Reading file backwards - Printable Version

Reading file backwards - Printable Version

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+--- Thread: Reading file backwards (/showthread.php?tid=665266)

Reading file backwards - Suttix - 28.03.2019

Is there a way to read a log file backwards because i've been looking for solution but nothing found.
Can someone help me with that.Thanks

Re: Reading file backwards - Suttix - 28.03.2019

Anyone?

Re: Reading file backwards - TokicMajstor - 28.03.2019

If you know exact amount of characters in that (string) you can extract one by one character starting from last one, using strcat

Re: Reading file backwards - Suttix - 29.03.2019

Jok buraz,need better solution.

Re: Reading file backwards - introzen - 29.03.2019

Found this snippet by using the search function. Don't know if it's what you're looking for though.

pawn Code:

Function:Reverse(string[])
{
         // Setting vars
    new string1[256];
               lengthOfString = strlen(string);

        // Processing 
    for(new i = 0; i < strlen(string); i++)
    {
        string1[i] = string[(lengthOfString-i)];
    }

        // Returning processed string
    return string1;
}

Re: Reading file backwards - Logic_ - 29.03.2019

You can try experimenting with something like:

PHP Code:



// Open "file.txt" in "read only" mode

new File:handle = fopen("file.txt", io_read);

 

// If "file.txt" is open

if(handle) {

    // Jump to the last byte of "file.txt", and print its position

    printf("End of file position: %d", fseek(handle, 0, seek_end));


    fclose(handle);

}

( Taken from SA-MP wiki https://sampwiki.blast.hk/wiki/Fseek )

Re: Reading file backwards - Suttix - 29.03.2019

Quote:

Originally Posted by Logic_

You can try experimenting with something like:

PHP Code:



// Open "file.txt" in "read only" mode

new File:handle = fopen("file.txt", io_read);

 

// If "file.txt" is open

if(handle) {

    // Jump to the last byte of "file.txt", and print its position

    printf("End of file position: %d", fseek(handle, 0, seek_end));


    fclose(handle);

}

( Taken from SA-MP wiki https://sampwiki.blast.hk/wiki/Fseek )

I don't know if I could use this for my log file because i need something like:

Code:

while(fread(handle, data))

but read it upwards(last 30 lines).

This is my current load function that loads file string normally from begining

PHP Code:



function givendmg_load(playerid){

    new f[64]; format(f, 64, givendmg_file, GetName(playerid));

    new Data[256], x=0, arrCoords[6][64];


    new File:handle = fopen(f, io_read);

    

    if(!fexist(f)) return printf("File %s ne postoji te se sistem nije ucitao", f);

    

    while(fread(handle, Data)){

        split(Data, arrCoords, ',');

        strmid(givendmgInfo[playerid][x][dmgDate], arrCoords[0], 0, strlen(arrCoords[0]));

        strmid(givendmgInfo[playerid][x][dmgTime], arrCoords[1], 0, strlen(arrCoords[1]));

        strmid(givendmgInfo[playerid][x][dmgGivenTo], arrCoords[2], 0, strlen(arrCoords[2]));

        strmid(givendmgInfo[playerid][x][dmgGivenBy], arrCoords[3], 0, strlen(arrCoords[3]));

        givendmgInfo[playerid][x][dmgAmount] = strval(arrCoords[4]);

        givendmgInfo[playerid][x][dmgWeapon] = strval(arrCoords[5]);

        x++;

    }

    fclose(handle);


    return 1;

}

Can anyone give me an example how to reverse fread()

Re: Reading file backwards - Suttix - 29.03.2019

Quote:

Originally Posted by Y_Less

There is no good method. You could try fseek to get to the end. Also, English only here please (in your post at least, not code snippets).

Ok,sure.

Re: Reading file backwards - NaS - 29.03.2019

https://forum.sa-mp.com/showpost.php...82&postcount=8

This should be what you are looking for. It doesn't actually read the file backwards, but it creates a copy with reversed line order which you can open afterwards and use regular file functions.

You must define MAX_LINE_LENGTH to what you guess will be the max. line length. Unfortunately it buffers each line so that is required to know.

Re: Reading file backwards - Suttix - 29.03.2019

Quote:

Originally Posted by NaS

https://forum.sa-mp.com/showpost.php...82&postcount=8

This should be what you are looking for. It doesn't actually read the file backwards, but it creates a copy with reversed line order which you can open afterwards and use regular file functions.

You must define MAX_LINE_LENGTH to what you guess will be the max. line length. Unfortunately it buffers each line so that is required to know.

I came across on this function but i didn't know how could I use it.
I'll try it next time,thanks.