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+/* lzo1x_oo.ch -- LZO1X compressed data optimizer
+
+ 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/
+ */
+
+
+#define TEST_IP (ip < ip_end)
+#define TEST_OP (op <= op_end)
+
+#define NO_LIT LZO_UINT_MAX
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+static void copy2(lzo_bytep ip, const lzo_bytep m_pos, lzo_uint off)
+{
+ assert(off > 0);
+ ip[0] = m_pos[0];
+ if (off == 1)
+ ip[1] = m_pos[0];
+ else
+ ip[1] = m_pos[1];
+}
+
+
+static void copy3(lzo_bytep ip, const lzo_bytep m_pos, lzo_uint off)
+{
+ assert(off > 0);
+ ip[0] = m_pos[0];
+ if (off == 1)
+ {
+ ip[2] = ip[1] = m_pos[0];
+ }
+ else if (off == 2)
+ {
+ ip[1] = m_pos[1];
+ ip[2] = m_pos[0];
+ }
+ else
+ {
+ ip[1] = m_pos[1];
+ ip[2] = m_pos[2];
+ }
+}
+
+
+/***********************************************************************
+// optimize a block of data.
+************************************************************************/
+
+LZO_PUBLIC(int)
+DO_OPTIMIZE ( lzo_bytep in , lzo_uint in_len,
+ lzo_bytep out, lzo_uintp out_len,
+ lzo_voidp wrkmem )
+{
+ lzo_bytep op;
+ lzo_bytep ip;
+ lzo_uint t;
+ lzo_bytep m_pos;
+ lzo_bytep const ip_end = in + in_len;
+ lzo_bytep const op_end = out + *out_len;
+ lzo_bytep litp = NULL;
+ lzo_uint lit = 0;
+ lzo_uint next_lit = NO_LIT;
+ lzo_uint nl;
+ unsigned long o_m1_a = 0, o_m1_b = 0, o_m2 = 0, o_m3_a = 0, o_m3_b = 0;
+
+ LZO_UNUSED(wrkmem);
+
+ *out_len = 0;
+
+ op = out;
+ ip = in;
+
+ assert(in_len >= 3);
+ if (*ip > 17)
+ {
+ t = *ip++ - 17;
+ if (t < 4)
+ goto match_next;
+ goto first_literal_run;
+ }
+ assert(*ip < 16 || (*ip == 17 && in_len == 3));
+
+ while (TEST_IP && TEST_OP)
+ {
+ t = *ip++;
+ if (t >= 16)
+ goto match;
+ /* a literal run */
+ litp = ip - 1;
+ if (t == 0)
+ {
+ t = 15;
+ while (*ip == 0)
+ t += 255, ip++;
+ t += *ip++;
+ }
+ lit = t + 3;
+ /* copy literals */
+copy_literal_run:
+ *op++ = *ip++; *op++ = *ip++; *op++ = *ip++;
+first_literal_run:
+ do *op++ = *ip++; while (--t > 0);
+
+
+ t = *ip++;
+
+ if (t >= 16)
+ goto match;
+#if defined(LZO1X)
+ m_pos = op - 1 - 0x800;
+#elif defined(LZO1Y)
+ m_pos = op - 1 - 0x400;
+#endif
+ m_pos -= t >> 2;
+ m_pos -= *ip++ << 2;
+ *op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++;
+ lit = 0;
+ goto match_done;
+
+
+ /* handle matches */
+ do {
+ if (t < 16) /* a M1 match */
+ {
+ m_pos = op - 1;
+ m_pos -= t >> 2;
+ m_pos -= *ip++ << 2;
+
+ if (litp == NULL)
+ goto copy_m1;
+
+ /* assert that there was a match just before */
+ assert(lit >= 1 && lit <= 3);
+ assert(litp == ip - 2 - lit - 2);
+ assert((lzo_uint)(*litp & 3) == lit);
+ nl = ip[-2] & 3;
+ /* test if a match follows */
+ if (nl == 0 && lit == 1 && ip[0] >= 16)
+ {
+ next_lit = nl;
+ /* adjust length of previous short run */
+ lit += 2;
+ *litp = LZO_BYTE((*litp & ~3) | lit);
+ /* copy over the 2 literals that replace the match */
+ copy2(ip-2,m_pos,pd(op,m_pos));
+ o_m1_a++;
+ }
+ /* test if a literal run follows */
+ else if (nl == 0 && ip[0] < 16 && ip[0] != 0 &&
+ (lit + 2 + ip[0] < 16))
+ {
+ t = *ip++;
+ /* remove short run */
+ *litp &= ~3;
+ /* copy over the 2 literals that replace the match */
+ copy2(ip-3+1,m_pos,pd(op,m_pos));
+ /* move literals 1 byte ahead */
+ litp += 2;
+ if (lit > 0)
+ lzo_memmove(litp+1,litp,lit);
+ /* insert new length of long literal run */
+ lit += 2 + t + 3; assert(lit <= 18);
+ *litp = LZO_BYTE(lit - 3);
+
+ o_m1_b++;
+ *op++ = *m_pos++; *op++ = *m_pos++;
+ goto copy_literal_run;
+ }
+copy_m1:
+ *op++ = *m_pos++; *op++ = *m_pos++;
+ }
+ else
+ {
+match:
+ if (t >= 64) /* a M2 match */
+ {
+ m_pos = op - 1;
+#if defined(LZO1X)
+ m_pos -= (t >> 2) & 7;
+ m_pos -= *ip++ << 3;
+ t = (t >> 5) - 1;
+#elif defined(LZO1Y)
+ m_pos -= (t >> 2) & 3;
+ m_pos -= *ip++ << 2;
+ t = (t >> 4) - 3;
+#endif
+ if (litp == NULL)
+ goto copy_m;
+
+ nl = ip[-2] & 3;
+ /* test if in beetween two long literal runs */
+ if (t == 1 && lit > 3 && nl == 0 &&
+ ip[0] < 16 && ip[0] != 0 && (lit + 3 + ip[0] < 16))
+ {
+ assert(*litp == lit - 3);
+ t = *ip++;
+ /* copy over the 3 literals that replace the match */
+ copy3(ip-1-2,m_pos,pd(op,m_pos));
+ /* set new length of previous literal run */
+ lit += 3 + t + 3; assert(lit <= 18);
+ *litp = LZO_BYTE(lit - 3);
+ o_m2++;
+ *op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++;
+ goto copy_literal_run;
+ }
+ }
+ else
+ {
+ if (t >= 32) /* a M3 match */
+ {
+ t &= 31;
+ if (t == 0)
+ {
+ t = 31;
+ while (*ip == 0)
+ t += 255, ip++;
+ t += *ip++;
+ }
+ m_pos = op - 1;
+ m_pos -= *ip++ >> 2;
+ m_pos -= *ip++ << 6;
+ }
+ else /* a M4 match */
+ {
+ m_pos = op;
+ m_pos -= (t & 8) << 11;
+ t &= 7;
+ if (t == 0)
+ {
+ t = 7;
+ while (*ip == 0)
+ t += 255, ip++;
+ t += *ip++;
+ }
+ m_pos -= *ip++ >> 2;
+ m_pos -= *ip++ << 6;
+ if (m_pos == op)
+ goto eof_found;
+ m_pos -= 0x4000;
+ }
+ if (litp == NULL)
+ goto copy_m;
+
+ nl = ip[-2] & 3;
+ /* test if in beetween two matches */
+ if (t == 1 && lit == 0 && nl == 0 && ip[0] >= 16)
+ {
+ assert(litp == ip - 3 - lit - 2);
+ assert((lzo_uint)(*litp & 3) == lit);
+ next_lit = nl;
+ /* make a previous short run */
+ lit += 3;
+ *litp = LZO_BYTE((*litp & ~3) | lit);
+ /* copy over the 3 literals that replace the match */
+ copy3(ip-3,m_pos,pd(op,m_pos));
+ o_m3_a++;
+ }
+ /* test if a literal run follows */
+ else if (t == 1 && lit <= 3 && nl == 0 &&
+ ip[0] < 16 && ip[0] != 0 && (lit + 3 + ip[0] < 16))
+ {
+ assert(litp == ip - 3 - lit - 2);
+ assert((lzo_uint)(*litp & 3) == lit);
+ t = *ip++;
+ /* remove short run */
+ *litp &= ~3;
+ /* copy over the 3 literals that replace the match */
+ copy3(ip-4+1,m_pos,pd(op,m_pos));
+ /* move literals 1 byte ahead */
+ litp += 2;
+ if (lit > 0)
+ lzo_memmove(litp+1,litp,lit);
+ /* insert new length of long literal run */
+ lit += 3 + t + 3; assert(lit <= 18);
+ *litp = LZO_BYTE(lit - 3);
+
+ o_m3_b++;
+ *op++ = *m_pos++; *op++ = *m_pos++; *op++ = *m_pos++;
+ goto copy_literal_run;
+ }
+ }
+copy_m:
+ *op++ = *m_pos++; *op++ = *m_pos++;
+ do *op++ = *m_pos++; while (--t > 0);
+ }
+
+match_done:
+ if (next_lit == NO_LIT)
+ {
+ t = ip[-2] & 3;
+ lit = t;
+ litp = ip - 2;
+ }
+ else
+ t = next_lit;
+ assert(t <= 3);
+ next_lit = NO_LIT;
+ if (t == 0)
+ break;
+ /* copy literals */
+match_next:
+ do *op++ = *ip++; while (--t > 0);
+ t = *ip++;
+ } while (TEST_IP && TEST_OP);
+ }
+
+ /* no EOF code was found */
+ *out_len = pd(op, out);
+ return LZO_E_EOF_NOT_FOUND;
+
+eof_found:
+ assert(t == 1);
+#if 0
+ printf("optimize: %5lu %5lu %5lu %5lu %5lu\n",
+ o_m1_a, o_m1_b, o_m2, o_m3_a, o_m3_b);
+#endif
+ LZO_UNUSED(o_m1_a); LZO_UNUSED(o_m1_b); LZO_UNUSED(o_m2);
+ LZO_UNUSED(o_m3_a); LZO_UNUSED(o_m3_b);
+ *out_len = pd(op, out);
+ return (ip == ip_end ? LZO_E_OK :
+ (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
+}
+
+
+/*
+vi:ts=4:et
+*/
+
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