path: root/camel/camel-stream-buffered-fs.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-stream-buffered-fs.c : file system based stream with buffer*/

/* 
 *
 * Author : 
 *  Bertrand Guiheneuf <bertrand@helixcode.com>
 *
 * Copyright 1999, 2000 HelixCode (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-buffered-fs.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include "camel-log.h"

static CamelStreamFsClass *parent_class=NULL;


/* Returns the class for a CamelStreamBufferedFs */
#define CSBFS_CLASS(so) CAMEL_STREAM_BUFFERED_FS_CLASS (GTK_OBJECT(so)->klass)
#define CSFS_CLASS(so) CAMEL_STREAM_FS_CLASS (GTK_OBJECT(so)->klass)
#define CS_CLASS(so) CAMEL_STREAM_CLASS (GTK_OBJECT(so)->klass)

static gint _read (CamelStream *stream, gchar *buffer, gint n);
static gint _write (CamelStream *stream, const gchar *buffer, gint n);
static void _flush (CamelStream *stream);
static gint _available (CamelStream *stream);
static gboolean _eos (CamelStream *stream);
static void _close (CamelStream *stream);
static gint _seek (CamelStream *stream, gint offset, CamelStreamSeekPolicy policy);

static void _finalize (GtkObject *object);
static void _destroy (GtkObject *object);

static void
camel_stream_buffered_fs_class_init (CamelStreamBufferedFsClass *camel_stream_buffered_fs_class)
{
    CamelStreamClass *camel_stream_class = CAMEL_STREAM_CLASS (camel_stream_buffered_fs_class);
    GtkObjectClass *gtk_object_class = GTK_OBJECT_CLASS (camel_stream_buffered_fs_class);

    parent_class = gtk_type_class (camel_stream_fs_get_type ());
    
    /* virtual method definition */

    /* virtual method overload */
    camel_stream_class->read = _read;

    gtk_object_class->finalize = _finalize;
    gtk_object_class->destroy = _destroy;

}

static void
camel_stream_buffered_fs_init (gpointer   object,  gpointer   klass)
{
    CamelStreamBufferedFs *stream = CAMEL_STREAM_BUFFERED_FS (object);

    stream->buffer_size = 200;
    stream->read_buffer = g_new (gchar, stream->buffer_size);
    stream->write_buffer = g_new (gchar, stream->buffer_size);
    stream->read_pos = 0;
    stream->read_pos_max = 0;
    stream->write_pos = 0;
    stream->write_pos_max = stream->buffer_size;
}

GtkType
camel_stream_buffered_fs_get_type (void)
{
    static GtkType camel_stream_buffered_fs_type = 0;
    
    gdk_threads_enter ();
    if (!camel_stream_buffered_fs_type) {
        GtkTypeInfo camel_stream_buffered_fs_info = 
        {
            "CamelStreamBufferedFs",
            sizeof (CamelStreamBufferedFs),
            sizeof (CamelStreamBufferedFsClass),
            (GtkClassInitFunc) camel_stream_buffered_fs_class_init,
            (GtkObjectInitFunc) camel_stream_buffered_fs_init,
                /* reserved_1 */ NULL,
                /* reserved_2 */ NULL,
            (GtkClassInitFunc) NULL,
        };
        
        camel_stream_buffered_fs_type = gtk_type_unique (camel_stream_fs_get_type (), &camel_stream_buffered_fs_info);
    }
    gdk_threads_leave ();
    return camel_stream_buffered_fs_type;
}


static void           
_destroy (GtkObject *object)
{
    CamelStreamBufferedFs *stream_buffered_fs = CAMEL_STREAM_BUFFERED_FS (object);
    
    CAMEL_LOG_FULL_DEBUG ("Entering CamelStreamBufferedFs::destroy\n");
    

    GTK_OBJECT_CLASS (parent_class)->destroy (object);
    
    CAMEL_LOG_FULL_DEBUG ("Leaving CamelStreamBufferedFs::destroy\n");
}


static void           
_finalize (GtkObject *object)
{
    CamelStreamBufferedFs *stream_buffered_fs = CAMEL_STREAM_BUFFERED_FS (object);


    CAMEL_LOG_FULL_DEBUG ("Entering CamelStreamBufferedFs::finalize\n");
    
    g_free (stream_buffered_fs->read_buffer);
    g_free (stream_buffered_fs->write_buffer);
    
    GTK_OBJECT_CLASS (parent_class)->finalize (object);
    CAMEL_LOG_FULL_DEBUG ("Leaving CamelStreamBufferedFs::finalize\n");
}



CamelStream *
camel_stream_buffered_fs_new_with_name (const gchar *name, CamelStreamFsMode mode)
{
    CamelStreamFs *stream_buffered_fs;
    stream_buffered_fs = gtk_type_new (camel_stream_buffered_fs_get_type ());
    CSFS_CLASS (stream_buffered_fs)->init_with_name (stream_buffered_fs, name, mode);
    
    return CAMEL_STREAM (stream_buffered_fs);
    
}

CamelStream *
camel_stream_buffered_fs_new_with_fd (int fd)
{
    CamelStreamFs *stream_buffered_fs;
    
    CAMEL_LOG_FULL_DEBUG ( "Entering CamelStream::new_with_fd  fd=%d\n",fd);
    stream_buffered_fs = gtk_type_new (camel_stream_buffered_fs_get_type ());
    CSFS_CLASS (stream_buffered_fs)->init_with_fd (stream_buffered_fs, fd);

    
    return CAMEL_STREAM (stream_buffered_fs);
}

/**
 * _read: read bytes from a stream
 * @stream: stream
 * @buffer: buffer where bytes are stored
 * @n: max number of bytes to read
 * 
 * 
 * 
 * Return value: number of bytes actually read.
 **/
static gint
_read (CamelStream *stream, gchar *buffer, gint n)
{
    CamelStreamBufferedFs *sbf = CAMEL_STREAM_BUFFERED_FS (stream);
    gint v;
    gint nb_bytes_buffered;
    gint nb_bytes_to_read = n;
    gint nb_bytes_read = 0;
    gint bytes_chunk;
    gboolean eof = FALSE;

    g_return_val_if_fail (n>0, n);

    nb_bytes_buffered = sbf->read_pos_max - sbf->read_pos;
    while ( (!eof) && (nb_bytes_to_read>0)) { 
        if (nb_bytes_buffered <= 0) {
            /* have to read some data on disk */
            v = CAMEL_STREAM_CLASS (parent_class)->read (stream, sbf->read_buffer, sbf->buffer_size);
            nb_bytes_buffered = v;
            sbf->read_pos_max = v;
            sbf->read_pos = 0;
        }
        
        /* nb of bytes to put inside buffer */
        bytes_chunk = MIN (nb_bytes_buffered, nb_bytes_to_read);

        if (bytes_chunk > 0) {
            /* copy some bytes from the cache */
            memcpy (buffer, sbf->read_buffer + sbf->read_pos, bytes_chunk);
            nb_bytes_buffered -= bytes_chunk;
            nb_bytes_to_read -= bytes_chunk;
            nb_bytes_read += bytes_chunk;
            sbf->read_pos += bytes_chunk;
             
        } else /* nb_bytes_to_read is >0 so if bytes_chunk is <0 
            * there was no data available */
            eof = TRUE;
    }
            
    
    
    return nb_bytes_read;
}


static gint
_write (CamelStream *stream, const gchar *buffer, gint n)
{
    return 0;
}



static void
_flush (CamelStream *stream)
{
    
}



static gint 
_available (CamelStream *stream)
{
    return 0;
}


static gboolean
_eos (CamelStream *stream)
{
    return FALSE;
}



static void
_close (CamelStream *stream)
{
    
}


static gint
_seek (CamelStream *stream, gint offset, CamelStreamSeekPolicy policy)
{
    return 0;
}