String Classes

//Pre-Alpha String Classes
//by Rupert Millard, December 2003

import std.utf;
import std.c.stdio;

alias char utf8byte;
alias dchar utf32char;

interface String
{

	void opCatAssign(StringUTF32);
	void opCatAssign(StringUTF8);
    	
	String opSlice();

	//individual character manipulation functions
	//these are fast on utf32 strings, slower on utf8 ones
	int length();
	utf32char opIndex(int i);
    void opIndex(int i, utf32char value);
    String opSlice(int x, int y);
    
    //this is just for quick and dirty output
    //this will not make it to beta
    void print();
}

class StringUTF32 : String
{
	private utf32char[] chars;
	
	this(StringUTF8 s)
	{
		chars = toUTF32(s.bytes);
	}
	
	this(utf32char[] s)
	{
		chars = s;
	}
	
	void opCatAssign(StringUTF32 s)
	{
		chars ~= s.chars;
	}
	
	void opCatAssign(StringUTF8 s)
	{
		chars ~= toUTF32(s.bytes);
	}
	
    String opSlice()
    {
	    return new StringUTF32(chars[]);
    }

	int length()
	{
		return chars.length;
	}
	
	utf32char opIndex(int i)
	{
		return chars[i];
	}
	
    void opIndex(int i, utf32char c)
    {
	    chars[i] = c;
    }
    
    String opSlice(int x, int y)
    {
	    return new StringUTF32(chars[x .. y]);
    }

    void print()
    {
	    printf("%.*s\n", toUTF8(chars));
    }   
    
}

class StringUTF8 : String
{
	public utf8byte[] bytes;

	this(utf8byte[] s)
	{
		bytes = s;
	}
	
	this(StringUTF32 s)
	{
		bytes = toUTF8(s.chars);
	}
	
	void opCatAssign(StringUTF32 s)
	{
		bytes ~= toUTF8(s.chars);
	}
	
	void opCatAssign(StringUTF8 s)
	{
		bytes ~= s.bytes;
	}
    	
    String opSlice()
    {
	    return new StringUTF8(bytes[]);
    }

	int length()
	{
		int n=0;
		foreach (utf8byte c; bytes)
		{
			if(c<0x80 || c>0xBF)
				n++;
		}
		
		return n;
	}
	
	utf32char opIndex(int i)
    {
	    int n=0;
	    uint p=0;
	    
	    while (n<i)
	   	{
		   	decode(bytes, p);
		   	n++;
	   	}
	   	return decode(bytes, p);
    }
	
    void opIndex(int i, utf32char value)
    {
	    // NOT DONE YET
	    assert(false);	    
    }
    
    String opSlice(int x, int y)
    {
	    int n=0;
	    uint px=0, py;
	    
	    while (n<x)
	   	{
		   	decode(bytes, px);
		   	n++;
	   	}
	   	
	   	py=px;
	   	
	   	while (n<y)
	   	{
		   	decode(bytes, py);
		   	n++;
	   	}
	   	
	   	return new StringUTF8(bytes[px .. py]);
    }

    void print()
    {
	    printf("%.*s\n", bytes);
    }
}


int main (char[][] args)
{
	StringUTF8 a = new StringUTF8("String i");
	StringUTF32 b = new StringUTF32("n two parts");

	a~=b;
	a.print();
	
	a=new StringUTF8(b);
	a.print();
	
	return 0;
}