[xmp] Add --fix-sample-loop option

This option passes XMP_FLAGS_FIXLOOP to the library. See README.fixloop
in the library documentation for more details.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>

src/options.c

@@ -32,7 +32,8 @@ enum {
 	OPT_PROBEONLY,
 	OPT_LOADONLY,
 	OPT_NOCMD,
-	OPT_VBLANK
+	OPT_VBLANK,
+	OPT_FIXLOOP,
 };
 
 static void usage(char *s)
@@ -61,6 +62,7 @@ static void usage(char *s)
 	printf("\nPlayer control options:\n"
 "   -D parameter[=val]     Pass configuration parameter to the output driver\n"
 "   -d --driver name       Force output to the specified device\n"
+"   --fix-sample-loops     Use sample loop start /2 in MOD/UNIC/NP3\n"
 "   -l --loop              Enable module looping\n"
 "   -M --mute ch-list      Mute the specified channels\n"
 "   --nocmd                Disable interactive commands\n"
@@ -99,6 +101,7 @@ static struct option lopt[] = {
 	{ "amplify",		1, 0, 'a' },
 	{ "bits",		1, 0, 'b' },
 	{ "driver",		1, 0, 'd' },
+	{ "fix-sample-loops",	0, 0, OPT_FIXLOOP },
 	{ "frequency",		1, 0, 'f' },
 	{ "help",		0, 0, 'h' },
 	{ "instrument-path",	1, 0, 'I' },
@@ -162,6 +165,9 @@ void get_options(int argc, char **argv, struct options *options)
 		case 'f':
 			options->rate = strtoul(optarg, NULL, 0);
 			break;
+		case OPT_FIXLOOP:
+			options->flags |= XMP_FLAGS_FIXLOOP;
+			break;
 		case 'I':
 			options->ins_path = optarg;
 			break;

src/xmp.1

@@ -12,6 +12,7 @@ xmp - Extended Module Player
 [\fB-d, --driver\fP \fIdriver\fP]
 [\fB-F, --nofilter\fP]
 [\fB-f, --frequency\fP \fIrate\fP]
+[\fB--fix-sample-loop\fP]
 [\fB-h, --help\fP]
 [\fB-I, --instrument-path\fP]
 [\fB-i, --interpolation \fItype\fP]
@@ -63,6 +64,10 @@ probe each available driver\&.
 Disable IT lowpass filter effect and envelopes.
 .IP "\fB-f, --frequency\fP \fIrate\fP" 
 Set the software mixer sampling rate in hertz\&.
+.IP "\fB--fix-sample-loop\fP"
+Halve sample loop start values\&. Use it to work around bad conversions
+from 15-instrument modules and to correctly play NoisePacker v2 and certain
+UNIC files.
 .IP "\fB-h, --help\fP" 
 Show a short summary of command-line options\&.
 .IP "\fB-I, --instrument-path\fP \fIpath\fP"