/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-stream.c : abstract class for a stream */


/* 
 *
 * Author : 
 *  Bertrand Guiheneuf <bertrand@helixcode.com>
 *
 * Copyright 1999, 2000 Helix Code, Inc. (http://www.helixcode.com)
 *
 * This program is free software; you can redistribute it and/or 
 * modify it under the terms of the GNU General Public License as 
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */
#include <config.h>
#include "camel-stream.h"


enum {
  DATA_AVAILABLE,
  LAST_SIGNAL
};

static guint camel_stream_signals[LAST_SIGNAL] = { 0 };

static GtkObjectClass *parent_class = NULL;


/* Returns the class for a CamelStream */
#define CS_CLASS(so) CAMEL_STREAM_CLASS (GTK_OBJECT(so)->klass)

static void
default_camel_flush (CamelStream *stream)
{
	/* nothing */
}

static void
default_camel_close (CamelStream *stream)
{
	/* nothing */
}

static gboolean
eos (CamelStream *stream)
{
	return stream->eos;
}


static void
camel_stream_class_init (CamelStreamClass *camel_stream_class)
{
	GtkObjectClass *gtk_object_class = GTK_OBJECT_CLASS (camel_stream_class);

	parent_class = gtk_type_class (gtk_object_get_type ());

	/* virtual method definition */
	camel_stream_class->read = NULL;
	camel_stream_class->write = NULL;
	camel_stream_class->flush = default_camel_flush;
	camel_stream_class->eos = eos;
	camel_stream_class->close = default_camel_close;
	camel_stream_class->close = NULL;

	/* virtual method overload */
	
	/* signal definition */
	camel_stream_signals[DATA_AVAILABLE] =
		gtk_signal_new ("data_available",
				GTK_RUN_LAST,
				gtk_object_class->type,
				GTK_SIGNAL_OFFSET (CamelStreamClass, data_available),
				gtk_marshal_NONE__NONE,
				GTK_TYPE_NONE, 0);
	
	gtk_object_class_add_signals (gtk_object_class, camel_stream_signals, LAST_SIGNAL);
	
}

GtkType
camel_stream_get_type (void)
{
	static GtkType camel_stream_type = 0;
	
	if (!camel_stream_type)	{
		GtkTypeInfo camel_stream_info =	
		{
			"CamelStream",
			sizeof (CamelStream),
			sizeof (CamelStreamClass),
			(GtkClassInitFunc) camel_stream_class_init,
			(GtkObjectInitFunc) NULL,
				/* reserved_1 */ NULL,
				/* reserved_2 */ NULL,
			(GtkClassInitFunc) NULL,
		};
		
		camel_stream_type = gtk_type_unique (gtk_object_get_type (), &camel_stream_info);
	}
	
	return camel_stream_type;
}

/**
 * camel_stream_read: 
 * @stream: a CamelStream.
 * @buffer: buffer where bytes pulled from the stream are stored.
 * @n: max number of bytes to read.
 * 
 * Read at most @n bytes from the @stream object and stores them
 * in the buffer pointed at by @buffer.
 * 
 * Return value: number of bytes actually read.
 **/
gint 
camel_stream_read (CamelStream *stream, gchar *buffer, gint n)
{
	return CS_CLASS (stream)->read (stream, buffer, n);
}

/**
 * camel_stream_write: 
 * @stream: a CamelStream object.
 * @buffer: buffer to write.
 * @n: number of bytes to write
 *
 * Write @n bytes from the buffer pointed at by @buffer into @stream.
 *
 * Return value: the number of bytes actually written
 *  in the stream.
 **/
gint
camel_stream_write (CamelStream *stream, const gchar *buffer, gint n)
{
	return CS_CLASS (stream)->write (stream, buffer, n);
}

/**
 * camel_stream_flush:
 * @stream: a CamelStream object
 * 
 * Flushes the contents of the stream to its backing store.
 **/
void
camel_stream_flush (CamelStream *stream)
{
	CS_CLASS (stream)->flush (stream);
}

/**
 * camel_stream_eos: 
 * @stream: a CamelStream object
 * 
 * Test if there are bytes left to read on the @stream object.
 * 
 * Return value: %TRUE if all the contents on the stream has been read, or
 * %FALSE if information is still available.
 **/
gboolean
camel_stream_eos (CamelStream *stream)
{
	return CS_CLASS (stream)->eos (stream);
}


/**
 * camel_stram_close: 
 * @stream: a CamelStream object.
 * 
 * Close the @stream object.
 **/
void
camel_stream_close (CamelStream *stream)
{
	CS_CLASS (stream)->close (stream);
}

/**
 * camel_stream_reset: reset a stream
 * @stream: the stream object
 * 
 * Reset a stream, that is put it in a state
 * where it can be read from the begining. 
 * All streams in camel are not seekable, 
 * but they must all be resettable. 
 * 
 **/
void 
camel_stream_reset (CamelStream *stream)
{	
	CS_CLASS (stream)->reset (stream);
}

/***************** Utility functions ********************/

/**
 * came_stream_write_strings:
 * @stream: a CamelStream object.
 * @...: A %NULL terminated list of strings.
 *
 * This is a utility function that writes the list of
 * strings into the @stream object.
 *
 * Returns number of successfully written bytes.
 */
int
camel_stream_write_strings (CamelStream *stream, ... )
{
	va_list args;
	const char *string;
	int total = 0;

	va_start(args, stream);
	string = va_arg (args, const char *);
	
	while (string) {
		int ret = camel_stream_write_string (stream, string);
		if (ret == -1)
			return -1;
		total += ret;
		string = va_arg (args, char *);
	}
	va_end (args);
	return total;
}

int camel_stream_printf (CamelStream *stream, const char *fmt, ... )
{
	va_list args;
	char *string;
	int ret = 0;

	va_start(args, fmt);
	/* sigh, this allocates ... */
	string = g_strdup_vprintf(fmt, args);
	if (string) {
		ret = camel_stream_write_string(stream, string);
		g_free(string);
	}
	va_end(args);

	return ret;
}

/**
 * camel_stream_write_to_stream:
 * @stream: Source CamelStream.
 * @output_stream: Destination CamelStream.
 * 
 * Write all of a stream (until eos) into another stream, in a blocking
 * fashion.
 *
 * Return Value: Returns -1 on error, or the number of bytes succesfully
 * copied across streams.
 **/
int
camel_stream_write_to_stream (CamelStream *stream,
			      CamelStream *output_stream)
{
	gchar tmp_buf[4096];
	int total = 0;
	gint nb_read;
	gint nb_written;

	/* 
	 * default implementation that uses the input 
	 * stream and stream it in a blocking way
	 * to an output stream.
	 */
	g_assert (output_stream);
	g_assert (stream);
	
	while (!camel_stream_eos (CAMEL_STREAM (stream))) {
		nb_read = camel_stream_read (CAMEL_STREAM (stream), tmp_buf, 4096);
		if (nb_read < 0)
			return -1;
		else if (nb_read>0) {
			nb_written = 0;
		
			while (nb_written < nb_read) {
				int len = camel_stream_write (output_stream, tmp_buf + nb_written, nb_read - nb_written);
				if (len<0)
					return -1;
				nb_written += len;
			}
			total += nb_written;
		}
	}
	return total;
}