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Diffstat (limited to 'src/lzo1f_1.c')
| -rw-r--r-- | src/lzo1f_1.c | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/src/lzo1f_1.c b/src/lzo1f_1.c new file mode 100644 index 0000000..27608ce --- /dev/null +++ b/src/lzo1f_1.c @@ -0,0 +1,312 @@ +/* lzo1f_1.c -- implementation of the LZO1F-1 compression 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 "lzo_conf.h" +#include "lzo/lzo1f.h" + + +/*********************************************************************** +// +************************************************************************/ + +#define M2_MAX_OFFSET 0x0800 +#define M3_MAX_OFFSET 0x3fff +#define M3_MARKER 224 + + +#ifndef LZO_HASH +#define LZO_HASH LZO_HASH_LZO_INCREMENTAL_A +#endif +#define D_BITS 14 +#define D_INDEX1(d,p) d = DM(DMUL(0x21,DX3(p,5,5,6)) >> 5) +#define D_INDEX2(d,p) d = (d & (D_MASK & 0x7ff)) ^ (D_HIGH | 0x1f) +#include "lzo_dict.h" + + +/*********************************************************************** +// compress a block of data. +************************************************************************/ + +static __lzo_noinline +int do_compress ( const lzo_bytep in , lzo_uint in_len, + lzo_bytep out, lzo_uintp out_len, + lzo_voidp wrkmem ) +{ + register const lzo_bytep ip; + lzo_bytep op; + const lzo_bytep const in_end = in + in_len; + const lzo_bytep const ip_end = in + in_len - 9; + const lzo_bytep ii; + lzo_dict_p const dict = (lzo_dict_p) wrkmem; + + op = out; + ip = in; + ii = ip; + + ip++; + for (;;) + { + register const lzo_bytep m_pos; + lzo_uint m_off; + lzo_uint m_len; + lzo_uint dindex; + lzo_uint lit; + + DINDEX1(dindex,ip); + GINDEX(m_pos,m_off,dict,dindex,in); + if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M3_MAX_OFFSET)) + goto literal; +#if 1 + if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3]) + goto try_match; + DINDEX2(dindex,ip); +#endif + GINDEX(m_pos,m_off,dict,dindex,in); + if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M3_MAX_OFFSET)) + goto literal; + if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3]) + goto try_match; + goto literal; + + +try_match: +#if 0 && defined(LZO_UNALIGNED_OK_2) + if (* (const lzo_ushortp) m_pos != * (const lzo_ushortp) ip) +#else + if (m_pos[0] != ip[0] || m_pos[1] != ip[1]) +#endif + { + } + else + { + if (m_pos[2] == ip[2]) + { + m_pos += 3; +#if 0 + if (m_off <= M2_MAX_OFFSET) + goto match; + if (lit <= 3) + goto match; + if (lit == 3) /* better compression, but slower */ + { + assert(op - 2 > out); op[-2] |= LZO_BYTE(3); + *op++ = *ii++; *op++ = *ii++; *op++ = *ii++; + goto code_match; + } + if (*m_pos == ip[3]) +#endif + goto match; + } + } + + + /* a literal */ +literal: + UPDATE_I(dict,0,dindex,ip,in); + if (++ip >= ip_end) + break; + continue; + + + /* a match */ +match: + UPDATE_I(dict,0,dindex,ip,in); + /* store current literal run */ + lit = pd(ip,ii); + if (lit > 0) + { + register lzo_uint t = lit; + + if (t < 4 && op > out) + op[-2] |= LZO_BYTE(t); + else if (t <= 31) + *op++ = LZO_BYTE(t); + else + { + register lzo_uint tt = t - 31; + + *op++ = 0; + while (tt > 255) + { + tt -= 255; + *op++ = 0; + } + assert(tt > 0); + *op++ = LZO_BYTE(tt); + } + do *op++ = *ii++; while (--t > 0); + } + assert(ii == ip); + + + /* code the match */ + ip += 3; + if (*m_pos++ != *ip++ || *m_pos++ != *ip++ || *m_pos++ != *ip++ || + *m_pos++ != *ip++ || *m_pos++ != *ip++ || *m_pos++ != *ip++) + { + --ip; + m_len = pd(ip, ii); + assert(m_len >= 3); assert(m_len <= 8); + + if (m_off <= M2_MAX_OFFSET) + { + m_off -= 1; + *op++ = LZO_BYTE(((m_len - 2) << 5) | ((m_off & 7) << 2)); + *op++ = LZO_BYTE(m_off >> 3); + } + else if (m_len == 3 && m_off <= 2*M2_MAX_OFFSET && lit > 0) + { + m_off -= 1; + /* m_off -= M2_MAX_OFFSET; */ + *op++ = LZO_BYTE(((m_off & 7) << 2)); + *op++ = LZO_BYTE(m_off >> 3); + } + else + { + *op++ = LZO_BYTE(M3_MARKER | (m_len - 2)); + *op++ = LZO_BYTE((m_off & 63) << 2); + *op++ = LZO_BYTE(m_off >> 6); + } + } + else + { + { + const lzo_bytep end; + end = in_end; + while (ip < end && *m_pos == *ip) + m_pos++, ip++; + m_len = pd(ip, ii); + } + assert(m_len >= 3); + + if (m_len <= 33) + *op++ = LZO_BYTE(M3_MARKER | (m_len - 2)); + else + { + m_len -= 33; + *op++ = M3_MARKER | 0; + while (m_len > 255) + { + m_len -= 255; + *op++ = 0; + } + assert(m_len > 0); + *op++ = LZO_BYTE(m_len); + } + *op++ = LZO_BYTE((m_off & 63) << 2); + *op++ = LZO_BYTE(m_off >> 6); + } + + ii = ip; + if (ip >= ip_end) + break; + } + + + /* store final literal run */ + if (pd(in_end,ii) > 0) + { + register lzo_uint t = pd(in_end,ii); + + if (t < 4 && op > out) + op[-2] |= LZO_BYTE(t); + else if (t <= 31) + *op++ = LZO_BYTE(t); + else + { + register lzo_uint tt = t - 31; + + *op++ = 0; + while (tt > 255) + { + tt -= 255; + *op++ = 0; + } + assert(tt > 0); + *op++ = LZO_BYTE(tt); + } + do *op++ = *ii++; while (--t > 0); + } + + *out_len = pd(op, out); + return LZO_E_OK; +} + + +/*********************************************************************** +// public entry point +************************************************************************/ + +LZO_PUBLIC(int) +lzo1f_1_compress ( const lzo_bytep in , lzo_uint in_len, + lzo_bytep out, lzo_uintp out_len, + lzo_voidp wrkmem ) +{ + lzo_bytep op = out; + int r = LZO_E_OK; + + if (in_len <= 0) + *out_len = 0; + else if (in_len <= 10) + { + *op++ = LZO_BYTE(in_len); + do *op++ = *in++; while (--in_len > 0); + *out_len = pd(op, out); + } + else + r = do_compress(in,in_len,out,out_len,wrkmem); + + if (r == LZO_E_OK) + { + op = out + *out_len; + *op++ = M3_MARKER | 1; + *op++ = 0; + *op++ = 0; + *out_len += 3; + } + + return r; +} + + +/* +vi:ts=4:et +*/ + |