hexdump: add hd alias, add -R option

2 files changed, 87 insertions, 19 deletions

diff --git a/util-linux/Config.in b/util-linux/Config.in
index 107382f51..8b0bbd65d 100644
--- a/util-linux/Config.in
+++ b/util-linux/Config.in
@@ -210,6 +210,22 @@ config HEXDUMP
           The hexdump utility is used to display binary data in a readable
           way that is comparable to the output from most hex editors.
 
+config HD
+        bool "hd"
+        default n
+        help
+          hd is an alias to hexdump -C.
+
+config FEATURE_HEXDUMP_REVERSE
+        bool "Support -R, reverse of 'hexdump -Cv'"
+        default n
+        depends on HEXDUMP
+        help
+          The hexdump utility is used to display binary data in an ascii
+          readable way. This option creates binary data from an ascii input.
+          NB: this option is non-standard. It's unwise to use it in scripts
+          aimed to be portable.
+
 config HWCLOCK
         bool "hwclock"
         default n
diff --git a/util-linux/hexdump.c b/util-linux/hexdump.c
index e6820ae8d..670867054 100644
--- a/util-linux/hexdump.c
+++ b/util-linux/hexdump.c
@@ -45,7 +45,7 @@ static const char *const add_strings[] = {
 
 static const char add_first[] ALIGN1 = "\"%07.7_Ax\n\"";
 
-static const char hexdump_opts[] ALIGN1 = "bcdoxCe:f:n:s:v";
+static const char hexdump_opts[] ALIGN1 = "bcdoxCe:f:n:s:v" USE_FEATURE_HEXDUMP_REVERSE("R");
 
 static const struct suffix_mult suffixes[] = {
         { "b", 512 },
@@ -59,10 +59,21 @@ int hexdump_main(int argc, char **argv)
 {
         const char *p;
         int ch;
+#if ENABLE_FEATURE_HEXDUMP_REVERSE
+        FILE *fp;
+        smallint rdump = 0;
+#endif
 
         bb_dump_vflag = FIRST;
         bb_dump_length = -1;
 
+        if (ENABLE_HD && !applet_name[2]) { /* we are "hd" */
+                ch = 'C';
+                goto hd_applet;
+        }
+
+        /* We cannot use getopt32: in hexdump options are cumulative.
+         * E.g. hexdump -C -C file should dump each line twice */
         while ((ch = getopt(argc, argv, hexdump_opts)) > 0) {
                 p = strchr(hexdump_opts, ch);
                 if (!p)
@@ -70,28 +81,34 @@ int hexdump_main(int argc, char **argv)
                 if ((p - hexdump_opts) < 5) {
                         bb_dump_add(add_first);
                         bb_dump_add(add_strings[(int)(p - hexdump_opts)]);
-                } else if (ch == 'C') {
+                }
+                /* Save a little bit of space below by omitting the 'else's. */
+                if (ch == 'C') {
+ hd_applet:
                         bb_dump_add("\"%08.8_Ax\n\"");
                         bb_dump_add("\"%08.8_ax  \" 8/1 \"%02x \" \"  \" 8/1 \"%02x \" ");
                         bb_dump_add("\"  |\" 16/1 \"%_p\" \"|\\n\"");
-                } else {
-                        /* Save a little bit of space below by omitting the 'else's. */
-                        if (ch == 'e') {
-                                bb_dump_add(optarg);
-                        } /* else */
-                        if (ch == 'f') {
-                                bb_dump_addfile(optarg);
-                        } /* else */
-                        if (ch == 'n') {
-                                bb_dump_length = xatoi_u(optarg);
-                        } /* else */
-                        if (ch == 's') {
-                                bb_dump_skip = xatoul_range_sfx(optarg, 0, LONG_MAX, suffixes);
-                        } /* else */
-                        if (ch == 'v') {
-                                bb_dump_vflag = ALL;
-                        }
                 }
+                if (ch == 'e') {
+                        bb_dump_add(optarg);
+                } /* else */
+                if (ch == 'f') {
+                        bb_dump_addfile(optarg);
+                } /* else */
+                if (ch == 'n') {
+                        bb_dump_length = xatoi_u(optarg);
+                } /* else */
+                if (ch == 's') {
+                        bb_dump_skip = xatoul_range_sfx(optarg, 0, LONG_MAX, suffixes);
+                } /* else */
+                if (ch == 'v') {
+                        bb_dump_vflag = ALL;
+                }
+#if ENABLE_FEATURE_HEXDUMP_REVERSE
+                if (ch == 'R') {
+                        rdump = 1;
+                }
+#endif
         }
 
         if (!bb_dump_fshead) {
@@ -101,5 +118,40 @@ int hexdump_main(int argc, char **argv)
 
         argv += optind;
 
+#if !ENABLE_FEATURE_HEXDUMP_REVERSE
         return bb_dump_dump(argv);
+#else
+        if (!rdump) {
+                return bb_dump_dump(argv);
+        }
+
+        /* -R: reverse of 'hexdump -Cv' */
+        fp = stdin;
+        if (!*argv) {
+                argv--;
+                goto jump_in;
+        }
+
+        do {
+                char *buf;
+                fp = xfopen(*argv, "r");
+ jump_in:
+                while ((buf = xmalloc_getline(fp)) != NULL) {
+                        p = buf;
+                        while (1) {
+                                /* skip address or previous byte */
+                                while (isxdigit(*p)) p++;
+                                while (*p == ' ') p++;
+                                /* '|' char will break the line */
+                                if (!isxdigit(*p) || sscanf(p, "%x ", &ch) != 1)
+                                        break;
+                                putchar(ch);
+                        }
+                        free(buf);
+                }
+                fclose(fp);
+        } while (*++argv);
+
+        fflush_stdout_and_exit(EXIT_SUCCESS);
+#endif
 }