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| -rw-r--r-- | lib/dynarray.h | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/lib/dynarray.h b/lib/dynarray.h new file mode 100644 index 0000000..ca6439d --- /dev/null +++ b/lib/dynarray.h @@ -0,0 +1,284 @@ +/* Type-safe arrays which grow dynamically. + Copyright 2021-2022 Free Software Foundation, Inc. + + This file 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. + + This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Written by Paul Eggert and Bruno Haible, 2021. */ + +#ifndef _GL_DYNARRAY_H +#define _GL_DYNARRAY_H + +/* Before including this file, you need to define: + + 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: + */ + +/* Initialize a dynamic array object. This must be called before any + use of the object. */ +#if 0 +static void + DYNARRAY_PREFIX##init (struct DYNARRAY_STRUCT *list); +#endif + +/* Deallocate the dynamic array and its elements. */ +#if 0 +static void + DYNARRAY_PREFIX##free (struct DYNARRAY_STRUCT *list); +#endif + +/* Return true if the dynamic array is in an error state. */ +#if 0 +static bool + DYNARRAY_PREFIX##has_failed (const struct DYNARRAY_STRUCT *list); +#endif + +/* Mark the dynamic array as failed. All elements are deallocated as + a side effect. */ +#if 0 +static void + DYNARRAY_PREFIX##mark_failed (struct DYNARRAY_STRUCT *list); +#endif + +/* Return the number of elements which have been added to the dynamic + array. */ +#if 0 +static size_t + DYNARRAY_PREFIX##size (const struct DYNARRAY_STRUCT *list); +#endif + +/* Return a pointer to the first array element, if any. For a + zero-length array, the pointer can be NULL even though the dynamic + array has not entered the failure state. */ +#if 0 +static DYNARRAY_ELEMENT * + DYNARRAY_PREFIX##begin (const struct DYNARRAY_STRUCT *list); +#endif + +/* Return a pointer one element past the last array element. For a + zero-length array, the pointer can be NULL even though the dynamic + array has not entered the failure state. */ +#if 0 +static DYNARRAY_ELEMENT * + DYNARRAY_PREFIX##end (const struct DYNARRAY_STRUCT *list); +#endif + +/* Return a pointer to the array element at INDEX. Terminate the + process if INDEX is out of bounds. */ +#if 0 +static DYNARRAY_ELEMENT * + DYNARRAY_PREFIX##at (struct DYNARRAY_STRUCT *list, size_t index); +#endif + +/* 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. */ +#if 0 +static void + DYNARRAY_PREFIX##add (struct DYNARRAY_STRUCT *list, + DYNARRAY_ELEMENT item); +#endif + +/* 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. */ +#if 0 +static DYNARRAY_ELEMENT * + DYNARRAY_PREFIX##emplace (struct DYNARRAY_STRUCT *list); +#endif + +/* 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). */ +#if 0 +static bool + DYNARRAY_PREFIX##resize (struct DYNARRAY_STRUCT *list, size_t size); +#endif + +/* Remove the last element of LIST if it is present. */ +#if 0 +static void + DYNARRAY_PREFIX##remove_last (struct DYNARRAY_STRUCT *list); +#endif + +/* Remove all elements from the list. The elements are freed, but the + list itself is not. */ +#if 0 +static void + DYNARRAY_PREFIX##clear (struct DYNARRAY_STRUCT *list); +#endif + +#if defined 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. */ +#if 0 +static bool + DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *list, + DYNARRAY_FINAL_TYPE *result); +#endif +#else /* !defined 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. */ +#if 0 +static DYNARRAY_ELEMENT * + DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *list, + size_t *lengthp); +#endif +#endif + +/* A minimal example which provides a growing list of integers can be + defined like this: + + struct int_array + { + // Pointer to result array followed by its length, + // as required by DYNARRAY_FINAL_TYPE. + int *array; + size_t length; + }; + + #define DYNARRAY_STRUCT dynarray_int + #define DYNARRAY_ELEMENT int + #define DYNARRAY_PREFIX dynarray_int_ + #define DYNARRAY_FINAL_TYPE struct int_array + #include <malloc/dynarray-skeleton.c> + + To create a three-element array with elements 1, 2, 3, use this + code: + + struct dynarray_int dyn; + dynarray_int_init (&dyn); + for (int i = 1; i <= 3; ++i) + { + int *place = dynarray_int_emplace (&dyn); + assert (place != NULL); + *place = i; + } + struct int_array result; + bool ok = dynarray_int_finalize (&dyn, &result); + assert (ok); + assert (result.length == 3); + assert (result.array[0] == 1); + assert (result.array[1] == 2); + assert (result.array[2] == 3); + free (result.array); + + If the elements contain resources which must be freed, define + DYNARRAY_ELEMENT_FREE appropriately, like this: + + struct str_array + { + char **array; + size_t length; + }; + + #define DYNARRAY_STRUCT dynarray_str + #define DYNARRAY_ELEMENT char * + #define DYNARRAY_ELEMENT_FREE(ptr) free (*ptr) + #define DYNARRAY_PREFIX dynarray_str_ + #define DYNARRAY_FINAL_TYPE struct str_array + #include <malloc/dynarray-skeleton.c> + */ + + +/* The implementation is imported from glibc. */ + +/* Avoid possible conflicts with symbols exported by the GNU libc. */ +#define __libc_dynarray_at_failure gl_dynarray_at_failure +#define __libc_dynarray_emplace_enlarge gl_dynarray_emplace_enlarge +#define __libc_dynarray_finalize gl_dynarray_finalize +#define __libc_dynarray_resize_clear gl_dynarray_resize_clear +#define __libc_dynarray_resize gl_dynarray_resize + +#if defined DYNARRAY_STRUCT || defined DYNARRAY_ELEMENT || defined DYNARRAY_PREFIX + +# ifndef _GL_LIKELY +/* Rely on __builtin_expect, as provided by the module 'builtin-expect'. */ +# define _GL_LIKELY(cond) __builtin_expect ((cond), 1) +# define _GL_UNLIKELY(cond) __builtin_expect ((cond), 0) +# endif + +/* Define auxiliary structs and declare auxiliary functions, common to all + instantiations of dynarray. */ +# include <malloc/dynarray.gl.h> + +/* Define the instantiation, specified through + DYNARRAY_STRUCT + DYNARRAY_ELEMENT + DYNARRAY_PREFIX + etc. */ +# include <malloc/dynarray-skeleton.gl.h> + +#else + +/* This file is being included from one of the malloc/dynarray_*.c files. */ +# include <malloc/dynarray.h> + +#endif + +#endif /* _GL_DYNARRAY_H */ |