Files
Compsys-2021-Assignments/A2/fhistogram.c
Nikolaj 456adc7611 😄
2021-10-26 16:12:26 +02:00

94 lines
1.9 KiB
C

// Setting _DEFAULT_SOURCE is necessary to activate visibility of
// certain header file contents on GNU/Linux systems.
#define _DEFAULT_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fts.h>
// err.h contains various nonstandard BSD extensions, but they are
// very handy.
#include <err.h>
#include "histogram.h"
int global_histogram[8] = { 0 };
int fhistogram(char const *path) {
FILE *f = fopen(path, "r");
int local_histogram[8] = { 0 };
if (f == NULL) {
fflush(stdout);
warn("failed to open %s", path);
return -1;
}
int i = 0;
char c;
while (fread(&c, sizeof(c), 1, f) == 1) {
i++;
update_histogram(local_histogram, c);
if ((i % 100000) == 0) {
merge_histogram(local_histogram, global_histogram);
print_histogram(global_histogram);
}
}
fclose(f);
merge_histogram(local_histogram, global_histogram);
print_histogram(global_histogram);
return 0;
}
int main(int argc, char * const *argv) {
if (argc < 2) {
err(1, "usage: paths...");
exit(1);
}
char * const *paths = &argv[1];
// FTS_LOGICAL = follow symbolic links
// FTS_NOCHDIR = do not change the working directory of the process
//
// (These are not particularly important distinctions for our simple
// uses.)
int fts_options = FTS_LOGICAL | FTS_NOCHDIR;
FTS *ftsp;
if ((ftsp = fts_open(paths, fts_options, NULL)) == NULL) {
err(1, "fts_open() failed");
return -1;
}
FTSENT *p;
while ((p = fts_read(ftsp)) != NULL) {
switch (p->fts_info) {
case FTS_D:
break;
case FTS_F:
fhistogram(p->fts_path);
break;
default:
break;
}
}
fts_close(ftsp);
move_lines(9);
return 0;
}