patch 9.1.0980: no support for base64 en-/decoding functions in Vim Script

Problem:  no support for base64 en-/decoding functions in Vim Script
          (networkhermit)
Solution: Add the base64_encode() and base64_decode() functions
          (Yegappan Lakshmanan)

fixes: #16291
closes: #16330

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/builtin.txt

@@ -1,4 +1,4 @@
-*builtin.txt*	For Vim version 9.1.  Last change: 2024 Dec 03
+*builtin.txt*	For Vim version 9.1.  Last change: 2024 Dec 30
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -67,6 +67,8 @@ autocmd_get([{opts}])		List	return a list of autocmds
 balloon_gettext()		String	current text in the balloon
 balloon_show({expr})		none	show {expr} inside the balloon
 balloon_split({msg})		List	split {msg} as used for a balloon
+base64_decode({string})		Blob	base-64 decode {string} characters
+base64_encode({blob})		String	base-64 encode the bytes in {blob}
 bindtextdomain({package}, {path})
 				Bool	bind text domain to specified path
 blob2list({blob})		List	convert {blob} into a list of numbers
@@ -1169,6 +1171,43 @@ autocmd_get([{opts}])					*autocmd_get()*
 		Return type: list<dict<any>>
 
 
+base64_decode({string})					*base64_decode()*
+		Return a Blob containing the bytes decoded from the base64
+		characters in {string}.
+
+		The {string} argument should contain only base64-encoded
+		characters and should have a length that is a multiple of 4.
+
+		Returns an empty blob on error.
+
+		Examples: >
+		    " Write the decoded contents to a binary file
+		    call writefile(base64_decode(s), 'tools.bmp')
+		    " Decode a base64-encoded string
+		    echo list2str(blob2list(base64_decode(encodedstr)))
+<
+		Can also be used as a |method|: >
+			GetEncodedString()->base64_decode()
+<
+		Return type: |Blob|
+
+
+base64_encode({blob})					*base64_encode()*
+		Return a base64-encoded String representing the bytes in
+		{blob}.  The base64 alphabet defined in RFC 4648 is used.
+
+		Examples: >
+		    " Encode the contents of a binary file
+		    echo base64_encode(readblob('somefile.bin'))
+		    " Encode a string
+		    echo base64_encode(list2blob(str2list(somestr)))
+<
+		Can also be used as a |method|: >
+			GetBinaryData()->base64_encode()
+<
+		Return type: |String|
+
+
 balloon_gettext()					*balloon_gettext()*
 		Return the current text in the balloon.  Only for the string,
 		not used for the List.  Returns an empty string if balloon

runtime/doc/tags

@@ -6164,6 +6164,8 @@ balloon_show()	builtin.txt	/*balloon_show()*
 balloon_split()	builtin.txt	/*balloon_split()*
 bar	motion.txt	/*bar*
 bars	help.txt	/*bars*
+base64_decode()	builtin.txt	/*base64_decode()*
+base64_encode()	builtin.txt	/*base64_encode()*
 base_font_name_list	mbyte.txt	/*base_font_name_list*
 basic.vim	syntax.txt	/*basic.vim*
 beep	options.txt	/*beep*

runtime/doc/todo.txt

@@ -1,4 +1,4 @@
-*todo.txt*      For Vim version 9.1.  Last change: 2024 Dec 16
+*todo.txt*      For Vim version 9.1.  Last change: 2024 Dec 30
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -4198,8 +4198,6 @@ Vim script language:
 	char2hex()		convert char string to hex string.
 	crypt()			encrypt string
 	decrypt()		decrypt string
-	base64enc()		base 64 encoding
-	base64dec()		base 64 decoding
 	attributes()		return file protection flags "drwxrwxrwx"
 	shorten(fname)		shorten a file name, like home_replace()
 	perl(cmd)		call Perl and return string

runtime/doc/usr_41.txt

@@ -1,4 +1,4 @@
-*usr_41.txt*	For Vim version 9.1.  Last change: 2024 Nov 11
+*usr_41.txt*	For Vim version 9.1.  Last change: 2024 Dec 30
 
 		     VIM USER MANUAL - by Bram Moolenaar
 
@@ -1263,6 +1263,8 @@ Inter-process communication:		    *channel-functions*
 	json_decode()		decode a JSON string to Vim types
 	js_encode()		encode an expression to a JSON string
 	js_decode()		decode a JSON string to Vim types
+	base64_encode()		encode a blob into a base64 string
+	base64_decode()		decode a base64 string into a blob
 	err_teapot()		give error 418 or 503
 
 Jobs:						*job-functions*

runtime/doc/version9.txt

@@ -1,4 +1,4 @@
-*version9.txt*  For Vim version 9.1.  Last change: 2024 Dec 29
+*version9.txt*  For Vim version 9.1.  Last change: 2024 Dec 30
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -41629,13 +41629,15 @@ Various syntax, indent and other plugins were added.
 
 Functions: ~
 
+|base64_decode()|	decode a base64 string into a blob
+|base64_encode()|	encode a blob into a base64 string
 |bindtextdomain()|	set message lookup translation base path
 |diff()|		diff two Lists of strings
 |filecopy()|		copy a file {from} to {to}
 |foreach()|		apply function to List items
+|getcellpixels()|	get List of terminal cell pixel size
 |getcmdcomplpat()|	Shell command line completion
 |getcmdprompt()|	get prompt for input()/confirm()
-|getcellpixels()|	get List of terminal cell pixel size
 |getregion()|		get a region of text from a buffer
 |getregionpos()|	get a list of positions for a region
 |id()|			get unique identifier for a Dict, List, Object,