uncompress.c 1.69 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
/*
 * uncompress.c
 *
 * (C) Copyright 1999 Linus Torvalds
 *
 * cramfs interfaces to the uncompression library. There's really just
 * three entrypoints:
 *
 *  - cramfs_uncompress_init() - called to initialize the thing.
 *  - cramfs_uncompress_exit() - tell me when you're done
 *  - cramfs_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/kernel.h>
#include <linux/errno.h>
#include <linux/vmalloc.h>
#include <linux/zlib.h>
22
#include <linux/cramfs_fs.h>
Linus Torvalds's avatar
Linus Torvalds committed
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

static z_stream stream;
static int initialized;

/* Returns length of decompressed data. */
int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen)
{
	int err;

	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("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;
	return stream.total_out;

err:
	printk("Error %d while decompressing!\n", err);
	printk("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen);
53
	return -EIO;
Linus Torvalds's avatar
Linus Torvalds committed
54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70
}

int cramfs_uncompress_init(void)
{
	if (!initialized++) {
		stream.workspace = vmalloc(zlib_inflate_workspacesize());
		if ( !stream.workspace ) {
			initialized = 0;
			return -ENOMEM;
		}
		stream.next_in = NULL;
		stream.avail_in = 0;
		zlib_inflateInit(&stream);
	}
	return 0;
}

71
void cramfs_uncompress_exit(void)
Linus Torvalds's avatar
Linus Torvalds committed
72 73 74 75 76 77
{
	if (!--initialized) {
		zlib_inflateEnd(&stream);
		vfree(stream.workspace);
	}
}