stew

commit ce8510fcd42ff72dddc14bc3530fb7e2d7b27f02
parent b2abf1f22277fcbacb784c97e1b1e6e922ca8a35
Author: rpa <rpa@laika>
Date:   Fri, 10 Feb 2023 22:38:54 +0000

src/shuf: shuffle lines

Diffstat:
A
src/mkfile
 | 
5
+++++
A
src/shuf.c
 | 
38
++++++++++++++++++++++++++++++++++++++

2 files changed, 43 insertions(+), 0 deletions(-)
diff --git a/src/mkfile b/src/mkfile
@@ -0,0 +1,5 @@
+</$objtype/mkfile
+TARG=shuf
+HFILES=
+OFILES=
+</sys/src/cmd/mkmany
diff --git a/src/shuf.c b/src/shuf.c
@@ -0,0 +1,38 @@
+/*
+	Read lines and write them back in random order.
+*/
+
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+typedef struct Line Line;
+struct Line {
+	char *s;
+	Line *next;
+};
+long i, r, n;
+Line start, *lp, *lr;
+char *s;
+void
+main(void)
+{
+	srand(truerand());
+	Biobuf *bp = Bfdopen(0, OREAD);
+	lp = &start;
+	while ((s = Brdstr(bp, '\n', 0)) != nil) {
+		lp->next = malloc(sizeof(Line));
+		lp = lp->next;
+		if (lp == nil) sysfatal("nil");
+		*lp = (Line){s, start.next};
+		n++;
+	}
+	for (i = n; i > 0; i--) {
+		r = lnrand(i);
+		for (r = lnrand(i); r > 0; r--) {
+			lp = lp->next;
+			if (lp == nil) sysfatal("nil");
+		}
+		print("%s", lp->next->s);
+		lp->next = lp->next->next;
+	};
+}