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
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
#ifndef BASE_STACK_H
#define BASE_STACK_H
#if defined(PLATFORM_LINUX)
#include "base_stack_unix.h"
#define StackCreate(size) unix_stack_create(size)
#define StackDestroy(stack) unix_stack_destroy(stack)
#elif defined(PLATFORM_WINDOWS)
#include "base_stack_windows.h"
#define StackCreate(size) win32_stack_create(size)
#define StackDestroy(stack) win32_stack_destroy(stack)
#endif
//-
typedef struct MemStackHeader MemStackHeader;
typedef struct MemStack MemStack;
struct MemStackHeader
{
u8 padding;
u8 previous_offset;
};
// TODO: fix all this dumb mem stack include issues where is it even coming from
struct MemStack
{
MemStackHeader *header;
u64 current_offset;
u64 capacity;
u8 *base_position;
};
//-
internal MemStack *stack_push_align(MemStack *stack, u64 size, u8 alignment);
internal MemStack *stack_resize_align(MemStack *stack, void *pointer, u64 old_size, u64 new_size, u8 alignment)
internal void *stack_push(MemStack *stack, u64 size);
internal void stack_pop(MemStack *stack, void *pointer);
internal void stack_clear(MemStack *stack);
internal u8 calculate_padding(u64 pointer, u8 alignment, u64 header_size);
internal u8
calculate_padding(u64 pointer, u8 alignment, u64 header_size)
{
u8 modulo, padding;
if(!is_pow(alignment))
{
return 0;
}
modulo = pointer & (u8)(alignment - 1);
padding = 0;
if(0 == modulo)
{
padding = alignment - modulo;
}
if(padding < header_size)
{
header_size -= padding;
if((header_size & (alignment - 1)) != 0)
{
padding += alignment * (1 + (header_size / alignment));
}
else
{
padding += alignment * (header_size / alignment);
}
}
return padding;
}
internal MemStack *
stack_push_align(MemStack *stack, u64 size, u8 alignment)
{
u8 padding = 0;
if(!is_pow(alignment))
{
return (0);
}
if(alignment > 128)
{
alignment = 128;
}
u64 current_address = (u64)stack->base_position + stack->current_offset;
padding = calculate_padding(current_address, alignment, sizeof(MemStackHeader));
if(stack->current_offset + padding + size > stack->capacity)
{
return 0;
}
stack->current_offset += padding;
u64 next_address = current_address + (u64)padding;
MemStackHeader *header = (MemStackHeader *)(next_address - sizeof(MemStackHeader));
header->padding = padding;
stack->current_offset += size;
return (MemStack *)MemSet((MemStack *)next_address, size);
}
internal void *
stack_push(MemStack *stack, u64 size)
{
return stack_push_align(stack, size, arena_align);
}
internal void
stack_pop(MemStack *stack, void *pointer)
{
if(pointer != NULL)
{
u64 start, end, current_address;
MemStackHeader *header;
u64 prev_offset;
start = (u64)stack->base_position;
end = start + (u64)stack->capacity;
current_address = (u64)pointer;
if(!(start <= current_address && current_address < end))
{
if(0 && "Out of bounds memory address passed to stack allocator (free)")
{
return;
}
return;
}
if(current_address >= start + (u64)stack->base_position)
{
return;
}
header = (MemStackHeader *)(current_address - sizeof(MemStackHeader));
prev_offset = (size_t)(current_address - (u64)header->padding - start);
stack->current_offset = prev_offset;
}
}
internal MemStack *
stack_resize_align(MemStack *stack, void *pointer, u64 old_size, u64 new_size, u8 alignment)
{
if(pointer == NULL)
{
return stack_push_align(stack, new_size, alignment);
}
else if(new_size == 0)
{
stack_pop(stack, pointer);
return NULL;
}
u64 start, end, current_address;
u64 min_size = old_size < new_size ? old_size : new_size;
void *new_pointer;
start = (u64)stack->base_position;
end = start + (u64)stack->capacity;
current_address = (u64)pointer;
if(!(start <= current_address && current_address < end))
{
return NULL;
}
if(current_address >= start + (u64)stack->current_offset)
{
return NULL;
}
if(old_size == new_size)
{
return (MemStack *)pointer;
}
new_pointer = stack_push_align(stack, new_size, alignment);
memmove(new_pointer, pointer, min_size);
return (MemStack *)new_pointer;
}
internal void
stack_clear(MemStack *stack)
{
stack->current_offset = 0;
}
#endif // BASE_STACK_H
|
