AntonioND/nitro-engine
1
Fork 0
mirror of https://github.com/AntonioND/nitro-engine.git synced 2025-06-18 16:45:33 -04:00
Code Issues Actions Packages Projects Releases Wiki Activity

library: Extract common code in allocation functions

Browse Source
This commit is contained in:
Antonio Niño Díaz 2022-10-27 23:07:50 +01:00
parent 3b09697a91
commit 8d512b55f6
1 changed files with 60 additions and 80 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

140
source/NEAlloc.c
View File

@ -47,6 +47,58 @@ int NE_AllocEnd(NEChunk **first_chunk)
return 0;
}
// The function resizes this chunk to the provided size, and creates a new chunk
// with the remaining size.
//
// +-----------------+------+
// | THIS | NEXT | Before
// +-----------------+------+
//
// +------+----------+------+
// | THIS | NEW | NEXT | After
// +------+----------+------+
//
// It returns a pointer to the new chunk.
static NEChunk *ne_split_chunk(NEChunk *this, size_t this_size)
{
// Get next chunk and create a new one.
NEChunk *next = this->next;
NEChunk *new = malloc(sizeof(NEChunk));
NE_AssertPointer(new, "Couldn't allocate chunk metadata.");
// Update pointers in the linked list
// ----------------------------------
new->previous = this;
this->next = new;
if (next == NULL)
{
new->next = NULL;
}
else
{
new->next = next;
next->previous = new;
// It shouldn't be free because deallocating a chunk should merge it
// with any free chunk next to it.
NE_Assert(next->state != NE_STATE_FREE,
"Possible list corruption");
}
// Update pointers to start and end of this chunk and the new chunk
// ----------------------------------------------------------------
new->end = this->end;
this->end = (void *)((uintptr_t)this->start + this_size);
new->start = this->end;
return new;
}
void *NE_Alloc(NEChunk *first_chunk, size_t size)
{
if ((first_chunk == NULL) || (size == 0))
@ -65,10 +117,7 @@ void *NE_Alloc(NEChunk *first_chunk, size_t size)
if (this->state != NE_STATE_FREE)
continue;
uintptr_t this_start = (uintptr_t)this->start;
uintptr_t this_end = (uintptr_t)this->end;
size_t this_size = this_end - this_start;
size_t this_size = (size_t)this->end - (size_t)this->start;
// If this chunk doesn't have enough space, simply skip it.
if (this_size < size)
@ -91,45 +140,11 @@ void *NE_Alloc(NEChunk *first_chunk, size_t size)
// +------+----------+------+ After
// | USED | NOT USED | USED |
// Get next chunk and create a new one.
NEChunk *new = ne_split_chunk(this, size);
NEChunk *next = this->next;
NEChunk *new = malloc(sizeof(NEChunk));
NE_AssertPointer(new, "Couldn't allocate chunk metadata.");
// Flag the new chunk as free and this one as used
new->state = NE_STATE_FREE;
// Flag this chunk as used and the new one as free
this->state = NE_STATE_USED;
// Update pointers in the linked list
// ----------------------------------
new->previous = this;
this->next = new;
if (next == NULL)
{
new->next = NULL;
}
else
{
new->next = next;
next->previous = new;
// It shouldn't be free because deallocating a chunk should merge it
// with any free chunk next to it.
NE_Assert(next->state != NE_STATE_FREE,
"Possible list corruption");
}
// Update pointers to start and end of this chunk and the new chunk
// ----------------------------------------------------------------
new->end = this->end;
this->end = (void *)(this_start + size);
new->start = this->end;
new->state = NE_STATE_FREE;
return this->start;
}
@ -160,10 +175,7 @@ void *NE_AllocFromEnd(NEChunk *first_chunk, size_t size)
if (this->state != NE_STATE_FREE)
continue;
uintptr_t this_start = (uintptr_t)this->start;
uintptr_t this_end = (uintptr_t)this->end;
size_t this_size = this_end - this_start;
size_t this_size = (size_t)this->end - (size_t)this->start;
// If this chunk doesn't have enough space, simply skip it.
if (this_size < size)
@ -186,45 +198,13 @@ void *NE_AllocFromEnd(NEChunk *first_chunk, size_t size)
// +-----------+------+------+ After
// | NOT USED | USED | USED |
// Get next chunk and create a new one.
NEChunk *new = malloc(sizeof(NEChunk));
NE_AssertPointer(new, "Couldn't allocate chunk metadata.");
NEChunk *next = this->next;
// The size of this chunk has to be the current one minus the requested
// size for the new chunk.
NEChunk *new = ne_split_chunk(this, this_size - size);
// Flag the new chunk as used
new->state = NE_STATE_USED;
// Update pointers in the linked list
// ----------------------------------
this->next = new;
new->previous = this;
if (next == NULL)
{
new->next = NULL;
}
else
{
new->next = next;
next->previous = new;
// It shouldn't be free because deallocating a chunk should merge it
// with any free chunk next to it.
NE_Assert(next->state != NE_STATE_FREE,
"Possible list corruption");
}
// Update pointers to start and end of this chunk and the new chunk
// ----------------------------------------------------------------
new->end = this->end;
new->start = (void *)(this_end - size);
this->end = new->start;
return new->start;
}