+++ /dev/null
-/*
- * 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 "lzfP.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 > (u8 *)in_data
-#if STRICT_ALIGN
- && ref[0] == ip[0]
- && ref[1] == ip[1]
- && ref[2] == ip[2]
-#else
- && *(u16 *)ref == *(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;
-
- op [- lit - 1] = lit - 1; /* stop run */
- op -= !lit; /* undo run if length is zero */
-
- if (expect_false (op + 3 + 1 >= out_end))
- return 0;
-
- 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;
-}
-
projects / redis.git / blobdiff