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Diffstat (limited to 'src/lzo1b_d.ch')
| -rw-r--r-- | src/lzo1b_d.ch | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/src/lzo1b_d.ch b/src/lzo1b_d.ch new file mode 100644 index 0000000..fe5f361 --- /dev/null +++ b/src/lzo1b_d.ch @@ -0,0 +1,285 @@ +/* lzo1b_d.ch -- implementation of the LZO1B decompression algorithm + + This file is part of the LZO real-time data compression library. + + Copyright (C) 2011 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2010 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2009 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer + Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer + All Rights Reserved. + + The LZO library is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2 of + the License, or (at your option) any later version. + + The LZO library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with the LZO library; see the file COPYING. + If not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + + Markus F.X.J. Oberhumer + <markus@oberhumer.com> + http://www.oberhumer.com/opensource/lzo/ + */ + + +#include "lzo1_d.ch" + + +/*********************************************************************** +// decompress a block of data. +************************************************************************/ + +LZO_PUBLIC(int) +DO_DECOMPRESS ( const lzo_bytep in , lzo_uint in_len, + lzo_bytep out, lzo_uintp out_len, + lzo_voidp wrkmem ) +{ + register lzo_bytep op; + register const lzo_bytep ip; + register lzo_uint t; + register const lzo_bytep m_pos; + + const lzo_bytep const ip_end = in + in_len; +#if defined(HAVE_ANY_OP) + lzo_bytep const op_end = out + *out_len; +#endif + + LZO_UNUSED(wrkmem); + + op = out; + ip = in; + + while (TEST_IP && TEST_OP) + { + t = *ip++; /* get marker */ + + if (t < R0MIN) /* a literal run */ + { + if (t == 0) /* a R0 literal run */ + { + NEED_IP(1); + t = *ip++; + if (t >= R0FAST - R0MIN) /* a long R0 run */ + { + t -= R0FAST - R0MIN; + if (t == 0) + t = R0FAST; + else + { +#if 0 + t = 256u << ((unsigned) t); +#else + /* help the optimizer */ + lzo_uint tt = 256; + do tt <<= 1; while (--t > 0); + t = tt; +#endif + } + + NEED_IP(t); NEED_OP(t); +#if 1 && defined(LZO_UNALIGNED_OK_4) + do { + UA_COPY32(op+0, ip+0); + UA_COPY32(op+4, ip+4); + op += 8; ip += 8; + t -= 8; + } while (t > 0); +#else + MEMCPY8_DS(op,ip,t); +#endif + continue; + } + t += R0MIN; /* a short R0 run */ + } + + NEED_IP(t); NEED_OP(t); + /* copy literal run */ +#if 1 && defined(LZO_UNALIGNED_OK_4) + if (t >= 4) + { + do { + UA_COPY32(op, ip); + op += 4; ip += 4; t -= 4; + } while (t >= 4); + if (t > 0) do *op++ = *ip++; while (--t > 0); + } + else +#endif + { +#if (M3O_BITS < 7) +literal1: +#endif + do *op++ = *ip++; while (--t > 0); + } + +#if (M3O_BITS == 7) +literal2: +#endif + + /* after a literal a match must follow */ + while (TEST_IP && TEST_OP) + { + t = *ip++; /* get R1 marker */ + if (t >= R0MIN) + goto match; + + NEED_IP(2); NEED_OP(M2_MIN_LEN + 1); + + /* R1 match - a M2_MIN_LEN match + 1 byte literal */ + assert((t & M2O_MASK) == t); + m_pos = op - M2_MIN_OFFSET; + m_pos -= t | (((lzo_uint) *ip++) << M2O_BITS); + assert(m_pos >= out); assert(m_pos < op); + TEST_LB(m_pos); + COPY_M2; + *op++ = *ip++; + } + +#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP) + break; +#endif + } + +match: + + if (t >= M2_MARKER) /* a M2 match */ + { + /* get match offset */ + NEED_IP(1); + m_pos = op - M2_MIN_OFFSET; + m_pos -= (t & M2O_MASK) | (((lzo_uint) *ip++) << M2O_BITS); + assert(m_pos >= out); assert(m_pos < op); + TEST_LB(m_pos); + + /* get match len */ + t = (t >> M2O_BITS) - 1; + NEED_OP(t + M2_MIN_LEN - 1); + COPY_M2X; + MEMCPY_DS(op,m_pos,t); + } + else /* a M3 or M4 match */ + { + /* get match len */ + t &= M3L_MASK; + if (t == 0) /* a M4 match */ + { + NEED_IP(1); + while (*ip == 0) + { + t += 255; + ip++; + NEED_IP(1); + } + t += (M4_MIN_LEN - M3_MIN_LEN) + *ip++; + } + + /* get match offset */ + NEED_IP(2); + m_pos = op - (M3_MIN_OFFSET - M3_EOF_OFFSET); + m_pos -= *ip++ & M3O_MASK; + m_pos -= (lzo_uint)(*ip++) << M3O_BITS; +#if defined(LZO_EOF_CODE) + if (m_pos == op) + goto eof_found; +#endif + + /* copy match */ + assert(m_pos >= out); assert(m_pos < op); + TEST_LB(m_pos); NEED_OP(t + M3_MIN_LEN - 1); +#if defined(LZO_UNALIGNED_OK_4) + if (t >= 2 * 4 - (M3_MIN_LEN - 1) && (op - m_pos) >= 4) + { + UA_COPY32(op, m_pos); + op += 4; m_pos += 4; t -= 4 - (M3_MIN_LEN - 1); + do { + UA_COPY32(op, m_pos); + op += 4; m_pos += 4; t -= 4; + } while (t >= 4); + if (t > 0) do *op++ = *m_pos++; while (--t > 0); + } + else +#endif + { + COPY_M3X; + MEMCPY_DS(op,m_pos,t); + } + + +#if (M3O_BITS < 7) + t = ip[-2] >> M3O_BITS; + if (t) + { + NEED_IP(t); NEED_OP(t); + goto literal1; + } +#elif (M3O_BITS == 7) + /* optimized version */ + if (ip[-2] & (1 << M3O_BITS)) + { + NEED_IP(1); NEED_OP(1); + *op++ = *ip++; + goto literal2; + } +#endif + } + } + + +#if defined(LZO_EOF_CODE) +#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP) + /* no EOF code was found */ + *out_len = pd(op, out); + return LZO_E_EOF_NOT_FOUND; +#endif + +eof_found: + assert(t == 1); +#endif + *out_len = pd(op, out); + return (ip == ip_end ? LZO_E_OK : + (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN)); + + +#if defined(HAVE_NEED_IP) +input_overrun: + *out_len = pd(op, out); + return LZO_E_INPUT_OVERRUN; +#endif + +#if defined(HAVE_NEED_OP) +output_overrun: + *out_len = pd(op, out); + return LZO_E_OUTPUT_OVERRUN; +#endif + +#if defined(LZO_TEST_OVERRUN_LOOKBEHIND) +lookbehind_overrun: + *out_len = pd(op, out); + return LZO_E_LOOKBEHIND_OVERRUN; +#endif +} + + +/* +vi:ts=4:et +*/ + |