1/* lzo2a_d.ch -- implementation of the LZO2A decompression algorithm 2 3 This file is part of the LZO real-time data compression library. 4 5 Copyright (C) 2011 Markus Franz Xaver Johannes Oberhumer 6 Copyright (C) 2010 Markus Franz Xaver Johannes Oberhumer 7 Copyright (C) 2009 Markus Franz Xaver Johannes Oberhumer 8 Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer 9 Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer 10 Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer 11 Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer 12 Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer 13 Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer 14 Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer 15 Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer 16 Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer 17 Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer 18 Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer 19 Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer 20 Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer 21 All Rights Reserved. 22 23 The LZO library is free software; you can redistribute it and/or 24 modify it under the terms of the GNU General Public License as 25 published by the Free Software Foundation; either version 2 of 26 the License, or (at your option) any later version. 27 28 The LZO library is distributed in the hope that it will be useful, 29 but WITHOUT ANY WARRANTY; without even the implied warranty of 30 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 31 GNU General Public License for more details. 32 33 You should have received a copy of the GNU General Public License 34 along with the LZO library; see the file COPYING. 35 If not, write to the Free Software Foundation, Inc., 36 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 37 38 Markus F.X.J. Oberhumer 39 <markus@oberhumer.com> 40 http://www.oberhumer.com/opensource/lzo/ 41 */ 42 43 44#include "lzo1_d.ch" 45 46 47/*********************************************************************** 48// decompress a block of data. 49************************************************************************/ 50 51#define _NEEDBYTE NEED_IP(1) 52#define _NEXTBYTE (*ip++) 53 54LZO_PUBLIC(int) 55DO_DECOMPRESS ( const lzo_bytep in , lzo_uint in_len, 56 lzo_bytep out, lzo_uintp out_len, 57 lzo_voidp wrkmem ) 58{ 59 register lzo_bytep op; 60 register const lzo_bytep ip; 61 register const lzo_bytep m_pos; 62 63 lzo_uint t; 64 const lzo_bytep const ip_end = in + in_len; 65#if defined(HAVE_ANY_OP) 66 lzo_bytep const op_end = out + *out_len; 67#endif 68 69 lzo_uint32 b = 0; /* bit buffer */ 70 unsigned k = 0; /* bits in bit buffer */ 71 72 LZO_UNUSED(wrkmem); 73 74 op = out; 75 ip = in; 76 77 while (TEST_IP && TEST_OP) 78 { 79 NEEDBITS(1); 80 if (MASKBITS(1) == 0) 81 { 82 DUMPBITS(1); 83 /* a literal */ 84 NEED_IP(1); NEED_OP(1); 85 *op++ = *ip++; 86 continue; 87 } 88 DUMPBITS(1); 89 90 NEEDBITS(1); 91 if (MASKBITS(1) == 0) 92 { 93 DUMPBITS(1); 94 /* a M1 match */ 95 NEEDBITS(2); 96 t = M1_MIN_LEN + (lzo_uint) MASKBITS(2); 97 DUMPBITS(2); 98 NEED_IP(1); NEED_OP(t); 99 m_pos = op - 1 - *ip++; 100 assert(m_pos >= out); assert(m_pos < op); 101 TEST_LB(m_pos); 102 MEMCPY_DS(op,m_pos,t); 103 continue; 104 } 105 DUMPBITS(1); 106 107 NEED_IP(2); 108 t = *ip++; 109 m_pos = op; 110 m_pos -= (t & 31) | (((lzo_uint) *ip++) << 5); 111 t >>= 5; 112 if (t == 0) 113 { 114#if (SWD_N >= 8192) 115 NEEDBITS(1); 116 t = MASKBITS(1); 117 DUMPBITS(1); 118 if (t == 0) 119 t = 10 - 1; 120 else 121 { 122 /* a M3 match */ 123 m_pos -= 8192; /* t << 13 */ 124 t = M3_MIN_LEN - 1; 125 } 126#else 127 t = 10 - 1; 128#endif 129 NEED_IP(1); 130 while (*ip == 0) 131 { 132 t += 255; 133 ip++; 134 NEED_IP(1); 135 } 136 t += *ip++; 137 } 138 else 139 { 140#if defined(LZO_EOF_CODE) 141 if (m_pos == op) 142 goto eof_found; 143#endif 144 t += 2; 145 } 146 assert(m_pos >= out); assert(m_pos < op); 147 TEST_LB(m_pos); 148 NEED_OP(t); 149 MEMCPY_DS(op,m_pos,t); 150 } 151 152 153#if defined(LZO_EOF_CODE) 154#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP) 155 /* no EOF code was found */ 156 *out_len = pd(op, out); 157 return LZO_E_EOF_NOT_FOUND; 158#endif 159 160eof_found: 161 assert(t == 1); 162#endif 163 *out_len = pd(op, out); 164 return (ip == ip_end ? LZO_E_OK : 165 (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN)); 166 167 168#if defined(HAVE_NEED_IP) 169input_overrun: 170 *out_len = pd(op, out); 171 return LZO_E_INPUT_OVERRUN; 172#endif 173 174#if defined(HAVE_NEED_OP) 175output_overrun: 176 *out_len = pd(op, out); 177 return LZO_E_OUTPUT_OVERRUN; 178#endif 179 180#if defined(LZO_TEST_OVERRUN_LOOKBEHIND) 181lookbehind_overrun: 182 *out_len = pd(op, out); 183 return LZO_E_LOOKBEHIND_OVERRUN; 184#endif 185} 186 187 188/* 189vi:ts=4:et 190*/ 191 192