w4rt24ffg3g35g

#include <inttypes.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define NUM_SAMPLES 500000000

int randomInt(int min, int max) {
    return rand() % max + min;
}

int main() {
    srand(42);

    printf("Starting.\n");

    // Create a large (500M?) array of int16_t numbers to represent sound samples.
    int16_t* samples = calloc(NUM_SAMPLES, sizeof(int16_t));

    for (int i = 0; i < NUM_SAMPLES; i++) {
        samples[i] = randomInt(INT16_MIN, INT16_MAX);
    }

    // Pre-calculate a lookup table (array) of all possible sample
    // values multiplied by the volume factor.
    int16_t* lookup075 = calloc(UINT16_MAX, sizeof(int16_t));
    for (int16_t i = INT16_MIN; i < INT16_MAX; i++) {
        lookup075[(uint16_t)i] = i * 0.75;
    }

    clock_t begin = clock();

    // TEST
    // look up each sample in that table to get the scaled values
    for (int i = 0; i < NUM_SAMPLES; i++) {
        samples[i] = lookup075[(uint16_t)samples[i]];
    }
    // /TEST

    clock_t end = clock();

    // Anti-optimization
    int sum = 0;
    for (int i = 0; i < NUM_SAMPLES; i++) {
        sum += samples[i];
    }
    // /Anti-optimization

    double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;

    printf("Sum: %d, Time spent: %.3f\n", sum, time_spent);

    return 0;
}