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Forum Index : Microcontroller and PC projects : Promote for Base 64 Coded Strings and Data Transfer
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TassyJim Guru  Joined: 07/08/2011 Location: AustraliaPosts: 6102 |
If nothing else, Base64 makes the transfer 30% bigger = 30% slower. VK7JH MMedit MMBasic Help |
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CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2080 |
precisely! give me a good set of really optimized primitives all day long - I'll build everything else. Thing is as well, beyond some fringe function being used by a tiny percentage of users; it will only appear once in the code too. I think there are some things missing from MMBasic but I quite enjoy the canter to create them - many of my own published functions are labelled "VB-work-a-like" I was looking at PeterMs "is this too silly" thread and in some reading-around, I found a thread from a few years back (discussing +=, -= etc.) and he said "It isn't BASIC" - that struck me because he's spot on ... x=x+1 is bread and butter BASIC. Yes I get the performance nudges of the number of things in an expression and the number of times you call up a variable etc. but if you are into stuff that breaks the accepted constructs and syntax then find a language that gives what you want - C has just about everything you could need but I find it largely unfathomable, so i stick with what I like. It is what it is. Of course there are things that break this (<< and >>) and I use them. I wrestle with my hypocrisy. Edited 2023-03-17 12:45 by CaptainBoing |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6814 |
TBH I don't have a problem with the shifts. They are often included in loops and are convoluted and awkward to do in ordinary BASIC but lightning fast in code so I think there's a place for them. I do have a bit of a problem with INC, although I do use it. X=X+1 is fine with me. I just don't worry myself with what's going on "under the hood". :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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Martin H. Guru Joined: 04/06/2022 Location: GermanyPosts: 1115 |
Here are some Program examples of how to encode and decode Base64 Encode Decode not im MM Basic but it should be no Rocket Science to convert some of the code-examples to it. my 2c Mart!n Edited 2023-03-17 18:59 by Martin H. 'no comment |
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| Martin H. Guru Joined: 04/06/2022 Location: GermanyPosts: 1115 |
Here is what CHatGPT answers:  can you write a function in bbc basic to encode something in BASE64? Sure, here's an example function written in BBC BASIC for encoding a string in BASE64: DEFPROCbase64encode(str$) REM BASE64 encoding table LOCAL b64$ = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" REM Initialize variables LOCAL len%, i%, j%, k%, b1%, b2%, b3%, enc$ = "" REM Determine the length of the input string len% = LEN(str$) REM Loop through each three bytes of the input string and encode them FOR i% = 1 TO len% STEP 3 b1% = ASC(MID$(str$, i%, 1)) b2% = IF(i% + 1 <= len%, ASC(MID$(str$, i% + 1, 1)), 0) b3% = IF(i% + 2 <= len%, ASC(MID$(str$, i% + 2, 1)), 0) j% = b1% DIV 4 k% = (b1% AND 3) * 16 + b2% DIV 16 enc$ += MID$(b64$, j% + 1, 1) + MID$(b64$, k% + 1, 1) IF b2% > 0 THEN j% = (b2% AND 15) * 4 + b3% DIV 64 k% = b3% AND 63 enc$ += MID$(b64$, j% + 1, 1) + MID$(b64$, k% + 1, 1) ENDIF NEXT i% REM Pad the output string with "=" characters if necessary IF len% MOD 3 = 1 THEN enc$ += "==" IF len% MOD 3 = 2 THEN enc$ += "=" REM Return the encoded string ENDPROC enc$ You can call this function by passing in a string to be encoded, like this: mystring$ = "Hello, world!" PRINT PROCbase64encode(mystring$) This should output the BASE64-encoded string for "Hello, world!", which is "SGVsbG8sIHdvcmxkIQ==". --------- can you also wrIte the function to decode? Certainly! Here's an example function written in BBC BASIC for decoding a BASE64-encoded string: DEFPROCbase64decode(enc$) REM BASE64 decoding table LOCAL b64$ = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" REM Initialize variables LOCAL len%, i%, j%, k%, b1%, b2%, b3%, b4%, dec$ = "" REM Determine the length of the input string len% = LEN(enc$) REM Loop through each four bytes of the input string and decode them FOR i% = 1 TO len% STEP 4 b1% = INSTR(b64$, MID$(enc$, i%, 1)) - 1 b2% = INSTR(b64$, MID$(enc$, i% + 1, 1)) - 1 b3% = IF(i% + 2 <= len%, INSTR(b64$, MID$(enc$, i% + 2, 1)) - 1, 0) b4% = IF(i% + 3 <= len%, INSTR(b64$, MID$(enc$, i% + 3, 1)) - 1, 0) j% = (b1% * 4) + (b2% DIV 16) k% = ((b2% AND 15) * 256) + (b3% * 4) + (b4% DIV 64) dec$ += CHR$(j%) + CHR$(k%) IF b3% > 0 THEN j% = ((b4% AND 63) * 16) + (b3% DIV 4) k% = (b3% AND 3) * 64 + b4% dec$ += CHR$(j%) IF b4% > 0 THEN dec$ += CHR$(k%) ENDIF NEXT i% REM Return the decoded string ENDPROC dec$ You can call this function by passing in a BASE64-encoded string to be decoded, like this: myencoded$ = "SGVsbG8sIHdvcmxkIQ==" PRINT PROCbase64decode(myencoded$) This should output the decoded string for "SGVsbG8sIHdvcmxkIQ==", which is "Hello, world!". 'no comment |
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