1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
/*
* Copyright (C) the libgit2 contributors. All rights reserved.
*
* This file is part of libgit2, distributed under the GNU GPL v2 with
* a Linking Exception. For full terms see the included COPYING file.
*/
#ifndef INCLUDE_pool_h__
#define INCLUDE_pool_h__
#include "common.h"
typedef struct git_pool_page git_pool_page;
/**
* Chunked allocator.
*
* A `git_pool` can be used when you want to cheaply allocate
* multiple items of the same type and are willing to free them
* all together with a single call. The two most common cases
* are a set of fixed size items (such as lots of OIDs) or a
* bunch of strings.
*
* Internally, a `git_pool` allocates pages of memory and then
* deals out blocks from the trailing unused portion of each page.
* The pages guarantee that the number of actual allocations done
* will be much smaller than the number of items needed.
*
* For examples of how to set up a `git_pool` see `git_pool_init`.
*/
typedef struct {
git_pool_page *open; /* pages with space left */
git_pool_page *full; /* pages with no space left */
void *free_list; /* optional: list of freed blocks */
uint32_t item_size; /* size of single alloc unit in bytes */
uint32_t page_size; /* size of page in bytes */
uint32_t items;
unsigned has_string_alloc : 1; /* was the strdup function used */
unsigned has_multi_item_alloc : 1; /* was items ever > 1 in malloc */
unsigned has_large_page_alloc : 1; /* are any pages > page_size */
} git_pool;
#define GIT_POOL_INIT_STRINGPOOL { 0, 0, 0, 1, 4000, 0, 0, 0, 0 }
/**
* Initialize a pool.
*
* To allocation strings, use like this:
*
* git_pool_init(&string_pool, 1, 0);
* my_string = git_pool_strdup(&string_pool, your_string);
*
* To allocate items of fixed size, use like this:
*
* git_pool_init(&pool, sizeof(item), 0);
* my_item = git_pool_malloc(&pool, 1);
*
* Of course, you can use this in other ways, but those are the
* two most common patterns.
*/
extern int git_pool_init(
git_pool *pool, uint32_t item_size, uint32_t items_per_page);
/**
* Free all items in pool
*/
extern void git_pool_clear(git_pool *pool);
/**
* Swap two pools with one another
*/
extern void git_pool_swap(git_pool *a, git_pool *b);
/**
* Allocate space for one or more items from a pool.
*/
extern void *git_pool_malloc(git_pool *pool, uint32_t items);
/**
* Allocate space and zero it out.
*/
GIT_INLINE(void *) git_pool_mallocz(git_pool *pool, uint32_t items)
{
void *ptr = git_pool_malloc(pool, items);
if (ptr)
memset(ptr, 0, (size_t)items * (size_t)pool->item_size);
return ptr;
}
/**
* Allocate space and duplicate string data into it.
*
* This is allowed only for pools with item_size == sizeof(char)
*/
extern char *git_pool_strndup(git_pool *pool, const char *str, size_t n);
/**
* Allocate space and duplicate a string into it.
*
* This is allowed only for pools with item_size == sizeof(char)
*/
extern char *git_pool_strdup(git_pool *pool, const char *str);
/**
* Allocate space and duplicate a string into it, NULL is no error.
*
* This is allowed only for pools with item_size == sizeof(char)
*/
extern char *git_pool_strdup_safe(git_pool *pool, const char *str);
/**
* Allocate space for the concatenation of two strings.
*
* This is allowed only for pools with item_size == sizeof(char)
*/
extern char *git_pool_strcat(git_pool *pool, const char *a, const char *b);
/**
* Push a block back onto the free list for the pool.
*
* This is allowed only if the item_size is >= sizeof(void*).
*
* In some cases, it is helpful to "release" an allocated block
* for reuse. Pools don't support a general purpose free, but
* they will keep a simple free blocks linked list provided the
* native block size is large enough to hold a void pointer
*/
extern void git_pool_free(git_pool *pool, void *ptr);
/**
* Push an array of pool allocated blocks efficiently onto the free list.
*
* This has the same constraints as `git_pool_free()` above.
*/
extern void git_pool_free_array(git_pool *pool, size_t count, void **ptrs);
/*
* Misc utilities
*/
extern uint32_t git_pool__open_pages(git_pool *pool);
extern uint32_t git_pool__full_pages(git_pool *pool);
extern bool git_pool__ptr_in_pool(git_pool *pool, void *ptr);
extern uint32_t git_pool__suggest_items_per_page(uint32_t item_size);
#endif
|
