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freebsd/sbin/hastd/lzf.c
Pedro F. Giffuni 1de7b4b805 various: general adoption of SPDX licensing ID tags. 
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.
2017-11-27 15:37:16 +00:00

409 lines
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de>
*
* Redistribution and use in source and binary forms, with or without modifica-
* tion, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Alternatively, the contents of this file may be used under the terms of
* the GNU General Public License ("GPL") version 2 or any later version,
* in which case the provisions of the GPL are applicable instead of
* the above. If you wish to allow the use of your version of this file
* only under the terms of the GPL and not to allow others to use your
* version of this file under the BSD license, indicate your decision
* by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL. If you do not delete the
* provisions above, a recipient may use your version of this file under
* either the BSD or the GPL.
*/
#include "lzf.h"
#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])
# if ULTRA_FAST
# define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1))
# elif VERY_FAST
# define IDX(h) ((( h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
# else
# define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1))
# endif
#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 compresses similarly.
*
* 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))
#if __GNUC__ >= 3
# define expect(expr,value) __builtin_expect ((expr),(value))
# define inline inline
#else
# define expect(expr,value) (expr)
# define inline static
#endif
#define expect_false(expr) expect ((expr) != 0, 0)
#define expect_true(expr) expect ((expr) != 0, 1)
/*
* compressed format
*
* 000LLLLL <L+1> ; literal
* LLLooooo oooooooo ; backref L
* 111ooooo LLLLLLLL oooooooo ; backref L+7
*
*/
unsigned int
lzf_compress (const void *const in_data, unsigned int in_len,
void *out_data, unsigned int 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;
/* off requires a type wide enough to hold a general pointer difference.
* ISO C doesn't have that (size_t might not be enough and ptrdiff_t only
* works for differences within a single object). We also assume that no
* no bit pattern traps. Since the only platform that is both non-POSIX
* and fails to support both assumptions is windows 64 bit, we make a
* special workaround for it.
*/
#if defined (WIN32) && defined (_M_X64)
unsigned _int64 off; /* workaround for missing POSIX compliance */
#else
unsigned long off;
#endif
unsigned int hval;
int lit;
if (!in_len || !out_len)
return 0;
#if INIT_HTAB
memset (htab, 0, sizeof (htab));
# if 0
for (hslot = htab; hslot < htab + HSIZE; hslot++)
*hslot++ = ip;
# endif
#endif
lit = 0; op++; /* start run */
hval = FRST (ip);
while (ip < in_end - 2)
{
hval = NEXT (hval, ip);
hslot = htab + IDX (hval);
ref = *hslot; *hslot = ip;
if (1
#if INIT_HTAB
&& 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;
unsigned int maxlen = in_end - ip - len;
maxlen = maxlen > MAX_REF ? MAX_REF : maxlen;
if (expect_false (op + 3 + 1 >= out_end)) /* first a faster conservative test */
if (op - !lit + 3 + 1 >= out_end) /* second the exact but rare test */
return 0;
op [- lit - 1] = lit - 1; /* stop run */
op -= !lit; /* undo run if length is zero */
for (;;)
{
if (expect_true (maxlen > 16))
{
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
len++; if (ref [len] != ip [len]) break;
}
do
len++;
while (len < maxlen && ref[len] == ip[len]);
break;
}
len -= 2; /* len is now #octets - 1 */
ip++;
if (len < 7)
{
*op++ = (off >> 8) + (len << 5);
}
else
{
*op++ = (off >> 8) + ( 7 << 5);
*op++ = len - 7;
}
*op++ = off;
lit = 0; op++; /* start run */
ip += len + 1;
if (expect_false (ip >= in_end - 2))
break;
#if ULTRA_FAST || VERY_FAST
--ip;
# 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
ip -= len + 1;
do
{
hval = NEXT (hval, ip);
htab[IDX (hval)] = ip;
ip++;
}
while (len--);
#endif
}
else
{
/* one more literal byte we must copy */
if (expect_false (op >= out_end))
return 0;
lit++; *op++ = *ip++;
if (expect_false (lit == MAX_LIT))
{
op [- lit - 1] = lit - 1; /* stop run */
lit = 0; op++; /* start run */
}
}
}
if (op + 3 > out_end) /* at most 3 bytes can be missing here */
return 0;
while (ip < in_end)
{
lit++; *op++ = *ip++;
if (expect_false (lit == MAX_LIT))
{
op [- lit - 1] = lit - 1; /* stop run */
lit = 0; op++; /* start run */
}
}
op [- lit - 1] = lit - 1; /* end run */
op -= !lit; /* undo run if length is zero */
return op - (u8 *)out_data;
}
#if AVOID_ERRNO
# define SET_ERRNO(n)
#else
# include <errno.h>
# define SET_ERRNO(n) errno = (n)
#endif
#if (__i386 || __amd64) && __GNUC__ >= 3
# define lzf_movsb(dst, src, len) \
asm ("rep movsb" \
: "=D" (dst), "=S" (src), "=c" (len) \
: "0" (dst), "1" (src), "2" (len));
#endif
unsigned int
lzf_decompress (const void *const in_data, unsigned int in_len,
void *out_data, unsigned int 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
#ifdef lzf_movsb
lzf_movsb (op, 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;
}
#ifdef lzf_movsb
len += 2;
lzf_movsb (op, ref, len);
#else
*op++ = *ref++;
*op++ = *ref++;
do
*op++ = *ref++;
while (--len);
#endif
}
}
while (ip < in_end);
return op - (u8 *)out_data;
}
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