| /* lzo1f_d.ch -- implementation of the LZO1F decompression algorithm |
| |
| This file is part of the LZO real-time data compression library. |
| |
| 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 { |
| * (lzo_uint32p) op = * (const lzo_uint32p) 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 -= (* (const lzo_ushortp) 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) |
| { |
| * (lzo_uint32p) op = * (const lzo_uint32p) m_pos; |
| op += 4; m_pos += 4; t -= 4 - (3 - 1); |
| do { |
| * (lzo_uint32p) op = * (const lzo_uint32p) 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 |
| */ |
| |
