rev: new applet

   text   data    bss    dec    hexfilename
    377      0      0    377    179rev.o

Signed-off-by: Marek Polacek <mmpolacek@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/util-linux/rev.c b/util-linux/rev.c
new file mode 100644 (file)
index 0000000..fa3a453
--- /dev/null
+++ b/util-linux/rev.c
@@ -0,0 +1,121 @@
+/*
+ * rev implementation for busybox
+ *
+ * Copyright (C) 2010 Marek Polacek <mmpolacek@gmail.com>
+ *
+ * Licensed under GPLv2, see file License in this tarball for details.
+ */
+
+//applet:IF_REV(APPLET(rev, _BB_DIR_BIN, _BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_REV) += rev.o
+
+//config:config REV
+//config:      bool "rev"
+//config:      default y
+//config:      help
+//config:        Reverse lines of a file or files.
+
+//usage:#define rev_trivial_usage
+//usage:       "[FILE]..."
+//usage:#define rev_full_usage "\n\n"
+//usage:       "Reverse lines of FILE"
+
+#include "libbb.h"
+#include "unicode.h"
+
+#undef CHAR_T
+#if ENABLE_UNICODE_SUPPORT
+# define CHAR_T wchar_t
+#else
+# define CHAR_T char
+#endif
+
+/* In-place invert */
+static void strrev(CHAR_T *s, int len)
+{
+       int i;
+
+       if (len != 0) {
+               len--;
+               if (len != 0 && s[len] == '\n')
+                       len--;
+       }
+
+       for (i = 0; i < len; i++, len--) {
+               CHAR_T c = s[i];
+               s[i] = s[len];
+               s[len] = c;
+       }
+}
+
+int rev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int rev_main(int argc UNUSED_PARAM, char **argv)
+{
+       int retval;
+       size_t bufsize;
+       char *buf;
+
+       init_unicode();
+
+       getopt32(argv, "");
+       argv += optind;
+       if (!argv[0])
+               argv = (char **)&bb_argv_dash;
+
+       retval = EXIT_SUCCESS;
+       bufsize = 256;
+       buf = xmalloc(bufsize);
+       do {
+               size_t pos;
+               FILE *fp;
+
+               fp = fopen_or_warn_stdin(*argv++);
+               if (!fp) {
+                       retval = EXIT_FAILURE;
+                       continue;
+               }
+
+               pos = 0;
+               while (1) {
+                       /* Read one line */
+                       buf[bufsize - 1] = 1; /* not 0 */
+                       if (!fgets(buf + pos, bufsize - pos, fp))
+                               break; /* EOF/error */
+                       if (buf[bufsize - 1] == '\0' /* fgets filled entire buffer */
+                        && buf[bufsize - 2] != '\n' /* and did not read '\n' */
+                        && !feof(fp)
+                       ) {
+                               /* Line is too long, extend buffer */
+                               pos = bufsize - 1;
+                               bufsize += 64 + bufsize / 8;
+                               buf = xrealloc(buf, bufsize);
+                               continue;
+                       }
+
+                       /* Process and print it */
+#if ENABLE_UNICODE_SUPPORT
+                       {
+                               wchar_t *tmp = xmalloc(bufsize * sizeof(wchar_t));
+                               /* Convert to wchar_t (might error out!) */
+                               int len  = mbstowcs(tmp, buf, bufsize);
+                               if (len >= 0) {
+                                       strrev(tmp, len);
+                                       /* Convert back to char */
+                                       wcstombs(buf, tmp, bufsize);
+                               }
+                               free(tmp);
+                       }
+#else
+                       strrev(buf, strlen(buf));
+#endif
+                       fputs(buf, stdout);
+               }
+               fclose(fp);
+       } while (*argv);
+
+       if (ENABLE_FEATURE_CLEAN_UP)
+               free(buf);
+
+       fflush_stdout_and_exit(retval);
+}