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Shrink array when capacity is double length

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Warwick 2024-12-18 17:03:08 +00:00
parent ed9e7b31e3
commit 9a8beb4020
3 changed files with 17 additions and 7 deletions
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18
src/dyn_arr.c
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@ -6,6 +6,7 @@
#include <string.h>
#define ARRAY_GROWTH_MULTIPLIER 1.3
#define ARRAY_SHRINK_TRIGGER 2
void *dyn_arr_init(size_t item_size, size_t capacity) {
void *dyna_ptr = NULL;
@ -27,16 +28,25 @@ void *dyna_ensure_capacity(void *array, int64_t item_count) {
dyna_header *header = dyna_get_header(array);
size_t minimum_capacity = header->length + item_count;
size_t maximum_capacity =
header->length + item_count * ARRAY_GROWTH_MULTIPLIER;
(header->length + item_count) * ARRAY_SHRINK_TRIGGER;
printf("%zu %zu %zu\n", header->capacity, minimum_capacity, maximum_capacity);
// Return if capacity is in acceptable range.
if (header->capacity > minimum_capacity &&
header->capacity < maximum_capacity) {
printf("AAAAA\n");
return header + 1;
}
size_t new_capacity = header->capacity * ARRAY_GROWTH_MULTIPLIER;
while (new_capacity < minimum_capacity) {
new_capacity *= ARRAY_GROWTH_MULTIPLIER;
size_t new_capacity = minimum_capacity * ARRAY_GROWTH_MULTIPLIER;
printf("%zu\n", new_capacity);
// Return if the array is valid and so small it's not worth reallocating
if (header->capacity > minimum_capacity &&
header->capacity <= ARRAY_INITIAL_CAPACITY) {
printf("pfft\n");
return header + 1;
}
size_t new_size = sizeof(dyna_header) + new_capacity * item_size;

2
src/dyn_arr.h
View file

@ -3,7 +3,7 @@
#include <stdbool.h>
#include <stdlib.h>
#define ARRAY_INITIAL_CAPACITY 4
#define ARRAY_INITIAL_CAPACITY 10
/* TODO:
* Functions to implement to match what I want:

4
src/main.c
View file

@ -6,13 +6,13 @@
int main() {
uint64_t *dyna_array = dyna_init(uint64_t);
for (uint64_t i = 0; i < 19; i++) {
for (uint64_t i = 0; i < 100; i++) {
dyna_append(dyna_array, i);
printf("length: %zu capacity: %zu value: %lu\n", dyna_length(dyna_array),
dyna_capacity(dyna_array), dyna_array[i - 1]);
}
for (uint64_t i = 19; i > 0; i--) {
for (uint64_t i = 100; i > 0; i--) {
printf("length: %zu capacity: %zu value: %lu\n", dyna_length(dyna_array),
dyna_capacity(dyna_array), dyna_array[i - 1]);
dyna_pop(dyna_array);