• Alan Knowles (6/6) Mar 14 2006 Since I got such good feedback before, I though I'd post about the
• Regan Heath (57/61) Mar 15 2006 Here is how I would write it.
• Alan Knowles (11/86) Mar 15 2006 You missed the challenge of the task :)
• Regan Heath (5/9) Mar 15 2006 You're right. I didn't imagine that possibility (due in part to the way ...

Alan Knowles <alan akbhome.com> writes:

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.

Regards
Alan

"Regan Heath" <regan netwin.co.nz> writes:

On Wed, 15 Mar 2006 11:38:15 +0800, Alan Knowles <alan 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;
}

Alan Knowles <alan akbkhome.com> writes:

You missed the challenge of the task :)

looking for "- ABC - DEF -" in "test - ABC - ABC - DEF -"
as you need to backtrack as you have eaten too many characters, by the 
time you get to the real match..

the nested functions look like a good idea. -> it does make things a bit 
cleaner.

The original code returned eof, although you are right, the caller 
should really check the Stream for eof, rather than this method.

Thanks
Alan

Regan Heath wrote:
 On Wed, 15 Mar 2006 11:38:15 +0800, Alan Knowles <alan 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_str
ng_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;
 }

"Regan Heath" <regan netwin.co.nz> writes:

On Thu, 16 Mar 2006 09:58:55 +0800, Alan Knowles <alan akbkhome.com> wrote:
 You missed the challenge of the task :)

 looking for "- ABC - DEF -" in "test - ABC - ABC - DEF -"
 as you need to backtrack as you have eaten too many characters, by the  
 time you get to the real match..

You're right. I didn't imagine that possibility (due in part to the way  
the original code sidestepped the problem with it's revolving buffer and  
custom compare function).

Regan