I want to save and load levels for my game. The std.stream module doesn't have much examples.

Here is my code:
void saveLevel( string fileName ) {
	auto bfile = new std.stream.File;

	int ver = 1;
	string verStr = "version:";
	with( bfile ) {
		scope( exit )
			close;
		create( fileName );
		write( verStr ); write( ver ); // version
	}

	int ver2;
	char[] verStr2;
	auto bfile2 = new std.stream.File;
	with( bfile2 ) {
		scope( exit )
			close;
		create( fileName );
		read( verStr2 ); read( ver2 ); // version
	}
	writeln( verStr, ver );
}

And this is the result:
std.stream.ReadException@std\stream.d(46): Stream is not readable

- Joel

I've settled on std.stdio as opposed to std.stream and std.cstream.

On Wed, 29 Jun 2011 10:07:13 +1200, Joel Christensen wrote:

> I want to save and load levels for my game. The std.stream module doesn't have much examples.
> 
> Here is my code:
> void saveLevel( string fileName ) {
> 	auto bfile = new std.stream.File;
> 
> 	int ver = 1;
> 	string verStr = "version:";
> 	with( bfile ) {
> 		scope( exit )
> 			close;
> 		create( fileName );
> 		write( verStr ); write( ver ); // version
> 	}
> 
> 	int ver2;
> 	char[] verStr2;
> 	auto bfile2 = new std.stream.File;
> 	with( bfile2 ) {
> 		scope( exit )
> 			close;
> 		create( fileName );

That is copy-paste mistake, right? You don't want create() before reading. You must have meant open:

		open( fileName );

It works with that change.

> 		read( verStr2 ); read( ver2 ); // version
> 	}
> 	writeln( verStr, ver );
> }
> 
> And this is the result:
> std.stream.ReadException@std\stream.d(46): Stream is not readable
> 
> - Joel

Ali

Thanks for your reply Ali.

Your right about changing create to open when reading. And, yes, I was thinking of trying std.stdio myself.

- Joel

On 29-Jun-11 6:48 PM, Ali Çehreli wrote:
> I've settled on std.stdio as opposed to std.stream and std.cstream.
>
> On Wed, 29 Jun 2011 10:07:13 +1200, Joel Christensen wrote:
>
>> I want to save and load levels for my game. The std.stream module
>> doesn't have much examples.
>>
>> Here is my code:
>> void saveLevel( string fileName ) {
>> 	auto bfile = new std.stream.File;
>>
>> 	int ver = 1;
>> 	string verStr = "version:";
>> 	with( bfile ) {
>> 		scope( exit )
>> 			close;
>> 		create( fileName );
>> 		write( verStr ); write( ver ); // version
>> 	}
>>
>> 	int ver2;
>> 	char[] verStr2;
>> 	auto bfile2 = new std.stream.File;
>> 	with( bfile2 ) {
>> 		scope( exit )
>> 			close;
>> 		create( fileName );
>
> That is copy-paste mistake, right? You don't want create() before
> reading. You must have meant open:
>
> 		open( fileName );
>
> It works with that change.
>
>> 		read( verStr2 ); read( ver2 ); // version
>> 	}
>> 	writeln( verStr, ver );
>> }
>>
>> And this is the result:
>> std.stream.ReadException@std\stream.d(46): Stream is not readable
>>
>> - Joel
>
> Ali

With the char[], I can't use spaces in it the way I've got it here, (like if I tried using a phrase):

void saveLevel( string fileName ) {
	int ver = 1;
	auto house = "two".dup;
	double rnum = 3.0;
	
	{
		auto fout = File( fileName, "wb"); // open for binary writing
		scope( exit )
			fout.close;
		fout.writef( "%d %s %f", ver, house, rnum );
	}
	
	ver = 593;
	house = "asdfghf".dup;
	rnum = 57.23;

	{
		auto fin = File( fileName, "rb"); // open for binary reading
		scope( exit )
			fin.close;
		fin.readf( "%d %s %f", &ver, &house, &rnum );
	}

	writeln( "\nint: ", ver, " string: '", house, "' rnum: ", rnum );
}

- Joel

On Wed, 29 Jun 2011 19:55:38 +1200, Joel Christensen wrote:

> With the char[], I can't use spaces in it the way I've got it here,
> (like if I tried using a phrase):

There has been a thread very recently about reading strings. Look for the thread "readf with strings" (dated 22-Jun-2011 in my reader). Or, if it works here:

http://www.digitalmars.com/webnews/newsgroups.php? art_group=digitalmars.D.learn&article_id=27762

Reading the entire line:

    string s = chomp(readln());

Kai Meyer suggested parsing the string directly:

     string[] buffer;
     int a;
     float b;
     string c;
     buffer = chomp(readln()).split(" ");
     a = to!(int)(buffer[0]);
     b = to!(float)(buffer[1]);
     c = buffer[2..$].join(" ");
     writef("Read in: '%d' '%f' '%s'\n", a, b, c);

> 
> void saveLevel( string fileName ) {
> 	int ver = 1;
> 	auto house = "two".dup;
> 	double rnum = 3.0;
> 
> 	{
> 		auto fout = File( fileName, "wb"); // open for binary
writing scope(
> 		exit )
> 			fout.close;

You are not supposed to need to close the File object yourself. Being a struct, its destructor should be called automatically.

Ali

I'm thinking more about handling binary files. With the C version I would write a int for how many letters in the string, then put in the the string along side ([0005][house]). That way I can have any character at all (though I just thinking of char's).

Actually, I've just looked the output file and it's a text file. So in that case I would use read line to have spaces in strings, though what if I wanted to have new line character(s) in the one string. I still want to work with binary files.

On 30-Jun-11 2:23 AM, Ali Çehreli wrote:
> On Wed, 29 Jun 2011 19:55:38 +1200, Joel Christensen wrote:
>
>> With the char[], I can't use spaces in it the way I've got it here,
>> (like if I tried using a phrase):
>
> There has been a thread very recently about reading strings. Look for the
> thread "readf with strings" (dated 22-Jun-2011 in my reader). Or, if it
> works here:
>
> http://www.digitalmars.com/webnews/newsgroups.php?
> art_group=digitalmars.D.learn&article_id=27762
>
> Reading the entire line:
>
>      string s = chomp(readln());
>
> Kai Meyer suggested parsing the string directly:
>
>       string[] buffer;
>       int a;
>       float b;
>       string c;
>       buffer = chomp(readln()).split(" ");
>       a = to!(int)(buffer[0]);
>       b = to!(float)(buffer[1]);
>       c = buffer[2..$].join(" ");
>       writef("Read in: '%d' '%f' '%s'\n", a, b, c);
>
>>
>> void saveLevel( string fileName ) {
>> 	int ver = 1;
>> 	auto house = "two".dup;
>> 	double rnum = 3.0;
>> 	
>> 	{
>> 		auto fout = File( fileName, "wb"); // open for binary
> writing scope(
>> 		exit )
>> 			fout.close;
>
> You are not supposed to need to close the File object yourself. Being a
> struct, its destructor should be called automatically.
>
> Ali

On Thu, 30 Jun 2011 15:52:59 +1200, Joel Christensen wrote:

> I'm thinking more about handling binary files. With the C version I would write a int for how many letters in the string, then put in the the string along side ([0005][house]). That way I can have any character at all (though I just thinking of char's).

I would still use a portable text format myself.

For binary, you should consider rawWrite() and rawRead(). Here is just a start:

import std.stdio;

void main()
{
    int i = 42;
    auto file = File("deleteme.bin", "w");
    file.rawWrite((&i)[0..1]);
}

(Aside: The 'b' for binary mode does nothing in POSIX systems; so it's not necessary.)

The parameter to rawWrite() above is a nice feature of D: slicing a raw pointer produces a safe slice:

  http://digitalmars.com/d/2.0/arrays.html

<quote>
Slicing is not only handy for referring to parts of other arrays, but for
converting pointers into bounds-checked arrays:

int* p;
int[] b = p[0..8];
</quote>

For strings (actually arrays), you would need .length and .ptr properties.

I've never used it but you might want to consider the serialization library Orange as well:

  http://www.dsource.org/projects/orange

Ali

Yes, portability, I hadn't thought of that.

Shouldn't file.rawWrite((&i)[0..1]); have [0..4]? Or am I missing some thing?

- Joel

On 30-Jun-11 7:53 PM, Ali Çehreli wrote:
> On Thu, 30 Jun 2011 15:52:59 +1200, Joel Christensen wrote:
>
>> I'm thinking more about handling binary files. With the C version I
>> would write a int for how many letters in the string, then put in the
>> the string along side ([0005][house]). That way I can have any character
>> at all (though I just thinking of char's).
>
> I would still use a portable text format myself.
>
> For binary, you should consider rawWrite() and rawRead(). Here is just a
> start:
>
> import std.stdio;
>
> void main()
> {
>      int i = 42;
>      auto file = File("deleteme.bin", "w");
>      file.rawWrite((&i)[0..1]);
> }
>
> (Aside: The 'b' for binary mode does nothing in POSIX systems; so it's
> not necessary.)
>
> The parameter to rawWrite() above is a nice feature of D: slicing a raw
> pointer produces a safe slice:
>
>    http://digitalmars.com/d/2.0/arrays.html
>
> <quote>
> Slicing is not only handy for referring to parts of other arrays, but for
> converting pointers into bounds-checked arrays:
>
> int* p;
> int[] b = p[0..8];
> </quote>
>
> For strings (actually arrays), you would need .length and .ptr properties.
>
> I've never used it but you might want to consider the serialization
> library Orange as well:
>
>    http://www.dsource.org/projects/orange
>
> Ali

On Fri, 01 Jul 2011 05:28:56 +1200, Joel Christensen wrote:

> Shouldn't file.rawWrite((&i)[0..1]); have [0..4]? Or am I missing some
> thing?

[0..1] follows the regular slicing syntax there: those are element indexes. Since &i is an int*, [0..1] slices the first int. It would be different if it were ubyte* or void*.

Ali

Ok, I get you. A whole int*, not one byte of the int* data.

- Joel

On 01-Jul-11 6:07 AM, Ali Çehreli wrote:
> On Fri, 01 Jul 2011 05:28:56 +1200, Joel Christensen wrote:
>
>> Shouldn't file.rawWrite((&i)[0..1]); have [0..4]? Or am I missing some
>> thing?
>
> [0..1] follows the regular slicing syntax there: those are element
> indexes. Since&i is an int*, [0..1] slices the first int. It would be
> different if it were ubyte* or void*.
>
> Ali