Another short blog post/tutorial (Finding a string in a stream)

[Regan Heath]

On Wed, 15 Mar 2006 11:38:15 +0800, Alan Knowles <alan at akbhome.com> wrote:
> Since I got such good feedback before, I though I'd post about the  
> latest short tutorial...
>
> http://www.akbkhome.com/blog.php/View/116/More_DigitalMars_D__finding_a_string_in_a_stream.html
>
> Feel free to comment / make suggestions.

Here is how I would write it.

NOTE:
  - eof is (and belongs) in the MimeStream.
  - eof is used with property syntax i.e. no () on the method call.
  - there is absolutely no need to copy the characters or allocate memory
  - nested functions are your friends

import std.stdio;

void main () {
     MimeStream x = new MimeStream("This is a test  - hello  with XXX -  
hello world - in the middle");
     uint lines = 0;
     bool ret = skipUntilBoundary(x,"- hello world -",lines);
     if (!ret) writefln("NO MATCH");
     else {
     	char c;
     	
     	writefln("GOT STRING! rest:");
     	while(x.getChar(c)) writef(c);
     }
}

class MimeStream
{
     char[] thestring = "";
     int pos = 0;

     this(char[] string) { thestring = string.dup; }

     bool getChar(inout char c)
     {
         if (eof) return false;
         c = thestring[pos++];
         return true;
     }

     bool eof()
     {
     	return (pos >= thestring.length);
     }
}

bool skipUntilBoundary(MimeStream x, char[] delim, inout uint lines)
{
	char c;	
	uint i;
	
	bool compareDelim()
	{	
		for(i = 0; i < delim.length; i++) {
			if (c != delim[i]) break;
			if (!x.getChar(c)) return false;
		}
		return (i == delim.length);
	}
	
	while(x.getChar(c) && !compareDelim()) {
		if (c == '\n') lines++;
	}
	
	return !x.eof;
}