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-rw-r--r--lzo/src/lzo1.c638
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diff --git a/lzo/src/lzo1.c b/lzo/src/lzo1.c
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-/* lzo1.c -- implementation of the LZO1 algorithm
-
- This file is part of the LZO real-time data compression library.
-
- Copyright (C) 2011 Markus Franz Xaver Johannes Oberhumer
- Copyright (C) 2010 Markus Franz Xaver Johannes Oberhumer
- Copyright (C) 2009 Markus Franz Xaver Johannes Oberhumer
- 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/lzo1.h"
-
-
-/***********************************************************************
-// The next two defines can be changed to customize LZO1.
-// The default version is LZO1-5/1.
-************************************************************************/
-
-/* run bits (3 - 5) - the compressor and the decompressor
- * must use the same value. */
-#if !defined(RBITS)
-# define RBITS 5
-#endif
-
-/* compression level (1 - 9) - this only affects the compressor.
- * 1 is fastest, 9 is best compression ratio */
-#if !defined(CLEVEL)
-# define CLEVEL 1 /* fastest by default */
-#endif
-
-
-/* check configuration */
-#if (RBITS < 3 || RBITS > 5)
-# error "invalid RBITS"
-#endif
-#if (CLEVEL < 1 || CLEVEL > 9)
-# error "invalid CLEVEL"
-#endif
-
-
-/***********************************************************************
-// You should not have to change anything below this line.
-************************************************************************/
-
-/*
- Format of the marker byte
-
-
- 76543210
- --------
- 00000000 a long run (a 'R0' run) - there are short and long R0 runs
- 000rrrrr a short run with len r
- mmmooooo a short match (len = 2+m, o = offset low bits)
- 111ooooo a long match (o = offset low bits)
-*/
-
-
-#define RSIZE (1 << RBITS)
-#define RMASK (RSIZE - 1)
-
-#define OBITS RBITS /* offset and run-length use same bits */
-#define OSIZE (1 << OBITS)
-#define OMASK (OSIZE - 1)
-
-#define MBITS (8 - OBITS)
-#define MSIZE (1 << MBITS)
-#define MMASK (MSIZE - 1)
-
-
-/* sanity checks */
-#if (OBITS < 3 || OBITS > 5)
-# error "invalid OBITS"
-#endif
-#if (MBITS < 3 || MBITS > 5)
-# error "invalid MBITS"
-#endif
-
-
-/***********************************************************************
-// some macros to improve readability
-************************************************************************/
-
-/* Minimum len of a match */
-#define MIN_MATCH 3
-#define THRESHOLD (MIN_MATCH - 1)
-
-/* Minimum len of match coded in 2 bytes */
-#define MIN_MATCH_SHORT MIN_MATCH
-
-/* Maximum len of match coded in 2 bytes */
-#define MAX_MATCH_SHORT (THRESHOLD + (MSIZE - 2))
-/* MSIZE - 2: 0 is used to indicate runs,
- * MSIZE-1 is used to indicate a long match */
-
-/* Minimum len of match coded in 3 bytes */
-#define MIN_MATCH_LONG (MAX_MATCH_SHORT + 1)
-
-/* Maximum len of match coded in 3 bytes */
-#define MAX_MATCH_LONG (MIN_MATCH_LONG + 255)
-
-/* Maximum offset of a match */
-#define MAX_OFFSET (1 << (8 + OBITS))
-
-
-/*
-
-RBITS | MBITS MIN THR. MSIZE MAXS MINL MAXL MAXO R0MAX R0FAST
-======+===============================================================
- 3 | 5 3 2 32 32 33 288 2048 263 256
- 4 | 4 3 2 16 16 17 272 4096 271 264
- 5 | 3 3 2 8 8 9 264 8192 287 280
-
- */
-
-
-/***********************************************************************
-// internal configuration
-// all of these affect compression only
-************************************************************************/
-
-/* choose the hashing strategy */
-#ifndef LZO_HASH
-#define LZO_HASH LZO_HASH_LZO_INCREMENTAL_A
-#endif
-#define D_INDEX1(d,p) d = DM(DMUL(0x21,DX2(p,5,5)) >> 5)
-#define D_INDEX2(d,p) d = d ^ D_MASK
-
-#define DBITS (8 + RBITS)
-#include "lzo_dict.h"
-#define DVAL_LEN DVAL_LOOKAHEAD
-
-
-/***********************************************************************
-// get algorithm info, return memory required for compression
-************************************************************************/
-
-LZO_EXTERN(lzo_uint) lzo1_info ( int *rbits, int *clevel );
-
-LZO_PUBLIC(lzo_uint)
-lzo1_info ( int *rbits, int *clevel )
-{
- if (rbits)
- *rbits = RBITS;
- if (clevel)
- *clevel = CLEVEL;
- return D_SIZE * lzo_sizeof(lzo_bytep);
-}
-
-
-/***********************************************************************
-// decode a R0 literal run (a long run)
-************************************************************************/
-
-#define R0MIN (RSIZE) /* Minimum len of R0 run of literals */
-#define R0MAX (R0MIN + 255) /* Maximum len of R0 run of literals */
-#define R0FAST (R0MAX & ~7u) /* R0MAX aligned to 8 byte boundary */
-
-#if (R0MAX - R0FAST != 7) || ((R0FAST & 7) != 0)
-# error "something went wrong"
-#endif
-
-/* 7 special codes from R0FAST+1 .. R0MAX
- * these codes mean long R0 runs with lengths
- * 512, 1024, 2048, 4096, 8192, 16384, 32768 */
-
-
-/***********************************************************************
-// LZO1 decompress a block of data.
-//
-// Could be easily translated into assembly code.
-************************************************************************/
-
-LZO_PUBLIC(int)
-lzo1_decompress ( const lzo_bytep in , lzo_uint in_len,
- lzo_bytep out, lzo_uintp out_len,
- lzo_voidp wrkmem )
-{
- lzo_bytep op;
- const lzo_bytep ip;
- const lzo_bytep const ip_end = in + in_len;
- lzo_uint t;
-
- LZO_UNUSED(wrkmem);
-
- op = out;
- ip = in;
- while (ip < ip_end)
- {
- t = *ip++; /* get marker */
-
- if (t < R0MIN) /* a literal run */
- {
- if (t == 0) /* a R0 literal run */
- {
- t = *ip++;
- if (t >= R0FAST - R0MIN) /* a long R0 run */
- {
- t -= R0FAST - R0MIN;
- if (t == 0)
- t = R0FAST;
- else
- {
-#if 0
- t = 256u << ((unsigned) t);
-#else
- /* help the optimizer */
- lzo_uint tt = 256;
- do tt <<= 1; while (--t > 0);
- t = tt;
-#endif
- }
- MEMCPY8_DS(op,ip,t);
- continue;
- }
- t += R0MIN;
- }
- MEMCPY_DS(op,ip,t);
- }
- else /* a match */
- {
- lzo_uint tt;
- /* get match offset */
- const lzo_bytep m_pos = op - 1;
- m_pos -= (lzo_uint)(t & OMASK) | (((lzo_uint) *ip++) << OBITS);
-
- /* get match len */
- if (t >= ((MSIZE - 1) << OBITS)) /* all m-bits set */
- tt = (MIN_MATCH_LONG - THRESHOLD) + *ip++; /* a long match */
- else
- tt = t >> OBITS; /* a short match */
-
- assert(m_pos >= out);
- assert(m_pos < op);
- /* a half unrolled loop */
- *op++ = *m_pos++;
- *op++ = *m_pos++;
- MEMCPY_DS(op,m_pos,tt);
- }
- }
-
- *out_len = pd(op, out);
-
- /* the next line is the only check in the decompressor ! */
- return (ip == ip_end ? LZO_E_OK :
- (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
-}
-
-
-/***********************************************************************
-// code a literal run
-************************************************************************/
-
-static
-#if LZO_ARCH_AVR
-__lzo_noinline
-#endif
-lzo_bytep
-store_run(lzo_bytep op, const lzo_bytep ii, lzo_uint r_len)
-{
- assert(r_len > 0);
-
- /* code a long R0 run */
- if (r_len >= 512)
- {
- unsigned r_bits = 7; /* 256 << 7 == 32768 */
- do {
- while (r_len >= (256u << r_bits))
- {
- r_len -= (256u << r_bits);
- *op++ = 0; *op++ = LZO_BYTE((R0FAST - R0MIN) + r_bits);
- MEMCPY8_DS(op, ii, (256u << r_bits));
- }
- } while (--r_bits > 0);
- }
- while (r_len >= R0FAST)
- {
- r_len -= R0FAST;
- *op++ = 0; *op++ = R0FAST - R0MIN;
- MEMCPY8_DS(op, ii, R0FAST);
- }
-
- if (r_len >= R0MIN)
- {
- /* code a short R0 run */
- *op++ = 0; *op++ = LZO_BYTE(r_len - R0MIN);
- MEMCPY_DS(op, ii, r_len);
- }
- else if (r_len > 0)
- {
- /* code a 'normal' run */
- *op++ = LZO_BYTE(r_len);
- MEMCPY_DS(op, ii, r_len);
- }
-
- assert(r_len == 0);
- return op;
-}
-
-
-
-/***********************************************************************
-// LZO1 compress a block of data.
-//
-// Could be translated into assembly code without too much effort.
-//
-// I apologize for the spaghetti code, but it really helps the optimizer.
-************************************************************************/
-
-static int
-do_compress ( const lzo_bytep in , lzo_uint in_len,
- lzo_bytep out, lzo_uintp out_len,
- lzo_voidp wrkmem )
-{
- const lzo_bytep ip;
-#if defined(__LZO_HASH_INCREMENTAL)
- lzo_xint dv;
-#endif
- lzo_bytep op;
- const lzo_bytep m_pos;
- const lzo_bytep const ip_end = in+in_len - DVAL_LEN - MIN_MATCH_LONG;
- const lzo_bytep const in_end = in+in_len - DVAL_LEN;
- const lzo_bytep ii;
- lzo_dict_p const dict = (lzo_dict_p) wrkmem;
-
-#if !defined(NDEBUG)
- const lzo_bytep m_pos_sav;
-#endif
-
- op = out;
- ip = in;
- ii = ip; /* point to start of literal run */
- if (in_len <= MIN_MATCH_LONG + DVAL_LEN + 1)
- goto the_end;
-
- /* init dictionary */
-#if (LZO_DETERMINISTIC)
- BZERO8_PTR(wrkmem,sizeof(lzo_dict_t),D_SIZE);
-#endif
-
- DVAL_FIRST(dv,ip);
- UPDATE_D(dict,0,dv,ip,in);
- ip++;
- DVAL_NEXT(dv,ip);
-
- do {
- LZO_DEFINE_UNINITIALIZED_VAR(lzo_uint, m_off, 0);
- lzo_uint dindex;
-
- DINDEX1(dindex,ip);
- GINDEX(m_pos,m_off,dict,dindex,in);
- if (LZO_CHECK_MPOS(m_pos,m_off,in,ip,MAX_OFFSET))
- goto literal;
- if (m_pos[0] == ip[0] && m_pos[1] == ip[1] && m_pos[2] == ip[2])
- goto match;
- DINDEX2(dindex,ip);
- GINDEX(m_pos,m_off,dict,dindex,in);
- if (LZO_CHECK_MPOS(m_pos,m_off,in,ip,MAX_OFFSET))
- goto literal;
- if (m_pos[0] == ip[0] && m_pos[1] == ip[1] && m_pos[2] == ip[2])
- goto match;
- goto literal;
-
-
-literal:
- UPDATE_I(dict,0,dindex,ip,in);
- if (++ip >= ip_end)
- break;
- continue;
-
-match:
- UPDATE_I(dict,0,dindex,ip,in);
-#if !defined(NDEBUG) && (LZO_DICT_USE_PTR)
- m_pos_sav = m_pos;
-#endif
- m_pos += 3;
- {
- /* we have found a match (of at least length 3) */
-#if !defined(NDEBUG) && !(LZO_DICT_USE_PTR)
- assert((m_pos_sav = ip - m_off) == (m_pos - 3));
-#endif
- /* 1) store the current literal run */
- if (pd(ip,ii) > 0)
- {
- lzo_uint t = pd(ip,ii);
-#if 1
- /* OPTIMIZED: inline the copying of a short run */
- if (t < R0MIN)
- {
- *op++ = LZO_BYTE(t);
- MEMCPY_DS(op, ii, t);
- }
- else
-#endif
- op = store_run(op,ii,t);
- }
-
- /* 2a) compute match len */
- ii = ip; /* point to start of current match */
-
- /* we already matched MIN_MATCH bytes,
- * m_pos also already advanced MIN_MATCH bytes */
- ip += MIN_MATCH;
- assert(m_pos < ip);
-
- /* try to match another MIN_MATCH_LONG - MIN_MATCH bytes
- * to see if we get a long match */
-
-#define PS *m_pos++ != *ip++
-
-#if (MIN_MATCH_LONG - MIN_MATCH == 2) /* MBITS == 2 */
- if (PS || PS)
-#elif (MIN_MATCH_LONG - MIN_MATCH == 6) /* MBITS == 3 */
- if (PS || PS || PS || PS || PS || PS)
-#elif (MIN_MATCH_LONG - MIN_MATCH == 14) /* MBITS == 4 */
- if (PS || PS || PS || PS || PS || PS || PS ||
- PS || PS || PS || PS || PS || PS || PS)
-#elif (MIN_MATCH_LONG - MIN_MATCH == 30) /* MBITS == 5 */
- if (PS || PS || PS || PS || PS || PS || PS || PS ||
- PS || PS || PS || PS || PS || PS || PS || PS ||
- PS || PS || PS || PS || PS || PS || PS || PS ||
- PS || PS || PS || PS || PS || PS)
-#else
-# error "MBITS not yet implemented"
-#endif
- {
- lzo_uint m_len;
-
- /* 2b) code a short match */
- assert(pd(ip,m_pos) == m_off);
- --ip; /* ran one too far, point back to non-match */
- m_len = pd(ip, ii);
- assert(m_len >= MIN_MATCH_SHORT);
- assert(m_len <= MAX_MATCH_SHORT);
- assert(m_off > 0);
- assert(m_off <= MAX_OFFSET);
- assert(ii-m_off == m_pos_sav);
- assert(lzo_memcmp(m_pos_sav,ii,m_len) == 0);
- --m_off;
- /* code short match len + low offset bits */
- *op++ = LZO_BYTE(((m_len - THRESHOLD) << OBITS) |
- (m_off & OMASK));
- /* code high offset bits */
- *op++ = LZO_BYTE(m_off >> OBITS);
-
-
- /* 2c) Insert phrases (beginning with ii+1) into the dictionary. */
-
-#define SI /* nothing */
-#define DI ++ii; DVAL_NEXT(dv,ii); UPDATE_D(dict,0,dv,ii,in);
-#define XI assert(ii < ip); ii = ip; DVAL_FIRST(dv,(ip));
-
-#if (CLEVEL == 9) || (CLEVEL >= 7 && MBITS <= 4) || (CLEVEL >= 5 && MBITS <= 3)
- /* Insert the whole match (ii+1)..(ip-1) into dictionary. */
- ++ii;
- do {
- DVAL_NEXT(dv,ii);
- UPDATE_D(dict,0,dv,ii,in);
- } while (++ii < ip);
- DVAL_NEXT(dv,ii);
- assert(ii == ip);
- DVAL_ASSERT(dv,ip);
-#elif (CLEVEL >= 3)
- SI DI DI XI
-#elif (CLEVEL >= 2)
- SI DI XI
-#else
- XI
-#endif
-
- }
- else
- {
- /* we've found a long match - see how far we can still go */
- const lzo_bytep end;
- lzo_uint m_len;
-
- assert(ip <= in_end);
- assert(ii == ip - MIN_MATCH_LONG);
-
- if (pd(in_end,ip) <= (MAX_MATCH_LONG - MIN_MATCH_LONG))
- end = in_end;
- else
- {
- end = ip + (MAX_MATCH_LONG - MIN_MATCH_LONG);
- assert(end < in_end);
- }
-
- while (ip < end && *m_pos == *ip)
- m_pos++, ip++;
- assert(ip <= in_end);
-
- /* 2b) code the long match */
- m_len = pd(ip, ii);
- assert(m_len >= MIN_MATCH_LONG);
- assert(m_len <= MAX_MATCH_LONG);
- assert(m_off > 0);
- assert(m_off <= MAX_OFFSET);
- assert(ii-m_off == m_pos_sav);
- assert(lzo_memcmp(m_pos_sav,ii,m_len) == 0);
- assert(pd(ip,m_pos) == m_off);
- --m_off;
- /* code long match flag + low offset bits */
- *op++ = LZO_BYTE(((MSIZE - 1) << OBITS) | (m_off & OMASK));
- /* code high offset bits */
- *op++ = LZO_BYTE(m_off >> OBITS);
- /* code match len */
- *op++ = LZO_BYTE(m_len - MIN_MATCH_LONG);
-
-
- /* 2c) Insert phrases (beginning with ii+1) into the dictionary. */
-#if (CLEVEL == 9)
- /* Insert the whole match (ii+1)..(ip-1) into dictionary. */
- /* This is not recommended because it is slow. */
- ++ii;
- do {
- DVAL_NEXT(dv,ii);
- UPDATE_D(dict,0,dv,ii,in);
- } while (++ii < ip);
- DVAL_NEXT(dv,ii);
- assert(ii == ip);
- DVAL_ASSERT(dv,ip);
-#elif (CLEVEL >= 8)
- SI DI DI DI DI DI DI DI DI XI
-#elif (CLEVEL >= 7)
- SI DI DI DI DI DI DI DI XI
-#elif (CLEVEL >= 6)
- SI DI DI DI DI DI DI XI
-#elif (CLEVEL >= 5)
- SI DI DI DI DI XI
-#elif (CLEVEL >= 4)
- SI DI DI DI XI
-#elif (CLEVEL >= 3)
- SI DI DI XI
-#elif (CLEVEL >= 2)
- SI DI XI
-#else
- XI
-#endif
- }
-
- /* ii now points to the start of next literal run */
- assert(ii == ip);
- }
- } while (ip < ip_end);
-
-
-
-the_end:
- assert(ip <= in_end);
-
-
-#if defined(LZO_RETURN_IF_NOT_COMPRESSIBLE)
- /* return -1 if op == out to indicate that we
- * couldn't compress and didn't copy anything.
- */
- if (op == out)
- {
- *out_len = 0;
- return LZO_E_NOT_COMPRESSIBLE;
- }
-#endif
-
-
- /* store the final literal run */
- if (pd(in_end+DVAL_LEN,ii) > 0)
- op = store_run(op,ii,pd(in_end+DVAL_LEN,ii));
-
- *out_len = pd(op, out);
- return 0; /* compression went ok */
-}
-
-
-/***********************************************************************
-// compress public entry point.
-************************************************************************/
-
-LZO_PUBLIC(int)
-lzo1_compress ( const lzo_bytep in , lzo_uint in_len,
- lzo_bytep out, lzo_uintp out_len,
- lzo_voidp wrkmem )
-{
- int r = LZO_E_OK;
-
- /* don't try to compress a block that's too short */
- if (in_len == 0)
- *out_len = 0;
- else if (in_len <= MIN_MATCH_LONG + DVAL_LEN + 1)
- {
-#if defined(LZO_RETURN_IF_NOT_COMPRESSIBLE)
- r = LZO_E_NOT_COMPRESSIBLE;
-#else
- *out_len = pd(store_run(out,in,in_len), out);
-#endif
- }
- else
- r = do_compress(in,in_len,out,out_len,wrkmem);
-
- return r;
-}
-
-
-/*
-vi:ts=4:et
-*/