add: test to galloc and advance on galloc

This commit is contained in:
Camille Chauvet 2023-06-14 15:51:21 +00:00
parent 5bc4e3ee51
commit 9e53614c44
2 changed files with 79 additions and 23 deletions

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@ -1,24 +1,49 @@
define header_size = 3;
define protection_size = 4;
define heap_size = 65536
define PADDING_SIZE = 4;
define HEADER_SIZE = PADDING_SIZE * 2 + 5;
global heap[header_size] = 0;
define HEAP_SIZE = 65536;
global heap[HEADER_SIZE] = 0;
🗿HEADER REPRESENTATION
🗿+-------------------------+-----------------------------+-----------------------------+---------+---------+---------+
🗿| index of the next block | index of the previous block | used (if the block is used) | padding | data | padding |
🗿| 1 case | 1 case | 1 case | 4 cases | n cases | 4 cases |
🗿+-------------------------+-----------------------------+-----------------------------+---------+---------+---------+
🗿+-------------+--------+--------+---------------------------+-------------------------------+---------+---------+---------+
🗿| initialised | used | size | pointer to the next block | pointer to the previous block | padding | data | padding |
🗿| 1 case | 1 case | 1 case | 1 case | 1 case | 4 cases | n cases | 4 cases |
🗿+-------------+--------+--------+---------------------------+-------------------------------+---------+---------+---------+
🗿 padding is use to check invalid write
🗿 INITIALISED
🗿 a boolean to state if the block is initialised
🗿 USED
🗿 a boolean to state if the block is used
setup_header(pos, size, preview_pos)
🗿 SIZE
🗿 The size of the data
🗿 POINTER
🗿 The address of block
🗿 PADDING
🗿 Is used to check invalid write
🗿 If a case doesn't equal to 0 it is an invalid write
define LOCATION_INITIALISED = 0;
define LOCATION_USED = 1;
define LOCATION_SIZE = 2;
define LOCATION_NEXT = 3;
define LOCATION_PREV = 4;
define LOCATION_DATA = 9;
setup_header(ptr, used, size, next_block, prev_block)
{
local i;
[ptr] = pos;
[ptr + 1] = 0;
if (size + PADDING_SIZE * 2 + HEADER_SIZE)
return (1);
[ptr] = 1; 🗿 initialised
[ptr + 1] = used; 🗿 used
[ptr + 2] = size; 🗿 size
[ptr + 3] = next_block; 🗿 next block
[ptr + 4] = prev_block; 🗿 previous block
i = header_size;
loop {
@ -28,27 +53,53 @@ setup_header(pos, size, preview_pos)
[ptr + i + size] = 0;
i++;
}
return (0);
}
find_next_space(size)
{
local current;
local next;
current = 0;
current = heap;
loop
{
if (current > header_size)
if ([current + LOCATION_USED] == 0
& [current + LOCATION_SIZE] >= size)
return (current);
current = [current + LOCATION_NEXT];
if ([current] == 0)
return (0);
next_block = heap + current;
if ([next_block] == 0) 🗿check if the block is the last
| ([heap + current + 1] == 0) 🗿check if the block is not used
return (heap + current);
current = [heap + next_block];
}
}
salloc (size)
divise_block(ptr, size)
{
local p;
local old_next;
local next;
if (size + HEADER_SIZE >= [ptr + LOCATION_SIZE])
return (0);
old_next = [ptr + LOCATION_NEXT];
next = [ptr + size + HEADER_SIZE];
setup_header(next, 0, [ptr + LOCATION_SIZE] - HEADER_SIZE * 2, [ptr + LOCATION_SIZE] + HEADER_SIZE, old_next, ptr);
setup_header(ptr, 1, size, next, [ptr + LOCATION_PREV]);
return (0);
}
salloc(size)
{
local ptr;
if ([heap] == 0) 🗿 if the heap is not initialised
setup_header(HEAP_SIZE - 2 * PADDING_SIZE - HEADER_SIZE, 0, 0, 0); 🗿 initialised all the heap
ptr = find_next_space(size);
if (ptr == 0)
return (0);
if ([ptr + LOCATION_SIZE] == size)
{
[ptr + LOCATION_USED] = 1;
return (ptr + LOCATION_DATA);
}
divise_block(ptr, size);
return (ptr);
}

5
tests/galloc.🗿 Normal file
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@ -0,0 +1,5 @@
main()
{
name = "galloc";
test(galloc(1), heap + LOCATION_DATA, "");
}