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-rw-r--r--src/staart.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/src/staart.c b/src/staart.c
new file mode 100644
index 0000000..c2d65f3
--- /dev/null
+++ b/src/staart.c
@@ -0,0 +1,101 @@
+#include <assert.h>
+#include <getopt.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "io/read_file.h"
+#include "util/debug.h"
+#include "util/error.h"
+#include "util/loop_files.h"
+#include "util/versie.h"
+
+static int gn, gc;
+
+static void usage(FILE *f) {
+ fprintf(f,
+ "Gebruik: staart [-nchV] [BESTAND]...\n"
+ "\n"
+ "Toon de laatste 10 regels van elk BESTAND naar standaard uitvoer\n"
+ "\n"
+ " -n AANTAL Aantal regels om weer te geven\n"
+ " -c AANTAL Aantal karakters om weer te geven\n"
+ " -h Toon deze hulptekst\n"
+ " -V Toon versienummer\n");
+}
+
+// Returns pointer to argument array containing the file names
+static char** parse_options(int argc, char **argv, int *n, int *c) {
+ int opt;
+ while ((opt = getopt(argc, argv, "n:c:hV")) != -1) {
+ switch (opt) {
+ case 'c':
+ *c = atoi(optarg);
+ *n = -1;
+ break;
+
+ case 'n':
+ *c = -1;
+ *n = atoi(optarg);
+ break;
+
+ case 'h':
+ usage(stdout);
+ exit(0);
+
+ case 'V':
+ drukkedoos_print_versie(stdout);
+ exit(0);
+
+ case '?':
+ usage(stderr);
+ exit(1);
+ }
+ }
+
+ return argv + optind;
+}
+
+static int process(struct filebuf *fb, char*, bool) {
+ // handle byte limits
+ if (gc != -1) {
+ assert(gc >= 0);
+ fwrite(fb->buf+fb->sz-gc, 1, gc, stdout);
+ goto done;
+ }
+
+ assert(gn >= 0);
+ size_t n = gn;
+ if (fb->buf[fb->sz - 1] == '\n') {
+ // if the file has a trailing newline, we should ignore it. So we should
+ // except one newline more
+ n += 1;
+ }
+
+ ssize_t i;
+ for (i = fb->sz - 1; i >= 0; i--) {
+ if (fb->buf[i] == '\n') n--;
+ if (n == 0) break;
+ }
+
+ if (i < 0) {
+ // we haven't encountered the maximum of newlines, write everything
+ fwrite(fb->buf, 1, fb->sz, stdout);
+ goto done;
+ }
+
+ fwrite(fb->buf + i + 1, 1, fb->sz - i, stdout);
+
+done:
+ free_filebuf(fb);
+ return 0;
+}
+
+int entry_staart(int argc, char **argv) {
+ gn = 10;
+ gc = -1;
+ char **args = parse_options(argc, argv, &gn, &gc);
+ return loop_files(args, process);
+}