lib/lz4/lz4defs.h

   1 #ifndef __LZ4DEFS_H__
   2 #define __LZ4DEFS_H__
   3
   4 /*
   5  * lz4defs.h -- common and architecture specific defines for the kernel usage
   6
   7  * LZ4 - Fast LZ compression algorithm
   8  * Copyright (C) 2011-2016, Yann Collet.
   9  * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions are
  12  * met:
  13  *      * Redistributions of source code must retain the above copyright
  14  *        notice, this list of conditions and the following disclaimer.
  15  *      * Redistributions in binary form must reproduce the above
  16  * copyright notice, this list of conditions and the following disclaimer
  17  * in the documentation and/or other materials provided with the
  18  * distribution.
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  * You can contact the author at :
  31  *      - LZ4 homepage : http://www.lz4.org
  32  *      - LZ4 source repository : https://github.com/lz4/lz4
  33  *
  34  *      Changed for kernel usage by:
  35  *      Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
  36  */
  37
  38 #include <asm/unaligned.h>
  39 #include <linux/string.h>        /* memset, memcpy */
  40
  41 #define FORCE_INLINE __always_inline
  42
  43 /*-************************************
  44  *      Basic Types
  45  **************************************/
  46 #include <linux/types.h>
  47
  48 typedef uint8_t BYTE;
  49 typedef uint16_t U16;
  50 typedef uint32_t U32;
  51 typedef int32_t S32;
  52 typedef uint64_t U64;
  53 typedef uintptr_t uptrval;
  54
  55 /*-************************************
  56  *      Architecture specifics
  57  **************************************/
  58 #if defined(CONFIG_64BIT)
  59 #define LZ4_ARCH64 1
  60 #else
  61 #define LZ4_ARCH64 0
  62 #endif
  63
  64 #if defined(__LITTLE_ENDIAN)
  65 #define LZ4_LITTLE_ENDIAN 1
  66 #else
  67 #define LZ4_LITTLE_ENDIAN 0
  68 #endif
  69
  70 /*-************************************
  71  *      Constants
  72  **************************************/
  73 #define MINMATCH 4
  74
  75 #define WILDCOPYLENGTH 8
  76 #define LASTLITERALS 5
  77 #define MFLIMIT (WILDCOPYLENGTH + MINMATCH)
  78 /*
  79  * ensure it's possible to write 2 x wildcopyLength
  80  * without overflowing output buffer
  81  */
  82 #define MATCH_SAFEGUARD_DISTANCE  ((2 * WILDCOPYLENGTH) - MINMATCH)
  83
  84 /* Increase this value ==> compression run slower on incompressible data */
  85 #define LZ4_SKIPTRIGGER 6
  86
  87 #define HASH_UNIT sizeof(size_t)
  88
  89 #define KB (1 << 10)
  90 #define MB (1 << 20)
  91 #define GB (1U << 30)
  92
  93 #define MAXD_LOG 16
  94 #define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
  95 #define STEPSIZE sizeof(size_t)
  96
  97 #define ML_BITS 4
  98 #define ML_MASK ((1U << ML_BITS) - 1)
  99 #define RUN_BITS (8 - ML_BITS)
 100 #define RUN_MASK ((1U << RUN_BITS) - 1)
 101
 102 /*-************************************
 103  *      Reading and writing into memory
 104  **************************************/
 105 static FORCE_INLINE U16 LZ4_read16(const void *ptr)
 106 {
 107         return get_unaligned((const U16 *)ptr);
 108 }
 109
 110 static FORCE_INLINE U32 LZ4_read32(const void *ptr)
 111 {
 112         return get_unaligned((const U32 *)ptr);
 113 }
 114
 115 static FORCE_INLINE size_t LZ4_read_ARCH(const void *ptr)
 116 {
 117         return get_unaligned((const size_t *)ptr);
 118 }
 119
 120 static FORCE_INLINE void LZ4_write16(void *memPtr, U16 value)
 121 {
 122         put_unaligned(value, (U16 *)memPtr);
 123 }
 124
 125 static FORCE_INLINE void LZ4_write32(void *memPtr, U32 value)
 126 {
 127         put_unaligned(value, (U32 *)memPtr);
 128 }
 129
 130 static FORCE_INLINE U16 LZ4_readLE16(const void *memPtr)
 131 {
 132         return get_unaligned_le16(memPtr);
 133 }
 134
 135 static FORCE_INLINE void LZ4_writeLE16(void *memPtr, U16 value)
 136 {
 137         return put_unaligned_le16(value, memPtr);
 138 }
 139
 140 /*
 141  * LZ4 relies on memcpy with a constant size being inlined. In freestanding
 142  * environments, the compiler can't assume the implementation of memcpy() is
 143  * standard compliant, so apply its specialized memcpy() inlining logic. When
 144  * possible, use __builtin_memcpy() to tell the compiler to analyze memcpy()
 145  * as-if it were standard compliant, so it can inline it in freestanding
 146  * environments. This is needed when decompressing the Linux Kernel, for example.
 147  */
 148 #define LZ4_memcpy(dst, src, size) __builtin_memcpy(dst, src, size)
 149 #define LZ4_memmove(dst, src, size) __builtin_memmove(dst, src, size)
 150
 151 static FORCE_INLINE void LZ4_copy8(void *dst, const void *src)
 152 {
 153 #if LZ4_ARCH64
 154         U64 a = get_unaligned((const U64 *)src);
 155
 156         put_unaligned(a, (U64 *)dst);
 157 #else
 158         U32 a = get_unaligned((const U32 *)src);
 159         U32 b = get_unaligned((const U32 *)src + 1);
 160
 161         put_unaligned(a, (U32 *)dst);
 162         put_unaligned(b, (U32 *)dst + 1);
 163 #endif
 164 }
 165
 166 /*
 167  * customized variant of memcpy,
 168  * which can overwrite up to 7 bytes beyond dstEnd
 169  */
 170 static FORCE_INLINE void LZ4_wildCopy(void *dstPtr,
 171         const void *srcPtr, void *dstEnd)
 172 {
 173         BYTE *d = (BYTE *)dstPtr;
 174         const BYTE *s = (const BYTE *)srcPtr;
 175         BYTE *const e = (BYTE *)dstEnd;
 176
 177         do {
 178                 LZ4_copy8(d, s);
 179                 d += 8;
 180                 s += 8;
 181         } while (d < e);
 182 }
 183
 184 static FORCE_INLINE unsigned int LZ4_NbCommonBytes(register size_t val)
 185 {
 186 #if LZ4_LITTLE_ENDIAN
 187         return __ffs(val) >> 3;
 188 #else
 189         return (BITS_PER_LONG - 1 - __fls(val)) >> 3;
 190 #endif
 191 }
 192
 193 static FORCE_INLINE unsigned int LZ4_count(
 194         const BYTE *pIn,
 195         const BYTE *pMatch,
 196         const BYTE *pInLimit)
 197 {
 198         const BYTE *const pStart = pIn;
 199
 200         while (likely(pIn < pInLimit - (STEPSIZE - 1))) {
 201                 size_t const diff = LZ4_read_ARCH(pMatch) ^ LZ4_read_ARCH(pIn);
 202
 203                 if (!diff) {
 204                         pIn += STEPSIZE;
 205                         pMatch += STEPSIZE;
 206                         continue;
 207                 }
 208
 209                 pIn += LZ4_NbCommonBytes(diff);
 210
 211                 return (unsigned int)(pIn - pStart);
 212         }
 213
 214 #if LZ4_ARCH64
 215         if ((pIn < (pInLimit - 3))
 216                 && (LZ4_read32(pMatch) == LZ4_read32(pIn))) {
 217                 pIn += 4;
 218                 pMatch += 4;
 219         }
 220 #endif
 221
 222         if ((pIn < (pInLimit - 1))
 223                 && (LZ4_read16(pMatch) == LZ4_read16(pIn))) {
 224                 pIn += 2;
 225                 pMatch += 2;
 226         }
 227
 228         if ((pIn < pInLimit) && (*pMatch == *pIn))
 229                 pIn++;
 230
 231         return (unsigned int)(pIn - pStart);
 232 }
 233
 234 typedef enum { noLimit = 0, limitedOutput = 1 } limitedOutput_directive;
 235 typedef enum { byPtr, byU32, byU16 } tableType_t;
 236
 237 typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
 238 typedef enum { noDictIssue = 0, dictSmall } dictIssue_directive;
 239
 240 typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
 241 typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive;
 242
 243 #define LZ4_STATIC_ASSERT(c)    BUILD_BUG_ON(!(c))
 244
 245 #endif