1 /* lzo1b_d.ch -- implementation of the LZO1B decompression algorithm
3 This file is part of the LZO real-time data compression library.
5 Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
6 Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
7 Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
8 Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
9 Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
10 Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
11 Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
12 Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
13 Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
14 Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
15 Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
16 Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
17 Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
20 The LZO library is free software; you can redistribute it and/or
21 modify it under the terms of the GNU General Public License as
22 published by the Free Software Foundation; either version 2 of
23 the License, or (at your option) any later version.
25 The LZO library is distributed in the hope that it will be useful,
26 but WITHOUT ANY WARRANTY; without even the implied warranty of
27 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
28 GNU General Public License for more details.
30 You should have received a copy of the GNU General Public License
31 along with the LZO library; see the file COPYING.
32 If not, write to the Free Software Foundation, Inc.,
33 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
35 Markus F.X.J. Oberhumer
36 <markus@oberhumer.com>
37 http://www.oberhumer.com/opensource/lzo/
44 /***********************************************************************
45 // decompress a block of data.
46 ************************************************************************/
49 DO_DECOMPRESS ( const lzo_bytep in , lzo_uint in_len,
50 lzo_bytep out, lzo_uintp out_len,
53 register lzo_bytep op;
54 register const lzo_bytep ip;
56 register const lzo_bytep m_pos;
58 const lzo_bytep const ip_end = in + in_len;
59 #if defined(HAVE_ANY_OP)
60 lzo_bytep const op_end = out + *out_len;
68 while (TEST_IP && TEST_OP)
70 t = *ip++; /* get marker */
72 if (t < R0MIN) /* a literal run */
74 if (t == 0) /* a R0 literal run */
78 if (t >= R0FAST - R0MIN) /* a long R0 run */
86 t = 256u << ((unsigned) t);
88 /* help the optimizer */
90 do tt <<= 1; while (--t > 0);
95 NEED_IP(t); NEED_OP(t);
96 #if 1 && defined(LZO_UNALIGNED_OK_4)
98 * (lzo_uint32p) (op+0) = * (const lzo_uint32p) (ip+0);
99 * (lzo_uint32p) (op+4) = * (const lzo_uint32p) (ip+4);
108 t += R0MIN; /* a short R0 run */
111 NEED_IP(t); NEED_OP(t);
112 /* copy literal run */
113 #if 1 && defined(LZO_UNALIGNED_OK_4)
117 * (lzo_uint32p) op = * (const lzo_uint32p) ip;
118 op += 4; ip += 4; t -= 4;
120 if (t > 0) do *op++ = *ip++; while (--t > 0);
128 do *op++ = *ip++; while (--t > 0);
135 /* after a literal a match must follow */
136 while (TEST_IP && TEST_OP)
138 t = *ip++; /* get R1 marker */
142 NEED_IP(2); NEED_OP(M2_MIN_LEN + 1);
144 /* R1 match - a M2_MIN_LEN match + 1 byte literal */
145 assert((t & M2O_MASK) == t);
146 m_pos = op - M2_MIN_OFFSET;
147 m_pos -= t | (((lzo_uint) *ip++) << M2O_BITS);
148 assert(m_pos >= out); assert(m_pos < op);
154 #if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP)
161 if (t >= M2_MARKER) /* a M2 match */
163 /* get match offset */
165 m_pos = op - M2_MIN_OFFSET;
166 m_pos -= (t & M2O_MASK) | (((lzo_uint) *ip++) << M2O_BITS);
167 assert(m_pos >= out); assert(m_pos < op);
171 t = (t >> M2O_BITS) - 1;
172 NEED_OP(t + M2_MIN_LEN - 1);
174 MEMCPY_DS(op,m_pos,t);
176 else /* a M3 or M4 match */
180 if (t == 0) /* a M4 match */
189 t += (M4_MIN_LEN - M3_MIN_LEN) + *ip++;
192 /* get match offset */
194 m_pos = op - (M3_MIN_OFFSET - M3_EOF_OFFSET);
195 m_pos -= *ip++ & M3O_MASK;
196 m_pos -= (lzo_uint)(*ip++) << M3O_BITS;
197 #if defined(LZO_EOF_CODE)
203 assert(m_pos >= out); assert(m_pos < op);
204 TEST_LB(m_pos); NEED_OP(t + M3_MIN_LEN - 1);
205 #if defined(LZO_UNALIGNED_OK_4)
206 if (t >= 2 * 4 - (M3_MIN_LEN - 1) && (op - m_pos) >= 4)
208 * (lzo_uint32p) op = * (const lzo_uint32p) m_pos;
209 op += 4; m_pos += 4; t -= 4 - (M3_MIN_LEN - 1);
211 * (lzo_uint32p) op = * (const lzo_uint32p) m_pos;
212 op += 4; m_pos += 4; t -= 4;
214 if (t > 0) do *op++ = *m_pos++; while (--t > 0);
220 MEMCPY_DS(op,m_pos,t);
225 t = ip[-2] >> M3O_BITS;
228 NEED_IP(t); NEED_OP(t);
231 #elif (M3O_BITS == 7)
232 /* optimized version */
233 if (ip[-2] & (1 << M3O_BITS))
235 NEED_IP(1); NEED_OP(1);
244 #if defined(LZO_EOF_CODE)
245 #if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP)
246 /* no EOF code was found */
247 *out_len = pd(op, out);
248 return LZO_E_EOF_NOT_FOUND;
254 *out_len = pd(op, out);
255 return (ip == ip_end ? LZO_E_OK :
256 (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
259 #if defined(HAVE_NEED_IP)
261 *out_len = pd(op, out);
262 return LZO_E_INPUT_OVERRUN;
265 #if defined(HAVE_NEED_OP)
267 *out_len = pd(op, out);
268 return LZO_E_OUTPUT_OVERRUN;
271 #if defined(LZO_TEST_OVERRUN_LOOKBEHIND)
273 *out_len = pd(op, out);
274 return LZO_E_LOOKBEHIND_OVERRUN;