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 */