Online Base64 Encoder

The point of this program is to base64 encode a string that's been provided by the user, and then output the new encoded string.

The encoding is done by gathering 3 chars from the original string (each char being 8 bits) and then splitting them among 4 chars of 6 bits each.

How to properly access and manipulate the user-inputted string?

Currently the first iteration brings the correct output, but the second iteration always gives t2 the value "0", no matter the input, which stops the program with output A; both of which are wrong.

.datasentence: .space 64prompt: .asciiz "Enter the string: "ASC: .byte    'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/'.text.globl mainmain:la $s0, ASCla $a0, prompt      #ask for stringli $v0, 4syscallli $v0, 8            #take stringla $a0, sentence     #load byte space into addressli $a1, 64       #max number of bytessyscallla $t0, sentence    lb $t2, 0($t0)          #to load the first 8 bits   j read_ASCread_ASC: beq $t2, $0, exitlb $t2, 0($t0)          #to load the first 8 bitsandi $a0, $t2, 63   #takes first 6 bits of string    #srl $t0, $t0, 6    #removes the 6 bits we just tooksub $t0, $t0, $t2   #removes the char we just tookaddu $t1, $a0, $s0  #s0 being the base of the table, $a0 being the offset#lbu $a0, ASC($a0)lbu $a0, 0($t1)     #sees value of the 6 bits from string to retrieve encoded value from tableli $v0, 11      #prints the new encoded charsyscallj read_ASCexit:   li $v0, 10      #endsyscall

I know what base64 encoding is and how to calculate base64 encoding in C#, however I have seen several times that when I convert a string into base64, there is an = at the end.

A few questions came up:

1. Does a base64 string always end with =?
2. Why does an = get appended at the end?

I am trying to base64 encode a binary string in NodeJS and python and I'm getting 2 different values.

Note that the value is i is 16 random bytes generated in python using os.urandom(16)

NodeJS

> var i = '>e\x93\x10\xabK\xbe\xfeX\x97\x9a$\r\xef\x8f3';> var s = new Buffer(i).toString('base64');> console.log(s);PmXCkxDCq0vCvsO+WMKXwpokDcOvwo8z

Python

>>> import base64>>> i = '>e\x93\x10\xabK\xbe\xfeX\x97\x9a$\r\xef\x8f3'>>> s = base64.b64encode(i)>>> print sPmWTEKtLvv5Yl5okDe+PMw==

Am I doing something wrong? It does work for regular string such as my name.

NodeJS

> var s = new Buffer('travis').toString('base64');undefined> console.log(s);dHJhdmlz

Python

>>> s = base64.b64encode('travis')>>> print sdHJhdmlz

I'm trying to encode a XML file to base64.

I'm using this method:

private static String encodeFileToBase64Binary( final String fileName ) throws IOException {    File file = new File( fileName );    byte[] encoded = Base64.encodeBase64( FileUtils.readFileToByteArray( file ) );    return new String( encoded, Charset.forName( "US-ASCII" ) );}

It works quite well, but when I give a XML file as input. It returns the encoded content of the file, and not the file itself, so no metadata here.

I'm using https://www.base64decode.org/ to decode by base64 string. And it returns plain text, not an xml file.

I'm using Mac OS 10.13.3. I'm trying to base64 encode a binary file but am having some issues. Specifically, I thought all base64 encoded files have to have a length that is a multiple of 4. However, when I encode my file, notice taht the length is not divisible by 4 ...

localhost:lib davea$ openssl base64 -in myfile.binary -out ~/Downloads/myfile.base64localhost:lib davea$ ls -al ~/Downloads/myfile.base64 -rw-r--r-- 1 davea staff 93162 May 31 14:22 /Users/davea/Downloads/myfile.base64

Also when I look at the contents of the base64 file, I don't see the traditional "=" or "==" at the end, which usually indicates padding

localhost:lib davea$ cat ~/Downloads/myfile.base64...C9vgMjoKSQYkXMLTrGKRleR558g3bY3VTqlsVvTqZXquCLp4JS4cprTG6N10H0u9i4pwPrVmSAP2DmE1V7mGwR2e4fiYEWnZjpSbHofpzlUo34yhiQ2/5kJoQZktD7BUuxYBAgQIECBAgBs2

Am I doing something wrong, or is there another way to base64 encode my file?