[2725] | 1 | /* implementation of the LZO1X decompression algorithm
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| 2 |
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| 3 | This file is part of the LZO real-time data compression library.
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| 4 |
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| 5 | Copyright (C) 1996..2008 Markus Franz Xaver Johannes Oberhumer
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| 6 | All Rights Reserved.
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| 7 |
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| 8 | Markus F.X.J. Oberhumer <markus@oberhumer.com>
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| 9 | http://www.oberhumer.com/opensource/lzo/
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| 10 |
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| 11 | The LZO library is free software; you can redistribute it and/or
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| 12 | modify it under the terms of the GNU General Public License as
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| 13 | published by the Free Software Foundation; either version 2 of
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| 14 | the License, or (at your option) any later version.
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| 15 |
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| 16 | The LZO library is distributed in the hope that it will be useful,
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| 17 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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[3232] | 18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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[2725] | 19 | GNU General Public License for more details.
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| 20 |
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| 21 | You should have received a copy of the GNU General Public License
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| 22 | along with the LZO library; see the file COPYING.
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| 23 | If not, write to the Free Software Foundation, Inc.,
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| 24 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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| 25 | */
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| 26 | #include "libbb.h"
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| 27 | #include "liblzo.h"
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| 28 |
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| 29 | /***********************************************************************
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| 30 | // decompress a block of data.
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| 31 | ************************************************************************/
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| 32 | /* safe decompression with overrun testing */
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| 33 | int lzo1x_decompress_safe(const uint8_t* in, unsigned in_len,
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| 34 | uint8_t* out, unsigned* out_len,
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| 35 | void* wrkmem UNUSED_PARAM)
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| 36 | {
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| 37 | register uint8_t* op;
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| 38 | register const uint8_t* ip;
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| 39 | register unsigned t;
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| 40 | #if defined(COPY_DICT)
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| 41 | unsigned m_off;
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| 42 | const uint8_t* dict_end;
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| 43 | #else
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| 44 | register const uint8_t* m_pos = NULL; /* possibly not needed */
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| 45 | #endif
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| 46 | const uint8_t* const ip_end = in + in_len;
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| 47 | #if defined(HAVE_ANY_OP)
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| 48 | uint8_t* const op_end = out + *out_len;
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| 49 | #endif
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| 50 | #if defined(LZO1Z)
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| 51 | unsigned last_m_off = 0;
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| 52 | #endif
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| 53 |
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| 54 | // LZO_UNUSED(wrkmem);
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| 55 |
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| 56 | #if defined(COPY_DICT)
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| 57 | if (dict) {
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| 58 | if (dict_len > M4_MAX_OFFSET) {
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| 59 | dict += dict_len - M4_MAX_OFFSET;
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| 60 | dict_len = M4_MAX_OFFSET;
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| 61 | }
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| 62 | dict_end = dict + dict_len;
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| 63 | } else {
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| 64 | dict_len = 0;
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| 65 | dict_end = NULL;
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| 66 | }
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| 67 | #endif /* COPY_DICT */
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| 68 |
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| 69 | *out_len = 0;
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| 70 |
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| 71 | op = out;
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| 72 | ip = in;
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| 73 |
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| 74 | if (*ip > 17) {
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| 75 | t = *ip++ - 17;
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| 76 | if (t < 4)
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| 77 | goto match_next;
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| 78 | assert(t > 0); NEED_OP(t); NEED_IP(t+1);
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| 79 | do *op++ = *ip++; while (--t > 0);
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| 80 | goto first_literal_run;
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| 81 | }
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| 82 |
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| 83 | while (TEST_IP && TEST_OP) {
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| 84 | t = *ip++;
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| 85 | if (t >= 16)
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| 86 | goto match;
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| 87 | /* a literal run */
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| 88 | if (t == 0) {
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| 89 | NEED_IP(1);
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| 90 | while (*ip == 0) {
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| 91 | t += 255;
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| 92 | ip++;
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| 93 | NEED_IP(1);
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| 94 | }
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| 95 | t += 15 + *ip++;
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| 96 | }
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| 97 | /* copy literals */
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| 98 | assert(t > 0);
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| 99 | NEED_OP(t+3);
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| 100 | NEED_IP(t+4);
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| 101 | #if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
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| 102 | # if !defined(LZO_UNALIGNED_OK_4)
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| 103 | if (PTR_ALIGNED2_4(op, ip))
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| 104 | # endif
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| 105 | {
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| 106 | COPY4(op, ip);
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| 107 | op += 4;
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| 108 | ip += 4;
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| 109 | if (--t > 0) {
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| 110 | if (t >= 4) {
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| 111 | do {
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| 112 | COPY4(op, ip);
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| 113 | op += 4;
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| 114 | ip += 4;
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| 115 | t -= 4;
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| 116 | } while (t >= 4);
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| 117 | if (t > 0)
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| 118 | do *op++ = *ip++; while (--t > 0);
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| 119 | } else {
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| 120 | do *op++ = *ip++; while (--t > 0);
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| 121 | }
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| 122 | }
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| 123 | }
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| 124 | # if !defined(LZO_UNALIGNED_OK_4)
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| 125 | else
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| 126 | # endif
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| 127 | #endif
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| 128 | #if !defined(LZO_UNALIGNED_OK_4)
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| 129 | {
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| 130 | *op++ = *ip++;
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| 131 | *op++ = *ip++;
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| 132 | *op++ = *ip++;
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| 133 | do *op++ = *ip++; while (--t > 0);
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| 134 | }
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| 135 | #endif
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| 136 |
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| 137 | first_literal_run:
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| 138 | t = *ip++;
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| 139 | if (t >= 16)
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| 140 | goto match;
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| 141 | #if defined(COPY_DICT)
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| 142 | #if defined(LZO1Z)
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| 143 | m_off = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
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| 144 | last_m_off = m_off;
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| 145 | #else
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| 146 | m_off = (1 + M2_MAX_OFFSET) + (t >> 2) + (*ip++ << 2);
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| 147 | #endif
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| 148 | NEED_OP(3);
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| 149 | t = 3; COPY_DICT(t,m_off)
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| 150 | #else /* !COPY_DICT */
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| 151 | #if defined(LZO1Z)
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| 152 | t = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
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| 153 | m_pos = op - t;
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| 154 | last_m_off = t;
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| 155 | #else
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| 156 | m_pos = op - (1 + M2_MAX_OFFSET);
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| 157 | m_pos -= t >> 2;
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| 158 | m_pos -= *ip++ << 2;
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| 159 | #endif
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| 160 | TEST_LB(m_pos); NEED_OP(3);
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| 161 | *op++ = *m_pos++;
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| 162 | *op++ = *m_pos++;
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| 163 | *op++ = *m_pos;
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| 164 | #endif /* COPY_DICT */
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| 165 | goto match_done;
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| 166 |
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| 167 | /* handle matches */
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| 168 | do {
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| 169 | match:
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| 170 | if (t >= 64) { /* a M2 match */
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| 171 | #if defined(COPY_DICT)
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| 172 | #if defined(LZO1X)
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| 173 | m_off = 1 + ((t >> 2) & 7) + (*ip++ << 3);
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| 174 | t = (t >> 5) - 1;
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| 175 | #elif defined(LZO1Y)
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| 176 | m_off = 1 + ((t >> 2) & 3) + (*ip++ << 2);
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| 177 | t = (t >> 4) - 3;
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| 178 | #elif defined(LZO1Z)
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| 179 | m_off = t & 0x1f;
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| 180 | if (m_off >= 0x1c)
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| 181 | m_off = last_m_off;
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| 182 | else {
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| 183 | m_off = 1 + (m_off << 6) + (*ip++ >> 2);
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| 184 | last_m_off = m_off;
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| 185 | }
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| 186 | t = (t >> 5) - 1;
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| 187 | #endif
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| 188 | #else /* !COPY_DICT */
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| 189 | #if defined(LZO1X)
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| 190 | m_pos = op - 1;
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| 191 | m_pos -= (t >> 2) & 7;
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| 192 | m_pos -= *ip++ << 3;
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| 193 | t = (t >> 5) - 1;
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| 194 | #elif defined(LZO1Y)
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| 195 | m_pos = op - 1;
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| 196 | m_pos -= (t >> 2) & 3;
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| 197 | m_pos -= *ip++ << 2;
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| 198 | t = (t >> 4) - 3;
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| 199 | #elif defined(LZO1Z)
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| 200 | {
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| 201 | unsigned off = t & 0x1f;
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| 202 | m_pos = op;
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| 203 | if (off >= 0x1c) {
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| 204 | assert(last_m_off > 0);
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| 205 | m_pos -= last_m_off;
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| 206 | } else {
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| 207 | off = 1 + (off << 6) + (*ip++ >> 2);
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| 208 | m_pos -= off;
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| 209 | last_m_off = off;
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| 210 | }
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| 211 | }
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| 212 | t = (t >> 5) - 1;
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| 213 | #endif
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| 214 | TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
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| 215 | goto copy_match;
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| 216 | #endif /* COPY_DICT */
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| 217 | }
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| 218 | else if (t >= 32) { /* a M3 match */
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| 219 | t &= 31;
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| 220 | if (t == 0) {
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| 221 | NEED_IP(1);
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| 222 | while (*ip == 0) {
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| 223 | t += 255;
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| 224 | ip++;
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| 225 | NEED_IP(1);
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| 226 | }
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| 227 | t += 31 + *ip++;
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| 228 | }
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| 229 | #if defined(COPY_DICT)
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| 230 | #if defined(LZO1Z)
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| 231 | m_off = 1 + (ip[0] << 6) + (ip[1] >> 2);
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| 232 | last_m_off = m_off;
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| 233 | #else
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| 234 | m_off = 1 + (ip[0] >> 2) + (ip[1] << 6);
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| 235 | #endif
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| 236 | #else /* !COPY_DICT */
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| 237 | #if defined(LZO1Z)
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| 238 | {
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| 239 | unsigned off = 1 + (ip[0] << 6) + (ip[1] >> 2);
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| 240 | m_pos = op - off;
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| 241 | last_m_off = off;
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| 242 | }
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| 243 | #elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN)
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| 244 | m_pos = op - 1;
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| 245 | m_pos -= (* (const lzo_ushortp) ip) >> 2;
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| 246 | #else
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| 247 | m_pos = op - 1;
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| 248 | m_pos -= (ip[0] >> 2) + (ip[1] << 6);
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| 249 | #endif
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| 250 | #endif /* COPY_DICT */
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| 251 | ip += 2;
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| 252 | }
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| 253 | else if (t >= 16) { /* a M4 match */
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| 254 | #if defined(COPY_DICT)
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| 255 | m_off = (t & 8) << 11;
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| 256 | #else /* !COPY_DICT */
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| 257 | m_pos = op;
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| 258 | m_pos -= (t & 8) << 11;
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| 259 | #endif /* COPY_DICT */
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| 260 | t &= 7;
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| 261 | if (t == 0) {
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| 262 | NEED_IP(1);
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| 263 | while (*ip == 0) {
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| 264 | t += 255;
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| 265 | ip++;
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| 266 | NEED_IP(1);
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| 267 | }
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| 268 | t += 7 + *ip++;
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| 269 | }
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| 270 | #if defined(COPY_DICT)
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| 271 | #if defined(LZO1Z)
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| 272 | m_off += (ip[0] << 6) + (ip[1] >> 2);
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| 273 | #else
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| 274 | m_off += (ip[0] >> 2) + (ip[1] << 6);
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| 275 | #endif
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| 276 | ip += 2;
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| 277 | if (m_off == 0)
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| 278 | goto eof_found;
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| 279 | m_off += 0x4000;
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| 280 | #if defined(LZO1Z)
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| 281 | last_m_off = m_off;
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| 282 | #endif
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| 283 | #else /* !COPY_DICT */
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| 284 | #if defined(LZO1Z)
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| 285 | m_pos -= (ip[0] << 6) + (ip[1] >> 2);
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| 286 | #elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN)
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| 287 | m_pos -= (* (const lzo_ushortp) ip) >> 2;
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| 288 | #else
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| 289 | m_pos -= (ip[0] >> 2) + (ip[1] << 6);
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| 290 | #endif
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| 291 | ip += 2;
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| 292 | if (m_pos == op)
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| 293 | goto eof_found;
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| 294 | m_pos -= 0x4000;
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| 295 | #if defined(LZO1Z)
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| 296 | last_m_off = pd((const uint8_t*)op, m_pos);
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| 297 | #endif
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| 298 | #endif /* COPY_DICT */
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| 299 | }
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| 300 | else { /* a M1 match */
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| 301 | #if defined(COPY_DICT)
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| 302 | #if defined(LZO1Z)
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| 303 | m_off = 1 + (t << 6) + (*ip++ >> 2);
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| 304 | last_m_off = m_off;
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| 305 | #else
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| 306 | m_off = 1 + (t >> 2) + (*ip++ << 2);
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| 307 | #endif
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| 308 | NEED_OP(2);
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| 309 | t = 2; COPY_DICT(t,m_off)
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| 310 | #else /* !COPY_DICT */
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| 311 | #if defined(LZO1Z)
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| 312 | t = 1 + (t << 6) + (*ip++ >> 2);
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| 313 | m_pos = op - t;
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| 314 | last_m_off = t;
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| 315 | #else
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| 316 | m_pos = op - 1;
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| 317 | m_pos -= t >> 2;
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| 318 | m_pos -= *ip++ << 2;
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| 319 | #endif
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| 320 | TEST_LB(m_pos); NEED_OP(2);
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| 321 | *op++ = *m_pos++;
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| 322 | *op++ = *m_pos;
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| 323 | #endif /* COPY_DICT */
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| 324 | goto match_done;
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| 325 | }
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| 326 |
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| 327 | /* copy match */
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| 328 | #if defined(COPY_DICT)
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| 329 |
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| 330 | NEED_OP(t+3-1);
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| 331 | t += 3-1; COPY_DICT(t,m_off)
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| 332 |
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| 333 | #else /* !COPY_DICT */
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| 334 |
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| 335 | TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
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| 336 | #if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
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| 337 | # if !defined(LZO_UNALIGNED_OK_4)
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| 338 | if (t >= 2 * 4 - (3 - 1) && PTR_ALIGNED2_4(op,m_pos)) {
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| 339 | assert((op - m_pos) >= 4); /* both pointers are aligned */
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| 340 | # else
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| 341 | if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
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| 342 | # endif
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| 343 | COPY4(op,m_pos);
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| 344 | op += 4; m_pos += 4; t -= 4 - (3 - 1);
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| 345 | do {
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| 346 | COPY4(op,m_pos);
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| 347 | op += 4; m_pos += 4; t -= 4;
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| 348 | } while (t >= 4);
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| 349 | if (t > 0)
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| 350 | do *op++ = *m_pos++; while (--t > 0);
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| 351 | }
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| 352 | else
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| 353 | #endif
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| 354 | {
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| 355 | copy_match:
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| 356 | *op++ = *m_pos++; *op++ = *m_pos++;
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| 357 | do *op++ = *m_pos++; while (--t > 0);
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| 358 | }
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| 359 |
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| 360 | #endif /* COPY_DICT */
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| 361 |
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| 362 | match_done:
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| 363 | #if defined(LZO1Z)
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| 364 | t = ip[-1] & 3;
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| 365 | #else
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| 366 | t = ip[-2] & 3;
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| 367 | #endif
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| 368 | if (t == 0)
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| 369 | break;
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| 370 |
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| 371 | /* copy literals */
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| 372 | match_next:
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| 373 | assert(t > 0);
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| 374 | assert(t < 4);
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| 375 | NEED_OP(t);
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| 376 | NEED_IP(t+1);
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| 377 | #if 0
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| 378 | do *op++ = *ip++; while (--t > 0);
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| 379 | #else
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| 380 | *op++ = *ip++;
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| 381 | if (t > 1) {
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| 382 | *op++ = *ip++;
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| 383 | if (t > 2)
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| 384 | *op++ = *ip++;
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| 385 | }
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| 386 | #endif
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| 387 | t = *ip++;
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| 388 | } while (TEST_IP && TEST_OP);
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| 389 | }
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| 390 |
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| 391 | //#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP)
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| 392 | /* no EOF code was found */
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| 393 | *out_len = pd(op, out);
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| 394 | return LZO_E_EOF_NOT_FOUND;
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| 395 | //#endif
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| 396 |
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| 397 | eof_found:
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| 398 | assert(t == 1);
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| 399 | *out_len = pd(op, out);
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| 400 | return (ip == ip_end ? LZO_E_OK :
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| 401 | (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
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| 402 |
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| 403 | //#if defined(HAVE_NEED_IP)
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| 404 | input_overrun:
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| 405 | *out_len = pd(op, out);
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| 406 | return LZO_E_INPUT_OVERRUN;
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| 407 | //#endif
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| 408 |
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| 409 | //#if defined(HAVE_NEED_OP)
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| 410 | output_overrun:
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| 411 | *out_len = pd(op, out);
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| 412 | return LZO_E_OUTPUT_OVERRUN;
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| 413 | //#endif
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| 414 |
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| 415 | //#if defined(LZO_TEST_OVERRUN_LOOKBEHIND)
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| 416 | lookbehind_overrun:
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| 417 | *out_len = pd(op, out);
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| 418 | return LZO_E_LOOKBEHIND_OVERRUN;
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| 419 | //#endif
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| 420 | }
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