[png2uri] Use "====" instead of "base64" to recognize the first line

because "base64" could conceivably appear within the data string.
Also implemented -u, --uri_only option.

png2uri

@@ -1,8 +1,6 @@
 #!/bin/sh
 #
-# png2uri
-#
-# version 1.0.0, July 3, 2012
+# png2uri version 1.0.1, July 4, 2012.
 #
 # NO COPYRIGHT RIGHTS ARE CLAIMED TO THIS SOFTWARE.
 #
@@ -23,29 +21,59 @@
 #     Glenn Randers-Pehrson <glennrp@users.sourceforge.net>
 #
 # png2uri is a command-line application that creates an HTML "img" tag on
-# standard output containing a data URI, from a PNG file or from standard
-# input.
+# standard output containing a data URI in accordance with RFC-2397, from
+# a PNG file or from a PNG datastream received from standard input.
 #
-# Usage: png2uri [file]
+# Usage: png2uri [-u|--uri_only] [file]
+#
+#        options: -u|--uri_only|--url_only: omit the surrounding "img" tag
+#                 and only write the data URI.
 #
 # Requires /bin/sh and a uuencode(1) that takes the "-m" option to mean
-# to encode in base64.
+# to encode in base64 according to RFC-3548.
 #
 # If you prefer a web-based converter or a java application, this isn't
 # it. Use your search engine and look for "png data uri" to find one.
 #
 
+uri_only="false"
+
+while true
+do
 case x$1 in
+  x-u|x--ur*)
+      uri_only="true"
+      shift
+      ;;
   x)
       # Convert standard input.
-      echo "<img alt=\"PNG\" title=\"PNG\" src=\"data:image/png;base64,"
-      uuencode -m PNG |grep -v base64|grep -v ====
-      echo "\">"
+      case $uri_only in
+         true)
+            echo "data:image/png;base64,"
+            uuencode -m ==== | grep -v ====
+            ;;
+         false)
+            echo "<img alt=\"PNG\" title=\"PNG\" src=\"data:image/png;base64,"
+            uuencode -m ==== | grep -v ====
+            echo "\">"
+            ;;
+      esac
+      exit
       ;;
   *)
       # Convert the named file.
-      echo "<img alt=\"$1\" title=\"$1\" src=\"data:image/png;base64,"
-      uuencode -m $1 $1 |grep -v base64|grep -v ====
-      echo "\">"
+      case $uri_only in
+         true)
+            echo "data:image/png;base64,"
+            uuencode -m $1 ==== | grep -v ====
+            ;;
+         false)
+            echo "<img alt=\"$1\" title=\"$1\" src=\"data:image/png;base64,"
+            uuencode -m $1 ==== | grep -v ====
+            echo "\">"
+            ;;
+      esac
+      exit
       ;;
 esac
+done

png2uri-README.txt

@@ -23,25 +23,55 @@
  standard output containing a data URI, from a PNG file or from standard
  input.
 
- Usage: png2uri [file]
+ Usage: png2uri [-u|--uri_only] [file]
+
+        options: -u|--uri_only|--url_only: omit the surrounding "img" tag
+                 and only write the data URI.
 
  Requires /bin/sh and a uuencode(1) that takes the "-m" option to mean
  to encode in base64.  A surprising number of machines that I've tried
- (3 out of 8) don't have uuencode installed.
+ (3 out of 9) don't have uuencode installed.
 
  REFERENCES:
     http://en.wikipedia.org/wiki/Data_URI_scheme
+
     Masinter, L. "RFC 2397 - The "data" URL scheme",
       Internet Engineering Task Force, August 1998
 
+    http://en.wikipedia.org/wiki/Base64
+
+    IETF, "RFC 3548 - The Base16, Base32, and Base64 Data Encodings",
+      July 2003.
+
+ OTHER IMPLEMENTATIONS
+
  If you prefer a web-based converter or a java application, this isn't
  it. Use your search engine and look for "png data uri" to find one.
 
- To do: test on various platforms. The following have been tried
+ CHANGE LOG
+
+   Version 1.0.0, July 3, 2012:
+
+      Initial release.
+
+   Version 1.0.1, July 4, 2012:
+
+      The string "base64" could conceivably appear within the encoded data
+      and any line containing "base64" is removed; revised script to
+      use "====" instead to remove the first line of uuencode output.
+
+      Implemented "-u" and "--url_only" option.
+
+ TO DO
+
+ 1. Test on various platforms. The following have been tried
 
     Ubuntu 10.04 (data is folded to 60 characters)
        Linux glenn.rp 2.6.32-41-generic #91-Ubuntu SMP Wed Jun 13 11:43:55
           UTC 2012 x86_64 GNU/Linux
+       Linux nancy.rp 2.6.32-41-generic #91-Ubuntu SMP Wed Jun 13 11:43:55
+          UTC 2012 x86_64 GNU/Linux (uuencode not found.  Fixed that with
+          "sudo aptitude install sharutils", then data folded to 60 chars)
 
     Ubuntu 12.04 (FAILED: uuencode not found but manpage for POSIX uuencode
     exists)
@@ -68,22 +98,16 @@
        Linux magick.imagemagick.org 3.4.4-3.fc17.x86_64 #1 SMP Tue Jun 26
            20:54:56 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
 
- This script can be trivially modified to support another image format
+ 2. This script can be trivially modified to support another image format
  (e.g., change PNG to JPG and "image/png" to "image/jpeg" throughout).
-
  To do: do that, via a "-f/--format jpg|jpeg|png|bmp|gif" option and by
  inspecting the filename extension.
 
- If you only want the data uri and not the surrounding "< img src= .. >"
- simply use your text editor to get rid of it.
-
- To do: do that via a -u/--uri-only option.
-
- To do: find out if the script works on Windows and Mac or can be modified to
+ 3. Find out if the script works on Windows and Mac or can be modified to
  do so.
 
- To do: make it work as a drag-and-drop application.
+ 4. Make it work as a drag-and-drop application.
 
- To do: But keep it simple!
+ 5. But keep it simple!
 
 */