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Author SHA1 Message Date
Eric-Paul Ickhorn a5e78dca9a bugfix(arena): Fixed crash-bug which is triggered by cloning a string into a full arena.
When allocating in a full arena, the function 'ufn_arena_alloc' returns NULL.
Up to now, the string-clone function would try to copy to there.
Now it returs NULL as string-copy when that would've happened.
2024-05-23 00:58:02 +02:00
Eric-Paul Ickhorn ee22b5df5c feature(arena): Added and documented string-clone function. 2024-05-23 00:56:59 +02:00
Eric-Paul Ickhorn f8749ba238 documentation(arena): Added comments to the functions and the arena-structure. 2024-05-23 00:52:48 +02:00
1 changed files with 51 additions and 3 deletions

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@ -1,4 +1,5 @@
// UFN Arena library. MIT-Licensed (c) Eric-Paul Ickhorn (epickh)
// ufn_arena.h: An arena allocator with maximum usage limiter.
// Under MIT-License. Copyright by Eric-Paul Ickhorn (epickh).
#ifndef UFN_ARENA_H
#define UFN_ARENA_H
@ -9,6 +10,8 @@
typedef struct ufn_arena ufn_arena_s;
/// @brief Arena structure which is being acted upon by the arena
/// functions. Manual modification may lead to undesired behaviour.
struct ufn_arena
{
uint32_t capacity;
@ -19,17 +22,50 @@ struct ufn_arena
ufn_arena_s *continuation;
};
/// @brief Allocates a new arena tree with up to 'max_tree_size' .
/// @warning No later but possibly earlier than when a total of
/// 'max_tree_size' was distributed, the allocation function
/// (ufn_arena_alloc) will return NULL.
/// @param capacity Number of bytes to allocate in the first arena;
/// Determines how many bytes can be distributed.
/// @param max_tree_size Maximum number of bytes to allocate for the
/// continuations. If this is less than or equal to
/// 'capacity' * 2, the next continuation will be
/// the last one.
/// @return Newly created dynamic arena.
ufn_arena_s * ufn_new_dynamic_arena(uint32_t capacity, uint32_t max_tree_size);
/// @brief Allocates a new arena with an immutable capacity.
/// @warning If this arena's allocation is full,
/// 'ufn_arena_alloc' will return NULL!
/// @note Internally calls 'ufn_new_dynamic_arena' with a maximum tree size of 0.
/// @param capacity Number of bytes to allocate in the arena;
/// Determines how many bytes can be distributed.
/// @return Newly created arena.
ufn_arena_s * ufn_new_static_arena(uint32_t capacity);
/// @brief Frees an arena and all its dynamic continuations.
/// @param arena Arena to free.
void ufn_free_arena(ufn_arena_s *arena);
/// @brief Allocates a block of size 'size' in the arena 'arena'
/// @warning Will return NULL if no memory block of length 'size'
/// is available in the arena or any of the continuations.
/// @param arena Arena to use for allocating 'size' bytes.
/// @param size Number of bytes to allocate.
/// @return Pointer to the newly allocated block.
void * ufn_arena_alloc(ufn_arena_s *arena, uint32_t size);
/// @brief Clones a string into the arena.
/// @param arena Arena to clone string into.
/// @param string String to clone.
/// @return Copied string. The size is immutable.
char * ufn_arena_clone_string(ufn_arena_s *arena, const char *string);
// END OF API, START OF IMPLEMENTATION.
#ifdef UFN_IMPLEMENTATION
#include <stdlib.h>
#include <string.h>
ufn_arena_s * ufn_new_dynamic_arena(uint32_t capacity, uint32_t max_tree_size)
{
@ -91,6 +127,18 @@ void * ufn_arena_alloc(ufn_arena_s *arena, uint32_t size)
return block;
}
char * ufn_arena_clone_string(ufn_arena_s *arena, const char *string)
{
uint32_t len_string = strlen(string);
char *string_copy = ufn_arena_alloc(arena, len_string + 1);
if(string_copy == NULL)
{
return NULL;
}
memcpy(string_copy, string, len_string + 1);
return string_copy;
}
#endif // UFN_IMPLEMENTATION
#endif // UFN_ARENA_H