Macierze POSIX

#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

typedef struct {
    int mat_size;
    int submat_size;
    int* submatA;
    int* submatB;
    int* submatC;
} matrix_struct;

int* createMatrix(char *nazwa, int size) {
    int *matrix = NULL;
    int fd;
    if ((fd = shm_open(nazwa, O_RDWR | O_CREAT, 0666)) == -1)
        perror("Błąd otwarcia SHM");
    if ((ftruncate(fd, size)) == -1)
        perror("Błąd ustalenia wielkości SHM");
    if ((matrix = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED)
        perror("Błąd mapowania pamięci");
    close(fd);
    return matrix;
}

void loadMatrix(int fd, int msize, int* matrix) {
    lseek(fd, 1, SEEK_CUR);
    int i, j, n;
    for (i = 0; i < msize; i++)
        for (j = 0; j < msize; j++) {
            read(fd, &n, 1);
            n = n - 48;
            matrix[msize * i + j] = n;
            lseek(fd, 1, SEEK_CUR);
        }
}

matrix_struct loadMatrixes(char* filename) {
    matrix_struct matrix;
    matrix.mat_size = 0;
    int size, i, j;
    int fd = open(filename,O_RDONLY);
    read(fd, &matrix.mat_size, 1);
    matrix.mat_size = matrix.mat_size - 48;
    lseek(fd, 1, SEEK_CUR);

    size = matrix.mat_size * matrix.mat_size * sizeof(int);

    matrix.submatA = createMatrix("/shm_matrix1", size);
    matrix.submatB = createMatrix("/shm_matrix2", size);
    matrix.submatC = createMatrix("/shm_matrix3", size);
    loadMatrix(fd, matrix.mat_size, matrix.submatA);
    loadMatrix(fd, matrix.mat_size, matrix.submatB);
    for (i = 0; i < matrix.mat_size; i++)
        for (j = 0; j < matrix.mat_size; j++)
            matrix.submatC[matrix.mat_size * i + j] = 0;
    return matrix;
}


void showMatrix(int *matrix, int msize, int mvo, int mho, int size) {
    int i, j;

    for (i = mvo; i < mvo + size; i++) {
        for (j = mho; j < mho + size; j++)
            printf("[%3d] ", matrix[msize * i + j]);
        puts("");
    }
    puts("");
}

void multiplyMatrixes(matrix_struct matrix) {
    int i, j, k, tmp;

    for (i = 0; i < matrix.submat_size; i++)
        for (j = 0; j < matrix.submat_size; j++) {
            tmp = 0;
            for (k = 0; k < matrix.submat_size; k++)
                tmp += matrix.submatA[matrix.mat_size * i + k] * matrix.submatB[matrix.mat_size * k + j];
            matrix.submatC[matrix.mat_size * i + j] = tmp;
        }
}

int main (int argc, char* argv[]) {
    matrix_struct matrix = loadMatrixes("mac.txt");

    matrix.submat_size = matrix.mat_size;
    multiplyMatrixes(matrix);
    showMatrix(matrix.submatA, matrix.mat_size, 0, 0, matrix.mat_size);
    showMatrix(matrix.submatB, matrix.mat_size, 0, 0, matrix.mat_size);
    showMatrix(matrix.submatC, matrix.mat_size, 0, 0, matrix.mat_size);

    return 0;
}