str.tru

unit str;

/*
	platform-independent string class
		
*/

var


/*
	6502 only handles bytes, the rest supports integers!

*/


@define sz integer
@ifdef CPU_MOS6502
@define sz byte
@endif
	
	p1,p2,p3 : ^byte;
	i,j : @sz;
	b,li,c,ii,jj:byte;
	num : integer;
	chars : string="0123456789ABCDEF";


/**

	Returns the length of a string. Note that
	this will only work for strings <256 bytes. 

**/

function strlen( p3 : global ^byte):byte;
begin
	li:=0;
	while (p3[li]<>0) do 
		li+=1;
		
	strlen:=li;	
end;

/**
 Reverses a string
 
 **/
 
procedure reverse(p2: global ^byte);
begin
	c:=strlen(p2);
	j:=c-1;
	i:=0;
	while i<j do
	begin
		b:=p2[i];
		p2[i]:=p2[j];
		p2[j]:=b;
		j-=1;
		i+=1;
	end;
end;

/**
	Converts a number to a string in base b
	example:
	<code>
itoa(1234, p1, 16); // coverts "1234" to a hexadecimal string stored in p1
	</code>

**/
procedure itoa( num:global integer; p1: global ^byte; b:global byte);
begin
	i:=0;
	
	if (num = 0) then
	begin
		p1[0]:=$30; // Simply 0
		p1[1]:=0; 
		return;
	end;
	
	while (num <> 0) do
	begin
 		p1[i] :=chars[mod(num,b)];
		i+=1;
		num:=num/b;
    end;
	p1[i]:=0; // null-term string    
	reverse(p1);	
	
end;
/**

	Appends a copy of the source string (p2) to the destination string (p1).
	The terminating null character in destination is overwritten by the first character of source, and a null-character is included at the end of the new string formed by the concatenation of both in destination.

**/
procedure strcat(p1,p2 : global ^byte); 
begin
	ii:=strlen(p1);
	jj:=0;
	while (p2[jj]<>0) do
	begin
		p1[ii]:=p2[jj];
		jj+=1;
		ii+=1;
	end;	
	p1[ii]:=0; // null-terminate

end;

/**

	Copies a substring from p2 to p1. The start position is given by b, and the length is c. 
	
<code>
   // Copies 4 bytes from position 14 (to 18)
   str::substr(#data, #myString, 14,4); 
</code>

**/

procedure substr(p1, p2: global ^byte; b,c : global @sz);
begin
	p2+=b;
	
@ifdef CPU_MOS6502	
	memcpy(p2,0,p1,c);
@endif
@ifdef CPU_Z80
	memcpy(p2,p1,c);
@endif 
	p1[c]:=0;
end; 

end.