/*
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* fs/logfs/compr.c - compression routines
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*
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* As should be obvious for Linux kernel code, license is GPLv2
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*
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* Copyright (c) 2005-2008 Joern Engel <joern@logfs.org>
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*/
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#include "logfs.h"
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#include <linux/vmalloc.h>
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#include <linux/zlib.h>
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#define COMPR_LEVEL 3
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static DEFINE_MUTEX(compr_mutex);
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static struct z_stream_s stream;
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int logfs_compress(void *in, void *out, size_t inlen, size_t outlen)
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{
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int err, ret;
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ret = -EIO;
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mutex_lock(&compr_mutex);
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err = zlib_deflateInit(&stream, COMPR_LEVEL);
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if (err != Z_OK)
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goto error;
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stream.next_in = in;
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stream.avail_in = inlen;
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stream.total_in = 0;
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stream.next_out = out;
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stream.avail_out = outlen;
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stream.total_out = 0;
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err = zlib_deflate(&stream, Z_FINISH);
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if (err != Z_STREAM_END)
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goto error;
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err = zlib_deflateEnd(&stream);
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if (err != Z_OK)
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goto error;
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if (stream.total_out >= stream.total_in)
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goto error;
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ret = stream.total_out;
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error:
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mutex_unlock(&compr_mutex);
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return ret;
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}
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int logfs_uncompress(void *in, void *out, size_t inlen, size_t outlen)
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{
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int err, ret;
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ret = -EIO;
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mutex_lock(&compr_mutex);
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err = zlib_inflateInit(&stream);
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if (err != Z_OK)
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goto error;
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stream.next_in = in;
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stream.avail_in = inlen;
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stream.total_in = 0;
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stream.next_out = out;
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stream.avail_out = outlen;
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stream.total_out = 0;
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err = zlib_inflate(&stream, Z_FINISH);
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if (err != Z_STREAM_END)
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goto error;
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err = zlib_inflateEnd(&stream);
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if (err != Z_OK)
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goto error;
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ret = 0;
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error:
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mutex_unlock(&compr_mutex);
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return ret;
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}
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int __init logfs_compr_init(void)
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{
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size_t size = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
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zlib_inflate_workspacesize());
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stream.workspace = vmalloc(size);
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if (!stream.workspace)
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return -ENOMEM;
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return 0;
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}
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void logfs_compr_exit(void)
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{
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vfree(stream.workspace);
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}
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