mirror of
https://gitlab.com/80486DX2-66/gists
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81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
/*
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* static-vs-dynamic-mem-alloc.c
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*
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* Author: Intel A80486DX2-66
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* License: Creative Commons Zero 1.0 Universal
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*/
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#define MULTIPLIER 268435456ULL
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void empty(uint8_t** mem);
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void static_memory_allocation(uint8_t** mem);
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void dynamic_memory_allocation(uint8_t** mem);
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long double measure(void (*function)(uint8_t**), long double* c);
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void empty(uint8_t** mem) {
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return;
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}
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void static_memory_allocation(uint8_t** mem) {
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*mem = malloc(MULTIPLIER * sizeof(uint8_t));
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if (*mem == NULL) {
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perror("malloc");
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exit(EXIT_FAILURE);
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}
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}
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void dynamic_memory_allocation(uint8_t** mem) {
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*mem = malloc(1 * sizeof(uint8_t));
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if (*mem == NULL) {
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perror("malloc");
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exit(EXIT_FAILURE);
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}
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for (size_t i = 1; i < MULTIPLIER; i++) {
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uint8_t* new_memory = realloc(*mem, i * sizeof(uint8_t));
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if (new_memory == NULL) {
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perror("realloc");
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exit(EXIT_FAILURE);
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}
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*mem = new_memory;
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}
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}
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long double measure(void (*function)(uint8_t**), long double* c) {
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clock_t start;
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start = clock();
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uint8_t* ptr = NULL;
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function(&ptr);
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if (ptr != NULL)
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free(ptr);
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clock_t end = clock();
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long double cpu_time_used = ((long double) (end - start) * 1000000000.l) /
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CLOCKS_PER_SEC;
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if (c != NULL) {
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cpu_time_used -= *c;
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printf(": ~%.0Lf nanoseconds\n", cpu_time_used);
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}
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return cpu_time_used;
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}
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int main(void) {
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long double c = measure(empty, NULL); // empty function call
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printf(" Static memory allocation");
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long double value1 = measure(static_memory_allocation, &c);
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printf("Dynamic memory allocation");
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long double value2 = measure(dynamic_memory_allocation, &c);
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printf("\nStatic memory allocation is ~%.0Lf nanoseconds faster",
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value2 - value1);
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return EXIT_SUCCESS;
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}
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