New option: -n, start at given picture

Makefile

@@ -1,6 +1,6 @@
 all: sxiv
 
-VERSION=git-20110522
+VERSION=git-20110525
 
 CC?=gcc
 DESTDIR?=

README.md

@@ -40,6 +40,7 @@ sxiv supports the following command-line options:
     -f           Start in fullscreen mode
     -g GEOMETRY  Set window position and size
                  (see section GEOMETRY SPECIFICATIONS of X(7))
+    -n NUM       Start at picture NUM
     -p           Pixelize, i.e. turn off image anti-aliasing
     -q           Be quiet, disable warnings
     -r           Search given directories recursively for images

main.c

@@ -231,14 +231,14 @@ int main(int argc, char **argv) {
 		}
 	}
 
-	filecnt = fileidx;
+	if (!fileidx) {
-	fileidx = 0;
-
-	if (!filecnt) {
 		fprintf(stderr, "sxiv: no valid image file given, aborting\n");
 		exit(1);
 	}
 
+	filecnt = fileidx;
+	fileidx = options->startnum < filecnt ? options->startnum : filecnt - 1;
+
 	win_init(&win);
 	img_init(&img, &win);
 

options.c

@@ -31,7 +31,7 @@ options_t _options;
 const options_t *options = (const options_t*) &_options;
 
 void print_usage() {
-	printf("usage: sxiv [-cdFfhpqrstvZ] [-g GEOMETRY] [-z ZOOM] FILES...\n");
+	printf("usage: sxiv [-cdFfhpqrstvZ] [-g GEOMETRY] [-n NUM] [-z ZOOM] FILES...\n");
 }
 
 void print_version() {
@@ -40,7 +40,9 @@ void print_version() {
 
 void parse_options(int argc, char **argv) {
 	float z;
-	int opt;
+	int n, opt;
+
+	_options.startnum = 0;
 
 	_options.scalemode = SCALE_MODE;
 	_options.zoom = 1.0;
@@ -55,7 +57,7 @@ void parse_options(int argc, char **argv) {
 	_options.clean_cache = 0;
 	_options.recursive = 0;
 
-	while ((opt = getopt(argc, argv, "cdFfg:hpqrstvZz:")) != -1) {
+	while ((opt = getopt(argc, argv, "cdFfg:hn:pqrstvZz:")) != -1) {
 		switch (opt) {
 			case '?':
 				print_usage();
@@ -78,6 +80,15 @@ void parse_options(int argc, char **argv) {
 			case 'h':
 				print_usage();
 				exit(0);
+			case 'n':
+				if (!sscanf(optarg, "%d", &n) || n < 1) {
+					fprintf(stderr, "sxiv: invalid argument for option -n: %s\n",
+					        optarg);
+					exit(1);
+				} else {
+					_options.startnum = n - 1;
+				}
+				break;
 			case 'p':
 				_options.aa = 0;
 				break;

options.h

@@ -23,8 +23,9 @@
 
 typedef struct {
 	const char **filenames;
-	int filecnt;
 	unsigned char from_stdin;
+	int filecnt;
+	int startnum;
 
 	scalemode_t scalemode;
 	float zoom;

sxiv.1

@@ -6,6 +6,8 @@ sxiv \- Simple (or small or suckless) X Image Viewer
 .RB [ \-cdFfhpqrstvZ ]
 .RB [ \-g
 .IR GEOMETRY ]
+.RB [ \-n
+.IR NUM ]
 .RB [ \-z
 .IR ZOOM ]
 .IR FILE ...
@@ -49,6 +51,9 @@ Set window position and size. See section GEOMETRY SPECIFICATIONS of X(7) for
 more information on
 .IR GEOMETRY .
 .TP
+.BI "\-n " NUM
+Start at picture number NUM.
+.TP
 .B \-h
 Print brief usage information to standard output and exit.
 .TP