1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 /* 30 * This is stolen from common/os/compress.c and will be removed once 31 * our changes have made it into the on10 source base. 32 * 33 * In particular, we are adding the "feature" that compress() can 34 * take a destination buffer size and return -1 if the data will not 35 * compress to d_len or less. 36 */ 37 38 #include <sys/types.h> 39 40 #define MATCH_BITS 6 41 #define MATCH_MIN 3 42 #define MATCH_MAX ((1 << MATCH_BITS) + (MATCH_MIN - 1)) 43 #define OFFSET_MASK ((1 << (16 - MATCH_BITS)) - 1) 44 #define LEMPEL_SIZE 256 45 46 size_t 47 lzjb_compress(void *s_start, void *d_start, size_t s_len, size_t d_len) 48 { 49 uchar_t *src = s_start; 50 uchar_t *dst = d_start; 51 uchar_t *cpy, *copymap; 52 int copymask = 1 << (NBBY - 1); 53 int mlen, offset; 54 uint16_t *hp; 55 uint16_t lempel[LEMPEL_SIZE]; /* uninitialized; see above */ 56 57 while (src < (uchar_t *)s_start + s_len) { 58 if ((copymask <<= 1) == (1 << NBBY)) { 59 if (dst >= (uchar_t *)d_start + d_len - 1 - 2 * NBBY) { 60 if (d_len != s_len) 61 return (s_len); 62 mlen = s_len; 63 for (src = s_start, dst = d_start; mlen; mlen--) 64 *dst++ = *src++; 65 return (s_len); 66 } 67 copymask = 1; 68 copymap = dst; 69 *dst++ = 0; 70 } 71 if (src > (uchar_t *)s_start + s_len - MATCH_MAX) { 72 *dst++ = *src++; 73 continue; 74 } 75 hp = &lempel[((src[0] + 13) ^ (src[1] - 13) ^ src[2]) & 76 (LEMPEL_SIZE - 1)]; 77 offset = (intptr_t)(src - *hp) & OFFSET_MASK; 78 *hp = (uint16_t)(uintptr_t)src; 79 cpy = src - offset; 80 if (cpy >= (uchar_t *)s_start && cpy != src && 81 src[0] == cpy[0] && src[1] == cpy[1] && src[2] == cpy[2]) { 82 *copymap |= copymask; 83 for (mlen = MATCH_MIN; mlen < MATCH_MAX; mlen++) 84 if (src[mlen] != cpy[mlen]) 85 break; 86 *dst++ = ((mlen - MATCH_MIN) << (NBBY - MATCH_BITS)) | 87 (offset >> NBBY); 88 *dst++ = (uchar_t)offset; 89 src += mlen; 90 } else { 91 *dst++ = *src++; 92 } 93 } 94 return (dst - (uchar_t *)d_start); 95 } 96 97 /*ARGSUSED*/ 98 int 99 lzjb_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len) 100 { 101 uchar_t *src = s_start; 102 uchar_t *dst = d_start; 103 uchar_t *d_end = (uchar_t *)d_start + d_len; 104 uchar_t *cpy, copymap; 105 int copymask = 1 << (NBBY - 1); 106 107 while (dst < d_end) { 108 if ((copymask <<= 1) == (1 << NBBY)) { 109 copymask = 1; 110 copymap = *src++; 111 } 112 if (copymap & copymask) { 113 int mlen = (src[0] >> (NBBY - MATCH_BITS)) + MATCH_MIN; 114 int offset = ((src[0] << NBBY) | src[1]) & OFFSET_MASK; 115 src += 2; 116 if ((cpy = dst - offset) < (uchar_t *)d_start) 117 return (-1); 118 while (--mlen >= 0 && dst < d_end) 119 *dst++ = *cpy++; 120 } else { 121 *dst++ = *src++; 122 } 123 } 124 return (0); 125 } 126