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Reading from
External Files - By Ad0
Well, I
had a goal today! I wanted to read a file, and then, Print the
content of the file to the console. I made it, with a bit help
from AnthonyJ. He made me look closer and correct my
stupidious little bug that I should have corrected myself, so
a BIG thanks to him!
I am still
sticking me to the server-side, also Game. And I will still
work in g_cmds.c. So open that file, and find an open space
for coding.
The
Function we are going to create is a function that reads the
file from an argument of our function, and puts the content on
the console.
Create a function, named "Cmd_ReadFile_f". The
function would look like this. Do not just paste this and
pretend like you understand all this - Read, Understand,
Learn, and then write it off, and even better: in your own,
personal way:
void Cmd_ReadFile_f( gentity_t *ent)
{
}
When we
write our function, we want to have some declarations first,
and the first declaration would be the dec. of the
filename:
char filename[MAX_STRING_TOKENS]; //max chars
for strings
Now we
have fixed the filename declaration. You could change
"filename" to if you want, but just remember to follow it down
the function.
When I looked a the read code, I saw that you
had to include the handle of the file. It's a definition. And
now, let's define it to, let's say: "t". The "alias would look
like this:
fileHandle_t f;
And now,
we have to add a declaration for our text buffer (the content
of the text stored in temp memory):
char buffer[MAX_ARENAS_TEXT]; //max
text
And now,
our last definition: The length if the text (in letters) the
buffer is. This is for checkingif the file contains anything,
and so on:
int length; //The int for length of
buffer
The first
thing to do now, is to catch the argument from the console.
This is also shown in my Command Argument tutorial. Look here,
and learn:
trap_Argv( 1, filename, sizeof( filename ) );
//Catches the command argument
Look at
this. Now it catches the file name.
Now, let's add a check
if you have typed any argument plus an error message in red
colour. I also have a tutorial containing use of
colours:
if ( !Q_stricmp( filename, "" ) ) //Triggers the
function under if no arguent
entered
trap_SendServerCommand( ent-g_entities, va("print
\""S_COLOR_RED"No file name entered!\n\""));
Done! Now,
let's check the length of the file:
length = trap_FS_FOpenFile( filename, &f,
FS_READ ); //Checks the file length
Logic,
isn't it?
And for not mixing file lengths, I added a
statement that cleared the buffer count:
buffer[length] = 0;
And now we
could add two ways of checking if it's the right file, or if
the file is empty in two ways. I just show you the code. The
rest is up to you. I am trying to learn as best as I
can:
if ( !length) { //If NOT any
length
trap_SendServerCommand( ent-g_entities, va("print
\"I could not open your file:
%s\n\"",filename));
return;
}
if (length < 0) { //If Length less than
zero
trap_SendServerCommand( ent-g_entities, va("print \"I
could not open your file: %s\n\"",filename));
return;
}
Now we got
the check done. As a limiter for larger files, we can add a
code for controlling the buffer. Thanks, AnthonyJ!:
if (length >= MAX_ARENAS_TEXT) //Checks if
length of file s bigger than limit length = MAX_ARENAS_TEXT-1;
//Cuts all text after 1 letter minus
I explored
how the file reading function worked by looking in the Quake
3: Arena source, and I found out that I had to add this code
for making it Read and close the current
file:
trap_FS_Read(buffer,length,f); //Reads the file
into the buffer trap_SendServerCommand( ent-g_entities,
va("print \"Here Goes:\n %s \n\"", buffer)); //Prints the
buffer to client
trap_FS_FCloseFile( f ); //Closes the
buffer
%s Prints
the buffer. %s get's the prameter at the end: buffer.
See?
The only
thing that remains, is to add this as a command in the command
list. Scroll down till you find that list of commands they all
look like my code I am foing to show.I show this for
reference:
else if (Q_stricmp (cmd, "read") ==
0)
Cmd_ReadFile_f( ent );
And this
adds the command (for those who didn't know
that).
I will add
a tutorial of controlling File Input, like read parts of the
text in chunks and print them out (so the buffer donesn't need
to be big).
And
remember: Quake doesn't allow to read files that exists in
other places than in, and under your mod directory you are
putting the compiled result in. q3key won't get read, beacause
Mr. Carmack didn't want it to. So don't try anything
smart.
I hope you understood
this, I really, really do! Just send questions to my mail
address above.
For my music, go here!
Cheers!
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