path: root/camel/camel-stream-mem.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/* camel-stream-mem.c : memory buffer based stream */

/* inspired by gnome-stream-mem.c in bonobo by Miguel de Icaza */
/* 
 *
 * 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-mem.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include "camel-log.h"

static CamelStreamClass *parent_class=NULL;


/* Returns the class for a CamelStreamMEM */
#define CSM_CLASS(so) CAMEL_STREAM_MEM_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 (CamelSeekableStream *stream, gint offset, CamelStreamSeekPolicy policy);

static void _finalize (GtkObject *object);

static void
camel_stream_mem_class_init (CamelStreamMemClass *camel_stream_mem_class)
{
    CamelSeekableStreamClass *camel_seekable_stream_class = CAMEL_SEEKABLE_STREAM_CLASS (camel_stream_mem_class);
    CamelStreamClass *camel_stream_class = CAMEL_STREAM_CLASS (camel_stream_mem_class);
    GtkObjectClass *gtk_object_class = GTK_OBJECT_CLASS (camel_stream_mem_class);
    
    parent_class = gtk_type_class (gtk_object_get_type ());
    
    /* virtual method definition */
    
    /* virtual method overload */
    camel_stream_class->read = _read;
    camel_stream_class->write = _write;
    camel_stream_class->flush = _flush;
    camel_stream_class->available = _available;
    camel_stream_class->eos = _eos;
    camel_stream_class->close = _close;

    camel_seekable_stream_class->seek = _seek;
    
    gtk_object_class->finalize = _finalize;
    
}

static void
camel_stream_mem_init (gpointer   object,  gpointer   klass)
{
    CamelStreamMem *camel_stream_mem = CAMEL_STREAM_MEM (object);
    camel_stream_mem->position = 0;
}

GtkType
camel_stream_mem_get_type (void)
{
    static GtkType camel_stream_mem_type = 0;
    
    if (!camel_stream_mem_type) {
        GtkTypeInfo camel_stream_mem_info = 
        {
            "CamelStreamMem",
            sizeof (CamelStreamMem),
            sizeof (CamelStreamMemClass),
            (GtkClassInitFunc) camel_stream_mem_class_init,
            (GtkObjectInitFunc) camel_stream_mem_init,
                /* reserved_1 */ NULL,
                /* reserved_2 */ NULL,
            (GtkClassInitFunc) NULL,
        };
        
        camel_stream_mem_type = gtk_type_unique (camel_seekable_stream_get_type (), &camel_stream_mem_info);
    }
    
    return camel_stream_mem_type;
}


CamelStream *
camel_stream_mem_new (CamelStreamMemMode mode)
{
    return camel_stream_mem_new_with_byte_array (g_byte_array_new (),
                             mode);
}

CamelStream *
camel_stream_mem_new_with_buffer (const char *buffer, unsigned int len,
                  CamelStreamMemMode mode)
{
    GByteArray *ba;

    ba = g_byte_array_new ();
    g_byte_array_append (ba, (const guint8 *)buffer, len);
    return camel_stream_mem_new_with_byte_array (ba, mode);
}

CamelStream *
camel_stream_mem_new_with_byte_array (GByteArray *byte_array,
                      CamelStreamMemMode mode)
{
    CamelStreamMem *stream_mem;
    
    stream_mem = gtk_type_new (camel_stream_mem_get_type ());
    stream_mem->mode = mode;
    stream_mem->buffer = byte_array;
    
    return CAMEL_STREAM (stream_mem);
}



static void           
_finalize (GtkObject *object)
{
    CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (object);

    if (stream_mem->buffer)
        g_byte_array_free (stream_mem->buffer, TRUE);

    GTK_OBJECT_CLASS (parent_class)->finalize (object);
}



/**
 * _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)
{
    CamelStreamMem *camel_stream_mem = CAMEL_STREAM_MEM (stream);
    gint nb_bytes_to_read;

    g_assert (stream);
    nb_bytes_to_read = MIN (n, (camel_stream_mem->buffer)->len - camel_stream_mem->position);
    if (nb_bytes_to_read>0) {
        memcpy (buffer, (camel_stream_mem->buffer)->data + camel_stream_mem->position, nb_bytes_to_read);
        camel_stream_mem->position += nb_bytes_to_read;
    } else nb_bytes_to_read = -1;

    return nb_bytes_to_read;
}


/**
 * _write: read bytes to a stream
 * @stream: the stream
 * @buffer: byte buffer
 * @n: number of bytes to write
 * 
 * 
 * 
 * Return value: the number of bytes actually written
 *  in the stream.
 **/
static gint
_write (CamelStream *stream, const gchar *buffer, gint n)
{
    CamelStreamMem *camel_stream_mem = CAMEL_STREAM_MEM (stream);

    g_assert (stream);
    g_return_val_if_fail (camel_stream_mem->position>=0, -1);
    camel_stream_mem->buffer = g_byte_array_append (camel_stream_mem->buffer, (const guint8 *)buffer, n);
    camel_stream_mem->position += n;
    
    return n;
}



/**
 * _flush: flush pending changes 
 * @stream: the stream
 * 
 * 
 **/
static void
_flush (CamelStream *stream)
{
    /* Nothing to do. */
    return;
}



/**
 * _available: return the number of bytes available for reading
 * @stream: the stream
 * 
 * Return the number of bytes available without blocking.
 * 
 * Return value: the number of bytes available
 **/
static gint 
_available (CamelStream *stream)
{
    CamelStreamMem *camel_stream_mem = CAMEL_STREAM_MEM (stream);

    return camel_stream_mem->buffer->len - camel_stream_mem->position;
}


/**
 * _eos: test if there are bytes left to read
 * @stream: the stream
 * 
 * Return value: true if all stream has been read
 **/
static gboolean
_eos (CamelStream *stream)
{
    return _available (stream) == 0;
}


/**
 * _close: close a stream
 * @stream: the stream
 * 
 * 
 **/
static void
_close (CamelStream *stream)
{
    CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (stream);

    if (stream_mem->buffer)
        g_byte_array_free (stream_mem->buffer, TRUE);
    stream_mem->buffer = NULL;
}



static gint
_seek (CamelSeekableStream *stream, gint offset, CamelStreamSeekPolicy policy)
{
    gint position;
    CamelStreamMem *camel_stream_mem = CAMEL_STREAM_MEM (stream);

    switch  (policy) {
    case CAMEL_STREAM_SET:
        position = offset;
        break;
    case CAMEL_STREAM_CUR:
        position = camel_stream_mem->position + offset;
        break;
    case CAMEL_STREAM_END:
        position = (camel_stream_mem->buffer)->len + offset;
        break;
    default:
        return -1;
    }
        
    position = MIN (position, (camel_stream_mem->buffer)->len);
    position = MAX (position, 0);

    camel_stream_mem->position = position;

    return position;
}