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freelist reallocate fix + minor changes
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@abxh
abxh committed Oct 13, 2024
1 parent 7c8296a commit b50d6c2
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Showing 2 changed files with 27 additions and 24 deletions.
2 changes: 1 addition & 1 deletion lib/arena.h
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Original file line number Diff line number Diff line change
Expand Up @@ -81,7 +81,7 @@ void temp_arena_memory_end(struct temp_arena_state temp)
* @param[in] len backing buffer length.
* @param[in] backing_buf backing buffer
*/
static inline void arena_init(struct arena *self, const size_t len, unsigned char backing_buf[len])
static inline void arena_init(struct arena *self, const size_t len, unsigned char *backing_buf)
{
assert(self);
assert(backing_buf);
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49 changes: 26 additions & 23 deletions lib/freelist.h
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Original file line number Diff line number Diff line change
Expand Up @@ -21,11 +21,6 @@
* @li https://github.com/csehydrogen/malloclab/blob/master/mm.c
*/

/**
* @example examples/freelist/chars_example.c
* Example of how `arena.h` header file is used in practice.
*/

#pragma once

#include <stdalign.h>
Expand Down Expand Up @@ -132,7 +127,7 @@ static inline void freelist_deallocate_all(struct freelist *self)
}

/* Initialize the freelist */
static inline void freelist_init(struct freelist *self, const size_t len, unsigned char backing_buf[len])
static inline void freelist_init(struct freelist *self, const size_t len, unsigned char *backing_buf)
{
assert(self);
assert(backing_buf);
Expand All @@ -147,6 +142,7 @@ static inline void freelist_init(struct freelist *self, const size_t len, unsign
freelist_deallocate_all(self);
}

/// @cond DO_NOT_DOCUMENT
static inline void *internal_freelist_init_block(struct freelist *self, char *block_ptr, struct freelist_header *next,
const size_t prev_size, const size_t block_size,
const size_t remaining_size)
Expand All @@ -171,15 +167,23 @@ static inline void *internal_freelist_init_block(struct freelist *self, char *bl
return (void *)((char *)curr_header + sizeof(struct freelist_header));
}

static inline size_t internal_freelist_calc_block_size(size_t requested_size)
{
size_t block_size = sizeof(struct freelist_header) + requested_size;
block_size = block_size >= sizeof(struct freetree_node) ? block_size : sizeof(struct freetree_node);
block_size = block_size + calc_alignment_padding(alignof(struct freetree_node), block_size);

return block_size;
}
/// @endcond

/* Get the pointer to a block of the freelist.*/
static inline void *freelist_allocate(struct freelist *self, const size_t requested_size)
{
assert(self);
assert(requested_size != 0);

size_t block_size = sizeof(struct freelist_header) + requested_size;
block_size = block_size >= sizeof(struct freetree_node) ? block_size : sizeof(struct freetree_node);
block_size = block_size + calc_alignment_padding(alignof(struct freetree_node), block_size);
const size_t block_size = internal_freelist_calc_block_size(requested_size);

struct freetree_node *node = internal_freetree_search_best_block(&self->rb_rootptr, block_size);

Expand All @@ -199,6 +203,8 @@ static inline void *freelist_allocate(struct freelist *self, const size_t reques
/* Deallocate a block from the freelist for further use. */
static inline void freelist_deallocate(struct freelist *self, void *ptr)
{
assert(self->buf_ptr <= (unsigned char *)ptr && (unsigned char *)ptr < &self->buf_ptr[self->buf_len]);

struct freelist_header *header = (struct freelist_header *)((char *)ptr - sizeof(struct freelist_header));

assert(!freelist_header_is_freed(header) && "double free detected!");
Expand All @@ -209,30 +215,27 @@ static inline void freelist_deallocate(struct freelist *self, void *ptr)
}

/* Reallocate a block and grow / shrink the block. */
/*
static inline void *freelist_reallocate(struct freelist *self, void *ptr, const size_t new_size)
{
assert(self);
assert(new_size != 0);

assert(self->buf_ptr <= (unsigned char *)ptr && (unsigned char *)ptr < &self->buf_ptr[self->buf_len]);

struct freelist_header *header = (struct freelist_header *)((char *)ptr - sizeof(struct freelist_header));
const size_t prev_size = freelist_header_prev_size(header);
const size_t old_size = header->curr_block_size - sizeof(struct freelist_header);

assert(freelist_header_is_freed(header) && "reallocating freed block!");

if (new_size <= old_size) {
size_t block_size = sizeof(struct freelist_header) + new_size;
block_size = block_size >= sizeof(struct freetree_node) ? block_size : sizeof(struct freetree_node);
block_size = block_size + calc_alignment_padding(alignof(max_align_t), block_size);
const size_t block_size = internal_freelist_calc_block_size(new_size);

if (block_size == header->curr_block_size) {
return ptr;
}
else {
return internal_freelist_init_block(self, (char *)header, freelist_header_next(header, self),
freelist_header_prev_size(header), block_size,
header->curr_block_size - block_size);
}
return internal_freelist_init_block(self, (char *)header, freelist_header_next(header, self), prev_size,
block_size, header->curr_block_size - block_size);
}

size_t bytes_acc = header->curr_block_size;
Expand All @@ -243,20 +246,20 @@ static inline void *freelist_reallocate(struct freelist *self, void *ptr, const
}

if (bytes_acc >= new_size) {
return internal_freelist_init_block(self, (char *)header, freelist_header_next(header, self),
freelist_header_prev_size(header),
new_size + sizeof(struct freelist_header), header->curr_block_size -);
return internal_freelist_init_block(self, (char *)header, next, prev_size, new_size, bytes_acc - new_size);
}

void *ptr_new = freelist_allocate(self, new_size);
if (!ptr_new) {
return NULL;
}
memcpy(ptr_new, ptr, header->curr_block_size - sizeof(struct freelist_header));

memcpy(ptr_new, ptr, old_size);

freelist_deallocate(self, ptr);

return ptr_new;
}
*/

/// @cond DO_NOT_DOCUMENT
static inline struct freetree_node *internal_freetree_search_best_block(struct freetree_node **rootptr_ptr,
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