linux/lib/zstd/mem.h

152 lines
4.7 KiB
C

/**
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of https://github.com/facebook/zstd.
* An additional grant of patent rights can be found in the PATENTS file in the
* same directory.
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2 as published by the
* Free Software Foundation. This program is dual-licensed; you may select
* either version 2 of the GNU General Public License ("GPL") or BSD license
* ("BSD").
*/
#ifndef MEM_H_MODULE
#define MEM_H_MODULE
/*-****************************************
* Dependencies
******************************************/
#include <asm/unaligned.h>
#include <linux/string.h> /* memcpy */
#include <linux/types.h> /* size_t, ptrdiff_t */
/*-****************************************
* Compiler specifics
******************************************/
#define ZSTD_STATIC static inline
/*-**************************************************************
* Basic Types
*****************************************************************/
typedef uint8_t BYTE;
typedef uint16_t U16;
typedef int16_t S16;
typedef uint32_t U32;
typedef int32_t S32;
typedef uint64_t U64;
typedef int64_t S64;
typedef ptrdiff_t iPtrDiff;
typedef uintptr_t uPtrDiff;
/*-**************************************************************
* Memory I/O
*****************************************************************/
ZSTD_STATIC unsigned ZSTD_32bits(void) { return sizeof(size_t) == 4; }
ZSTD_STATIC unsigned ZSTD_64bits(void) { return sizeof(size_t) == 8; }
#if defined(__LITTLE_ENDIAN)
#define ZSTD_LITTLE_ENDIAN 1
#else
#define ZSTD_LITTLE_ENDIAN 0
#endif
ZSTD_STATIC unsigned ZSTD_isLittleEndian(void) { return ZSTD_LITTLE_ENDIAN; }
ZSTD_STATIC U16 ZSTD_read16(const void *memPtr) { return get_unaligned((const U16 *)memPtr); }
ZSTD_STATIC U32 ZSTD_read32(const void *memPtr) { return get_unaligned((const U32 *)memPtr); }
ZSTD_STATIC U64 ZSTD_read64(const void *memPtr) { return get_unaligned((const U64 *)memPtr); }
ZSTD_STATIC size_t ZSTD_readST(const void *memPtr) { return get_unaligned((const size_t *)memPtr); }
ZSTD_STATIC void ZSTD_write16(void *memPtr, U16 value) { put_unaligned(value, (U16 *)memPtr); }
ZSTD_STATIC void ZSTD_write32(void *memPtr, U32 value) { put_unaligned(value, (U32 *)memPtr); }
ZSTD_STATIC void ZSTD_write64(void *memPtr, U64 value) { put_unaligned(value, (U64 *)memPtr); }
/*=== Little endian r/w ===*/
ZSTD_STATIC U16 ZSTD_readLE16(const void *memPtr) { return get_unaligned_le16(memPtr); }
ZSTD_STATIC void ZSTD_writeLE16(void *memPtr, U16 val) { put_unaligned_le16(val, memPtr); }
ZSTD_STATIC U32 ZSTD_readLE24(const void *memPtr) { return ZSTD_readLE16(memPtr) + (((const BYTE *)memPtr)[2] << 16); }
ZSTD_STATIC void ZSTD_writeLE24(void *memPtr, U32 val)
{
ZSTD_writeLE16(memPtr, (U16)val);
((BYTE *)memPtr)[2] = (BYTE)(val >> 16);
}
ZSTD_STATIC U32 ZSTD_readLE32(const void *memPtr) { return get_unaligned_le32(memPtr); }
ZSTD_STATIC void ZSTD_writeLE32(void *memPtr, U32 val32) { put_unaligned_le32(val32, memPtr); }
ZSTD_STATIC U64 ZSTD_readLE64(const void *memPtr) { return get_unaligned_le64(memPtr); }
ZSTD_STATIC void ZSTD_writeLE64(void *memPtr, U64 val64) { put_unaligned_le64(val64, memPtr); }
ZSTD_STATIC size_t ZSTD_readLEST(const void *memPtr)
{
if (ZSTD_32bits())
return (size_t)ZSTD_readLE32(memPtr);
else
return (size_t)ZSTD_readLE64(memPtr);
}
ZSTD_STATIC void ZSTD_writeLEST(void *memPtr, size_t val)
{
if (ZSTD_32bits())
ZSTD_writeLE32(memPtr, (U32)val);
else
ZSTD_writeLE64(memPtr, (U64)val);
}
/*=== Big endian r/w ===*/
ZSTD_STATIC U32 ZSTD_readBE32(const void *memPtr) { return get_unaligned_be32(memPtr); }
ZSTD_STATIC void ZSTD_writeBE32(void *memPtr, U32 val32) { put_unaligned_be32(val32, memPtr); }
ZSTD_STATIC U64 ZSTD_readBE64(const void *memPtr) { return get_unaligned_be64(memPtr); }
ZSTD_STATIC void ZSTD_writeBE64(void *memPtr, U64 val64) { put_unaligned_be64(val64, memPtr); }
ZSTD_STATIC size_t ZSTD_readBEST(const void *memPtr)
{
if (ZSTD_32bits())
return (size_t)ZSTD_readBE32(memPtr);
else
return (size_t)ZSTD_readBE64(memPtr);
}
ZSTD_STATIC void ZSTD_writeBEST(void *memPtr, size_t val)
{
if (ZSTD_32bits())
ZSTD_writeBE32(memPtr, (U32)val);
else
ZSTD_writeBE64(memPtr, (U64)val);
}
/* function safe only for comparisons */
ZSTD_STATIC U32 ZSTD_readMINMATCH(const void *memPtr, U32 length)
{
switch (length) {
default:
case 4: return ZSTD_read32(memPtr);
case 3:
if (ZSTD_isLittleEndian())
return ZSTD_read32(memPtr) << 8;
else
return ZSTD_read32(memPtr) >> 8;
}
}
#endif /* MEM_H_MODULE */