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 /*-*************************************
18 *  Dependencies
19 ***************************************/
20 #include "error_private.h"
21 #include "zstd_internal.h" /* declaration of ZSTD_isError, ZSTD_getErrorName, ZSTD_getErrorCode, ZSTD_getErrorString, ZSTD_versionNumber */
22 #include <linux/kernel.h>
23 
24 /*=**************************************************************
25 *  Custom allocator
26 ****************************************************************/
27 
28 #define stack_push(stack, size)                                 \
29 	({                                                      \
30 		void *const ptr = ZSTD_PTR_ALIGN((stack)->ptr); \
31 		(stack)->ptr = (char *)ptr + (size);            \
32 		(stack)->ptr <= (stack)->end ? ptr : NULL;      \
33 	})
34 
ZSTD_initStack(void * workspace,size_t workspaceSize)35 ZSTD_customMem ZSTD_initStack(void *workspace, size_t workspaceSize)
36 {
37 	ZSTD_customMem stackMem = {ZSTD_stackAlloc, ZSTD_stackFree, workspace};
38 	ZSTD_stack *stack = (ZSTD_stack *)workspace;
39 	/* Verify preconditions */
40 	if (!workspace || workspaceSize < sizeof(ZSTD_stack) || workspace != ZSTD_PTR_ALIGN(workspace)) {
41 		ZSTD_customMem error = {NULL, NULL, NULL};
42 		return error;
43 	}
44 	/* Initialize the stack */
45 	stack->ptr = workspace;
46 	stack->end = (char *)workspace + workspaceSize;
47 	stack_push(stack, sizeof(ZSTD_stack));
48 	return stackMem;
49 }
50 
ZSTD_stackAllocAll(void * opaque,size_t * size)51 void *ZSTD_stackAllocAll(void *opaque, size_t *size)
52 {
53 	ZSTD_stack *stack = (ZSTD_stack *)opaque;
54 	*size = (BYTE const *)stack->end - (BYTE *)ZSTD_PTR_ALIGN(stack->ptr);
55 	return stack_push(stack, *size);
56 }
57 
ZSTD_stackAlloc(void * opaque,size_t size)58 void *ZSTD_stackAlloc(void *opaque, size_t size)
59 {
60 	ZSTD_stack *stack = (ZSTD_stack *)opaque;
61 	return stack_push(stack, size);
62 }
ZSTD_stackFree(void * opaque,void * address)63 void ZSTD_stackFree(void *opaque, void *address)
64 {
65 	(void)opaque;
66 	(void)address;
67 }
68 
ZSTD_malloc(size_t size,ZSTD_customMem customMem)69 void *ZSTD_malloc(size_t size, ZSTD_customMem customMem) { return customMem.customAlloc(customMem.opaque, size); }
70 
ZSTD_free(void * ptr,ZSTD_customMem customMem)71 void ZSTD_free(void *ptr, ZSTD_customMem customMem)
72 {
73 	if (ptr != NULL)
74 		customMem.customFree(customMem.opaque, ptr);
75 }
76