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>

1 files changed, 121 insertions, 0 deletions

diff --git a/util-linux/rev.c b/util-linux/rev.c
new file mode 100644
index 000000000..fa3a453ae
--- /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);
+}