FreeBSD ZFS
The Zettabyte File System
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00001 /* 00002 * CDDL HEADER START 00003 * 00004 * The contents of this file are subject to the terms of the 00005 * Common Development and Distribution License (the "License"). 00006 * You may not use this file except in compliance with the License. 00007 * 00008 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 00009 * or http://www.opensolaris.org/os/licensing. 00010 * See the License for the specific language governing permissions 00011 * and limitations under the License. 00012 * 00013 * When distributing Covered Code, include this CDDL HEADER in each 00014 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 00015 * If applicable, add the following below this CDDL HEADER, with the 00016 * fields enclosed by brackets "[]" replaced with your own identifying 00017 * information: Portions Copyright [yyyy] [name of copyright owner] 00018 * 00019 * CDDL HEADER END 00020 */ 00021 00022 /* 00023 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 00024 * Use is subject to license terms. 00025 */ 00026 00034 #include <sys/types.h> 00035 #include <sys/sysmacros.h> 00036 00037 size_t 00038 zle_compress(void *s_start, void *d_start, size_t s_len, size_t d_len, int n) 00039 { 00040 uchar_t *src = s_start; 00041 uchar_t *dst = d_start; 00042 uchar_t *s_end = src + s_len; 00043 uchar_t *d_end = dst + d_len; 00044 00045 while (src < s_end && dst < d_end - 1) { 00046 uchar_t *first = src; 00047 uchar_t *len = dst++; 00048 if (src[0] == 0) { 00049 uchar_t *last = src + (256 - n); 00050 while (src < MIN(last, s_end) && src[0] == 0) 00051 src++; 00052 *len = src - first - 1 + n; 00053 } else { 00054 uchar_t *last = src + n; 00055 if (d_end - dst < n) 00056 break; 00057 while (src < MIN(last, s_end) - 1 && (src[0] | src[1])) 00058 *dst++ = *src++; 00059 if (src[0]) 00060 *dst++ = *src++; 00061 *len = src - first - 1; 00062 } 00063 } 00064 return (src == s_end ? dst - (uchar_t *)d_start : s_len); 00065 } 00066 00067 int 00068 zle_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len, int n) 00069 { 00070 uchar_t *src = s_start; 00071 uchar_t *dst = d_start; 00072 uchar_t *s_end = src + s_len; 00073 uchar_t *d_end = dst + d_len; 00074 00075 while (src < s_end && dst < d_end) { 00076 int len = 1 + *src++; 00077 if (len <= n) { 00078 while (len-- != 0) 00079 *dst++ = *src++; 00080 } else { 00081 len -= n; 00082 while (len-- != 0) 00083 *dst++ = 0; 00084 } 00085 } 00086 return (dst == d_end ? 0 : -1); 00087 }