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Convert Base64 Back To Binary

xmlnewbie asked
Last Modified: 2012-06-21
In MS Word 2003, any image inserted into the document is represented as a Base64 string in WordML. How can I take this Base64 string and convert it back to an image?
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http://en.wikipedia.org/wiki/Base64 has an overview of the Base64 algorithm. Although it is a little complicated, it is worth writing your own decoder for the experience. Basically the stream of data is chopped up six bits at a time, and each six bits converted to a number between 0 and 64, which then is used as an index in the string "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"

So to reverse the process you need to translate the base64 stream back to a stream of 6-bit characters, then concatenate those into an 8-bit Byte stream.

HINT: First learn how to use Hexadecimal to represent bit patterns, it will make things much easier.
Jens FiedererTest Developer/Validator

If you are not so interested in the experience, the Convert object has some useful methods, such as
its like a puzzle! have fun with the experience!


I'm not out to reinvent the wheel. I have been playing with Convert object. What I can't figure out is how to get a base 64 string and convert it to a binary. My hunch is that I need to use a BinaryStream -- but I can't figure out how to get the base 64 string into a BinaryStream and serialize it. Code anyone?
Test Developer/Validator
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