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+/* 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
+ <markus@oberhumer.com>
+ 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
+*/
+
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