LXR linux/lib/zstd/mem.h

   1/**
   2 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
   3 * All rights reserved.
   4 *
   5 * This source code is licensed under the BSD-style license found in the
   6 * LICENSE file in the root directory of https://github.com/facebook/zstd.
   7 * An additional grant of patent rights can be found in the PATENTS file in the
   8 * same directory.
   9 *
  10 * This program is free software; you can redistribute it and/or modify it under
  11 * the terms of the GNU General Public License version 2 as published by the
  12 * Free Software Foundation. This program is dual-licensed; you may select
  13 * either version 2 of the GNU General Public License ("GPL") or BSD license
  14 * ("BSD").
  15 */
  16
  17#ifndef MEM_H_MODULE
  18#define MEM_H_MODULE
  19
  20/*-****************************************
  21*  Dependencies
  22******************************************/
  23#include <asm/unaligned.h>
  24#include <linux/string.h> /* memcpy */
  25#include <linux/types.h>  /* size_t, ptrdiff_t */
  26
  27/*-****************************************
  28*  Compiler specifics
  29******************************************/
  30#define ZSTD_STATIC static __inline __attribute__((unused))
  31
  32/*-**************************************************************
  33*  Basic Types
  34*****************************************************************/
  35typedef uint8_t BYTE;
  36typedef uint16_t U16;
  37typedef int16_t S16;
  38typedef uint32_t U32;
  39typedef int32_t S32;
  40typedef uint64_t U64;
  41typedef int64_t S64;
  42typedef ptrdiff_t iPtrDiff;
  43typedef uintptr_t uPtrDiff;
  44
  45/*-**************************************************************
  46*  Memory I/O
  47*****************************************************************/
  48ZSTD_STATIC unsigned ZSTD_32bits(void) { return sizeof(size_t) == 4; }
  49ZSTD_STATIC unsigned ZSTD_64bits(void) { return sizeof(size_t) == 8; }
  50
  51#if defined(__LITTLE_ENDIAN)
  52#define ZSTD_LITTLE_ENDIAN 1
  53#else
  54#define ZSTD_LITTLE_ENDIAN 0
  55#endif
  56
  57ZSTD_STATIC unsigned ZSTD_isLittleEndian(void) { return ZSTD_LITTLE_ENDIAN; }
  58
  59ZSTD_STATIC U16 ZSTD_read16(const void *memPtr) { return get_unaligned((const U16 *)memPtr); }
  60
  61ZSTD_STATIC U32 ZSTD_read32(const void *memPtr) { return get_unaligned((const U32 *)memPtr); }
  62
  63ZSTD_STATIC U64 ZSTD_read64(const void *memPtr) { return get_unaligned((const U64 *)memPtr); }
  64
  65ZSTD_STATIC size_t ZSTD_readST(const void *memPtr) { return get_unaligned((const size_t *)memPtr); }
  66
  67ZSTD_STATIC void ZSTD_write16(void *memPtr, U16 value) { put_unaligned(value, (U16 *)memPtr); }
  68
  69ZSTD_STATIC void ZSTD_write32(void *memPtr, U32 value) { put_unaligned(value, (U32 *)memPtr); }
  70
  71ZSTD_STATIC void ZSTD_write64(void *memPtr, U64 value) { put_unaligned(value, (U64 *)memPtr); }
  72
  73/*=== Little endian r/w ===*/
  74
  75ZSTD_STATIC U16 ZSTD_readLE16(const void *memPtr) { return get_unaligned_le16(memPtr); }
  76
  77ZSTD_STATIC void ZSTD_writeLE16(void *memPtr, U16 val) { put_unaligned_le16(val, memPtr); }
  78
  79ZSTD_STATIC U32 ZSTD_readLE24(const void *memPtr) { return ZSTD_readLE16(memPtr) + (((const BYTE *)memPtr)[2] << 16); }
  80
  81ZSTD_STATIC void ZSTD_writeLE24(void *memPtr, U32 val)
  82{
  83        ZSTD_writeLE16(memPtr, (U16)val);
  84        ((BYTE *)memPtr)[2] = (BYTE)(val >> 16);
  85}
  86
  87ZSTD_STATIC U32 ZSTD_readLE32(const void *memPtr) { return get_unaligned_le32(memPtr); }
  88
  89ZSTD_STATIC void ZSTD_writeLE32(void *memPtr, U32 val32) { put_unaligned_le32(val32, memPtr); }
  90
  91ZSTD_STATIC U64 ZSTD_readLE64(const void *memPtr) { return get_unaligned_le64(memPtr); }
  92
  93ZSTD_STATIC void ZSTD_writeLE64(void *memPtr, U64 val64) { put_unaligned_le64(val64, memPtr); }
  94
  95ZSTD_STATIC size_t ZSTD_readLEST(const void *memPtr)
  96{
  97        if (ZSTD_32bits())
  98                return (size_t)ZSTD_readLE32(memPtr);
  99        else
 100                return (size_t)ZSTD_readLE64(memPtr);
 101}
 102
 103ZSTD_STATIC void ZSTD_writeLEST(void *memPtr, size_t val)
 104{
 105        if (ZSTD_32bits())
 106                ZSTD_writeLE32(memPtr, (U32)val);
 107        else
 108                ZSTD_writeLE64(memPtr, (U64)val);
 109}
 110
 111/*=== Big endian r/w ===*/
 112
 113ZSTD_STATIC U32 ZSTD_readBE32(const void *memPtr) { return get_unaligned_be32(memPtr); }
 114
 115ZSTD_STATIC void ZSTD_writeBE32(void *memPtr, U32 val32) { put_unaligned_be32(val32, memPtr); }
 116
 117ZSTD_STATIC U64 ZSTD_readBE64(const void *memPtr) { return get_unaligned_be64(memPtr); }
 118
 119ZSTD_STATIC void ZSTD_writeBE64(void *memPtr, U64 val64) { put_unaligned_be64(val64, memPtr); }
 120
 121ZSTD_STATIC size_t ZSTD_readBEST(const void *memPtr)
 122{
 123        if (ZSTD_32bits())
 124                return (size_t)ZSTD_readBE32(memPtr);
 125        else
 126                return (size_t)ZSTD_readBE64(memPtr);
 127}
 128
 129ZSTD_STATIC void ZSTD_writeBEST(void *memPtr, size_t val)
 130{
 131        if (ZSTD_32bits())
 132                ZSTD_writeBE32(memPtr, (U32)val);
 133        else
 134                ZSTD_writeBE64(memPtr, (U64)val);
 135}
 136
 137/* function safe only for comparisons */
 138ZSTD_STATIC U32 ZSTD_readMINMATCH(const void *memPtr, U32 length)
 139{
 140        switch (length) {
 141        default:
 142        case 4: return ZSTD_read32(memPtr);
 143        case 3:
 144                if (ZSTD_isLittleEndian())
 145                        return ZSTD_read32(memPtr) << 8;
 146                else
 147                        return ZSTD_read32(memPtr) >> 8;
 148        }
 149}
 150
 151#endif /* MEM_H_MODULE */
 152