Experimental new support for packet buffering.

[mLib] / selpk.c

diff --git a/selpk.c b/selpk.c
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+/* -*-c-*-
+ *
+ * $Id: selpk.c,v 1.1 2000/06/17 10:39:19 mdw Exp $
+ *
+ * Packet-buffering select handler
+ *
+ * (c) 1999 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------* 
+ *
+ * This file is part of the mLib utilities library.
+ *
+ * mLib is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ * 
+ * mLib 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 Library General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Library General Public
+ * License along with mLib; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Revision history --------------------------------------------------* 
+ *
+ * $Log: selpk.c,v $
+ * Revision 1.1  2000/06/17 10:39:19  mdw
+ * Experimental new support for packet buffering.
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#include "pkbuf.h"
+#include "sel.h"
+#include "selpk.h"
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @selpk_enable@ --- *
+ *
+ * Arguments:  @selpk *pk@ = pointer to buffer block
+ *
+ * Returns:    ---
+ *
+ * Use:                Enables a buffer for reading, and emits any queued packets
+ *             to the buffer's owner.
+ */
+
+void selpk_enable(selpk *pk)
+{
+  if (!(pk->pk.f & PKBUF_ENABLE)) {
+    pk->pk.f |= PKBUF_ENABLE;
+    sel_addfile(&pk->reader);
+    pkbuf_flush(&pk->pk, 0, 0);
+  }
+}
+
+/* --- @selpk_disable@ --- *
+ *
+ * Arguments:  @selpk *pk@ = pointer to a buffer block
+ *
+ * Returns:    ---
+ *
+ * Use:                Disables a buffer.  It won't be read from until it's
+ *             enabled again.
+ */
+
+void selpk_disable(selpk *pk)
+{
+  if (pk->pk.f & PKBUF_ENABLE) {
+    pk->pk.f &= ~PKBUF_ENABLE;
+    sel_rmfile(&pk->reader);
+  }
+}
+
+/* --- @selpk_read@ --- *
+ *
+ * Arguments:  @int fd@ = file descriptor to read from
+ *             @int mode@ = what we can do to the file
+ *             @void *vp@ = pointer to buffer context
+ *
+ * Returns:    ---
+ *
+ * Use:                Acts on the result of a @select@ call.
+ */
+
+static void selpk_read(int fd, unsigned mode, void *vp)
+{
+  selpk *pk = vp;
+  octet *p;
+  size_t sz;
+  int n;
+
+  sz = pkbuf_free(&pk->pk, &p);
+  n = read(fd, p, sz);
+  if (n == 0)
+    pkbuf_close(&pk->pk);
+  else if (n > 0)
+    pkbuf_flush(&pk->pk, p, n);
+  else switch (errno) {
+    case EINTR:
+    case EAGAIN:
+#if EAGAIN != EWOULDBLOCK
+    case EWOULDBLOCK:
+#endif
+      return;
+    default:
+      pkbuf_close(&pk->pk);
+  }
+}
+
+/* --- @selpk_want@ --- *
+ *
+ * Arguments:  @selpk *pk@ = pointer to buffer block
+ *             @size_t sz@ = size of buffer
+ *
+ * Returns:    ---
+ *
+ * Use:                Sets the size of the packet to be read next.
+ */
+
+void selpk_want(selpk *pk, size_t sz)
+{
+  pkbuf_want(&pk->pk, sz);
+}
+
+/* --- @selpk_init@ --- *
+ *
+ * Arguments:  @selpk *pk@ = pointer to buffer block
+ *             @sel_state *s@ = pointer to select state to attach to
+ *             @int fd@ = file descriptor to listen to
+ *             @void (*func)(char *s, void *p)@ = function to call
+ *             @void *p@ = argument for function
+ *
+ * Returns:    ---
+ *
+ * Use:                Initializes a buffer block.
+ */
+
+void selpk_init(selpk *pk,
+                sel_state *s,
+                int fd,
+                void (*func)(octet */*b*/, size_t /*sz*/, pkbuf */*pk*/,
+                             size_t */*keep*/, void */*p*/),
+                void *p)
+{
+  pkbuf_init(&pk->pk, func, p);
+  pk->pk.f &= ~PKBUF_ENABLE;
+  sel_initfile(s, &pk->reader, fd, SEL_READ, selpk_read, pk);
+  selpk_enable(pk);
+}
+
+/* --- @selpk_destroy@ --- *
+ *
+ * Arguments:  @selpk *pk@ = pointer to buffer block
+ *
+ * Returns:    ---
+ *
+ * Use:                Deallocates a packet buffer and frees any resources it owned.
+ */
+
+void selpk_destroy(selpk *pk)
+{
+  selpk_disable(pk);
+  pkbuf_destroy(&pk->pk);
+}
+
+/*----- That's all, folks -------------------------------------------------*/