osfmk/vm/lz4.h

   1 /*
   2  * Copyright (c) 2016-2016 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #pragma once
  30 #include <stdint.h>
  31 #include <stddef.h>
  32 #include <kern/assert.h>
  33 #include <machine/machlimits.h>
  34 #include "lz4_assembly_select.h"
  35 #include "lz4_constants.h"
  36
  37 #define memcpy __builtin_memcpy
  38
  39 #pragma mark - Building blocks
  40
  41 //  Represents a position in the input stream
  42 typedef struct { uint32_t offset; uint32_t word; } lz4_hash_entry_t;
  43 static const size_t lz4_hash_table_size = LZ4_COMPRESS_HASH_ENTRIES*sizeof(lz4_hash_entry_t);
  44
  45 // Worker function for lz4 encode.  Underlies both the buffer and stream encode operations.
  46 // Performs lz4 encoding of up to 2gb of data, updates dst_ptr and src_ptr to point to the
  47 // first byte of output and input that couldn't be completely processed, respectively.
  48 //
  49 // If skip_final_literals is 0, the entire src buffer is encoded, by emitting a final sequence of literals
  50 // at the end of the compressed payload.
  51 //
  52 // If skip_final_literals is not 0, this final literal sequence is not emitted, and the src buffer is
  53 // partially encoded (the length of this literal sequence varies).
  54 extern void lz4_encode_2gb(uint8_t **dst_ptr, size_t dst_size,
  55                            const uint8_t **src_ptr, const uint8_t *src_begin, size_t src_size,
  56                            lz4_hash_entry_t hash_table[LZ4_COMPRESS_HASH_ENTRIES],int skip_final_literals);
  57
  58 extern int lz4_decode(uint8_t **dst_ptr, uint8_t *dst_begin, uint8_t *dst_end,
  59                       const uint8_t **src_ptr, const uint8_t *src_end);
  60
  61 #if LZ4_ENABLE_ASSEMBLY_DECODE
  62 extern int lz4_decode_asm(uint8_t **dst_ptr, uint8_t *dst_begin, uint8_t *dst_end,
  63                           const uint8_t **src_ptr, const uint8_t *src_end);
  64 #endif
  65
  66 #pragma mark - Buffer interfaces
  67
  68 static const size_t lz4_encode_scratch_size = lz4_hash_table_size;
  69 static const size_t lz4_decode_scratch_size = 0;
  70
  71 #pragma mark - Buffer interfaces (LZ4 RAW)
  72
  73 size_t lz4raw_encode_buffer(uint8_t * __restrict dst_buffer, size_t dst_size,
  74                             const uint8_t * __restrict src_buffer, size_t src_size,
  75                             lz4_hash_entry_t hash_table[LZ4_COMPRESS_HASH_ENTRIES]);
  76
  77 size_t lz4raw_decode_buffer(uint8_t * __restrict dst_buffer, size_t dst_size,
  78                             const uint8_t * __restrict src_buffer, size_t src_size,
  79                             void * __restrict work __attribute__((unused)));
  80
  81 typedef __attribute__((__ext_vector_type__(8)))  uint8_t vector_uchar8;
  82 typedef __attribute__((__ext_vector_type__(16))) uint8_t vector_uchar16;
  83 typedef __attribute__((__ext_vector_type__(32))) uint8_t vector_uchar32;
  84 typedef __attribute__((__ext_vector_type__(64))) uint8_t vector_uchar64;
  85 typedef __attribute__((__ext_vector_type__(16),__aligned__(1))) uint8_t packed_uchar16;
  86 typedef __attribute__((__ext_vector_type__(32),__aligned__(1))) uint8_t packed_uchar32;
  87 typedef __attribute__((__ext_vector_type__(64),__aligned__(1))) uint8_t packed_uchar64;
  88
  89 typedef __attribute__((__ext_vector_type__(4))) uint16_t vector_ushort4;
  90 typedef __attribute__((__ext_vector_type__(4),__aligned__(2))) uint16_t packed_ushort4;
  91
  92 typedef __attribute__((__ext_vector_type__(2))) int32_t vector_int2;
  93 typedef __attribute__((__ext_vector_type__(4))) int32_t vector_int4;
  94 typedef __attribute__((__ext_vector_type__(8))) int32_t vector_int8;
  95
  96 typedef __attribute__((__ext_vector_type__(4))) uint32_t vector_uint4;
  97
  98 #define UTIL_FUNCTION static inline __attribute__((__always_inline__)) __attribute__((__overloadable__))
  99
 100 // Load N bytes from unaligned location PTR
 101 UTIL_FUNCTION uint16_t load2(const void * ptr) { uint16_t data; memcpy(&data,ptr,sizeof data); return data; }
 102 UTIL_FUNCTION uint32_t load4(const void * ptr) { uint32_t data; memcpy(&data,ptr,sizeof data); return data; }
 103 UTIL_FUNCTION uint64_t load8(const void * ptr) { uint64_t data; memcpy(&data,ptr,sizeof data); return data; }
 104 UTIL_FUNCTION vector_uchar16 load16(const void * ptr) { return (const vector_uchar16)*(const packed_uchar16 *)ptr; }
 105 UTIL_FUNCTION vector_uchar32 load32(const void * ptr) { return (const vector_uchar32)*(const packed_uchar32 *)ptr; }
 106 UTIL_FUNCTION vector_uchar64 load64(const void * ptr) { return (const vector_uchar64)*(const packed_uchar64 *)ptr; }
 107
 108 // Store N bytes to unaligned location PTR
 109 UTIL_FUNCTION void store2(void * ptr,uint16_t data) { memcpy(ptr,&data,sizeof data); }
 110 UTIL_FUNCTION void store4(void * ptr,uint32_t data) { memcpy(ptr,&data,sizeof data); }
 111 UTIL_FUNCTION void store8(void * ptr,uint64_t data) { memcpy(ptr,&data,sizeof data); }
 112 UTIL_FUNCTION void store16(void * ptr,vector_uchar16 data) { *(packed_uchar16 *)ptr = (packed_uchar16)data; }
 113 UTIL_FUNCTION void store32(void * ptr,vector_uchar32 data) { *(packed_uchar32 *)ptr = (packed_uchar32)data; }
 114 UTIL_FUNCTION void store64(void * ptr,vector_uchar64 data) { *(packed_uchar64 *)ptr = (packed_uchar64)data; }
 115
 116 // Load+Store N bytes from unaligned locations SRC to DST. No overlap allowed.
 117 UTIL_FUNCTION void copy8(void * dst,const void * src) { store8(dst,load8(src)); }
 118 UTIL_FUNCTION void copy16(void * dst,const void * src) { *(packed_uchar16 *)dst = *(const packed_uchar16 *)src; }
 119 UTIL_FUNCTION void copy32(void * dst,const void * src) { *(packed_uchar32 *)dst = *(const packed_uchar32 *)src; }
 120
 121 #undef memcpy