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-rw-r--r--camel/camel-seekable-substream.c442
1 files changed, 442 insertions, 0 deletions
diff --git a/camel/camel-seekable-substream.c b/camel/camel-seekable-substream.c
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+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+/* camel-stream-fs.c : file system based stream */
+
+/* inspired by gnome-stream-fs.c in bonobo by Miguel de Icaza */
+/*
+ *
+ * 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-seekable-substream.h"
+#include "camel-log.h"
+
+static CamelSeekableStreamClass *parent_class=NULL;
+
+
+/* Returns the class for a CamelSeekableSubStream */
+#define CSS_CLASS(so) CAMEL_SEEKABLE_SUBSTREAM_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 _destroy (GtkObject *object);
+
+static void _init_with_seekable_stream_and_bounds (CamelSeekableSubstream *seekable_substream,
+ CamelSeekableStream *parent_stream,
+ guint32 inf_bound,
+ guint32 sup_bound);
+
+
+
+
+static void
+camel_seekable_substream_class_init (CamelSeekableSubstreamClass *camel_seekable_substream_class)
+{
+ CamelSeekableStreamClass *camel_seekable_stream_class = CAMEL_SEEKABLE_STREAM_CLASS (camel_seekable_substream_class);
+ CamelStreamClass *camel_stream_class = CAMEL_STREAM_CLASS (camel_seekable_substream_class);
+ GtkObjectClass *gtk_object_class = GTK_OBJECT_CLASS (camel_seekable_substream_class);
+
+ parent_class = gtk_type_class (camel_seekable_stream_get_type ());
+
+ /* virtual method definition */
+ camel_seekable_substream_class->init_with_seekable_stream_and_bounds = _init_with_seekable_stream_and_bounds;
+
+ /* 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;
+ gtk_object_class->destroy = _destroy;
+
+}
+
+static void
+camel_seekable_substream_init (gpointer object, gpointer klass)
+{
+ /* does nothing */
+}
+
+
+
+
+GtkType
+camel_seekable_substream_get_type (void)
+{
+ static GtkType camel_seekable_substream_type = 0;
+
+ if (!camel_seekable_substream_type) {
+ GtkTypeInfo camel_seekable_substream_info =
+ {
+ "CamelSeekableSubstream",
+ sizeof (CamelSeekableSubstream),
+ sizeof (CamelSeekableSubstreamClass),
+ (GtkClassInitFunc) camel_seekable_substream_class_init,
+ (GtkObjectInitFunc) camel_seekable_substream_init,
+ /* reserved_1 */ NULL,
+ /* reserved_2 */ NULL,
+ (GtkClassInitFunc) NULL,
+ };
+
+ camel_seekable_substream_type = gtk_type_unique (camel_seekable_stream_get_type (), &camel_seekable_substream_info);
+ }
+
+ return camel_seekable_substream_type;
+}
+
+
+
+
+
+
+static void
+_destroy (GtkObject *object)
+{
+
+ CAMEL_LOG_FULL_DEBUG ("Entering CamelSeekableSubstream::destroy\n");
+
+ /* does nothing for the moment */
+ GTK_OBJECT_CLASS (parent_class)->destroy (object);
+
+ CAMEL_LOG_FULL_DEBUG ("Leaving CamelSeekableSubstream::destroy\n");
+}
+
+
+static void
+_finalize (GtkObject *object)
+{
+
+
+ CAMEL_LOG_FULL_DEBUG ("Entering CamelSeekableSubstream::finalize\n");
+
+ /* does nothing for the moment */
+ GTK_OBJECT_CLASS (parent_class)->finalize (object);
+ CAMEL_LOG_FULL_DEBUG ("Leaving CamelSeekableSubstream::finalize\n");
+}
+
+
+
+static void
+_set_bounds (CamelSeekableSubstream *seekable_substream, guint32 inf_bound, guint32 sup_bound)
+{
+ CAMEL_LOG_FULL_DEBUG ("CamelSeekableSubstream::_set_bounds entering\n");
+
+ g_assert (seekable_substream);
+ g_assert (seekable_substream->parent_stream);
+
+ /* store the bounds */
+ seekable_substream->inf_bound = inf_bound;
+ seekable_substream->sup_bound = sup_bound;
+
+ /* go to the first position */
+ camel_seekable_stream_seek (seekable_substream->parent_stream, inf_bound, SEEK_SET);
+
+ seekable_substream->cur_pos = inf_bound;
+
+ CAMEL_LOG_FULL_DEBUG ("In CamelSeekableSubstream::_set_bounds, "
+ "setting inf bound to %u, "
+ "sup bound to %ld, current postion to %u from %u\n",
+ seekable_substream->inf_bound, seekable_substream->sup_bound,
+ seekable_substream->cur_pos, inf_bound);
+
+ CAMEL_LOG_FULL_DEBUG ("CamelSeekableSubstream::_set_bounds Leaving\n");
+}
+
+
+
+static void
+_init_with_seekable_stream_and_bounds (CamelSeekableSubstream *seekable_substream,
+ CamelSeekableStream *parent_stream,
+ guint32 inf_bound,
+ guint32 sup_bound)
+{
+ /* sanity checks */
+ g_assert (seekable_substream);
+ g_assert (!seekable_substream->parent_stream);
+ g_assert (parent_stream);
+
+ /* store the parent stream */
+ seekable_substream->parent_stream = parent_stream;
+
+ /* set the bound of the substream */
+ _set_bounds (seekable_substream, inf_bound, sup_bound);
+}
+
+
+void
+camel_seekable_substream_init_with_seekable_stream_and_bounds (CamelSeekableSubstream *seekable_substream,
+ CamelSeekableStream *parent_stream,
+ guint32 inf_bound,
+ guint32 sup_bound)
+{
+
+ CSS_CLASS (seekable_substream)->init_with_seekable_stream_and_bounds (seekable_substream,
+ parent_stream,
+ inf_bound,
+ sup_bound);
+
+}
+
+
+
+
+
+/**
+ * _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)
+{
+ CamelSeekableStream *seekable_stream = CAMEL_SEEKABLE_STREAM (stream);
+ CamelSeekableSubstream *seekable_substream = CAMEL_SEEKABLE_SUBSTREAM (stream);
+ gint v;
+ gint nb_to_read;
+ guint32 parent_stream_current_position;
+ guint32 position_in_parent;
+
+ g_assert (stream);
+ g_assert (seekable_substream->parent_stream);
+ g_assert (seekable_substream->open);
+
+
+
+ /*
+ we are doing something quite infefficient :
+
+ each time we want to read a block, we store
+ the parent stream position so that we can
+ change it, and restore it before returning
+
+ This may change. I don't know yet.
+ It may be useless to reseek every time
+ and is incompatible with buffering.
+ */
+
+ parent_stream_current_position =
+ camel_seekable_stream_get_current_position (seekable_substream->parent_stream);
+
+ /* compute the position in the parent stream */
+ position_in_parent =
+ seekable_stream->cur_pos + seekable_substream->inf_bound;
+
+ /* go to our position in the parent stream */
+ camel_seekable_stream_seek (seekable_substream->parent_stream,
+ position_in_parent,
+ CAMEL_STREAM_SET);
+
+
+
+ /* compute how much byte should be read */
+ nb_to_read =
+ MIN (seekable_substream->sup_bound - position_in_parent, n);
+
+
+ /* Read the data */
+ if (nb_to_read >0 )
+ v = camel_stream_read ( CAMEL_STREAM (seekable_substream->parent_stream),
+ buffer,
+ nb_to_read);
+ else
+ v = 0;
+
+ /* if the return value is negative, an error occured,
+ we must do something FIXME : handle exception */
+ if (v<0)
+ CAMEL_LOG_FULL_DEBUG ("CamelSeekableSubstream::read v=%d\n", v);
+ else
+ seekable_stream->cur_pos += v;
+
+
+ /* restore the parent position */
+ camel_seekable_stream_seek (seekable_substream->parent_stream,
+ parent_stream_current_position,
+ CAMEL_STREAM_SET);
+
+
+ /* return the number of bytes read */
+ return v;
+}
+
+
+/**
+ * _write: write 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)
+{
+ /* NOT VALID ON SEEKABLE SUBSTREAM */
+ g_warning ("CamelSeekableSubstream:: seekable substream don't have a write method\n");
+ CAMEL_LOG_WARNING ( "CamelSeekableSubstream:: seekable substream don't have a write method\n");
+ return -1;
+}
+
+
+
+/**
+ * _flush: flush pending changes
+ * @stream: the stream
+ *
+ *
+ **/
+static void
+_flush (CamelStream *stream)
+{
+ /* NOT VALID ON SEEKABLE SUBSTREAM */
+ g_warning ("CamelSeekableSubstream:: seekable substream don't have a flush method\n");
+ CAMEL_LOG_WARNING ( "CamelSeekableSubstream:: seekable substream don't have a flush method\n");
+}
+
+
+
+/**
+ * _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)
+{
+ g_warning ("not implemented\n");
+ return -1;
+}
+
+
+/**
+ * _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)
+{
+ CamelSeekableSubstream *seekable_substream = CAMEL_SEEKABLE_SUBSTREAM (stream);
+ CamelSeekableStream *seekable_stream = CAMEL_SEEKABLE_STREAM (stream);
+ guint32 substream_len;
+
+
+ g_assert (stream);
+ g_assert (seekable_substream->open);
+
+ substream_len = seekable_substream->sup_bound - seekable_substream->inf_bound;
+
+ return ( seekable_stream->cur_pos > substream_len);
+}
+
+
+/**
+ * _close: close a stream
+ * @stream: the stream
+ *
+ *
+ **/
+static void
+_close (CamelStream *stream)
+{
+ CamelSeekableSubstream *seekable_substream = CAMEL_SEEKABLE_SUBSTREAM (stream);
+
+ g_assert (stream);
+ seekable_substream->open = FALSE;
+}
+
+
+static gint
+_seek (CamelSeekableStream *stream, gint offset, CamelStreamSeekPolicy policy)
+{
+ CamelSeekableSubstream *seekable_substream = CAMEL_SEEKABLE_SUBSTREAM (stream);
+ CamelSeekableStream *seekable_stream = CAMEL_SEEKABLE_STREAM (stream);
+ gint64 real_offset;
+ guint32 substream_len;
+
+
+ substream_len = seekable_substream->sup_bound - seekable_substream->inf_bound;
+
+ switch (policy) {
+
+ case CAMEL_STREAM_SET:
+ real_offset = offset;
+
+ break;
+
+ case CAMEL_STREAM_CUR:
+ real_offset = seekable_stream->cur_pos + offset;
+
+ break;
+
+ case CAMEL_STREAM_END:
+ real_offset = substream_len - offset;
+
+ break;
+
+ default:
+ return -1;
+ }
+
+ if (real_offset > 0) {
+ seekable_stream->cur_pos = MIN (real_offset, substream_len);
+ } else
+ seekable_stream->cur_pos = 0;
+
+
+
+ return seekable_stream->cur_pos;
+}
+
+