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Diffstat (limited to 'malloc/dynarray-skeleton.c')
| -rw-r--r-- | malloc/dynarray-skeleton.c | 499 |
1 files changed, 499 insertions, 0 deletions
diff --git a/malloc/dynarray-skeleton.c b/malloc/dynarray-skeleton.c new file mode 100644 index 0000000000..7a10e083f4 --- /dev/null +++ b/malloc/dynarray-skeleton.c @@ -0,0 +1,499 @@ +/* Type-safe arrays which grow dynamically. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +/* Pre-processor macros which act as parameters: + + DYNARRAY_STRUCT + The struct tag of dynamic array to be defined. + DYNARRAY_ELEMENT + The type name of the element type. Elements are copied + as if by memcpy, and can change address as the dynamic + array grows. + DYNARRAY_PREFIX + The prefix of the functions which are defined. + + The following parameters are optional: + + DYNARRAY_ELEMENT_FREE + DYNARRAY_ELEMENT_FREE (E) is evaluated to deallocate the + contents of elements. E is of type DYNARRAY_ELEMENT *. + DYNARRAY_ELEMENT_INIT + DYNARRAY_ELEMENT_INIT (E) is evaluated to initialize a new + element. E is of type DYNARRAY_ELEMENT *. + If DYNARRAY_ELEMENT_FREE but not DYNARRAY_ELEMENT_INIT is + defined, new elements are automatically zero-initialized. + Otherwise, new elements have undefined contents. + DYNARRAY_INITIAL_SIZE + The size of the statically allocated array (default: + at least 2, more elements if they fit into 128 bytes). + Must be a preprocessor constant. If DYNARRAY_INITIAL_SIZE is 0, + there is no statically allocated array at, and all non-empty + arrays are heap-allocated. + DYNARRAY_FINAL_TYPE + The name of the type which holds the final array. If not + defined, is PREFIX##finalize not provided. DYNARRAY_FINAL_TYPE + must be a struct type, with members of type DYNARRAY_ELEMENT and + size_t at the start (in this order). + + These macros are undefined after this header file has been + included. + + The following types are provided (their members are private to the + dynarray implementation): + + struct DYNARRAY_STRUCT + + The following functions are provided: + + void DYNARRAY_PREFIX##init (struct DYNARRAY_STRUCT *); + void DYNARRAY_PREFIX##free (struct DYNARRAY_STRUCT *); + bool DYNARRAY_PREFIX##has_failed (const struct DYNARRAY_STRUCT *); + void DYNARRAY_PREFIX##mark_failed (struct DYNARRAY_STRUCT *); + size_t DYNARRAY_PREFIX##size (const struct DYNARRAY_STRUCT *); + DYNARRAY_ELEMENT *DYNARRAY_PREFIX##at (struct DYNARRAY_STRUCT *, size_t); + void DYNARRAY_PREFIX##add (struct DYNARRAY_STRUCT *, DYNARRAY_ELEMENT); + DYNARRAY_ELEMENT *DYNARRAY_PREFIX##emplace (struct DYNARRAY_STRUCT *); + bool DYNARRAY_PREFIX##resize (struct DYNARRAY_STRUCT *, size_t); + void DYNARRAY_PREFIX##remove_last (struct DYNARRAY_STRUCT *); + void DYNARRAY_PREFIX##clear (struct DYNARRAY_STRUCT *); + + The following functions are provided are provided if the + prerequisites are met: + + bool DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *, + DYNARRAY_FINAL_TYPE *); + (if DYNARRAY_FINAL_TYPE is defined) + DYNARRAY_ELEMENT *DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *, + size_t *); + (if DYNARRAY_FINAL_TYPE is not defined) +*/ + +#include <malloc/dynarray.h> + +#include <errno.h> +#include <stdlib.h> +#include <string.h> + +#ifndef DYNARRAY_STRUCT +# error "DYNARRAY_STRUCT must be defined" +#endif + +#ifndef DYNARRAY_ELEMENT +# error "DYNARRAY_ELEMENT must be defined" +#endif + +#ifndef DYNARRAY_PREFIX +# error "DYNARRAY_PREFIX must be defined" +#endif + +#ifdef DYNARRAY_INITIAL_SIZE +# if DYNARRAY_INITIAL_SIZE < 0 +# error "DYNARRAY_INITIAL_SIZE must be non-negative" +# endif +# if DYNARRAY_INITIAL_SIZE > 0 +# define DYNARRAY_HAVE_SCRATCH 1 +# else +# define DYNARRAY_HAVE_SCRATCH 0 +# endif +#else +/* Provide a reasonable default which limits the size of + DYNARRAY_STRUCT. */ +# define DYNARRAY_INITIAL_SIZE \ + (sizeof (DYNARRAY_ELEMENT) > 64 ? 2 : 128 / sizeof (DYNARRAY_ELEMENT)) +# define DYNARRAY_HAVE_SCRATCH 1 +#endif + +/* Public type definitions. */ + +/* All fields of this struct are private to the implementation. */ +struct DYNARRAY_STRUCT +{ + union + { + struct dynarray_header dynarray_abstract; + struct + { + /* These fields must match struct dynarray_header. */ + size_t used; + size_t allocated; + DYNARRAY_ELEMENT *array; + } dynarray_header; + }; + +#if DYNARRAY_HAVE_SCRATCH + /* Initial inline allocation. */ + DYNARRAY_ELEMENT scratch[DYNARRAY_INITIAL_SIZE]; +#endif +}; + +/* Internal use only: Helper macros. */ + +/* Ensure macro-expansion of DYNARRAY_PREFIX. */ +#define DYNARRAY_CONCAT0(prefix, name) prefix##name +#define DYNARRAY_CONCAT1(prefix, name) DYNARRAY_CONCAT0(prefix, name) +#define DYNARRAY_NAME(name) DYNARRAY_CONCAT1(DYNARRAY_PREFIX, name) + +/* Address of the scratch buffer if any. */ +#if DYNARRAY_HAVE_SCRATCH +# define DYNARRAY_SCRATCH(list) (list)->scratch +#else +# define DYNARRAY_SCRATCH(list) NULL +#endif + +/* Internal use only: Helper functions. */ + +/* Internal function. Call DYNARRAY_ELEMENT_FREE with the array + elements. Name mangling needed due to the DYNARRAY_ELEMENT_FREE + macro expansion. */ +static inline void +DYNARRAY_NAME (free__elements__) (DYNARRAY_ELEMENT *__dynarray_array, + size_t __dynarray_used) +{ +#ifdef DYNARRAY_ELEMENT_FREE + for (size_t __dynarray_i = 0; __dynarray_i < __dynarray_used; ++__dynarray_i) + DYNARRAY_ELEMENT_FREE (&__dynarray_array[__dynarray_i]); +#endif /* DYNARRAY_ELEMENT_FREE */ +} + +/* Internal function. Free the non-scratch array allocation. */ +static inline void +DYNARRAY_NAME (free__array__) (struct DYNARRAY_STRUCT *list) +{ +#if DYNARRAY_HAVE_SCRATCH + if (list->dynarray_header.array != list->scratch) + free (list->dynarray_header.array); +#else + free (list->dynarray_header.array); +#endif +} + +/* Public functions. */ + +/* Initialize a dynamic array object. This must be called before any + use of the object. */ +__attribute__ ((nonnull (1))) +static void +DYNARRAY_NAME (init) (struct DYNARRAY_STRUCT *list) +{ + list->dynarray_header.used = 0; + list->dynarray_header.allocated = DYNARRAY_INITIAL_SIZE; + list->dynarray_header.array = DYNARRAY_SCRATCH (list); +} + +/* Deallocate the dynamic array and its elements. */ +__attribute__ ((unused, nonnull (1))) +static void +DYNARRAY_NAME (free) (struct DYNARRAY_STRUCT *list) +{ + DYNARRAY_NAME (free__elements__) + (list->dynarray_header.array, list->dynarray_header.used); + DYNARRAY_NAME (free__array__) (list); + DYNARRAY_NAME (init) (list); +} + +/* Return true if the dynamic array is in an error state. */ +__attribute__ ((nonnull (1))) +static inline bool +DYNARRAY_NAME (has_failed) (const struct DYNARRAY_STRUCT *list) +{ + return list->dynarray_header.allocated == __dynarray_error_marker (); +} + +/* Mark the dynamic array as failed. All elements are deallocated as + a side effect. */ +__attribute__ ((nonnull (1))) +static void +DYNARRAY_NAME (mark_failed) (struct DYNARRAY_STRUCT *list) +{ + DYNARRAY_NAME (free__elements__) + (list->dynarray_header.array, list->dynarray_header.used); + DYNARRAY_NAME (free__array__) (list); + list->dynarray_header.array = DYNARRAY_SCRATCH (list); + list->dynarray_header.used = 0; + list->dynarray_header.allocated = __dynarray_error_marker (); +} + +/* Return the number of elements which have been added to the dynamic + array. */ +__attribute__ ((nonnull (1))) +static inline size_t +DYNARRAY_NAME (size) (const struct DYNARRAY_STRUCT *list) +{ + return list->dynarray_header.used; +} + +/* Return a pointer to the array element at INDEX. Terminate the + process if INDEX is out of bounds. */ +__attribute__ ((nonnull (1))) +static inline DYNARRAY_ELEMENT * +DYNARRAY_NAME (at) (struct DYNARRAY_STRUCT *list, size_t index) +{ + if (__glibc_unlikely (index >= DYNARRAY_NAME (size) (list))) + __libc_dynarray_at_failure (DYNARRAY_NAME (size) (list), index); + return list->dynarray_header.array + index; +} + +/* Internal function. Slow path for the add function below. */ +static void +DYNARRAY_NAME (add__) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item) +{ + if (__glibc_unlikely + (!__libc_dynarray_emplace_enlarge (&list->dynarray_abstract, + DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT)))) + { + DYNARRAY_NAME (mark_failed) (list); + return; + } + + /* Copy the new element and increase the array length. */ + list->dynarray_header.array[list->dynarray_header.used++] = item; +} + +/* Add ITEM at the end of the array, enlarging it by one element. + Mark *LIST as failed if the dynamic array allocation size cannot be + increased. */ +__attribute__ ((unused, nonnull (1))) +static inline void +DYNARRAY_NAME (add) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item) +{ + /* Do nothing in case of previous error. */ + if (DYNARRAY_NAME (has_failed) (list)) + return; + + /* Enlarge the array if necessary. */ + if (__glibc_unlikely (list->dynarray_header.used + == list->dynarray_header.allocated)) + { + DYNARRAY_NAME (add__) (list, item); + return; + } + + /* Copy the new element and increase the array length. */ + list->dynarray_header.array[list->dynarray_header.used++] = item; +} + +/* Internal function. Building block for the emplace functions below. + Assumes space for one more element in *LIST. */ +static inline DYNARRAY_ELEMENT * +DYNARRAY_NAME (emplace__tail__) (struct DYNARRAY_STRUCT *list) +{ + DYNARRAY_ELEMENT *result + = &list->dynarray_header.array[list->dynarray_header.used]; + ++list->dynarray_header.used; +#if defined (DYNARRAY_ELEMENT_INIT) + DYNARRAY_ELEMENT_INIT (result); +#elif defined (DYNARRAY_ELEMENT_FREE) + memset (result, 0, sizeof (*result)); +#endif + return result; +} + +/* Internal function. Slow path for the emplace function below. */ +static DYNARRAY_ELEMENT * +DYNARRAY_NAME (emplace__) (struct DYNARRAY_STRUCT *list) +{ + if (__glibc_unlikely + (!__libc_dynarray_emplace_enlarge (&list->dynarray_abstract, + DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT)))) + { + DYNARRAY_NAME (mark_failed) (list); + return NULL; + } + return DYNARRAY_NAME (emplace__tail__) (list); +} + +/* Allocate a place for a new element in *LIST and return a pointer to + it. The pointer can be NULL if the dynamic array cannot be + enlarged due to a memory allocation failure. */ +__attribute__ ((unused, warn_unused_result, nonnull (1))) +static +/* Avoid inlining with the larger initialization code. */ +#if !(defined (DYNARRAY_ELEMENT_INIT) || defined (DYNARRAY_ELEMENT_FREE)) +inline +#endif +DYNARRAY_ELEMENT * +DYNARRAY_NAME (emplace) (struct DYNARRAY_STRUCT *list) +{ + /* Do nothing in case of previous error. */ + if (DYNARRAY_NAME (has_failed) (list)) + return NULL; + + /* Enlarge the array if necessary. */ + if (__glibc_unlikely (list->dynarray_header.used + == list->dynarray_header.allocated)) + return (DYNARRAY_NAME (emplace__) (list)); + return DYNARRAY_NAME (emplace__tail__) (list); +} + +/* Change the size of *LIST to SIZE. If SIZE is larger than the + existing size, new elements are added (which can be initialized). + Otherwise, the list is truncated, and elements are freed. Return + false on memory allocation failure (and mark *LIST as failed). */ +__attribute__ ((unused, nonnull (1))) +static bool +DYNARRAY_NAME (resize) (struct DYNARRAY_STRUCT *list, size_t size) +{ + if (size > list->dynarray_header.used) + { + bool ok; +#if defined (DYNARRAY_ELEMENT_INIT) + /* The new elements have to be initialized. */ + size_t old_size = list->dynarray_header.used; + ok = __libc_dynarray_resize (&list->dynarray_abstract, + size, DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT)); + if (ok) + for (size_t i = old_size; i < size; ++i) + { + DYNARRAY_ELEMENT_INIT (&list->dynarray_header.array[i]); + } +#elif defined (DYNARRAY_ELEMENT_FREE) + /* Zero initialization is needed so that the elements can be + safely freed. */ + ok = __libc_dynarray_resize_clear + (&list->dynarray_abstract, size, + DYNARRAY_SCRATCH (list), sizeof (DYNARRAY_ELEMENT)); +#else + ok = __libc_dynarray_resize (&list->dynarray_abstract, + size, DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT)); +#endif + if (__glibc_unlikely (!ok)) + DYNARRAY_NAME (mark_failed) (list); + return ok; + } + else + { + /* The list has shrunk in size. Free the removed elements. */ + DYNARRAY_NAME (free__elements__) + (list->dynarray_header.array + size, + list->dynarray_header.used - size); + list->dynarray_header.used = size; + return true; + } +} + +/* Remove the last element of LIST if it is present. */ +__attribute__ ((unused, nonnull (1))) +static void +DYNARRAY_NAME (remove_last) (struct DYNARRAY_STRUCT *list) +{ + /* used > 0 implies that the array is the non-failed state. */ + if (list->dynarray_header.used > 0) + { + size_t new_length = list->dynarray_header.used - 1; +#ifdef DYNARRAY_ELEMENT_FREE + DYNARRAY_ELEMENT_FREE (&list->dynarray_header.array[new_length]); +#endif + list->dynarray_header.used = new_length; + } +} + +/* Remove all elements from the list. The elements are freed, but the + list itself is not. */ +__attribute__ ((unused, nonnull (1))) +static void +DYNARRAY_NAME (clear) (struct DYNARRAY_STRUCT *list) +{ + /* free__elements__ does nothing if the list is in the failed + state. */ + DYNARRAY_NAME (free__elements__) + (list->dynarray_header.array, list->dynarray_header.used); + list->dynarray_header.used = 0; +} + +#ifdef DYNARRAY_FINAL_TYPE +/* Transfer the dynamic array to a permanent location at *RESULT. + Returns true on success on false on allocation failure. In either + case, *LIST is re-initialized and can be reused. A NULL pointer is + stored in *RESULT if LIST refers to an empty list. On success, the + pointer in *RESULT is heap-allocated and must be deallocated using + free. */ +__attribute__ ((unused, warn_unused_result, nonnull (1, 2))) +static bool +DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list, + DYNARRAY_FINAL_TYPE *result) +{ + struct dynarray_finalize_result res; + if (__libc_dynarray_finalize (&list->dynarray_abstract, + DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT), &res)) + { + /* On success, the result owns all the data. */ + DYNARRAY_NAME (init) (list); + *result = (DYNARRAY_FINAL_TYPE) { res.array, res.length }; + return true; + } + else + { + /* On error, we need to free all data. */ + DYNARRAY_NAME (free) (list); + errno = ENOMEM; + return false; + } +} +#else /* !DYNARRAY_FINAL_TYPE */ +/* Transfer the dynamic array to a heap-allocated array and return a + pointer to it. The pointer is NULL if memory allocation fails, or + if the array is empty, so this function should be used only for + arrays which are known not be empty (usually because they always + have a sentinel at the end). If LENGTHP is not NULL, the array + length is written to *LENGTHP. *LIST is re-initialized and can be + reused. */ +__attribute__ ((unused, warn_unused_result, nonnull (1))) +static DYNARRAY_ELEMENT * +DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list, size_t *lengthp) +{ + struct dynarray_finalize_result res; + if (__libc_dynarray_finalize (&list->dynarray_abstract, + DYNARRAY_SCRATCH (list), + sizeof (DYNARRAY_ELEMENT), &res)) + { + /* On success, the result owns all the data. */ + DYNARRAY_NAME (init) (list); + if (lengthp != NULL) + *lengthp = res.length; + return res.array; + } + else + { + /* On error, we need to free all data. */ + DYNARRAY_NAME (free) (list); + errno = ENOMEM; + return NULL; + } +} +#endif /* !DYNARRAY_FINAL_TYPE */ + +/* Undo macro definitions. */ + +#undef DYNARRAY_CONCAT0 +#undef DYNARRAY_CONCAT1 +#undef DYNARRAY_NAME +#undef DYNARRAY_SCRATCH +#undef DYNARRAY_HAVE_SCRATCH + +#undef DYNARRAY_STRUCT +#undef DYNARRAY_ELEMENT +#undef DYNARRAY_PREFIX +#undef DYNARRAY_ELEMENT_FREE +#undef DYNARRAY_ELEMENT_INIT +#undef DYNARRAY_INITIAL_SIZE +#undef DYNARRAY_FINAL_TYPE |