[hackers] [sbase] Add f-flag to tail(1) and refactor code || FRIGN

[git]

commit 2a83c2c8bef7f0e48d575e14d49aa22e44b649dd
Author: FRIGN <d...@frign.de>
Date:   Mon Feb 9 15:06:17 2015 +0100

    Add f-flag to tail(1) and refactor code

diff --git a/tail.c b/tail.c
index a678a93..3ea4739 100644
--- a/tail.c
+++ b/tail.c
@@ -8,26 +8,68 @@
 #include "text.h"
 #include "util.h"
 
-static void dropinit(FILE *, const char *, long);
-static void taketail(FILE *, const char *, long);
+static int fflag = 0;
+
+static void
+dropinit(FILE *fp, const char *str, long n)
+{
+       char *buf = NULL;
+       size_t size = 0;
+       ssize_t len;
+       unsigned long i = 0;
+
+       while (i < n && (len = getline(&buf, &size, fp)) != -1)
+               if (len > 0 && buf[len - 1] == '\n')
+                       i++;
+       free(buf);
+       concat(fp, str, stdout, "<stdout>");
+}
+
+static void
+taketail(FILE *fp, const char *str, long n)
+{
+       char **ring = NULL;
+       long i, j;
+       size_t *size = NULL;
+
+       ring = ecalloc(n, sizeof *ring);
+       size = ecalloc(n, sizeof *size);
+
+       for (i = j = 0; getline(&ring[i], &size[i], fp) != -1; 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);
+}
 
 static void
 usage(void)
 {
-       eprintf("usage: %s [-n lines] [file]\n", argv0);
+       eprintf("usage: %s [-f] [-n lines] [file ...]\n", argv0);
 }
 
 int
 main(int argc, char *argv[])
 {
-       long n = 10;
        FILE *fp;
+       size_t n = 10, tmpsize;
+       int ret = 0, newline, many;
+       char *lines, *tmp;
        void (*tail)(FILE *, const char *, long) = taketail;
-       char *lines;
-       int ret = 0;
-       int newline, many;
 
        ARGBEGIN {
+       case 'f':
+               fflag = 1;
+               break;
        case 'n':
                lines = EARGF(usage());
                n = estrtonum(lines, 0, LONG_MAX);
@@ -40,10 +82,12 @@ main(int argc, char *argv[])
        default:
                usage();
        } ARGEND;
-       if (argc == 0) {
+
+       if (argc == 0)
                tail(stdin, "<stdin>", n);
-       } else {
-               many = argc > 1;
+       else {
+               if ((many = argc > 1) && fflag)
+                       usage();
                for (newline = 0; argc > 0; argc--, argv++) {
                        if (!(fp = fopen(argv[0], "r"))) {
                                weprintf("fopen %s:", argv[0]);
@@ -55,48 +99,23 @@ main(int argc, char *argv[])
                                       newline ? "\n" : "", argv[0]);
                        newline = 1;
                        tail(fp, argv[0], n);
+
+                       if (fflag && argc == 1) {
+                               for(;; tmp = NULL, tmpsize = 0) {
+                                       while (getline(&tmp, &tmpsize, fp) != 
-1) {
+                                               fputs(tmp, stdout);
+                                               fflush(stdout);
+                                               free(tmp);
+                                               tmp = NULL;
+                                               tmpsize = 0;
+                                       }
+                                       if (ferror(fp))
+                                               eprintf("readline '%s':", 
argv[0]);
+                                       clearerr(fp);
+                               }
+                       }
                        fclose(fp);
                }
        }
        return ret;
 }
-
-static void
-dropinit(FILE *fp, const char *str, long n)
-{
-       char *buf = NULL;
-       size_t size = 0;
-       ssize_t len;
-       unsigned long i = 0;
-
-       while (i < n && ((len = getline(&buf, &size, fp)) != -1))
-               if (len && buf[len - 1] == '\n')
-                       i++;
-       free(buf);
-       concat(fp, str, stdout, "<stdout>");
-}
-
-static void
-taketail(FILE *fp, const char *str, long n)
-{
-       char **ring = NULL;
-       long i, j;
-       size_t *size = NULL;
-
-       ring = ecalloc(n, sizeof *ring);
-       size = ecalloc(n, sizeof *size);
-
-       for (i = j = 0; getline(&ring[i], &size[i], fp) != -1; 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);
-}