uint64 Filesize

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Thu, 2015-09-03 05:03

mritter0

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uint64 Filesize

This is my first time using uint64 to handle file sizes >2GB. I am having a terrible time converting it to a readable value to show as text.

Code snippet I am using to convert 3534359552 to GB

uint64 size, value;
 
// size=3534359552;
value=(size/1073741824*100000)/100000;  // = 3.291628......  rounded to 3
 
- or -
 
value=(size*100)/1073741824;    // = 329.16288.... rounded to 329

How to I format it to be like: 3.29 GB

This crashes:

IUtility->SNPrintf(BTUBuffer,15,"%llu%s%02llu GB",value,Locale->loc_DecimalPoint,value % 100);

Thu, 2015-09-03 10:46

salass00

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Joined: 2011-02-03 11:27

Re: uint64 Filesize

/* Compile with:
     gcc -O2 -Wall -Werror -Wwrite-strings -D__USE_INLINE__ -o uint64-filesize uint64-filesize.c -lauto
*/
#include <proto/dos.h>
#include <proto/utility.h>
#include <proto/locale.h>
 
int main(void) {
    struct Locale *locale;
    char buffer[16];
    uint64 size = 3534359552ULL;
    uint64 value = (size*100 + (1024*1024*1024/2)) / (1024*1024*1024);
 
    locale = OpenLocale(NULL);
 
    SNPrintf(buffer, sizeof(buffer), "%llu%s%s%02llu GB", value / 100,
        locale ? locale->loc_DecimalPoint : ".", "", value % 100);
    Printf("Size: %s\n", buffer);
 
    CloseLocale(locale);
 
    return RETURN_OK;
}

There is a bit of a problem with 64-bit values and RawDoFmt() based functions like SNPrintf() in that while RawDoFmt() doesn't expect any alignment the C compiler aligns them to 64-bit so that's why I've added an extra %s and "" to work around this.

Thu, 2015-09-03 10:47

(Reply to #2) #3

salass00

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Re: uint64 Filesize

BTW since the fraction part is limited to 0-99 there is strictly no need to use a 64-bit value there so the SNPrintf() could be changed to:

SNPrintf(buffer, sizeof(buffer), "%llu%s%02lu GB", value / 100,
        locale ? locale->loc_DecimalPoint : ".", (uint32)(value % 100));

Fri, 2015-09-04 01:44

mritter0

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Re: uint64 Filesize

Thank you. Works just like I needed.

Are there any other 64bit issues I need to look out for?

Tue, 2015-09-08 10:39

(Reply to #4) #5

salass00

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Re: uint64 Filesize

Are there any other 64bit issues I need to look out for?

Not that I can think of.

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