module dinc.mime.iconv;


typedef void* iconv_t;
/// allocate a converter between charsets fromcode and tocode
  extern (C) iconv_t iconv_open (char *tocode, char *fromcode);

  /// convert inbuf to outbuf and set inbytesleft to unused input and
  /// outbuf to unused output and return number of non-reversable 
  /// conversions or -1 on error.
  extern (C) size_t iconv (iconv_t cd, char **inbuf,
			   size_t *inbytesleft,
			   char **outbuf,
			   size_t *outbytesleft);

  /// close converter
  extern (C) int iconv_close (iconv_t cd);

  
	 


import std.string;
import std.stream;

 

class Iconv {
	iconv_t cv;
	char[] fcode;
	char[] tcode;
	this(char[] toCode, char[] fromCode)
	{
		fcode = std.string.tolower(fromCode);
		tcode = std.string.tolower(toCode);
		cv = iconv_open (std.string.toStringz( toCode), 
				std.string.toStringz(fromCode));
		if (cv == cast(iconv_t)-1) {
			throw new Exception("Unknown charset");
		}
		
	}
	
	void convStream(InputStream ifh, OutputStream ofh)
	{
		char[] l;
		//std.stdio.writefln("CONV STREAM:");
		while (!ifh.eof()) {
			
			l = ifh.readLine();
			//std.stdio.writefln("CONV<<: %s", l);
			l = conv(l);
			//std.stdio.writefln("CONV>>: %s", l);
			ofh.writeString(l);
			ofh.writeString("\n");
		}
		
		
	}
	char[] conv(char[] inbuf)
	{
		if (!inbuf.length) {
			return "";
		}
		 
		return conv_iconv(inbuf);
	}
	
	
	char[] conv_iconv(char[] inbuf)
	{
		size_t in_len = inbuf.length;
		size_t out_size = in_len * int.sizeof  + 15;
		size_t out_left = out_size;
		size_t result = 0;
		size_t in_size = in_len;
		
		//char* out_buf = NULL;
		size_t out_len = 0;
		size_t in_left = in_len;
		
		out_left = in_len + 32; /* Avoid realloc() most cases */ 
		out_size = 0;
		size_t bsz = out_left;
		char* out_buf = cast(char *) new char[bsz+1]; 
		char* out_p = out_buf;
		char* in_p = inbuf.ptr;
		
		while (in_left > 0) {
			result = iconv(cv, cast(char **) &in_p, &in_left, cast(char **) &out_p, &out_left);
			out_size = bsz - out_left;
			if (result == cast(size_t)(-1)) {
				break;
				/*
				if (errno == E2BIG && in_left > 0) {
					// converted string is longer than out buffer 
					bsz += in_len;

					tmp_buf = (char*) erealloc(out_buf, bsz+1);
					out_p = out_buf = tmp_buf;
					out_p += out_size;
					out_left = bsz - out_size;
					continue;	
				}
				*/
			}
			break;
		}
		if (result != cast(size_t)(-1)) {
			for (;;) {
				result = iconv(cv, null, null, cast(char **) &out_p, &out_left);
				out_size = bsz - out_left;

				if (result != cast(size_t)(-1)) {
					break;
				}
				/*
				if (errno == E2BIG) {
					bsz += 16;
					tmp_buf = (char *) erealloc(out_buf, bsz);
					
					out_p = out_buf = tmp_buf;
					out_p += out_size;
					out_left = bsz - out_size;
				} else {
					break;
				}
				*/
			}
		}
		 
		return out_buf[0..out_size];
		
	}
	~this()
	{
		if (cv) iconv_close (cv);
	}
	
}