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/*

 * JFFS2 -- Journalling Flash File System, Version 2.

 *

 * Copyright (C) 2001-2003 Red Hat, Inc.

 *

 * Created by David Woodhouse <dwmw2@infradead.org>

 *

 * For licensing information, see the file 'LICENCE' in this directory.

 *

 * $Id: compr_zlib.c,v 1.31 2005/05/20 19:30:06 gleixner Exp $

 *

 */

#if !defined(__KERNEL__) && !defined(__ECOS)

#error "The userspace support got too messy and was removed. Update your mkfs.jffs2"

#endif

#include <linux/config.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/slab.h>

#include <linux/zlib.h>

#include <linux/zutil.h>

#include "nodelist.h"

#include "compr.h"

        /* Plan: call deflate() with avail_in == *sourcelen,

                avail_out = *dstlen - 12 and flush == Z_FINISH.

                If it doesn't manage to finish, call it again with

                avail_in == 0 and avail_out set to the remaining 12

                bytes for it to clean up.

           Q: Is 12 bytes sufficient?

        */

#define STREAM_END_SPACE 12

static DECLARE_MUTEX(deflate_sem);

static DECLARE_MUTEX(inflate_sem);

static z_stream inf_strm, def_strm;

#ifdef __KERNEL__ /* Linux-only */

#include <linux/vmalloc.h>

#include <linux/init.h>

static int __init alloc_workspaces(void)

{

        def_strm.workspace = vmalloc(zlib_deflate_workspacesize());

        if (!def_strm.workspace) {

                printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize());

                return -ENOMEM;

        }

        D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize()));

        inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());

        if (!inf_strm.workspace) {

                printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());

                vfree(def_strm.workspace);

                return -ENOMEM;

        }

        D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));

        return 0;

}

static void free_workspaces(void)

{

        vfree(def_strm.workspace);

        vfree(inf_strm.workspace);

}

#else

#define alloc_workspaces() (0)

#define free_workspaces() do { } while(0)

#endif /* __KERNEL__ */

static int jffs2_zlib_compress(unsigned char *data_in,

                               unsigned char *cpage_out,

                               uint32_t *sourcelen, uint32_t *dstlen,

                               void *model)

{

        int ret;

        if (*dstlen <= STREAM_END_SPACE)

                return -1;

        down(&deflate_sem);

        if (Z_OK != zlib_deflateInit(&def_strm, 3)) {

                printk(KERN_WARNING "deflateInit failed\n");

                up(&deflate_sem);

                return -1;

        }

        def_strm.next_in = data_in;

        def_strm.total_in = 0;

        def_strm.next_out = cpage_out;

        def_strm.total_out = 0;

        while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {

                def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);

                def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);

                D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",

                          def_strm.avail_in, def_strm.avail_out));

                ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);

                D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",

                          def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));

                if (ret != Z_OK) {

                        D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));

                        zlib_deflateEnd(&def_strm);

                        up(&deflate_sem);

                        return -1;

                }

        }

        def_strm.avail_out += STREAM_END_SPACE;

        def_strm.avail_in = 0;

        ret = zlib_deflate(&def_strm, Z_FINISH);

        zlib_deflateEnd(&def_strm);

        if (ret != Z_STREAM_END) {

                D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));

                ret = -1;

                goto out;

        }

        if (def_strm.total_out >= def_strm.total_in) {

                D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",

                          def_strm.total_in, def_strm.total_out));

                ret = -1;

                goto out;

        }

        D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",

                  def_strm.total_in, def_strm.total_out));

        *dstlen = def_strm.total_out;

        *sourcelen = def_strm.total_in;

        ret = 0;

 out:

        up(&deflate_sem);

        return ret;

}

static int jffs2_zlib_decompress(unsigned char *data_in,

                                 unsigned char *cpage_out,

                                 uint32_t srclen, uint32_t destlen,

                                 void *model)

{

        int ret;

        int wbits = MAX_WBITS;

        down(&inflate_sem);

        inf_strm.next_in = data_in;

        inf_strm.avail_in = srclen;

        inf_strm.total_in = 0;

        inf_strm.next_out = cpage_out;

        inf_strm.avail_out = destlen;

        inf_strm.total_out = 0;

        /* If it's deflate, and it's got no preset dictionary, then

           we can tell zlib to skip the adler32 check. */

        if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&

            ((data_in[0] & 0x0f) == Z_DEFLATED) &&

            !(((data_in[0]<<8) + data_in[1]) % 31)) {

                D2(printk(KERN_DEBUG "inflate skipping adler32\n"));

                wbits = -((data_in[0] >> 4) + 8);

                inf_strm.next_in += 2;

                inf_strm.avail_in -= 2;

        } else {

                /* Let this remain D1 for now -- it should never happen */

                D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));

        }

        if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {

                printk(KERN_WARNING "inflateInit failed\n");

                up(&inflate_sem);

                return 1;

        }

        while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)

                ;

        if (ret != Z_STREAM_END) {

                printk(KERN_NOTICE "inflate returned %d\n", ret);

        }

        zlib_inflateEnd(&inf_strm);

        up(&inflate_sem);

        return 0;

}

static struct jffs2_compressor jffs2_zlib_comp = {

    .priority = JFFS2_ZLIB_PRIORITY,

    .name = "zlib",

    .compr = JFFS2_COMPR_ZLIB,

    .compress = &jffs2_zlib_compress,

    .decompress = &jffs2_zlib_decompress,

#ifdef JFFS2_ZLIB_DISABLED

    .disabled = 1,

#else

    .disabled = 0,

#endif

};

int __init jffs2_zlib_init(void)

{

    int ret;

    ret = alloc_workspaces();

    if (ret)

        return ret;

    ret = jffs2_register_compressor(&jffs2_zlib_comp);

    if (ret)

        free_workspaces();

    return ret;

}

void jffs2_zlib_exit(void)

{

    jffs2_unregister_compressor(&jffs2_zlib_comp);

    free_workspaces();

}