/* write a color bar with (roughly) logarithmic scale as BMP image to FILE.
*/
static void
write_scale(apr_file_t *file)
{
int x;
word value = 0, inc = 1;
/* write header to file */
write_bitmap_header(file, 64, 1);
for (x = 0; x < 64; ++x)
{
apr_size_t written;
byte color[3] = { 128, 128, 128 };
select_color(color, value);
if (value + (int)inc < 0x10000)
{
value += inc;
if (value >= 8 * inc)
inc *= 2;
}
written = sizeof(color);
apr_file_write(file, color, &written);
}
}
/* Write the cluster read map for all files in INFO as BMP image to FILE.
* If MAX_X is not 0, scale all lines to MAX_X pixels. Use POOL for
* allocations.
*/
static void
write_bitmap(apr_array_header_t *info,
int max_x,
apr_file_t *file,
apr_pool_t *pool)
{
int ysize = info->nelts;
int xsize = 0;
int x, y;
apr_size_t row_size;
apr_size_t written;
color_t *line, *scaled_line;
svn_boolean_t do_scale = max_x > 0;
/* xsize = max cluster number */
for (y = 0; y < ysize; ++y)
if (xsize < APR_ARRAY_IDX(info, y, file_stats_t *)->read_map->nelts)
xsize = APR_ARRAY_IDX(info, y, file_stats_t *)->read_map->nelts;
/* limit picture dimensions (16k pixels in each direction) */
if (xsize >= 0x4000)
xsize = 0x3fff;
if (ysize >= 0x4000)
ysize = 0x3fff;
if (max_x == 0)
max_x = xsize;
/* rows in BMP files must be aligned to 4 bytes */
row_size = APR_ALIGN(max_x * sizeof(color_t), 4);
/**/
line = apr_pcalloc(pool, xsize * sizeof(color_t));
scaled_line = apr_pcalloc(pool, row_size);
/* write header to file */
write_bitmap_header(file, max_x, ysize);
/* write all rows */
for (y = 0; y < ysize; ++y)
{
file_stats_t *file_info = APR_ARRAY_IDX(info, y, file_stats_t *);
int block_count = file_info->read_map->nelts;
for (x = 0; x < xsize; ++x)
{
color_t color = { 128, 128, 128 };
if (x < block_count)
{
word count = APR_ARRAY_IDX(file_info->read_map, x, word);
select_color(color, count);
}
memcpy(line[x], color, sizeof(color));
}
scale_line(scaled_line, max_x, line, block_count ? block_count : 1);
written = row_size;
apr_file_write(file, do_scale ? scaled_line : line, &written);
}
}
int generate_mandelbrot_simple(const char* filename)
{
int return_code = EXIT_FAILURE;
unsigned long start, end;
// Allocate buffer for picture data
pixel_data_t *data = calloc(WIDTH * HEIGHT, sizeof(pixel_data_t));
if (data)
{
// Create and open the output file
FILE *file = fopen(filename, "wb");
if (file)
{
// write the header
write_bitmap_header(file, WIDTH, HEIGHT);
// init time measurement
start = current_time_millis();
// calculate the data for the picture
calc_mandelbrot(data, WIDTH, HEIGHT, 0, 0, WIDTH, HEIGHT);
// write the data to the file
fwrite(data, sizeof(pixel_data_t), WIDTH * HEIGHT, file);
// close the file
fclose(file);
// print the measured time
end = current_time_millis();
printf("%.2f seconds\n", (double) (end - start) / 1000);
// success
return_code = EXIT_SUCCESS;
}
else
{
printf("Could not create the output file: %s\n", strerror(errno));
}
// free buffer
free(data);
}
else
{
printf("Could not allocate memory for buffer.\n");
}
return return_code;
}
int generate_mandelbrot_loop(const char* filename)
{
int return_code = EXIT_FAILURE;
unsigned long start, end;
// Create and open the output file, write header
FILE *file = fopen(filename, "wb");
if (!file) {
printf("Could not create the output file: %s\n", strerror(errno));
return return_code;
}
// write header
write_bitmap_header(file, WIDTH, HEIGHT);
// close file handler
fclose(file);
// init time measurement
start = current_time_millis();
//return -1;
// Loop
int i;
for (i=1; i<=MAX_PROCESSES; i++) {
// Slicing: Slice width, height and offsets
int sliceWidth = WIDTH;
int sliceHeight = HEIGHT/MAX_PROCESSES;
int widthOffset = 0;
int heightOffset = (i-1) * sliceHeight;
// Allocate buffers for picture data
pixel_data_t *data = calloc(sliceWidth * sliceHeight, sizeof(pixel_data_t));
if (data)
{
// Open the output file
FILE *file = fopen(filename, "a+");
if (file)
{
// calculate the data for the picture
calc_mandelbrot(data, WIDTH, HEIGHT, widthOffset, heightOffset, sliceWidth, sliceHeight);
// write the data to the file
fwrite(data, sizeof(pixel_data_t), sliceWidth * sliceHeight, file);
// close the file
fclose(file);
}
else
{
printf("Could not open the output file: %s\n", strerror(errno));
return return_code;
}
// free buffer
free(data);
}
else
{
printf("Could not allocate memory for buffer.\n");
return return_code;
}
}
// print the measured time
end = current_time_millis();
printf("\n%.2f seconds\n", (double) (end - start) / 1000);
// success
return_code = EXIT_SUCCESS;
return return_code;
}
int generate_mandelbrot_parallel(const char* filename)
{
int return_code = EXIT_FAILURE;
unsigned long start, end;
// Create and open the output file, write header
FILE *file = fopen(filename, "wb+");
if (!file) {
printf("Could not create the output file: %s\n", strerror(errno));
return return_code;
}
// write header
write_bitmap_header(file, WIDTH, HEIGHT);
// store header size for later offset
long headerOffset = ftell(file);
// close file handler
fclose(file);
// init time measurement
start = current_time_millis();
// set up loop and forking variables
int i, status;
pid_t pid = 1, wpid;
for (i=0; i<=MAX_PROCESSES; i++) {
if (pid>0) { // in parent process -> fork
pid = fork();
}
if (pid<0) { // error while forking -> exit program
printf("Error while forking: %s\n", strerror(errno));
return return_code;
} else if (pid==0) { // in child process -> do image generation work
// Slicing: Slice the dimensions of the image into equally sized, horizontal stripes
int sliceWidth = WIDTH;
int sliceHeight = HEIGHT/MAX_PROCESSES;
int widthOffset = 0;
int heightOffset = (i-1) * sliceHeight;
// Allocate buffers for picture data
pixel_data_t *data = calloc(sliceWidth * sliceHeight, sizeof(pixel_data_t));
if (data)
{
// Open the output file
FILE *file = fopen(filename, "rb+");
if (file)
{
// calculate the data for the picture
calc_mandelbrot(data, WIDTH, HEIGHT, widthOffset, heightOffset, sliceWidth, sliceHeight);
// seek right position
// SizeOfPixel * NumberOfPixels * PositionOfTheCurrentSlice + HeaderSize
long byteoffset = sizeof(pixel_data_t)*sliceWidth*sliceHeight*(i-1) + headerOffset;
fseek(file, byteoffset, SEEK_SET);
// write the data to the file
fwrite(data, sizeof(pixel_data_t), sliceWidth * sliceHeight, file);
// close the file
fclose(file);
// exit the process, return to main
exit(1);
}
else
{
printf("Could not open the output file: %s\n", strerror(errno));
return return_code;
}
// free buffer
free(data);
}
else
{
printf("Could not allocate memory for buffer.\n");
return return_code;
}
}
}
// wait for children to finish
for (i=0; i<MAX_PROCESSES; i++) {
wait(&status);
}
//re-write header in case it got overwritten - yes we know this is a bug. we don't know how to solve it. this gets around the symptoms, it's as good as we got it
file = fopen(filename, "rb+");
if (!file) {
printf("Could not create the output file: %s\n", strerror(errno));
return return_code;
}
fseek(file, 0, SEEK_SET);
// write header
write_bitmap_header(file, WIDTH, HEIGHT);
// close file handler
fclose(file);
// print the measured time
end = current_time_millis();
printf("\n%.2f seconds\n", (double) (end - start) / 1000);
// success
return_code = EXIT_SUCCESS;
return return_code;
}