Simplify stream->seek.

* include/mailutils/sys/stream.h (_mu_stream) <seek>: Remove the
`whence' parameter.
* mailbox/stream.c (mu_stream_seek): Update the seek method call.

* mailbox/streamref.c (_streamref_seek): Fix the signature. Remove
unnecessary code.
* mailbox/amd.c (amd_body_stream_seek): Likewise.
* mailbox/body.c (_body_seek): Likewise.
* mailbox/file_stream.c (fd_seek): Likewise.
* mailbox/filter_iconv.c (_icvt_seek): Likewise.
* mailbox/fltstream.c (filter_seek): Likewise.
* mailbox/header.c (header_seek): Likewise.
* mailbox/mapfile_stream.c (_mapfile_seek): Likewise.
* mailbox/memory_stream.c (_memory_seek): Likewise.
* mailbox/message.c (_message_stream_seek): Likewise.
* mailbox/message_stream.c (_message_stream_seek): Likewise.
* mailbox/mime.c (_mime_body_seek): Likewise.
* mailbox/stdio_stream.c (stdio_seek): Likewise.

@@ -47,7 +47,7 @@ struct _mu_stream
   int (*open) (struct _mu_stream *);
   int (*close) (struct _mu_stream *);
   void (*done) (struct _mu_stream *);
-  int (*seek) (struct _mu_stream *, mu_off_t, int, mu_off_t *);
+  int (*seek) (struct _mu_stream *, mu_off_t, mu_off_t *);
   int (*size) (struct _mu_stream *, mu_off_t *);
   int (*ctl) (struct _mu_stream *, int, void *);
   int (*wait) (struct _mu_stream *, int *, struct timeval *);

@@ -122,7 +122,7 @@ static int amd_body_stream_readdelim (mu_stream_t is,
 				      int delim,
 				      size_t *pnread);
 static int amd_body_stream_size (mu_stream_t str, mu_off_t *psize);
-static int amd_body_stream_seek (mu_stream_t str, mu_off_t off, int whence,
+static int amd_body_stream_seek (mu_stream_t str, mu_off_t off, 
 				 mu_off_t *presult);
 
 struct _amd_body_stream
@@ -1703,27 +1703,12 @@ amd_body_stream_readdelim (mu_stream_t is, char *buffer, size_t buflen,
 }
 
 static int
-amd_body_stream_seek (mu_stream_t str, mu_off_t off, int whence,
-		      mu_off_t *presult)
+amd_body_stream_seek (mu_stream_t str, mu_off_t off, mu_off_t *presult)
 {
   size_t size;
   struct _amd_body_stream *amdstr = (struct _amd_body_stream *)str;
-  mu_message_t msg = mu_body_get_owner (amdstr->body);
   
   amd_body_size (amdstr->body, &size);
-  switch (whence)
-    {
-    case MU_SEEK_SET:
-      break;
-
-    case MU_SEEK_CUR:
-      off += amdstr->off;
-      break;
-
-    case MU_SEEK_END:
-      off += size;
-      break;
-    }
 
   if (off < 0 || off >= size)
     return ESPIPE;

@@ -44,7 +44,7 @@ static int _body_truncate (mu_stream_t, mu_off_t);
 static int _body_size     (mu_stream_t, mu_off_t *);
 static int _body_write    (mu_stream_t, const char *, size_t, size_t *);
 static int _body_ioctl    (mu_stream_t, int, void *);
-static int _body_seek     (mu_stream_t, mu_off_t, int, mu_off_t *);
+static int _body_seek     (mu_stream_t, mu_off_t, mu_off_t *);
 static const char *_body_error_string (mu_stream_t, int);
 
 /* Our own defaults for the body.  */
@@ -281,11 +281,11 @@ mu_body_set_size (mu_body_t body, int (*_size)(mu_body_t, size_t*) , void *owner
 /* Stub function for the body stream.  */
 
 static int
-_body_seek (mu_stream_t stream, mu_off_t off, int whence, mu_off_t *presult)
+_body_seek (mu_stream_t stream, mu_off_t off, mu_off_t *presult)
 {
   struct _mu_body_stream *str = (struct _mu_body_stream*) stream;
   mu_body_t body = str->body;
-  return mu_stream_seek (body->fstream, off, whence, presult);
+  return mu_stream_seek (body->fstream, off, MU_SEEK_SET, presult);
 }
 
 static const char *

@@ -148,10 +148,10 @@ fd_open (struct _mu_stream *str)
 }
 
 int
-fd_seek (struct _mu_stream *str, mu_off_t off, int whence, mu_off_t *presult)
+fd_seek (struct _mu_stream *str, mu_off_t off, mu_off_t *presult)
 { 
   struct _mu_file_stream *fstr = (struct _mu_file_stream *) str;
-  off = lseek (fstr->fd, off, whence);
+  off = lseek (fstr->fd, off, SEEK_SET);
   if (off < 0)
     return errno;
   *presult = off;

@@ -415,11 +415,12 @@ _icvt_wait (mu_stream_t stream, int *pflags, struct timeval *tvp)
   return mu_stream_wait (s->transport, pflags, tvp);
 }
 
+/* FIXME: Seeks in the *transport* stream. */
 int
-_icvt_seek (mu_stream_t stream, mu_off_t off, int whence, mu_off_t *presult)
+_icvt_seek (mu_stream_t stream, mu_off_t off, mu_off_t *presult)
 {
   struct icvt_stream *s = (struct icvt_stream *)stream;
-  return mu_stream_seek (s->transport, off, whence, presult);
+  return mu_stream_seek (s->transport, off, MU_SEEK_SET, presult);
 }
 
 int
@@ -462,6 +463,6 @@ mu_filter_iconv_create (mu_stream_t *s, mu_stream_t transport,
   iptr->stream.ctl = _icvt_ioctl;
   iptr->stream.wait = _icvt_wait;
   iptr->stream.seek = _icvt_seek;
-  *s = iptr;
+  *s = (mu_stream_t)iptr;
   return 0;
 }

@@ -313,12 +313,12 @@ filter_wr_flush (mu_stream_t stream)
   return rc;
 }
 
+/* FIXME: Seeks in the *transport* stream */
 static int
-filter_seek (struct _mu_stream *stream, mu_off_t off, int whence,
-	     mu_off_t *ppos)
+filter_seek (struct _mu_stream *stream, mu_off_t off, mu_off_t *ppos)
 {
   struct _mu_filter_stream *fs = (struct _mu_filter_stream *)stream;
-  return mu_stream_seek (fs->transport, off, whence, ppos);
+  return mu_stream_seek (fs->transport, off, MU_SEEK_SET, ppos);
 }
 
 static int

@@ -931,24 +931,10 @@ mu_hdrent_unroll_fixup (mu_header_t hdr, struct mu_hdrent *ent)
 }
 
 int
-header_seek (mu_stream_t str, mu_off_t off, int whence, mu_off_t *presult)
+header_seek (mu_stream_t str, mu_off_t off, mu_off_t *presult)
 { 
   struct _mu_header_stream *hstr = (struct _mu_header_stream *) str;
 
-  switch (whence)
-    {
-    case MU_SEEK_SET:
-      break;
-
-    case MU_SEEK_CUR:
-      off += hstr->off;
-      break;
-
-    case MU_SEEK_END:
-      off += hstr->hdr->size;
-      break;
-    }
-
   if (off < 0 || off > hstr->hdr->size)
     return ESPIPE;
   hstr->off = off;

@@ -312,25 +312,10 @@ _mapfile_open (mu_stream_t stream)
 }
 
 static int
-_mapfile_seek (struct _mu_stream *str, mu_off_t off, int whence, mu_off_t *presult)
+_mapfile_seek (struct _mu_stream *str, mu_off_t off, mu_off_t *presult)
 { 
   struct _mu_mapfile_stream *mfs = (struct _mu_mapfile_stream *) str;
   
-  /* FIXME */
-  switch (whence)
-    {
-    case MU_SEEK_SET:
-      break;
-
-    case MU_SEEK_CUR:
-      off += mfs->offset;
-      break;
-
-    case MU_SEEK_END:
-      off += mfs->size;
-      break;
-    }
-
   if (off < 0 || off >= mfs->size)
     return ESPIPE;
   mfs->offset = off;

@@ -166,25 +166,10 @@ _memory_ioctl (struct _mu_stream *stream, int code, void *ptr)
 }
 
 static int
-_memory_seek (struct _mu_stream *stream, mu_off_t off, int whence,
-	      mu_off_t *presult)
+_memory_seek (struct _mu_stream *stream, mu_off_t off, mu_off_t *presult)
 { 
   struct _mu_memory_stream *mfs = (struct _mu_memory_stream *) stream;
 
-  switch (whence)
-    {
-    case MU_SEEK_SET:
-      break;
-
-    case MU_SEEK_CUR:
-      off += mfs->offset;
-      break;
-
-    case MU_SEEK_END:
-      off += mfs->size;
-      break;
-    }
-
   if (off < 0)
     return ESPIPE;
   mfs->offset = off;

@@ -149,8 +149,7 @@ _message_stream_size (struct _mu_stream *str, mu_off_t *psize)
 }
 
 static int
-_message_stream_seek (struct _mu_stream *str, mu_off_t off, int whence,
-		      mu_off_t *ppos)
+_message_stream_seek (struct _mu_stream *str, mu_off_t off, mu_off_t *ppos)
 {
   struct _mu_message_stream *sp = (struct _mu_message_stream *)str;
   size_t hsize, size;
@@ -163,25 +162,6 @@ _message_stream_seek (struct _mu_stream *str, mu_off_t off, int whence,
   mu_body_size (sp->msg->body, &size);
   size += hsize;
   
-  switch (whence)
-    {
-    case MU_SEEK_SET:
-      break;
-
-    case MU_SEEK_CUR:
-      {
-	mu_off_t cur;
-	rc = mu_stream_seek (sp->transport, 0, MU_SEEK_CUR, &cur);
-	if (rc)
-	  return rc;
-	off += cur;
-      }
-      break;
-
-    case MU_SEEK_END:
-      off += size;
-      break;
-    }
   if (off < 0 || off >= size)
     return ESPIPE;
 

@@ -303,27 +303,12 @@ _message_done (mu_stream_t stream)
 }
 
 static int
-_message_seek (struct _mu_stream *stream, mu_off_t off, int whence,
-	       mu_off_t *presult)
+_message_seek (struct _mu_stream *stream, mu_off_t off, mu_off_t *presult)
 { 
   struct _mu_message_stream *s = (struct _mu_message_stream*) stream;
   mu_off_t size;
 
   mu_stream_size (stream, &size);
-  switch (whence)
-    {
-    case MU_SEEK_SET:
-      break;
-
-    case MU_SEEK_CUR:
-      off += s->offset;
-      break;
-
-    case MU_SEEK_END:
-      off += size;
-      break;
-    }
-
   if (off < 0 || off >= size)
     return ESPIPE;
   s->offset = off;

@@ -544,24 +544,11 @@ struct _mime_body_stream
 
 /* FIXME: The seek method is defective */
 static int
-_mime_body_seek (mu_stream_t stream, mu_off_t off, int whence,
-		 mu_off_t *presult)
+_mime_body_seek (mu_stream_t stream, mu_off_t off, mu_off_t *presult)
 {
   struct _mime_body_stream *mstr = (struct _mime_body_stream *)stream;
   mu_mime_t mime = mstr->mime;
 
-  switch (whence)
-    {
-    case MU_SEEK_SET:
-      break;
-
-    case MU_SEEK_CUR:
-      off += mime->cur_offset;
-
-    case MU_SEEK_END:
-      return ESPIPE;
-    }
-    
   if (off == 0)
     {				/* reset message */
       mime->cur_offset = 0;

@@ -128,23 +128,9 @@ stdio_size (struct _mu_stream *str, off_t *psize)
 }
 
 static int
-stdio_seek (struct _mu_stream *str, mu_off_t off, int whence, mu_off_t *presult)
+stdio_seek (struct _mu_stream *str, mu_off_t off, mu_off_t *presult)
 { 
   struct _mu_stdio_stream *fs = (struct _mu_stdio_stream *) str;
-  /* FIXME */
-  switch (whence)
-    {
-    case MU_SEEK_SET:
-      break;
-
-    case MU_SEEK_CUR:
-      off += fs->offset;
-      break;
-
-    case MU_SEEK_END:
-      off += fs->size;
-      break;
-    }
 
   if (off < 0)
     return ESPIPE;

@@ -323,7 +323,7 @@ mu_stream_seek (mu_stream_t stream, mu_off_t offset, int whence,
     {
       if ((rc = _stream_flush_buffer (stream, 1)))
 	return rc;
-      rc = stream->seek (stream, offset, MU_SEEK_SET, &stream->offset);
+      rc = stream->seek (stream, offset, &stream->offset);
       if (rc)
 	return _stream_seterror (stream, rc, 1);
       _stream_cleareof (stream);

@@ -153,8 +153,7 @@ _streamref_done (struct _mu_stream *str)
 }
 
 static int
-_streamref_seek (struct _mu_stream *str, mu_off_t off, int whence,
-		 mu_off_t *ppos)
+_streamref_seek (struct _mu_stream *str, mu_off_t off, mu_off_t *ppos)
 {
   struct _mu_streamref *sp = (struct _mu_streamref *)str;
   mu_off_t cur = sp->offset - sp->start;
@@ -171,25 +170,6 @@ _streamref_seek (struct _mu_stream *str, mu_off_t off, int whence,
       size -= sp->start;
     }
   
-  switch (whence)
-    {
-    case MU_SEEK_SET:
-      break;
-
-    case MU_SEEK_CUR:
-      if (off == 0)
-	{
-	  *ppos = sp->offset - sp->start;
-	  return 0;
-	}
-      off += cur;
-      break;
-
-    case MU_SEEK_END:
-      off += size;
-      break;
-    }
-
   if (off < 0 || off >= size)
     return sp->stream.last_err = ESPIPE;
   rc = mu_stream_seek (sp->transport, sp->start + off, MU_SEEK_SET,