cramfs_inflateInit(&stream);
60 }
61 return 0;
62 }
63
64 int cramfs_uncompress_exit(void)
65 {
66 if (!--initialized)
67 cramfs_inflateEnd(&stream);
68 return 0;
69 }
70
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