313 lines
6.7 KiB
C
313 lines
6.7 KiB
C
/* lzo1f_1.c -- implementation of the LZO1F-1 compression algorithm
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This file is part of the LZO real-time data compression library.
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Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
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All Rights Reserved.
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The LZO library is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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The LZO library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with the LZO library; see the file COPYING.
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If not, write to the Free Software Foundation, Inc.,
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59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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Markus F.X.J. Oberhumer
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<markus@oberhumer.com>
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*/
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#include <lzo1f.h>
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#include "lzo_conf.h"
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/***********************************************************************
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//
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************************************************************************/
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#define M2_MAX_OFFSET 0x0800
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#define M3_MAX_OFFSET 0x3fff
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#define M3_MARKER 224
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#ifndef LZO_HASH
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#define LZO_HASH LZO_HASH_LZO_INCREMENTAL_A
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#endif
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#define D_BITS 14
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#define D_INDEX1(d,p) d = DM((0x21*DX3(p,5,5,6)) >> 5)
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#define D_INDEX2(d,p) d = (d & (D_MASK & 0x7ff)) ^ (D_HIGH | 0x1f)
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#include "lzo_dict.h"
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/***********************************************************************
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// compress a block of data.
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************************************************************************/
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static
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int do_compress ( const lzo_byte *in , lzo_uint in_len,
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lzo_byte *out, lzo_uintp out_len,
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lzo_voidp wrkmem )
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{
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#if 0 && defined(__GNUC__) && defined(__i386__)
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register const lzo_byte *ip __asm__("%esi");
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#else
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register const lzo_byte *ip;
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#endif
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lzo_byte *op;
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const lzo_byte * const in_end = in + in_len;
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const lzo_byte * const ip_end = in + in_len - 9;
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const lzo_byte *ii;
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lzo_dict_p const dict = (lzo_dict_p) wrkmem;
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op = out;
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ip = in;
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ii = ip;
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ip++;
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for (;;)
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{
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#if 0 && defined(__GNUC__) && defined(__i386__)
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register const lzo_byte *m_pos __asm__("%edi");
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#else
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register const lzo_byte *m_pos;
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#endif
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lzo_moff_t m_off;
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lzo_uint m_len;
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lzo_uint dindex;
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lzo_uint lit;
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DINDEX1(dindex,ip);
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GINDEX(m_pos,m_off,dict,dindex,in);
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if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M3_MAX_OFFSET))
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goto literal;
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#if 1
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if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
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goto try_match;
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DINDEX2(dindex,ip);
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#endif
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GINDEX(m_pos,m_off,dict,dindex,in);
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if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M3_MAX_OFFSET))
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goto literal;
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if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
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goto try_match;
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goto literal;
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try_match:
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#if 0 && defined(LZO_UNALIGNED_OK_2)
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if (* (const lzo_ushortp) m_pos != * (const lzo_ushortp) ip)
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#else
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if (m_pos[0] != ip[0] || m_pos[1] != ip[1])
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#endif
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{
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}
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else
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{
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if (m_pos[2] == ip[2])
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{
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m_pos += 3;
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#if 0
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if (m_off <= M2_MAX_OFFSET)
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goto match;
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if (lit <= 3)
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goto match;
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if (lit == 3) /* better compression, but slower */
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{
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assert(op - 2 > out); op[-2] |= LZO_BYTE(3);
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*op++ = *ii++; *op++ = *ii++; *op++ = *ii++;
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goto code_match;
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}
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if (*m_pos == ip[3])
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#endif
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goto match;
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}
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}
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/* a literal */
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literal:
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UPDATE_I(dict,0,dindex,ip,in);
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if (++ip >= ip_end)
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break;
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continue;
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/* a match */
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match:
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UPDATE_I(dict,0,dindex,ip,in);
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/* store current literal run */
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lit = pd(ip,ii);
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if (lit > 0)
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{
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register lzo_uint t = lit;
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if (t < 4 && op > out)
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op[-2] |= LZO_BYTE(t);
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else if (t <= 31)
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*op++ = LZO_BYTE(t);
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else
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{
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register lzo_uint tt = t - 31;
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*op++ = 0;
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while (tt > 255)
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{
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tt -= 255;
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*op++ = 0;
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}
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assert(tt > 0);
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*op++ = LZO_BYTE(tt);
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}
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do *op++ = *ii++; while (--t > 0);
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}
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assert(ii == ip);
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/* code the match */
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ip += 3;
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if (*m_pos++ != *ip++ || *m_pos++ != *ip++ || *m_pos++ != *ip++ ||
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*m_pos++ != *ip++ || *m_pos++ != *ip++ || *m_pos++ != *ip++)
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{
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--ip;
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m_len = ip - ii;
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assert(m_len >= 3); assert(m_len <= 8);
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if (m_off <= M2_MAX_OFFSET)
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{
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m_off -= 1;
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*op++ = LZO_BYTE(((m_len - 2) << 5) | ((m_off & 7) << 2));
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*op++ = LZO_BYTE(m_off >> 3);
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}
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else if (m_len == 3 && m_off <= 2*M2_MAX_OFFSET && lit > 0)
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{
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m_off -= 1;
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/* m_off -= M2_MAX_OFFSET; */
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*op++ = LZO_BYTE(((m_off & 7) << 2));
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*op++ = LZO_BYTE(m_off >> 3);
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}
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else
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{
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*op++ = LZO_BYTE(M3_MARKER | (m_len - 2));
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*op++ = LZO_BYTE((m_off & 63) << 2);
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*op++ = LZO_BYTE(m_off >> 6);
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}
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}
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else
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{
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{
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const lzo_byte *end;
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end = in_end;
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while (ip < end && *m_pos == *ip)
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m_pos++, ip++;
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m_len = (ip - ii);
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}
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assert(m_len >= 3);
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if (m_len <= 33)
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*op++ = LZO_BYTE(M3_MARKER | (m_len - 2));
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else
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{
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m_len -= 33;
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*op++ = M3_MARKER | 0;
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while (m_len > 255)
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{
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m_len -= 255;
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*op++ = 0;
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}
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assert(m_len > 0);
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*op++ = LZO_BYTE(m_len);
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}
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*op++ = LZO_BYTE((m_off & 63) << 2);
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*op++ = LZO_BYTE(m_off >> 6);
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}
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ii = ip;
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if (ip >= ip_end)
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break;
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}
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/* store final literal run */
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if (pd(in_end,ii) > 0)
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{
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register lzo_uint t = pd(in_end,ii);
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if (t < 4 && op > out)
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op[-2] |= LZO_BYTE(t);
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else if (t <= 31)
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*op++ = LZO_BYTE(t);
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else
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{
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register lzo_uint tt = t - 31;
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*op++ = 0;
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while (tt > 255)
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{
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tt -= 255;
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*op++ = 0;
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}
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assert(tt > 0);
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*op++ = LZO_BYTE(tt);
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}
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do *op++ = *ii++; while (--t > 0);
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}
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*out_len = op - out;
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return LZO_E_OK;
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}
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/***********************************************************************
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// public entry point
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************************************************************************/
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LZO_PUBLIC(int)
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lzo1f_1_compress ( const lzo_byte *in , lzo_uint in_len,
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lzo_byte *out, lzo_uintp out_len,
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lzo_voidp wrkmem )
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{
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lzo_byte *op = out;
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int r = LZO_E_OK;
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#if defined(__LZO_QUERY_COMPRESS)
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if (__LZO_IS_COMPRESS_QUERY(in,in_len,out,out_len,wrkmem))
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return __LZO_QUERY_COMPRESS(in,in_len,out,out_len,wrkmem,D_SIZE,lzo_sizeof(lzo_dict_t));
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#endif
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if (in_len <= 0)
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*out_len = 0;
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else if (in_len <= 10)
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{
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*op++ = LZO_BYTE(in_len);
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do *op++ = *in++; while (--in_len > 0);
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*out_len = op - out;
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}
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else
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r = do_compress(in,in_len,out,out_len,wrkmem);
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if (r == LZO_E_OK)
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{
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op = out + *out_len;
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*op++ = M3_MARKER | 1;
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*op++ = 0;
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*op++ = 0;
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*out_len += 3;
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}
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return r;
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}
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/*
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vi:ts=4:et
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*/
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//martysama0134's 2e58d0b8baeb072acdf3afc4a5d1999f
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