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 */

/*
 * Authors: Bertrand Guiheneuf <bertrand@helixcode.com>
 *      Michael Zucchi <notzed@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>

static CamelStreamClass *parent_class = NULL;

/* Returns the class for a CamelStreamMem */
#define CSM_CLASS(so) CAMEL_STREAM_MEM_CLASS (GTK_OBJECT(so)->klass)

static ssize_t stream_read (CamelStream *stream, char *buffer, size_t n);
static ssize_t stream_write (CamelStream *stream, const char *buffer, size_t n);
static gboolean stream_eos (CamelStream *stream);
static off_t stream_seek (CamelSeekableStream *stream, off_t 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 (camel_stream_get_type ());

    /* virtual method overload */
    camel_stream_class->read = stream_read;
    camel_stream_class->write = stream_write;
    camel_stream_class->eos = stream_eos;

    camel_seekable_stream_class->seek = stream_seek;

    gtk_object_class->finalize = finalize;
}

static void
camel_stream_mem_init (gpointer object, gpointer klass)
{
    CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (object);

    stream_mem->owner = FALSE;
    stream_mem->buffer = 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 (void)
{
    return camel_stream_mem_new_with_byte_array (g_byte_array_new ());
}

CamelStream *
camel_stream_mem_new_with_buffer (const char *buffer, size_t len)
{
    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);
}

CamelStream *
camel_stream_mem_new_with_byte_array (GByteArray *byte_array)
{
    CamelStreamMem *stream_mem;

    stream_mem = gtk_type_new (camel_stream_mem_get_type ());
    stream_mem->buffer = byte_array;
    stream_mem->owner = TRUE;

    return CAMEL_STREAM (stream_mem);
}

/* note: with these functions the caller is the 'owner' of the buffer */
void camel_stream_mem_set_byte_array (CamelStreamMem *s, GByteArray *buffer)
{
    if (s->buffer && s->owner)
        g_byte_array_free(s->buffer, TRUE);
    s->owner = FALSE;
    s->buffer = buffer;
}

void camel_stream_mem_set_buffer (CamelStreamMem *s, const char *buffer,
                  size_t len)
{
    GByteArray *ba;

    ba = g_byte_array_new ();
    g_byte_array_append (ba, (const guint8 *)buffer, len);
    camel_stream_mem_set_byte_array(s, ba);
}

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

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

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

static ssize_t
stream_read (CamelStream *stream, char *buffer, size_t n)
{
    CamelStreamMem *camel_stream_mem = CAMEL_STREAM_MEM (stream);
    CamelSeekableStream *seekable = CAMEL_SEEKABLE_STREAM (stream);
    ssize_t nread;

    if (seekable->bound_end != CAMEL_STREAM_UNBOUND)
        n = MIN(seekable->bound_end - seekable->position, n);

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

    return nread;
}

static ssize_t
stream_write (CamelStream *stream, const char *buffer, size_t n)
{
    CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (stream);
    CamelSeekableStream *seekable = CAMEL_SEEKABLE_STREAM (stream);
    ssize_t nwrite = n;
    
    if (seekable->bound_end != CAMEL_STREAM_UNBOUND)
        nwrite = MIN(seekable->bound_end - seekable->position, n);

#warning "g_byte_arrays use g_malloc and so are totally unsuitable for this object"
    if (seekable->position == stream_mem->buffer->len) {
        stream_mem->buffer =
            g_byte_array_append (stream_mem->buffer, (const guint8 *)buffer, nwrite);
    } else {
        g_byte_array_set_size (stream_mem->buffer,
                       nwrite + stream_mem->buffer->len);
        memcpy (stream_mem->buffer->data + seekable->position, buffer, nwrite);
    }
    seekable->position += nwrite;

    return nwrite;
}

static gboolean
stream_eos (CamelStream *stream)
{
    CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (stream);
    CamelSeekableStream *seekable_stream = CAMEL_SEEKABLE_STREAM (stream);

    return stream_mem->buffer->len <= seekable_stream->position;
}

static off_t
stream_seek (CamelSeekableStream *stream, off_t offset,
         CamelStreamSeekPolicy policy)
{
    off_t position;
    CamelStreamMem *stream_mem = CAMEL_STREAM_MEM (stream);

    switch  (policy) {
    case CAMEL_STREAM_SET:
        position = offset;
        break;
    case CAMEL_STREAM_CUR:
        position = stream->position + offset;
        break;
    case CAMEL_STREAM_END:
        position = (stream_mem->buffer)->len + offset;
        break;
    default:
        position = offset;
        break;
    }

    if (stream->bound_end == CAMEL_STREAM_UNBOUND)
        position = MIN (position, stream->bound_end);
    if (stream->bound_start == CAMEL_STREAM_UNBOUND)
        position = MAX (position, 0);
    else
        position = MAX (position, stream->bound_start);

    if (position > stream_mem->buffer->len) {
        int oldlen = stream_mem->buffer->len;
        g_byte_array_set_size (stream_mem->buffer, position);
        memset (stream_mem->buffer->data + oldlen, 0,
            position - oldlen);
    }

    stream->position = position;

    return position;
}