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d1d7e2689d
The vast majority of these changes are in Linux specific code. They are the result of not having an automated style checker to validate the code when it was originally written. Others were caused when the common code was slightly adjusted for Linux. This patch contains no functional changes. It only refreshes the code to conform to style guide. Everyone submitting patches for inclusion upstream should now run 'make checkstyle' and resolve any warning prior to opening a pull request. The automated builders have been updated to fail a build if when 'make checkstyle' detects an issue. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #1821
132 lines
3.8 KiB
C
132 lines
3.8 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
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*/
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/*
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* We keep our own copy of this algorithm for 3 main reasons:
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* 1. If we didn't, anyone modifying common/os/compress.c would
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* directly break our on disk format
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* 2. Our version of lzjb does not have a number of checks that the
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* common/os version needs and uses
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* 3. We initialize the lempel to ensure deterministic results,
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* so that identical blocks can always be deduplicated.
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* In particular, we are adding the "feature" that compress() can
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* take a destination buffer size and returns the compressed length, or the
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* source length if compression would overflow the destination buffer.
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*/
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#include <sys/zfs_context.h>
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#define MATCH_BITS 6
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#define MATCH_MIN 3
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#define MATCH_MAX ((1 << MATCH_BITS) + (MATCH_MIN - 1))
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#define OFFSET_MASK ((1 << (16 - MATCH_BITS)) - 1)
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#define LEMPEL_SIZE 1024
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/*ARGSUSED*/
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size_t
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lzjb_compress(void *s_start, void *d_start, size_t s_len, size_t d_len, int n)
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{
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uchar_t *src = s_start;
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uchar_t *dst = d_start;
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uchar_t *cpy;
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uchar_t *copymap = NULL;
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int copymask = 1 << (NBBY - 1);
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int mlen, offset, hash;
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uint16_t *hp;
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uint16_t *lempel;
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lempel = kmem_zalloc(LEMPEL_SIZE * sizeof (uint16_t), KM_PUSHPAGE);
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while (src < (uchar_t *)s_start + s_len) {
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if ((copymask <<= 1) == (1 << NBBY)) {
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if (dst >= (uchar_t *)d_start + d_len - 1 - 2 * NBBY) {
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kmem_free(lempel,
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LEMPEL_SIZE*sizeof (uint16_t));
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return (s_len);
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}
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copymask = 1;
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copymap = dst;
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*dst++ = 0;
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}
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if (src > (uchar_t *)s_start + s_len - MATCH_MAX) {
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*dst++ = *src++;
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continue;
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}
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hash = (src[0] << 16) + (src[1] << 8) + src[2];
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hash += hash >> 9;
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hash += hash >> 5;
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hp = &lempel[hash & (LEMPEL_SIZE - 1)];
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offset = (intptr_t)(src - *hp) & OFFSET_MASK;
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*hp = (uint16_t)(uintptr_t)src;
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cpy = src - offset;
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if (cpy >= (uchar_t *)s_start && cpy != src &&
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src[0] == cpy[0] && src[1] == cpy[1] && src[2] == cpy[2]) {
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*copymap |= copymask;
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for (mlen = MATCH_MIN; mlen < MATCH_MAX; mlen++)
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if (src[mlen] != cpy[mlen])
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break;
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*dst++ = ((mlen - MATCH_MIN) << (NBBY - MATCH_BITS)) |
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(offset >> NBBY);
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*dst++ = (uchar_t)offset;
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src += mlen;
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} else {
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*dst++ = *src++;
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}
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}
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kmem_free(lempel, LEMPEL_SIZE * sizeof (uint16_t));
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return (dst - (uchar_t *)d_start);
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}
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/*ARGSUSED*/
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int
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lzjb_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len, int n)
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{
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uchar_t *src = s_start;
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uchar_t *dst = d_start;
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uchar_t *d_end = (uchar_t *)d_start + d_len;
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uchar_t *cpy;
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uchar_t copymap = 0;
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int copymask = 1 << (NBBY - 1);
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while (dst < d_end) {
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if ((copymask <<= 1) == (1 << NBBY)) {
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copymask = 1;
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copymap = *src++;
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}
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if (copymap & copymask) {
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int mlen = (src[0] >> (NBBY - MATCH_BITS)) + MATCH_MIN;
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int offset = ((src[0] << NBBY) | src[1]) & OFFSET_MASK;
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src += 2;
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if ((cpy = dst - offset) < (uchar_t *)d_start)
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return (-1);
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while (--mlen >= 0 && dst < d_end)
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*dst++ = *cpy++;
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} else {
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*dst++ = *src++;
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}
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}
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return (0);
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}
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