Text file "converter"

[Scott Cadreau]

I have EBCDIC text files that I convert to comma delimited ASCII files for
load into a database system. There are a wide variety of "fields" that come
in the raw files (e.g. Packed/Zoned/Binary/Char) and I know how to use the
ascii/hex values of the ebcdic characters to extract the correct ascii text.
The current application that I am using is just not fast enough. My
thoughts are to rewrite the entire conversion application in C/C++/C#.

What I need help with is a tutorial or book that I can get that will give me
specifics as to how to read x bytes of a string, compare them to a matrix
that will probably load as an array (to get the ascii/hex values) and write
them out to a csv. I have programmed for ~20 years but only dabbled in C
for a few months back in high school. The little that I learned then has
long since been forgotten.

I don't need a fancy program with interfaces or anything. As long as I can
pass it parameters, I will be fine. I need it to be as stripped down and as
fast as possible as some of the files that I get are 1billion+ rows. I have
even considered doing this in ASM, but for sure do not have the time to
learn it well enough to do this.
Thanks

Scott