473,883 Members | 1,602 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Need Help with base64

Hi ,

I am currently trying to implement base64 encoding and decoding
scheme in C . Python has a module , base64 , that will do the
encoding and decoding with ease . I am aware of OpenSSL having support
for base64 encoding and decoding , but i will have to now implement
both in C without using the openssl libraries .

I was able to download a code w.r.t. base 64 encoding and
decoding . I am attaching the code below .

void encodeblock( unsigned char cin[3], unsigned char cout[4], int
nlen )
{

cout[0] = cb64[ cin[0] >2 ];
cout[1] = cb64[ ((cin[0] & 0x03) << 4) | ((cin[1] & 0xf0) >4) ];
cout[2] = (unsigned char) (nlen 1 ? cb64[ ((cin[1] & 0x0f) << 2)
| ((cin[2] & 0xc0) >6) ] : '=');
cout[3] = (unsigned char) (nlen 2 ? cb64[ cin[2] & 0x3f ] :
'=');

}

void decodeblock( unsigned char cin[4], unsigned char cout[3] )
{
cout[ 0 ] = (unsigned char ) (cin[0] << 2 | cin[1] >4);
cout[ 1 ] = (unsigned char ) (cin[1] << 4 | cin[2] >2);
cout[ 2 ] = (unsigned char ) (((cin[2] << 6) & 0xc0) | cin[3]);

}

int base641_decodes tring(char* pcstr,int size,char** ppcdest)
{
unsigned char cin[4] = {""};
unsigned char cout[3] = {""};
unsigned char cv = 0;
int ni = 0;
int nlen = 0;
char* cptr = pcstr;
*ppcdest = malloc(sizeof(c har)*160);
if (!*ppcdest)
{
return 1;
}
memset(*ppcdest ,0,sizeof(char) *160);

char* pcstring = malloc( sizeof(char) * SIZE);
if (!pcstring)
{
aps_log("APS_lo g.txt","\nbae64 .c:base64encode :malloc failed
\n");
return 1;
}
memset(pcstring ,'\0',SIZE);

for( nlen = 0, ni = 0; ni < 4; ni++ )
{
cv = 0;
while( cv == 0 )
{
cv = (unsigned char) *cptr;
cv = (unsigned char) ((cv < 43 || cv 122) ? 0 :
cd64[ cv - 43 ]);
if( cv )
{
cv = (unsigned char) ((cv == '$') ? 0 : cv - 61);
}
}
if( cptr++ )
{
nlen++;
if( cv )
{
cin[ ni ] = (unsigned char) (cv - 1);
}
}
else
{
cin[ni] = 0;
}
}
if( nlen )
{
decodeblock( cin, cout );

}
memcpy(*ppcdest ,cout,160);
return 0;

}/*end of base64_decode */

char* base64_encode(c har* pcstr)
{
unsigned char cin[3] = {""};
unsigned char cout[4] = {""};
int ni = 0;
int nlen = 0;
int flag = 1;
char* cptr = pcstr;
char* pcstring = malloc( sizeof(char) * SIZE);
if (!pcstring)
{
aps_log("APS_lo g.txt","\nbae64 .c:base64encode :malloc failed
\n");
return (void*)0;
}
memset(pcstring ,'\0',SIZE);
while( flag )
{
for( ni = 0; ni < 3; ni++ )
{
cin[ni] = (unsigned char)*cptr;
if( *++cptr != '\0' )
nlen++;
else
{
cin[ni] = 0;
flag = 0;
break;
}
}
encodeblock(cin , cout,nlen);
strcat(pcstring ,cout);
}

return pcstring;

}/* end of base64_encode */

But this code gives different hex values as compared to the
python base64.encodest ring and base64.decodest ring respectively .

I need some help on this matter . I need some pointers on
where is the mistake for the above file .

Jul 23 '07 #1
10 4064
On Mon, 23 Jul 2007 05:37:40 -0700, pycraze wrote:
But this code gives different hex values as compared to the
python base64.encodest ring and base64.decodest ring respectively .
I need some help on this matter . I need some pointers on
where is the mistake for the above file .
It's usually easier to re-use existing code than to implement (and
debug) something from scratch. Several Base64 implementations are
available, e.g. http://www.synesis.com.au/software/b64.html
--
Roland Pibinger
"The best software is simple, elegant, and full of drama" - Grady Booch
Jul 23 '07 #2
pycraze wrote:
Hi ,

I am currently trying to implement base64 encoding and decoding
scheme in C . Python has a module , base64 , that will do the
encoding and decoding with ease . I am aware of OpenSSL having support
for base64 encoding and decoding , but i will have to now implement
both in C without using the openssl libraries .

I was able to download a code w.r.t. base 64 encoding and
decoding . I am attaching the code below .
[Snip]
But this code gives different hex values as compared to the
python base64.encodest ring and base64.decodest ring respectively .

I need some help on this matter . I need some pointers on
where is the mistake for the above file .
On a brief test your code seemed compatible with that bundled into the
MIME support in a Java environment I had to hand. Perhaps the Python
support is based on a different standard/RFC? You might wish to enquire
somewhere where Python is on topic.
Jul 23 '07 #3
Roland Pibinger wrote:
On Mon, 23 Jul 2007 05:37:40 -0700, pycraze wrote:
> But this code gives different hex values as compared to the
python base64.encodest ring and base64.decodest ring respectively .
I need some help on this matter . I need some pointers on
where is the mistake for the above file .


It's usually easier to re-use existing code
He did ... He said
>I was able to download a code w.r.t. base 64 encoding and
decoding . I am attaching the code below .
I've downloaded and built the same code (it was easily found via Google)
and it seems to be compatible with the implementation in the Java
environment I have lying around, so I think the issue may be with the
way he's trying to use the Python implementation, but what do I know
about that?
Jul 23 '07 #4
On Jul 23, 8:29 pm, rpbg...@yahoo.c om (Roland Pibinger) wrote:
On Mon, 23 Jul 2007 05:37:40 -0700, pycraze wrote:
But this code gives different hex values as compared to the
python base64.encodest ring and base64.decodest ring respectively .
I need some help on this matter . I need some pointers on
where is the mistake for the above file .

It's usually easier to re-use existing code than to implement (and
debug) something from scratch. Several Base64 implementations are
available, e.g.http://www.synesis.com.au/software/b64.html

--
Roland Pibinger
"The best software is simple, elegant, and full of drama" - Grady Booch
Hi Roland ,

Thank you for your assistance . Python uses base64 encode and decode
schemes specified in RFC 3548 . I am looking to implement this in C .
In the link you have sent , the base64 library is according to RFC
1113 .
Jul 23 '07 #5
Mark Bluemel wrote:
pycraze wrote:
>Hi ,

I am currently trying to implement base64 encoding and decoding
scheme in C . Python has a module , base64 , that will do the
encoding and decoding with ease . I am aware of OpenSSL having support
for base64 encoding and decoding , but i will have to now implement
both in C without using the openssl libraries .

I was able to download a code w.r.t. base 64 encoding and
decoding . I am attaching the code below .
[Snip]
> But this code gives different hex values as compared to the
python base64.encodest ring and base64.decodest ring respectively .

I need some help on this matter . I need some pointers on
where is the mistake for the above file .

On a brief test your code seemed compatible with that bundled into the
MIME support in a Java environment I had to hand. Perhaps the Python
support is based on a different standard/RFC? You might wish to enquire
somewhere where Python is on topic.
I also checked with Python to a limited extent and that also seems OK.
What problems are you having?
Jul 23 '07 #6
On Jul 23, 8:46 pm, Mark Bluemel <mark_blue...@p obox.comwrote:
Mark Bluemel wrote:
pycraze wrote:
Hi ,
I am currently trying to implement base64 encoding and decoding
scheme in C . Python has a module , base64 , that will do the
encoding and decoding with ease . I am aware of OpenSSL having support
for base64 encoding and decoding , but i will have to now implement
both in C without using the openssl libraries .
I was able to download a code w.r.t. base 64 encoding and
decoding . I am attaching the code below .
[Snip]
But this code gives different hex values as compared to the
python base64.encodest ring and base64.decodest ring respectively .
I need some help on this matter . I need some pointers on
where is the mistake for the above file .
On a brief test your code seemed compatible with that bundled into the
MIME support in a Java environment I had to hand. Perhaps the Python
support is based on a different standard/RFC? You might wish to enquire
somewhere where Python is on topic.

I also checked with Python to a limited extent and that also seems OK.
What problems are you having?
Roland ,

The python's base64 module gives me a different string as compared
the above C code . I am currently using OpenSSL library for the base64
encode and decode schemes . The OpenSSL gives similar output as
compared to python base64 when i encode the same input string .

I do not want to use OpenSSL library and would want to implement
now in pure C . So i am stuck with only this code . I get to see
numerous C codes that have implemented base64 encoding and decoding
schemes . I am looking particularly for the RFC 3548 specification of
base64 encoding and decoding .
Jul 23 '07 #7
pycraze wrote:
Thank you for your assistance . Python uses base64 encode and decode
schemes specified in RFC 3548 . I am looking to implement this in C .
In the link you have sent , the base64 library is according to RFC
1113 .
So is the code you downloaded...

A little examination shows that 3548 and 1113 are very similar. See
http://www.faqs.org/rfcs/rfc<number>.htm l

The encoding alphabet is identical between the two. I have not read the
specs in detail, but suspect the differences are related to things like
line length, line endings, padding rules and the like. With a little
study these small differences should be fairly easy to understand and
adapt your code for.
Jul 23 '07 #8
pycraze wrote:
On Jul 23, 8:46 pm, Mark Bluemel <mark_blue...@p obox.comwrote:
>>Mark Bluemel wrote:
[Snip]
Roland ,
I'm not Roland
The python's base64 module gives me a different string as compared
the above C code .
How different?
I am currently using OpenSSL library for the base64
encode and decode schemes . The OpenSSL gives similar output as
compared to python base64 when i encode the same input string .

I do not want to use OpenSSL library and would want to implement
now in pure C . So i am stuck with only this code . I get to see
numerous C codes that have implemented base64 encoding and decoding
schemes . I am looking particularly for the RFC 3548 specification of
base64 encoding and decoding .
I've posted a link elsewhere in the thread, but simply doing a Google
search for "RFC 3548" would have found it.
Jul 23 '07 #9
On Mon, 23 Jul 2007 16:58:46 +0100, Mark Bluemel wrote:
>A little examination shows that 3548 and 1113 are very similar. See
http://www.faqs.org/rfcs/rfc<number>.htm l
So, assuming they are different, which is the right one? A format
primarily created for exchange of data can hardly be used in different
variants.
--
Roland Pibinger
"The best software is simple, elegant, and full of drama" - Grady Booch
Jul 23 '07 #10

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

2
2570
by: Karl Pech | last post by:
Hi all, I'm trying to write a program which can read in files in the following format: sos_encoded.txt: --- begin-base64 644 sos.txt UGxlYXNlLCBoZWxwIG1lIQ== ---
0
3565
by: simon | last post by:
Hi I am trying to install MIME::Base64 and MIME::QuotedPrint using CPAN on Suse 9.1. Suse comes with Perl v5.8.3 already installed. The error message I receive is as follows: MOOSE:/usr/local/cpanSGH # perl -MCPAN -e "install 'MIME::Base64'" CPAN: Storable loaded ok Going to read /usr/local/cpanSGH/Metadata Database was generated on Sat, 04 Dec 2004 02:50:14 GMT
4
5378
by: John | last post by:
Hi all, I've been going through google and yahoo looking for a certain base64 decoder in C without success. What I'm after is something that you can pass a base64 encoded string into and get back a decoded String. Any help is very much appreciated. Thanks Philip.
3
11077
by: AHanso | last post by:
Hey I am new to C# (My background is in Java), I am writing a C# application (that uses the Compact Framework) that communicates to a Java server. To login the server is expecting the password to be MD5 encrypted, and then base64 encoded. The Java client is doing this as follows, and it works with the server: private static String encodePassword(String password) { try {
4
5557
by: Russell Warren | last post by:
I've got a case where I want to convert binary blocks of data (various ctypes objects) to base64 strings. The conversion calls in the base64 module expect strings as input, so right now I'm converting the binary blocks to strings first, then converting the resulting string to base64. This seems highly inefficient and I'd like to just go straight from binary to a base64 string. Here is the conversion we're using from object to...
1
3889
by: Roland Rickborn | last post by:
Hallo zusammen, in meine Anwendung ist ein Bild eingebettet und oben in der Leiste soll ein Icon erscheinen. Ausserdem will ich nur _eine_ Datei ausgeben, also ohne zusärtliche Bild-Dateien etc. Dazu habe ich das Bild in base64 codiert und als String im Skript gespeichert, siehe unten. Beim Ausführen des Skripts wird dieser String decodiert, in ein Image umgewandelt und als Bitmap dargestellt.
1
4995
by: mirandacascade | last post by:
I am attempting to implement a process, and I'm pretty sure that a major roadblock is that I do not understand the nomenclature. The specs indicate that the goal is to calculate a message digest using an SHA-256 algorithm. There are 2 examples included with the specs. The label on the 2 examples are: 'HMAC samples'. In both examples, the message on which the digest is to be calculated is (the 33 chars within the quotes): 'This is a...
4
3806
by: pycraze | last post by:
Hi , I am working on Fedora core 5 and my OS version is 2.6.15-1.2054_FC5 . My GCC version is 4.1.1 20070105 (Red Hat 4.1.1-51) . I am currently using the openssl libraries to write a simple base64 encode routine and base64 decoding routine . My openssl version is 0.9.8a 11 Oct 2005 .
3
2088
by: pycraze | last post by:
Hi , I am currently trying to implement base64 encoding and decoding scheme in C . Python has a module , base64 , that will do the encoding and decoding with ease . I am aware of OpenSSL having support for base64 encoding and decoding , but i will have to now implement both in C without using the openssl libraries . I was able to download a code w.r.t. base 64 encoding and decoding . I am attaching the code below .
0
9779
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
11114
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
0
10730
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
1
10835
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
1
7960
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
0
7114
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5787
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
0
5982
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
3
3230
bsmnconsultancy
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.