* vlc_stream.h : oops again.

include/vlc_stream.h

+/*****************************************************************************
+ * vlc_stream.h
+ *****************************************************************************
+ * Copyright (C) 1999-2004 VideoLAN
+ * $Id: ninput.h 7930 2004-06-07 18:23:15Z fenrir $
+ *
+ * Authors: Laurent Aimar <fenrir@via.ecp.fr>
+ *
+ * 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, USA.
+ *****************************************************************************/
+
+#ifndef _VLC_STREAM_H
+#define _VLC_STREAM_H 1
+
+/**
+ * \defgroup stream Stream
+ *
+ *  This will allow you to easily handle read/seek in demuxer modules.
+ * @{
+ */
+
+/**
+ * Possible commands to send to stream_Control() and stream_vaControl()
+ */
+enum stream_query_e
+{
+    /* capabilities */
+    STREAM_CAN_SEEK,            /**< arg1= vlc_bool_t *   res=cannot fail*/
+    STREAM_CAN_FASTSEEK,        /**< arg1= vlc_bool_t *   res=cannot fail*/
+
+    /* */
+    STREAM_SET_POSITION,        /**< arg1= int64_t        res=can fail  */
+    STREAM_GET_POSITION,        /**< arg1= int64_t *      res=cannot fail*/
+
+    STREAM_GET_SIZE,            /**< arg1= int64_t *      res=cannot fail (0 if no sense)*/
+
+    STREAM_GET_MTU,             /**< arg1= int *          res=cannot fail (0 if no sense)*/
+
+    /* Special for direct access control from demuxer.
+     * XXX: avoid using it by all means */
+    STREAM_CONTROL_ACCESS,      /* arg1= int i_access_query, args   res: can fail
+                                   if access unreachable or access control answer */
+};
+
+/**
+ * stream_t definition
+ */
+struct stream_t
+{
+    VLC_COMMON_MEMBERS
+
+    block_t *(*pf_block)  ( stream_t *, int i_size );
+    int      (*pf_read)   ( stream_t *, void *p_read, int i_read );
+    int      (*pf_peek)   ( stream_t *, uint8_t **pp_peek, int i_peek );
+    int      (*pf_control)( stream_t *, int i_query, va_list );
+
+    stream_sys_t *p_sys;
+};
+
+/**
+ * Try to read "i_read" bytes into a buffer pointed by "p_read".  If
+ * "p_read" is NULL then data are skipped instead of read.  The return
+ * value is the real numbers of bytes read/skip. If this value is less
+ * than i_read that means that it's the end of the stream.
+ */
+static inline int stream_Read( stream_t *s, void *p_read, int i_read )
+{
+    return s->pf_read( s, p_read, i_read );
+}
+
+/**
+ * Store in pp_peek a pointer to the next "i_peek" bytes in the stream
+ * \return The real numbers of valid bytes, if it's less
+ * or equal to 0, *pp_peek is invalid.
+ * \note pp_peek is a pointer to internal buffer and it will be invalid as
+ * soons as other stream_* functions are called.
+ * \note Due to input limitation, it could be less than i_peek without meaning
+ * the end of the stream (but only when you have i_peek >=
+ * p_input->i_bufsize)
+ */
+static inline int stream_Peek( stream_t *s, uint8_t **pp_peek, int i_peek )
+{
+    return s->pf_peek( s, pp_peek, i_peek );
+}
+
+/**
+ * Use to control the "stream_t *". Look at #stream_query_e for
+ * possible "i_query" value and format arguments.  Return VLC_SUCCESS
+ * if ... succeed ;) and VLC_EGENERIC if failed or unimplemented
+ */
+static inline int stream_vaControl( stream_t *s, int i_query, va_list args )
+{
+    return s->pf_control( s, i_query, args );
+}
+static inline int stream_Control( stream_t *s, int i_query, ... )
+{
+    va_list args;
+    int     i_result;
+
+    va_start( args, i_query );
+    i_result = s->pf_control( s, i_query, args );
+    va_end( args );
+    return i_result;
+}
+static inline int64_t stream_Tell( stream_t *s )
+{
+    int64_t i_pos;
+    stream_Control( s, STREAM_GET_POSITION, &i_pos );
+    return i_pos;
+}
+static inline int64_t stream_Size( stream_t *s )
+{
+    int64_t i_pos;
+    stream_Control( s, STREAM_GET_SIZE, &i_pos );
+    return i_pos;
+}
+static inline int stream_MTU( stream_t *s )
+{
+    int i_mtu;
+    stream_Control( s, STREAM_GET_MTU, &i_mtu );
+    return i_mtu;
+}
+static inline int stream_Seek( stream_t *s, int64_t i_pos )
+{
+    return stream_Control( s, STREAM_SET_POSITION, i_pos );
+}
+
+/**
+ * Read "i_size" bytes and store them in a block_t. If less than "i_size"
+ * bytes are available then return what is left and if nothing is availble,
+ * return NULL.
+ */
+static inline block_t *stream_Block( stream_t *s, int i_size )
+{
+    if( i_size <= 0 ) return NULL;
+
+    if( s->pf_block )
+    {
+        return s->pf_block( s, i_size );
+    }
+    else
+    {
+        /* emulate block read */
+        block_t *p_bk = block_New( s, i_size );
+        if( p_bk )
+        {
+            p_bk->i_buffer = stream_Read( s, p_bk->p_buffer, i_size );
+            if( p_bk->i_buffer > 0 )
+            {
+                return p_bk;
+            }
+        }
+        if( p_bk ) block_Release( p_bk );
+        return NULL;
+    }
+}
+
+VLC_EXPORT( char *, stream_ReadLine, ( stream_t * ) );
+
+/**
+ * Create a special stream and a demuxer, this allows chaining demuxers
+ */
+#define stream_DemuxNew( a, b, c ) __stream_DemuxNew( VLC_OBJECT(a), b, c)
+VLC_EXPORT( stream_t *,__stream_DemuxNew, ( vlc_object_t *p_obj, char *psz_demux, es_out_t *out ) );
+VLC_EXPORT( void,      stream_DemuxSend,  ( stream_t *s, block_t *p_block ) );
+VLC_EXPORT( void,      stream_DemuxDelete,( stream_t *s ) );
+
+/**
+ * @}
+ */
+
+#endif