shuf: new applet

function                                             old     new   delta
shuf_main                                              -     478    +478
packed_usage                                       29571   29719    +148
applet_names                                        2460    2465      +5
applet_main                                         1428    1432      +4
applet_nameofs                                       714     716      +2
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(add/remove: 2/0 grow/shrink: 4/0 up/down: 637/0)             Total: 637 bytes

Based on the code by Bartosz Golaszewski <bartekgola@gmail.com>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/coreutils/shuf.c b/coreutils/shuf.c
new file mode 100644 (file)
index 0000000..f213d67
--- /dev/null
+++ b/coreutils/shuf.c
@@ -0,0 +1,150 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * shuf: Write a random permutation of the input lines to standard output.
+ *
+ * Copyright (C) 2014 by Bartosz Golaszewski <bartekgola@gmail.com>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+
+//config:config SHUF
+//config:      bool "shuf"
+//config:      default y
+//config:      help
+//config:        Generate random permutations
+
+//kbuild:lib-$(CONFIG_SHUF) += shuf.o
+//applet:IF_SHUF(APPLET_NOEXEC(shuf, shuf, BB_DIR_USR_BIN, BB_SUID_DROP, shuf))
+
+//usage:#define shuf_trivial_usage
+//usage:       "[-e|-i LO-HI] [-n NUM] [-o FILE] [-z] [FILE|ARG...]"
+//usage:#define shuf_full_usage "\n\n"
+//usage:       "Write a random permutation of the input lines to standard output\n"
+//usage:     "\n       -e      Treat each ARG as an input line"
+//usage:     "\n       -i L-H  Treat each number L through H as an input line"
+//usage:     "\n       -n NUM  Output at most NUM lines"
+//usage:     "\n       -o      Write result to FILE instead of standard output"
+//usage:     "\n       -z      End lines with zero byte, not newline"
+
+#include "libbb.h"
+
+/* This is a NOEXEC applet. Be very careful! */
+
+#define OPT_e          (1 << 0)
+#define OPT_i          (1 << 1)
+#define OPT_n          (1 << 2)
+#define OPT_o          (1 << 3)
+#define OPT_z          (1 << 4)
+#define OPT_STR                "ei:n:o:z"
+
+/*
+ * Use the Fisher-Yates shuffle algorithm on an array of lines.
+ */
+static void shuffle_lines(char **lines, unsigned numlines)
+{
+       unsigned i;
+       unsigned r;
+       char *tmp;
+
+       srand(monotonic_us());
+
+       for (i = numlines-1; i > 0; i--) {
+               r = rand();
+               /* RAND_MAX can be as small as 32767 */
+               if (i > RAND_MAX)
+                       r ^= rand() << 15;
+               r %= i;
+               tmp = lines[i];
+               lines[i] = lines[r];
+               lines[r] = tmp;
+       }
+}
+
+int shuf_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int shuf_main(int argc, char **argv)
+{
+       unsigned opts;
+       char *opt_i_str, *opt_n_str, *opt_o_str;
+       unsigned i;
+       char **lines;
+       unsigned numlines;
+       char eol;
+
+       opt_complementary = "e--i:i--e"; /* mutually exclusive */
+       opts = getopt32(argv, OPT_STR, &opt_i_str, &opt_n_str, &opt_o_str);
+
+       argc -= optind;
+       argv += optind;
+
+       /* Prepare lines for shuffling - either: */
+       if (opts & OPT_e) {
+               /* make lines from command-line arguments */
+
+               numlines = argc;
+               lines = argv;
+       } else
+       if (opts & OPT_i) {
+               /* create a range of numbers */
+               char *dash;
+               unsigned lo, hi;
+
+               dash = strchr(opt_i_str, '-');
+               if (!dash) {
+                       bb_error_msg_and_die("bad range '%s'", opt_i_str);
+               }
+               *dash = '\0';
+               lo = xatou(opt_i_str);
+               hi = xatou(dash + 1);
+               *dash = '-';
+               if (hi < lo) {
+                       bb_error_msg_and_die("bad range '%s'", opt_i_str);
+               }
+
+               numlines = (hi+1) - lo;
+               lines = xmalloc(numlines * sizeof(lines[0]));
+               for (i = 0; i < numlines; i++) {
+                       lines[i] = xstrdup(utoa(lo));
+                       lo++;
+               }
+       } else {
+               /* default - read lines from stdin or the input file */
+               FILE *fp;
+
+               if (argc > 1)
+                       bb_show_usage();
+
+               fp = xfopen_stdin(argv[0] ? argv[0] : "-");
+               lines = NULL;
+               numlines = 0;
+               for (;;) {
+                       char *line = xmalloc_fgetline(fp);
+                       if (!line)
+                               break;
+                       lines = xrealloc_vector(lines, 6, numlines);
+                       lines[numlines++] = line;
+               }
+               fclose_if_not_stdin(fp);
+       }
+
+       shuffle_lines(lines, numlines);
+
+       if (opts & OPT_o)
+               xmove_fd(xopen(opt_o_str, O_WRONLY|O_CREAT|O_TRUNC), STDOUT_FILENO);
+
+       if (opts & OPT_n) {
+               unsigned maxlines;
+               maxlines = xatou(opt_n_str);
+               if (numlines > maxlines)
+                       numlines = maxlines;
+       }
+
+       eol = '\n';
+       if (opts & OPT_z)
+               eol = '\0';
+
+       for (i = 0; i < numlines; i++) {
+               printf("%s%c", lines[i], eol);
+       }
+
+       fflush_stdout_and_exit(EXIT_SUCCESS);
+}