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Hi Everyone, I had posted an example in the old forum of a B...


Warren Hinchliffe

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Hi Everyone,

I had posted an example in the old forum of a Base64 encoder.

Well there is a decoder.

Its written in Dialog Manager. and is good for small strings. Have no idea how it would perform on a large string or a CLOB.

The encoded string is supplied via the variable &B64_String and is also returned decoded via the same variable.

-SET &BitString = '' ;

-SET &BASE64CHars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/' ;

 

-REPEAT ::To:Bits FOR &Cntr FROM 1 TO &B64_String.LENGTH ;

 

-SET &B64Chr = SUBSTRING(&B64_String, &Cntr, 1) ;

-SET &B64Num = POSITION(&B64Chr, &BASE64CHars) -1 ;

 

-IF &B64Num EQ -1 THEN GOTO ::To:Bits ;

 

-REPEAT ::Get:Bits FOR &BitCntr FROM 1 TO 6 ;

 

-SET &Div = DECODE &BitCntr(1 32 2 16 3 8 4 4 5 2 6 1) ;

-SET &Bit = &B64Num/&Div ;

-SET &B64Num= IMOD(&B64Num,&Div,I2) ;

-SET &BitString = RTRIM(&BitString) | &Bit ;

-::Get:Bits

 

-::To:Bits

 

-SET &B64_String = '' ;

 

-REPEAT ::Get:Byte FOR &Cntr FROM 1 TO &BitString.LENGTH ;

 

-IF &Cntr + 7 GT &BitString.LENGTH THEN GOTO ::Get:Byte ;

 

 

-SET &Test = SUBSTRING(&BitString,&Cntr+1,1) ;

 

-SET &ByteNum = 128 * SUBSTRING(&BitString,&Cntr ,1) +

- 64 * SUBSTRING(&BitString,&Cntr+1,1) +

- 32 * SUBSTRING(&BitString,&Cntr+2,1) +

- 16 * SUBSTRING(&BitString,&Cntr+3,1) +

- 8 * SUBSTRING(&BitString,&Cntr+4,1) +

- 4 * SUBSTRING(&BitString,&Cntr+5,1) +

- 2 * SUBSTRING(&BitString,&Cntr+6,1) +

- 1 * SUBSTRING(&BitString,&Cntr+7,1) ;

 

-SET &Cntr = &Cntr + 7 ;

 

-SET &B64_String = RTRIM(&B64_String) | HEXBYT(&ByteNum, 'A1') ;

 

-::Get:Byte

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