xxd: implement -o DISPLAYOFFSET

function                                             old     new   delta
xxd_main                                             680     710     +30
xstrtoll                                               -      30     +30
bb_dump_dump                                        1511    1531     +20
rewrite                                              941     951     +10
packed_usage                                       33629   33639     +10
.rodata                                           103250  103252      +2
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 5/0 up/down: 102/0)             Total: 102 bytes

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

1 files changed, 14 insertions, 5 deletions

diff --git a/util-linux/hexdump_xxd.c b/util-linux/hexdump_xxd.c
index 29bbc6633..817250c69 100644
--- a/util-linux/hexdump_xxd.c
+++ b/util-linux/hexdump_xxd.c
@@ -41,7 +41,7 @@
 //    -u          use upper case hex letters.
 
 //usage:#define xxd_trivial_usage
-//usage:       "[-pr] [-g N] [-c N] [-n LEN] [-s OFS] [FILE]"
+//usage:       "[-pr] [-g N] [-c N] [-n LEN] [-s OFS] [-o OFS] [FILE]"
 //usage:#define xxd_full_usage "\n\n"
 //usage:       "Hex dump FILE (or stdin)\n"
 //usage:     "\n        -g N            Bytes per group"
@@ -50,6 +50,7 @@
 // exactly the same help text lines in hexdump and xxd:
 //usage:     "\n        -l LENGTH       Show only first LENGTH bytes"
 //usage:     "\n        -s OFFSET       Skip OFFSET bytes"
+//usage:     "\n        -o OFFSET       Add OFFSET to displayed offset"
 //usage:     "\n        -r              Reverse (with -p, assumes no offsets in input)"
 
 #include "libbb.h"
@@ -62,6 +63,9 @@
 #define OPT_a (1 << 2)
 #define OPT_p (1 << 3)
 #define OPT_r (1 << 4)
+#define OPT_g (1 << 5)
+#define OPT_c (1 << 6)
+#define OPT_o (1 << 7)
 
 static void reverse(unsigned opt, unsigned cols, const char *filename)
 {
@@ -127,15 +131,15 @@ int xxd_main(int argc UNUSED_PARAM, char **argv)
 {
         char buf[80];
         dumper_t *dumper;
-        char *opt_l, *opt_s;
+        char *opt_l, *opt_s, *opt_o;
         unsigned bytes = 2;
         unsigned cols = 0;
         unsigned opt;
 
         dumper = alloc_dumper();
 
-        opt = getopt32(argv, "^" "l:s:aprg:+c:+" "\0" "?1" /* 1 argument max */,
-                        &opt_l, &opt_s, &bytes, &cols
+        opt = getopt32(argv, "^" "l:s:aprg:+c:+o:" "\0" "?1" /* 1 argument max */,
+                        &opt_l, &opt_s, &bytes, &cols, &opt_o
         );
         argv += optind;
 
@@ -158,6 +162,11 @@ int xxd_main(int argc UNUSED_PARAM, char **argv)
                 //BUGGY for /proc/version (unseekable?)
         }
 
+        if (opt & OPT_o) {
+                /* -o accepts negative numbers too */
+                dumper->xxd_displayoff = xstrtoll(opt_o, /*base:*/ 0);
+        }
+
         if (opt & OPT_p) {
                 if (cols == 0)
                         cols = 30;
@@ -206,7 +215,7 @@ int xxd_main(int argc UNUSED_PARAM, char **argv)
                 bb_dump_add(dumper, buf);
         } else {
                 bb_dump_add(dumper, "\"\n\"");
-                dumper->eofstring = "\n";
+                dumper->xxd_eofstring = "\n";
         }
 
         return bb_dump_dump(dumper, argv);