webpinfo: add -version option

Change-Id: I5861d5ccd2119dd6749dc70b65fd145b5a732f98

README

@@ -378,6 +378,7 @@ Usage: webpinfo [options] in_files
 Note: there could be multiple input files;
       options must come before input files.
 Options:
+  -version ........... Print version number and exit.
   -quiet ............. Do not show chunk parsing information.
   -diag .............. Show parsing error diagnosis.
   -summary ........... Show chunk stats summary.

examples/webpinfo.c

@@ -1106,6 +1106,7 @@ static void HelpLong(void) {
          "Note: there could be multiple input files;\n"
          "      options must come before input files.\n"
          "Options:\n"
+         "  -version ........... Print version number and exit.\n"
          "  -quiet ............. Do not show chunk parsing information.\n"
          "  -diag .............. Show parsing error diagnosis.\n"
          "  -summary ........... Show chunk stats summary.\n"
@@ -1139,6 +1140,11 @@ int main(int argc, const char* argv[]) {
       show_summary = 1;
     } else if (!strcmp(argv[c], "-bitstream_info")) {
       parse_bitstream = 1;
+    } else if (!strcmp(argv[c], "-version")) {
+      const int version = WebPGetDecoderVersion();
+      printf("WebP Decoder version: %d.%d.%d\n",
+             (version >> 16) & 0xff, (version >> 8) & 0xff, version & 0xff);
+      return 0;
     } else {  // Assume the remaining are all input files.
       break;
     }

man/webpinfo.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH WEBPINFO 1 "May 08, 2017"
+.TH WEBPINFO 1 "November 24, 2017"
 .SH NAME
 webpinfo \- print out the chunk level structure of WebP files
 along with basic integrity checks.
@@ -22,16 +22,19 @@ WebP format.
 
 .SH OPTIONS
 .TP
-.B -quiet
+.B \-version
+Print the version number (as major.minor.revision) and exit.
+.TP
+.B \-quiet
 Do not show chunk parsing information.
 .TP
-.B -diag
+.B \-diag
 Show parsing error diagnosis.
 .TP
-.B -summary
+.B \-summary
 Show chunk stats summary.
 .TP
-.BI -bitstream_info
+.BI \-bitstream_info
 Parse bitstream header.
 .TP
 .B \-h, \-help