/* lzo1x_d.ch -- implementation of the LZO1X 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 http://www.oberhumer.com/opensource/lzo/ */ #include "lzo1_d.ch" #undef __COPY4 #define __COPY4(dst,src) * (lzo_uint32p)(dst) = * (const lzo_uint32p)(src) #undef COPY4 #if defined(LZO_UNALIGNED_OK_4) # define COPY4(dst,src) __COPY4(dst,src) #elif defined(LZO_ALIGNED_OK_4) # define COPY4(dst,src) __COPY4((lzo_uintptr_t)(dst),(lzo_uintptr_t)(src)) #endif /*********************************************************************** // decompress a block of data. ************************************************************************/ #if defined(DO_DECOMPRESS) LZO_PUBLIC(int) DO_DECOMPRESS ( const lzo_bytep in , lzo_uint in_len, lzo_bytep out, lzo_uintp out_len, lzo_voidp wrkmem ) #endif { register lzo_bytep op; register const lzo_bytep ip; register lzo_uint t; #if defined(COPY_DICT) lzo_uint m_off; const lzo_bytep dict_end; #else register const lzo_bytep m_pos; #endif const lzo_bytep const ip_end = in + in_len; #if defined(HAVE_ANY_OP) lzo_bytep const op_end = out + *out_len; #endif #if defined(LZO1Z) lzo_uint last_m_off = 0; #endif LZO_UNUSED(wrkmem); #if defined(COPY_DICT) if (dict) { if (dict_len > M4_MAX_OFFSET) { dict += dict_len - M4_MAX_OFFSET; dict_len = M4_MAX_OFFSET; } dict_end = dict + dict_len; } else { dict_len = 0; dict_end = NULL; } #endif /* COPY_DICT */ *out_len = 0; op = out; ip = in; if (*ip > 17) { t = *ip++ - 17; if (t < 4) goto match_next; assert(t > 0); NEED_OP(t); NEED_IP(t+1); do *op++ = *ip++; while (--t > 0); goto first_literal_run; } while (TEST_IP && TEST_OP) { t = *ip++; if (t >= 16) goto match; /* a literal run */ if (t == 0) { NEED_IP(1); while (*ip == 0) { t += 255; ip++; NEED_IP(1); } t += 15 + *ip++; } /* copy literals */ assert(t > 0); NEED_OP(t+3); NEED_IP(t+4); #if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4) #if !defined(LZO_UNALIGNED_OK_4) if (PTR_ALIGNED2_4(op,ip)) { #endif COPY4(op,ip); op += 4; ip += 4; if (--t > 0) { if (t >= 4) { do { COPY4(op,ip); op += 4; ip += 4; t -= 4; } while (t >= 4); if (t > 0) do *op++ = *ip++; while (--t > 0); } else do *op++ = *ip++; while (--t > 0); } #if !defined(LZO_UNALIGNED_OK_4) } else #endif #endif #if !defined(LZO_UNALIGNED_OK_4) { *op++ = *ip++; *op++ = *ip++; *op++ = *ip++; do *op++ = *ip++; while (--t > 0); } #endif first_literal_run: t = *ip++; if (t >= 16) goto match; #if defined(COPY_DICT) #if defined(LZO1Z) m_off = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2); last_m_off = m_off; #else m_off = (1 + M2_MAX_OFFSET) + (t >> 2) + (*ip++ << 2); #endif NEED_OP(3); t = 3; COPY_DICT(t,m_off) #else /* !COPY_DICT */ #if defined(LZO1Z) t = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2); m_pos = op - t; last_m_off = t; #else m_pos = op - (1 + M2_MAX_OFFSET); m_pos -= t >> 2; m_pos -= *ip++ << 2; #endif TEST_LB(m_pos); NEED_OP(3); *op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos; #endif /* COPY_DICT */ goto match_done; /* handle matches */ do { match: if (t >= 64) /* a M2 match */ { #if defined(COPY_DICT) #if defined(LZO1X) m_off = 1 + ((t >> 2) & 7) + (*ip++ << 3); t = (t >> 5) - 1; #elif defined(LZO1Y) m_off = 1 + ((t >> 2) & 3) + (*ip++ << 2); t = (t >> 4) - 3; #elif defined(LZO1Z) m_off = t & 0x1f; if (m_off >= 0x1c) m_off = last_m_off; else { m_off = 1 + (m_off << 6) + (*ip++ >> 2); last_m_off = m_off; } t = (t >> 5) - 1; #endif #else /* !COPY_DICT */ #if defined(LZO1X) m_pos = op - 1; m_pos -= (t >> 2) & 7; m_pos -= *ip++ << 3; t = (t >> 5) - 1; #elif defined(LZO1Y) m_pos = op - 1; m_pos -= (t >> 2) & 3; m_pos -= *ip++ << 2; t = (t >> 4) - 3; #elif defined(LZO1Z) { lzo_uint off = t & 0x1f; m_pos = op; if (off >= 0x1c) { assert(last_m_off > 0); m_pos -= last_m_off; } else { off = 1 + (off << 6) + (*ip++ >> 2); m_pos -= off; last_m_off = off; } } t = (t >> 5) - 1; #endif TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1); goto copy_match; #endif /* COPY_DICT */ } else if (t >= 32) /* a M3 match */ { t &= 31; if (t == 0) { NEED_IP(1); while (*ip == 0) { t += 255; ip++; NEED_IP(1); } t += 31 + *ip++; } #if defined(COPY_DICT) #if defined(LZO1Z) m_off = 1 + (ip[0] << 6) + (ip[1] >> 2); last_m_off = m_off; #else m_off = 1 + (ip[0] >> 2) + (ip[1] << 6); #endif #else /* !COPY_DICT */ #if defined(LZO1Z) { lzo_uint off = 1 + (ip[0] << 6) + (ip[1] >> 2); m_pos = op - off; last_m_off = off; } #elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN) m_pos = op - 1; m_pos -= (* (const lzo_ushortp) ip) >> 2; #else m_pos = op - 1; m_pos -= (ip[0] >> 2) + (ip[1] << 6); #endif #endif /* COPY_DICT */ ip += 2; } else if (t >= 16) /* a M4 match */ { #if defined(COPY_DICT) m_off = (t & 8) << 11; #else /* !COPY_DICT */ m_pos = op; m_pos -= (t & 8) << 11; #endif /* COPY_DICT */ t &= 7; if (t == 0) { NEED_IP(1); while (*ip == 0) { t += 255; ip++; NEED_IP(1); } t += 7 + *ip++; } #if defined(COPY_DICT) #if defined(LZO1Z) m_off += (ip[0] << 6) + (ip[1] >> 2); #else m_off += (ip[0] >> 2) + (ip[1] << 6); #endif ip += 2; if (m_off == 0) goto eof_found; m_off += 0x4000; #if defined(LZO1Z) last_m_off = m_off; #endif #else /* !COPY_DICT */ #if defined(LZO1Z) m_pos -= (ip[0] << 6) + (ip[1] >> 2); #elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN) m_pos -= (* (const lzo_ushortp) ip) >> 2; #else m_pos -= (ip[0] >> 2) + (ip[1] << 6); #endif ip += 2; if (m_pos == op) goto eof_found; m_pos -= 0x4000; #if defined(LZO1Z) last_m_off = pd((const lzo_bytep)op, m_pos); #endif #endif /* COPY_DICT */ } else /* a M1 match */ { #if defined(COPY_DICT) #if defined(LZO1Z) m_off = 1 + (t << 6) + (*ip++ >> 2); last_m_off = m_off; #else m_off = 1 + (t >> 2) + (*ip++ << 2); #endif NEED_OP(2); t = 2; COPY_DICT(t,m_off) #else /* !COPY_DICT */ #if defined(LZO1Z) t = 1 + (t << 6) + (*ip++ >> 2); m_pos = op - t; last_m_off = t; #else m_pos = op - 1; m_pos -= t >> 2; m_pos -= *ip++ << 2; #endif TEST_LB(m_pos); NEED_OP(2); *op++ = *m_pos++; *op++ = *m_pos; #endif /* COPY_DICT */ goto match_done; } /* copy match */ #if defined(COPY_DICT) NEED_OP(t+3-1); t += 3-1; COPY_DICT(t,m_off) #else /* !COPY_DICT */ TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1); #if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4) #if !defined(LZO_UNALIGNED_OK_4) if (t >= 2 * 4 - (3 - 1) && PTR_ALIGNED2_4(op,m_pos)) { assert((op - m_pos) >= 4); /* both pointers are aligned */ #else if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) { #endif COPY4(op,m_pos); op += 4; m_pos += 4; t -= 4 - (3 - 1); do { COPY4(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); } #endif /* COPY_DICT */ match_done: #if defined(LZO1Z) t = ip[-1] & 3; #else t = ip[-2] & 3; #endif if (t == 0) break; /* copy literals */ match_next: assert(t > 0); assert(t < 4); NEED_OP(t); NEED_IP(t+1); #if 0 do *op++ = *ip++; while (--t > 0); #else *op++ = *ip++; if (t > 1) { *op++ = *ip++; if (t > 2) { *op++ = *ip++; } } #endif t = *ip++; } while (TEST_IP && TEST_OP); } #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 */