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Diffstat (limited to 'src/lzo1f_d.ch')
| -rw-r--r-- | src/lzo1f_d.ch | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/lzo1f_d.ch b/src/lzo1f_d.ch new file mode 100644 index 0000000..9e942f5 --- /dev/null +++ b/src/lzo1f_d.ch @@ -0,0 +1,226 @@ +/* lzo1f_d.ch -- implementation of the LZO1F 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); + + *out_len = 0; + + op = out; + ip = in; + + while (TEST_IP && TEST_OP) + { + t = *ip++; + if (t > 31) + goto match; + + /* a literal run */ + if (t == 0) + { + NEED_IP(1); + while (*ip == 0) + { + t += 255; + ip++; + NEED_IP(1); + } + t += 31 + *ip++; + } + /* copy literals */ + assert(t > 0); NEED_OP(t); NEED_IP(t+1); +#if 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 + do *op++ = *ip++; while (--t > 0); + + t = *ip++; + + while (TEST_IP && TEST_OP) + { + /* handle matches */ + if (t < 32) + { + m_pos = op - 1 - 0x800; + m_pos -= (t >> 2) & 7; + m_pos -= *ip++ << 3; + TEST_LB(m_pos); NEED_OP(3); + *op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++; + } + else + { +match: + if (t < M3_MARKER) + { + m_pos = op - 1; + m_pos -= (t >> 2) & 7; + m_pos -= *ip++ << 3; + t >>= 5; + TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1); + goto copy_match; + } + else + { + t &= 31; + if (t == 0) + { + NEED_IP(1); + while (*ip == 0) + { + t += 255; + ip++; + NEED_IP(1); + } + t += 31 + *ip++; + } + NEED_IP(2); + m_pos = op; +#if defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN) + m_pos -= UA_GET16(ip) >> 2; + ip += 2; +#else + m_pos -= *ip++ >> 2; + m_pos -= *ip++ << 6; +#endif + if (m_pos == op) + goto eof_found; + } + + /* copy match */ + TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1); +#if defined(LZO_UNALIGNED_OK_4) + if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) + { + UA_COPY32(op, m_pos); + op += 4; m_pos += 4; t -= 4 - (3 - 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_match: + *op++ = *m_pos++; *op++ = *m_pos++; + do *op++ = *m_pos++; while (--t > 0); + } + } + t = ip[-2] & 3; + if (t == 0) + break; + + /* copy literals */ + assert(t > 0); NEED_OP(t); NEED_IP(t+1); + do *op++ = *ip++; while (--t > 0); + t = *ip++; + } + } + +#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); + *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 +*/ + |