/* See LICENSE file for copyright and license details. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "text.h" #include "util.h" static void dropinit(FILE *, const char *, long); static void taketail(FILE *, const char *, long); int main(int argc, char *argv[]) { char c; long n = 10; FILE *fp; void (*tail)(FILE *, const char *, long) = taketail; while((c = getopt(argc, argv, "n:")) != -1) switch(c) { case 'n': n = abs(estrtol(optarg, 0)); if(optarg[0] == '+') tail = dropinit; break; default: exit(EXIT_FAILURE); } if(optind == argc) tail(stdin, "<stdin>", n); else if(optind == argc-1) { if(!(fp = fopen(argv[optind], "r"))) eprintf("fopen %s:", argv[optind]); tail(fp, argv[optind], n); fclose(fp); } else eprintf("usage: %s [-n lines] [file]\n", argv[0]); return EXIT_SUCCESS; } void dropinit(FILE *fp, const char *str, long n) { char buf[BUFSIZ]; long i = 0; while(i < n && fgets(buf, sizeof buf, fp)) if(buf[strlen(buf)-1] == '\n') i++; concat(fp, str, stdout, "<stdout>"); } void taketail(FILE *fp, const char *str, long n) { char **ring; long i, j; size_t *size = NULL; if(!(ring = calloc(n, sizeof *ring)) || !(size = calloc(n, sizeof *size))) eprintf("calloc:"); for(i = j = 0; afgets(&ring[i], &size[i], fp); i = j = (i+1)%n) ; if(ferror(fp)) eprintf("%s: read error:", str); do { if(ring[j]) { fputs(ring[j], stdout); free(ring[j]); } } while((j = (j+1)%n) != i); free(ring); free(size); }