document options in man page, implement -o.

3 files changed, 65 insertions, 7 deletions

diff --git a/uxd.1 b/uxd.1
index 171929e..cbfad7e 100644
--- a/uxd.1
+++ b/uxd.1
@@ -27,7 +27,7 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .in \\n[rst2man-indent\\n[rst2man-indent-level]]u
 ..
-.TH "UXD" 1 "2024-12-13" "0.1.0" "Urchlay's Utilities"
+.TH "UXD" 1 "2024-12-14" "0.1.0" "Urchlay's Utilities"
 .SH NAME
 uxd \- UTF-8 hex dumper
 .SH SYNOPSIS
@@ -51,8 +51,38 @@ terminal. It\(aqs assumed that the terminal supports ANSI\-style color and
 UTF\-8. See \fBTERMINAL SUPPORT\fP below. If you want to pipe the output
 to a pager, try \fBless \-R\fP\&.
 .SH OPTIONS
-.sp
-There are no options yet.
+.INDENT 0.0
+.TP
+.B  \-r
+Highlight multi\-byte sequences in reverse video, in the hex output.
+.TP
+.B  \-m
+Monochrome mode. Uses underline, bold, reverse video instead of color.
+Use this if you have trouble distinguishing the colors, or if they
+look too much like angry fruit salad.
+NOT IMPLEMENTED YET.
+.TP
+.BI \-o \ offset
+Add this amount to the hex offsets (left column). May be negative,
+if you can think of a reason to want it to be. Can be given in
+decimal, hex (with \fI0x\fP prefix), or octal (with \fI0\fP prefix).
+.TP
+.BI \-s \ position
+Seek in input before starting to dump. Positive \fIposition\fP means
+seek from the start of the input. Negative \fIposition\fP only works
+on files (not standard input); it means seek backward from EOF.
+NOT IMPLEMENTED YET.
+.TP
+.B  \-u
+Use uppercase hex digits A\-F. Default is lowercase.
+NOT IMPLEMENTED YET.
+.TP
+.B  \-h\fP,\fB  \-\-help
+Print built\-in usage message and exit.
+.TP
+.B  \-v\fP,\fB  \-\-version
+Print version number and exit.
+.UNINDENT
 .SH OUTPUT FORMAT
 .sp
 The output is designed to fit in an 80\-column terminal.
diff --git a/uxd.c b/uxd.c
index f58c24e..3f9d363 100644
--- a/uxd.c
+++ b/uxd.c
@@ -128,10 +128,10 @@ void parse_options(int argc, char **argv) {
 			case 'm':
 				mono = 1; break;
 			case 'o':
-				display_offset = atoi(optarg);
+				display_offset = strtol(optarg, NULL, 0);
 				break;
 			case 's':
-				seekpos = atoi(optarg);
+				seekpos = strtol(optarg, NULL, 0);
 				break;
 			case 'u':
 				uppercase = 1; break;
@@ -227,7 +227,7 @@ void append_left(unsigned char byte, int dash, int fgcolor, int bgcolor) {
 	char tmpbuf[100];
 
 	if(!dump_column)
-		sprintf(left_buf, "%04x: ", filepos);
+		sprintf(left_buf, "%04x: ", filepos + display_offset);
 
 	append_color(left_buf, fgcolor, bgcolor);
 	sprintf(tmpbuf, "%02x", byte);
diff --git a/uxd.rst b/uxd.rst
index 48c6af3..e466adb 100644
--- a/uxd.rst
+++ b/uxd.rst
@@ -42,7 +42,35 @@ to a pager, try **less -R**.
 OPTIONS
 =======
 
-There are no options yet.
+-r
+  Highlight multi-byte sequences in reverse video, in the hex output.
+
+-m
+  Monochrome mode. Uses underline, bold, reverse video instead of color.
+  Use this if you have trouble distinguishing the colors, or if they
+  look too much like angry fruit salad.
+  NOT IMPLEMENTED YET.
+
+-o offset
+  Add this amount to the hex offsets (left column). May be negative,
+  if you can think of a reason to want it to be. Can be given in
+  decimal, hex (with *0x* prefix), or octal (with *0* prefix).
+
+-s position
+  Seek in input before starting to dump. Positive *position* means
+  seek from the start of the input. Negative *position* only works
+  on files (not standard input); it means seek backward from EOF.
+  NOT IMPLEMENTED YET.
+
+-u
+  Use uppercase hex digits A-F. Default is lowercase.
+  NOT IMPLEMENTED YET.
+
+-h, --help
+  Print built-in usage message and exit.
+
+-v, --version
+  Print version number and exit.
 
 OUTPUT FORMAT
 =============