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/* lzo1x_oo.ch -- LZO1X compressed data optimizer
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This file is part of the LZO real-time data compression library.
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Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 1996 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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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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Markus F.X.J. Oberhumer
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<markus@oberhumer.com>
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http://www.oberhumer.com/opensource/lzo/
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*/
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#define TEST_IP (ip < ip_end)
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#define TEST_OP (op <= op_end)
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#define NO_LIT LZO_UINT_MAX
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/***********************************************************************
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//
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************************************************************************/
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static void copy2(lzo_bytep ip, const lzo_bytep m_pos, lzo_uint off)
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{
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assert(off > 0);
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ip[0] = m_pos[0];
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if (off == 1)
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ip[1] = m_pos[0];
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else
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ip[1] = m_pos[1];
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}
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static void copy3(lzo_bytep ip, const lzo_bytep m_pos, lzo_uint off)
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{
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assert(off > 0);
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ip[0] = m_pos[0];
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if (off == 1)
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{
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ip[2] = ip[1] = m_pos[0];
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}
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else if (off == 2)
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{
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ip[1] = m_pos[1];
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ip[2] = m_pos[0];
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}
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else
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{
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ip[1] = m_pos[1];
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ip[2] = m_pos[2];
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}
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}
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/***********************************************************************
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// optimize a block of data.
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************************************************************************/
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LZO_PUBLIC(int)
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DO_OPTIMIZE ( lzo_bytep in , lzo_uint in_len,
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lzo_bytep out, lzo_uintp out_len,
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lzo_voidp wrkmem )
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{
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lzo_bytep op;
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lzo_bytep ip;
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lzo_uint t;
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lzo_bytep m_pos;
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lzo_bytep const ip_end = in + in_len;
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lzo_bytep const op_end = out + *out_len;
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lzo_bytep litp = NULL;
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lzo_uint lit = 0;
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lzo_uint next_lit = NO_LIT;
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lzo_uint nl;
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unsigned long o_m1_a = 0, o_m1_b = 0, o_m2 = 0, o_m3_a = 0, o_m3_b = 0;
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LZO_UNUSED(wrkmem);
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*out_len = 0;
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op = out;
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ip = in;
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assert(in_len >= 3);
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if (*ip > 17)
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{
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t = *ip++ - 17;
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if (t < 4)
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goto match_next;
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goto first_literal_run;
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}
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assert(*ip < 16 || (*ip == 17 && in_len == 3));
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while (TEST_IP && TEST_OP)
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{
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t = *ip++;
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if (t >= 16)
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goto match;
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/* a literal run */
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litp = ip - 1;
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if (t == 0)
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{
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t = 15;
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while (*ip == 0)
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t += 255, ip++;
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t += *ip++;
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}
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lit = t + 3;
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/* copy literals */
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copy_literal_run:
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*op++ = *ip++; *op++ = *ip++; *op++ = *ip++;
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first_literal_run:
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do *op++ = *ip++; while (--t > 0);
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t = *ip++;
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if (t >= 16)
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goto match;
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#if defined(LZO1X)
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m_pos = op - 1 - 0x800;
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#elif defined(LZO1Y)
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m_pos = op - 1 - 0x400;
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#endif
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m_pos -= t >> 2;
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m_pos -= *ip++ << 2;
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*op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++;
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lit = 0;
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goto match_done;
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/* handle matches */
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do {
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if (t < 16) /* a M1 match */
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{
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m_pos = op - 1;
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m_pos -= t >> 2;
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m_pos -= *ip++ << 2;
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if (litp == NULL)
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goto copy_m1;
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/* assert that there was a match just before */
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assert(lit >= 1 && lit <= 3);
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assert(litp == ip - 2 - lit - 2);
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assert((lzo_uint)(*litp & 3) == lit);
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nl = ip[-2] & 3;
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/* test if a match follows */
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if (nl == 0 && lit == 1 && ip[0] >= 16)
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{
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next_lit = nl;
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/* adjust length of previous short run */
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lit += 2;
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*litp = LZO_BYTE((*litp & ~3) | lit);
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/* copy over the 2 literals that replace the match */
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copy2(ip-2,m_pos,pd(op,m_pos));
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o_m1_a++;
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}
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/* test if a literal run follows */
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else if (nl == 0 && ip[0] < 16 && ip[0] != 0 &&
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(lit + 2 + ip[0] < 16))
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{
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t = *ip++;
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/* remove short run */
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*litp &= ~3;
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/* copy over the 2 literals that replace the match */
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copy2(ip-3+1,m_pos,pd(op,m_pos));
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/* move literals 1 byte ahead */
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litp += 2;
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if (lit > 0)
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lzo_memmove(litp+1,litp,lit);
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/* insert new length of long literal run */
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lit += 2 + t + 3; assert(lit <= 18);
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*litp = LZO_BYTE(lit - 3);
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o_m1_b++;
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*op++ = *m_pos++; *op++ = *m_pos++;
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goto copy_literal_run;
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}
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copy_m1:
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*op++ = *m_pos++; *op++ = *m_pos++;
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}
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else
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{
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match:
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if (t >= 64) /* a M2 match */
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{
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m_pos = op - 1;
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#if defined(LZO1X)
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m_pos -= (t >> 2) & 7;
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m_pos -= *ip++ << 3;
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t = (t >> 5) - 1;
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#elif defined(LZO1Y)
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m_pos -= (t >> 2) & 3;
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m_pos -= *ip++ << 2;
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t = (t >> 4) - 3;
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#endif
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if (litp == NULL)
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goto copy_m;
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nl = ip[-2] & 3;
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/* test if in beetween two long literal runs */
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if (t == 1 && lit > 3 && nl == 0 &&
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ip[0] < 16 && ip[0] != 0 && (lit + 3 + ip[0] < 16))
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{
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assert(*litp == lit - 3);
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t = *ip++;
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/* copy over the 3 literals that replace the match */
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copy3(ip-1-2,m_pos,pd(op,m_pos));
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/* set new length of previous literal run */
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lit += 3 + t + 3; assert(lit <= 18);
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*litp = LZO_BYTE(lit - 3);
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o_m2++;
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*op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++;
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goto copy_literal_run;
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}
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}
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else
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{
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if (t >= 32) /* a M3 match */
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{
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t &= 31;
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if (t == 0)
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{
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t = 31;
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while (*ip == 0)
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t += 255, ip++;
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t += *ip++;
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}
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m_pos = op - 1;
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m_pos -= *ip++ >> 2;
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m_pos -= *ip++ << 6;
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}
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else /* a M4 match */
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{
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m_pos = op;
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m_pos -= (t & 8) << 11;
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t &= 7;
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if (t == 0)
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{
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t = 7;
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while (*ip == 0)
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t += 255, ip++;
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t += *ip++;
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}
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m_pos -= *ip++ >> 2;
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m_pos -= *ip++ << 6;
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if (m_pos == op)
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goto eof_found;
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m_pos -= 0x4000;
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}
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if (litp == NULL)
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goto copy_m;
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nl = ip[-2] & 3;
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/* test if in beetween two matches */
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if (t == 1 && lit == 0 && nl == 0 && ip[0] >= 16)
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{
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assert(litp == ip - 3 - lit - 2);
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assert((lzo_uint)(*litp & 3) == lit);
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next_lit = nl;
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/* make a previous short run */
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lit += 3;
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*litp = LZO_BYTE((*litp & ~3) | lit);
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/* copy over the 3 literals that replace the match */
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copy3(ip-3,m_pos,pd(op,m_pos));
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o_m3_a++;
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}
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/* test if a literal run follows */
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else if (t == 1 && lit <= 3 && nl == 0 &&
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ip[0] < 16 && ip[0] != 0 && (lit + 3 + ip[0] < 16))
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{
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assert(litp == ip - 3 - lit - 2);
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assert((lzo_uint)(*litp & 3) == lit);
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t = *ip++;
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/* remove short run */
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*litp &= ~3;
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/* copy over the 3 literals that replace the match */
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copy3(ip-4+1,m_pos,pd(op,m_pos));
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/* move literals 1 byte ahead */
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litp += 2;
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if (lit > 0)
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lzo_memmove(litp+1,litp,lit);
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/* insert new length of long literal run */
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lit += 3 + t + 3; assert(lit <= 18);
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*litp = LZO_BYTE(lit - 3);
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o_m3_b++;
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*op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++;
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goto copy_literal_run;
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}
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}
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copy_m:
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*op++ = *m_pos++; *op++ = *m_pos++;
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do *op++ = *m_pos++; while (--t > 0);
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}
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match_done:
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| 326 |
if (next_lit == NO_LIT)
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{
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| 328 |
t = ip[-2] & 3;
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| 329 |
lit = t;
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| 330 |
litp = ip - 2;
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| 331 |
}
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| 332 |
else
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| 333 |
t = next_lit;
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assert(t <= 3);
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next_lit = NO_LIT;
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| 336 |
if (t == 0)
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break;
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/* copy literals */
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| 339 |
match_next:
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| 340 |
do *op++ = *ip++; while (--t > 0);
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t = *ip++;
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} while (TEST_IP && TEST_OP);
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}
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| 344 |
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| 345 |
/* no EOF code was found */
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| 346 |
*out_len = pd(op, out);
|
| 347 |
return LZO_E_EOF_NOT_FOUND;
|
| 348 |
|
| 349 |
eof_found:
|
| 350 |
assert(t == 1);
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| 351 |
#if 0
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| 352 |
printf("optimize: %5lu %5lu %5lu %5lu %5lu\n",
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o_m1_a, o_m1_b, o_m2, o_m3_a, o_m3_b);
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| 354 |
#endif
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| 355 |
LZO_UNUSED(o_m1_a); LZO_UNUSED(o_m1_b); LZO_UNUSED(o_m2);
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| 356 |
LZO_UNUSED(o_m3_a); LZO_UNUSED(o_m3_b);
|
| 357 |
*out_len = pd(op, out);
|
| 358 |
return (ip == ip_end ? LZO_E_OK :
|
| 359 |
(ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
|
| 360 |
}
|
| 361 |
|
| 362 |
|
| 363 |
/*
|
| 364 |
vi:ts=4:et
|
| 365 |
*/
|
| 366 |
|
