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SRB2/src/lzf.c
Monster Iestyn 302d0425e0 Incinerated WinCE
2017-09-29 23:25:34 +01:00

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9.1 KiB
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// SONIC ROBO BLAST 2
//-----------------------------------------------------------------------------
// Copyright (C) 2000-2005 by Marc Alexander Lehmann <schmorp@schmorp.de>
//
// This program is free software distributed under the
// terms of the GNU General Public License, version 2.
// See the 'LICENSE' file for more details.
//-----------------------------------------------------------------------------
/// \file lzf.c
/// \brief LZF de/compression routines
/* LZF decompression routines copied from lzf_d.c from liblzf 1.7 */
/* LZF compression routines copied from lzf_c.c from liblzf 1.7 */
/*
* lzfP.h included here by Graue.
*/
#ifndef LZFP_h
#define LZFP_h
#include "lzf.h"
#include "doomdef.h"
/*
* Size of hashtable is (1 << HLOG) * sizeof (char *)
* decompression is independent of the hash table size
* the difference between 15 and 14 is very small
* for small blocks (and 14 is usually a bit faster).
* For a low-memory/faster configuration, use HLOG == 13;
* For best compression, use 15 or 16 (or more).
*/
#ifndef HLOG
# define HLOG 15
#endif
/*
* Sacrifice very little compression quality in favour of compression speed.
* This gives almost the same compression as the default code, and is
* (very roughly) 15% faster. This is the preferable mode of operation.
*/
#ifndef VERY_FAST
# define VERY_FAST 1
#endif
/*
* Sacrifice some more compression quality in favour of compression speed.
* (roughly 1-2% worse compression for large blocks and
* 9-10% for small, redundant, blocks and >>20% better speed in both cases)
* In INT16: when in need for speed, enable this for binary data,
* possibly disable this for text data.
*/
#ifndef ULTRA_FAST
# define ULTRA_FAST 0
#endif
/*
* Unconditionally aligning does not cost very much, so do it if unsure
*/
#ifndef STRICT_ALIGN
#if !(defined(__i386) || defined (__amd64)) || defined (__clang__)
#define STRICT_ALIGN 1
#else
#define STRICT_ALIGN 0
#endif
#endif
/*
* Use string functions to copy memory.
* this is usually a loss, even with glibc's optimized memcpy
*/
#ifndef USE_MEMCPY
#ifdef _MSC_VER
# define USE_MEMCPY 0
#else
# define USE_MEMCPY 1
#endif
#endif
/*
* You may choose to pre-set the hash table (might be faster on some
* modern cpus and large (>>64k) blocks)
*/
#ifndef INIT_HTAB
# define INIT_HTAB 1
#endif
/*
* Avoid assigning values to errno variable? for some embedding purposes
* (linux kernel for example), this is neccessary. NOTE: this breaks
* the documentation in lzf.h.
*/
#ifndef AVOID_ERRNO
# define AVOID_ERRNO 0
#endif
/*
* Wether to pass the LZF_STATE variable as argument, or allocate it
* on the stack. For small-stack environments, define this to 1.
* NOTE: this breaks the prototype in lzf.h.
*/
#ifndef LZF_STATE_ARG
# define LZF_STATE_ARG 0
#endif
/*
* Wether to add extra checks for input validity in lzf_decompress
* and return EINVAL if the input stream has been corrupted. This
* only shields against overflowing the input buffer and will not
* detect most corrupted streams.
* This check is not normally noticable on modern hardware
* (<1% slowdown), but might slow down older cpus considerably.
*/
#ifndef CHECK_INPUT
# define CHECK_INPUT 1
#endif
/*****************************************************************************/
/* nothing should be changed below */
typedef unsigned char u8;
typedef const u8 *LZF_STATE[1 << (HLOG)];
#if !STRICT_ALIGN
/* for unaligned accesses we need a 16 bit datatype. */
# include <limits.h>
# if USHRT_MAX == 65535
typedef unsigned short u16;
# elif UINT_MAX == 65535
typedef unsigned int u16;
# else
# undef STRICT_ALIGN
# define STRICT_ALIGN 1
# endif
#endif
#if ULTRA_FAST
# if defined(VERY_FAST)
# undef VERY_FAST
# endif
#endif
#if USE_MEMCPY || INIT_HTAB
# ifdef __cplusplus
# include <cstring>
# else
# include <string.h>
# endif
#endif
#endif
/*
* lzfP.h ends here. lzf_d.c follows.
*/
#if AVOID_ERRNO
# define SET_ERRNO(n)
#else
# include <errno.h>
# define SET_ERRNO(n) errno = (n)
#endif
size_t
lzf_decompress (const void *const in_data, size_t in_len,
void *out_data, size_t out_len)
{
u8 const *ip = (const u8 *)in_data;
u8 *op = (u8 *)out_data;
u8 const *const in_end = ip + in_len;
u8 *const out_end = op + out_len;
do
{
unsigned int ctrl = *ip++;
if (ctrl < (1 << 5)) /* literal run */
{
ctrl++;
if (op + ctrl > out_end)
{
SET_ERRNO (E2BIG);
return 0;
}
#if CHECK_INPUT
if (ip + ctrl > in_end)
{
SET_ERRNO (EINVAL);
return 0;
}
#endif
#if USE_MEMCPY
M_Memcpy (op, ip, ctrl);
op += ctrl;
ip += ctrl;
#else
do
*op++ = *ip++;
while (--ctrl);
#endif
}
else /* back reference */
{
unsigned int len = ctrl >> 5;
u8 *ref = op - ((ctrl & 0x1f) << 8) - 1;
#if CHECK_INPUT
if (ip >= in_end)
{
SET_ERRNO (EINVAL);
return 0;
}
#endif
if (len == 7)
{
len += *ip++;
#if CHECK_INPUT
if (ip >= in_end)
{
SET_ERRNO (EINVAL);
return 0;
}
#endif
}
ref -= *ip++;
if (op + len + 2 > out_end)
{
SET_ERRNO (E2BIG);
return 0;
}
if (ref < (u8 *)out_data)
{
SET_ERRNO (EINVAL);
return 0;
}
*op++ = *ref++;
*op++ = *ref++;
do
*op++ = *ref++;
while (--len);
}
}
while (ip < in_end);
return op - (u8 *)out_data;
}
/*
* lzf_d.c ends here. lzf_c.c follows.
*/
#define HSIZE (1 << (HLOG))
/*
* don't play with this unless you benchmark!
* decompression is not dependent on the hash function
* the hashing function might seem strange, just believe me
* it works ;)
*/
#ifndef FRST
# define FRST(p) (((p[0]) << 8) | p[1])
# define NEXT(v,p) (((v) << 8) | p[2])
# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
#endif
/*
* IDX works because it is very similar to a multiplicative hash, e.g.
* ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1))
* the latter is also quite fast on newer CPUs, and sligthly better
*
* the next one is also quite good, albeit slow ;)
* (int)(cos(h & 0xffffff) * 1e6)
*/
#if 0
/* original lzv-like hash function, much worse and thus slower */
# define FRST(p) (p[0] << 5) ^ p[1]
# define NEXT(v,p) ((v) << 5) ^ p[2]
# define IDX(h) ((h) & (HSIZE - 1))
#endif
#define MAX_LIT (1 << 5)
#define MAX_OFF (1 << 13)
#define MAX_REF ((1 << 8) + (1 << 3))
/*
* compressed format
*
* 000LLLLL <L+1> ; literal
* LLLooooo oooooooo ; backref L
* 111ooooo LLLLLLLL oooooooo ; backref L+7
*
*/
size_t
lzf_compress (const void *const in_data,size_t in_len,
void *out_data, size_t out_len
#if LZF_STATE_ARG
, LZF_STATE *htab
#endif
)
{
#if !LZF_STATE_ARG
LZF_STATE htab;
#endif
const u8 **hslot;
const u8 *ip = (const u8 *)in_data;
u8 *op = (u8 *)out_data;
const u8 *in_end = ip + in_len;
u8 *out_end = op + out_len;
const u8 *ref = NULL;
unsigned int hval = FRST (ip);
size_t off;
int lit = 0;
#if INIT_HTAB
# if USE_MEMCPY
memset (htab, 0, sizeof (htab));
# else
for (hslot = htab; hslot < htab + HSIZE; hslot++)
*hslot++ = ip;
# endif
#endif
for (;;)
{
if (ip < in_end - 2)
{
hval = NEXT (hval, ip);
hslot = htab + IDX (hval);
ref = *hslot; *hslot = ip;
if (
#if INIT_HTAB && !USE_MEMCPY
ref < ip /* the next test will actually take care of this, but this is faster */
&&
#endif
(off = ip - ref - 1) < MAX_OFF
&& ip + 4 < in_end
&& ref > (const u8 *)in_data
#if STRICT_ALIGN
&& ref[0] == ip[0]
&& ref[1] == ip[1]
&& ref[2] == ip[2]
#else
&& *(const u16 *)ref == *(const u16 *)ip
&& ref[2] == ip[2]
#endif
)
{
/* match found at *ref++ */
unsigned int len = 2;
size_t maxlen = in_end - ip - len;
maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
if (op + lit + 1 + 3 >= out_end)
return 0;
do
len++;
while (len < maxlen && ref[len] == ip[len]);
if (lit)
{
*op++ = (u8)(lit - 1);
lit = -lit;
do
*op++ = ip[lit];
while (++lit);
}
len -= 2;
ip++;
if (len < 7)
{
*op++ = (u8)((off >> 8) + (len << 5));
}
else
{
*op++ = (u8)((off >> 8) + ( 7 << 5));
*op++ = (u8)(len - 7);
}
*op++ = (u8)off;
#if ULTRA_FAST || VERY_FAST
ip += len;
#if VERY_FAST && !ULTRA_FAST
--ip;
#endif
hval = FRST (ip);
hval = NEXT (hval, ip);
htab[IDX (hval)] = ip;
ip++;
#if VERY_FAST && !ULTRA_FAST
hval = NEXT (hval, ip);
htab[IDX (hval)] = ip;
ip++;
#endif
#else
do
{
hval = NEXT (hval, ip);
htab[IDX (hval)] = ip;
ip++;
}
while (len--);
#endif
continue;
}
}
else if (ip == in_end)
break;
/* one more literal byte we must copy */
lit++;
ip++;
if (lit == MAX_LIT)
{
if (op + 1 + MAX_LIT >= out_end)
return 0;
*op++ = MAX_LIT - 1;
#if USE_MEMCPY
M_Memcpy (op, ip - MAX_LIT, MAX_LIT);
op += MAX_LIT;
lit = 0;
#else
lit = -lit;
do
*op++ = ip[lit];
while (++lit);
#endif
}
}
if (lit)
{
if (op + lit + 1 >= out_end)
return 0;
*op++ = (u8)(lit - 1);
lit = -lit;
do
*op++ = ip[lit];
while (++lit);
}
return op - (u8 *) out_data;
}
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