uniq(1): support arbitrarily long input lines

Switch from fgets(3) to getline(3) to support input lines of any
length.

Tested by sthen@, who uncovered a dumb bug that cut throughput in
half.  getline(3) is indeed slower than fgets(3), but not *twice* as
slow.

millert@ suggests that preallocating both line buffers might be
worthwhile.  I will need to do some additional testing to figure out
whether 8KB buffers (like we had for fgets(3)) are appropriate
starting lengths.  For now I am not preallocating either buffer.

ok millert@ sthen@

diff --git a/usr.bin/uniq/uniq.c b/usr.bin/uniq/uniq.c
index ff972b5..67698f0 100644 (file)
--- a/usr.bin/uniq/uniq.c
+++ b/usr.bin/uniq/uniq.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uniq.c,v 1.27 2018/07/31 02:55:57 deraadt Exp $       */
+/*     $OpenBSD: uniq.c,v 1.28 2021/11/01 23:20:35 cheloha Exp $       */
 /*     $NetBSD: uniq.c,v 1.7 1995/08/31 22:03:48 jtc Exp $     */
 
 /*
@@ -45,8 +45,6 @@
 #include <wchar.h>
 #include <wctype.h>
 
-#define        MAXLINELEN      (8 * 1024)
-
 int cflag, dflag, iflag, uflag;
 int numchars, numfields, repeats;
 
@@ -59,10 +57,10 @@ __dead void usage(void);
 int
 main(int argc, char *argv[])
 {
-       char *t1, *t2;
+       char *prevline, *t1, *t2, *thisline;
        FILE *ifp = NULL, *ofp = NULL;
+       size_t prevsize, thissize, tmpsize;
        int ch;
-       char *prevline, *thisline;
 
        setlocale(LC_CTYPE, "");
 
@@ -133,15 +131,18 @@ main(int argc, char *argv[])
        if (pledge("stdio", NULL) == -1)
                err(1, "pledge");
 
-       prevline = malloc(MAXLINELEN);
-       thisline = malloc(MAXLINELEN);
-       if (prevline == NULL || thisline == NULL)
-               err(1, "malloc");
-
-       if (fgets(prevline, MAXLINELEN, ifp) == NULL)
+       prevsize = 0;
+       prevline = NULL;
+       if (getline(&prevline, &prevsize, ifp) == -1) {
+               free(prevline);
+               if (ferror(ifp))
+                       err(1, "getline");
                exit(0);
-
-       while (fgets(thisline, MAXLINELEN, ifp)) {
+       }
+       
+       thissize = 0;
+       thisline = NULL;
+       while (getline(&thisline, &thissize, ifp) != -1) {
                /* If requested get the chosen fields + character offsets. */
                if (numfields || numchars) {
                        t1 = skip(thisline);
@@ -157,11 +158,20 @@ main(int argc, char *argv[])
                        t1 = prevline;
                        prevline = thisline;
                        thisline = t1;
+                       tmpsize = prevsize;
+                       prevsize = thissize;
+                       thissize = tmpsize;
                        repeats = 0;
                } else
                        ++repeats;
        }
+       free(thisline);
+       if (ferror(ifp))
+               err(1, "getline");
+
        show(ofp, prevline);
+       free(prevline);
+
        exit(0);
 }