diff options
Diffstat (limited to 'darray.h')
| -rw-r--r-- | darray.h | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/darray.h b/darray.h new file mode 100644 index 0000000000..d24e3c3eb5 --- /dev/null +++ b/darray.h @@ -0,0 +1,191 @@ +#ifndef RUBY_DARRAY_H +#define RUBY_DARRAY_H + +#include <stdint.h> +#include <stddef.h> +#include <stdlib.h> + +#include "internal/bits.h" + +// Type for a dynamic array. Use to declare a dynamic array. +// It is a pointer so it fits in st_table nicely. Designed +// to be fairly type-safe. +// +// NULL is a valid empty dynamic array. +// +// Example: +// rb_darray(char) char_array = NULL; +// rb_darray_append(&char_array, 'e'); +// printf("pushed %c\n", *rb_darray_ref(char_array, 0)); +// rb_darray_free(char_array); +// +#define rb_darray(T) struct { rb_darray_meta_t meta; T data[]; } * + +// Copy an element out of the array. Warning: not bounds checked. +// +// T rb_darray_get(rb_darray(T) ary, size_t idx); +// +#define rb_darray_get(ary, idx) ((ary)->data[(idx)]) + +// Assign to an element. Warning: not bounds checked. +// +// void rb_darray_set(rb_darray(T) ary, size_t idx, T element); +// +#define rb_darray_set(ary, idx, element) ((ary)->data[(idx)] = (element)) + +// Get a pointer to an element. Warning: not bounds checked. +// +// T *rb_darray_ref(rb_darray(T) ary, size_t idx); +// +#define rb_darray_ref(ary, idx) (&((ary)->data[(idx)])) + +/* Copy a new element into the array. ptr_to_ary is evaluated multiple times. + * + * void rb_darray_append(rb_darray(T) *ptr_to_ary, T element); + */ +#define rb_darray_append(ptr_to_ary, element) \ + rb_darray_append_impl(ptr_to_ary, element) + +#define rb_darray_append_impl(ptr_to_ary, element) do { \ + rb_darray_ensure_space((ptr_to_ary), \ + sizeof(**(ptr_to_ary)), \ + sizeof((*(ptr_to_ary))->data[0])); \ + rb_darray_set(*(ptr_to_ary), \ + (*(ptr_to_ary))->meta.size, \ + (element)); \ + (*(ptr_to_ary))->meta.size++; \ +} while (0) + +// Iterate over items of the array in a for loop +// +#define rb_darray_foreach(ary, idx_name, elem_ptr_var) \ + for (size_t idx_name = 0; idx_name < rb_darray_size(ary) && ((elem_ptr_var) = rb_darray_ref(ary, idx_name)); ++idx_name) + +// Iterate over valid indices in the array in a for loop +// +#define rb_darray_for(ary, idx_name) \ + for (size_t idx_name = 0; idx_name < rb_darray_size(ary); ++idx_name) + +/* Make a dynamic array of a certain size. All bytes backing the elements are set to zero. + * Return 1 on success and 0 on failure. + * + * Note that NULL is a valid empty dynamic array. + * + * void rb_darray_make(rb_darray(T) *ptr_to_ary, size_t size); + */ +#define rb_darray_make(ptr_to_ary, size) \ + rb_darray_make_impl((ptr_to_ary), size, sizeof(**(ptr_to_ary)), sizeof((*(ptr_to_ary))->data[0])) + +/* Resize the darray to a new capacity. The new capacity must be greater than + * or equal to the size of the darray. + * + * void rb_darray_resize_capa(rb_darray(T) *ptr_to_ary, size_t capa); + */ +#define rb_darray_resize_capa(ptr_to_ary, capa) \ + rb_darray_resize_capa_impl((ptr_to_ary), capa, sizeof(**(ptr_to_ary)), sizeof((*(ptr_to_ary))->data[0])) + +#define rb_darray_data_ptr(ary) ((ary)->data) + +typedef struct rb_darray_meta { + size_t size; + size_t capa; +} rb_darray_meta_t; + +/* Set the size of the array to zero without freeing the backing memory. + * Allows reusing the same array. */ +static inline void +rb_darray_clear(void *ary) +{ + rb_darray_meta_t *meta = ary; + if (meta) { + meta->size = 0; + } +} + +// Get the size of the dynamic array. +// +static inline size_t +rb_darray_size(const void *ary) +{ + const rb_darray_meta_t *meta = ary; + return meta ? meta->size : 0; +} + +// Get the capacity of the dynamic array. +// +static inline size_t +rb_darray_capa(const void *ary) +{ + const rb_darray_meta_t *meta = ary; + return meta ? meta->capa : 0; +} + +/* Free the dynamic array. */ +static inline void +rb_darray_free(void *ary) +{ + xfree(ary); +} + +/* Internal function. Resizes the capacity of a darray. The new capacity must + * be greater than or equal to the size of the darray. */ +static inline void +rb_darray_resize_capa_impl(void *ptr_to_ary, size_t new_capa, size_t header_size, size_t element_size) +{ + rb_darray_meta_t **ptr_to_ptr_to_meta = ptr_to_ary; + rb_darray_meta_t *meta = *ptr_to_ptr_to_meta; + + rb_darray_meta_t *new_ary = xrealloc(meta, new_capa * element_size + header_size); + + if (meta == NULL) { + /* First allocation. Initialize size. On subsequence allocations + * realloc takes care of carrying over the size. */ + new_ary->size = 0; + } + + RUBY_ASSERT(new_ary->size <= new_capa); + + new_ary->capa = new_capa; + + // We don't have access to the type of the dynamic array in function context. + // Write out result with memcpy to avoid strict aliasing issue. + memcpy(ptr_to_ary, &new_ary, sizeof(new_ary)); +} + +// Internal function +// Ensure there is space for one more element. +// Note: header_size can be bigger than sizeof(rb_darray_meta_t) when T is __int128_t, for example. +static inline void +rb_darray_ensure_space(void *ptr_to_ary, size_t header_size, size_t element_size) +{ + rb_darray_meta_t **ptr_to_ptr_to_meta = ptr_to_ary; + rb_darray_meta_t *meta = *ptr_to_ptr_to_meta; + size_t current_capa = rb_darray_capa(meta); + if (rb_darray_size(meta) < current_capa) return; + + // Double the capacity + size_t new_capa = current_capa == 0 ? 1 : current_capa * 2; + + rb_darray_resize_capa_impl(ptr_to_ary, new_capa, header_size, element_size); +} + +static inline void +rb_darray_make_impl(void *ptr_to_ary, size_t array_size, size_t header_size, size_t element_size) +{ + rb_darray_meta_t **ptr_to_ptr_to_meta = ptr_to_ary; + if (array_size == 0) { + *ptr_to_ptr_to_meta = NULL; + return; + } + + rb_darray_meta_t *meta = xcalloc(array_size * element_size + header_size, 1); + + meta->size = array_size; + meta->capa = array_size; + + // We don't have access to the type of the dynamic array in function context. + // Write out result with memcpy to avoid strict aliasing issue. + memcpy(ptr_to_ary, &meta, sizeof(meta)); +} + +#endif /* RUBY_DARRAY_H */ |