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C fork based multiprocess mandelbrot algorithm implementation.
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| #include <sys/stat.h> | |
| #include <fcntl.h> | |
| #include <limits.h> | |
| #include <sys/mman.h> | |
| #include <string.h> | |
| #include <stdlib.h> | |
| #include <stdio.h> | |
| #include <math.h> | |
| typedef unsigned char bool; | |
| #define true 0xff | |
| #define false 0x00 | |
| int process_qty = 8; | |
| const double yMin = -1.0; | |
| const double yMax = +1.0; | |
| const double xMin = -2.0; | |
| const double xMax = +0.5; | |
| const double dxy = 0.00025; | |
| void* childProcess(unsigned long process, unsigned char* result, bool* rows_processed, unsigned long cols, unsigned long rows) { | |
| double cx; | |
| double zx, zy, new_zx; | |
| unsigned char n; | |
| unsigned long nx; | |
| int cy = (int) process; | |
| while (cy < rows) { | |
| if (rows_processed[cy] == false) { | |
| rows_processed[cy] = true; | |
| for (cx = xMin, nx = 0; cx < xMax; cx += dxy, nx++) { | |
| zx = 0.0; | |
| zy = 0.0; | |
| n = 0; | |
| while ((zx*zx + zy*zy < 8.0) && (n != UCHAR_MAX)) { | |
| new_zx = zx*zx - zy*zy + cx; | |
| zy = 2.0*zx*zy + yMin + cy*dxy; | |
| zx = new_zx; | |
| n++; | |
| } | |
| *(result + cy*cols + nx) = n; | |
| } | |
| } | |
| cy++; | |
| } | |
| _exit(1); | |
| } | |
| int main(int argc, char *argv[]){ | |
| // Calculo alto y ancho de la imagen resultante: | |
| unsigned long cols = (unsigned long) ceil(fabs(xMax - xMin) / dxy); | |
| unsigned long rows = (unsigned long) ceil(fabs(yMax - yMin) / dxy); | |
| // Pido shared para array de filas procesadas: | |
| int fd_rp; | |
| fd_rp = shm_open("/rowsProcessed", O_RDWR | O_CREAT, 0777); | |
| ftruncate(fd_rp, rows); | |
| bool* rows_processed = (bool*) mmap(NULL, rows, PROT_READ | PROT_WRITE, MAP_SHARED, fd_rp, 0); | |
| // Inicializo en 0 rows_processed | |
| unsigned long i; | |
| for (i = 0; i < rows; i++) { | |
| rows_processed[i] = false; | |
| } | |
| // Pido shared memory para la imagen | |
| int fd; | |
| fd = shm_open("/result", O_RDWR | O_CREAT, 0777); | |
| ftruncate(fd, cols*rows); | |
| void* result = mmap(NULL, cols*rows, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); | |
| // Ejecuto los threads: | |
| pid_t pid; | |
| for (i = 0; i < process_qty; i++) { | |
| if ((pid = fork()) == 0) { | |
| childProcess(i, (unsigned char *) result, (bool*) rows_processed, cols, rows); | |
| _exit(1); | |
| } | |
| } | |
| // Espero por los porcesos hijos: | |
| int status; | |
| while (wait(&status) > 0); | |
| unsigned long written = 0; | |
| unsigned long bytes; | |
| while (written != cols*rows) { | |
| bytes = write(1, (unsigned char*) result + written, cols*rows); | |
| written += bytes; | |
| } | |
| shm_unlink("/result"); | |
| shm_unlink("/rowsProcessed"); | |
| fprintf(stderr, "To process the image: convert -depth 8 -size %dx%d gray:output out.jpg\n", cols, rows); | |
| return 0; | |
| } |
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