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/*

 * 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>

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);

        return 0;

}

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;

}

int cramfs_uncompress_exit(void)

{

        if (!--initialized) {

                zlib_inflateEnd(&stream);

                vfree(stream.workspace);

        }

        return 0;

}