maintainer changed: was lord, now jimb; first import

libguile/arbiters.c

@@ -0,0 +1,150 @@
+/*	Copyright (C) 1995,1996 Free Software Foundation, Inc.
+ * 
+ * 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, 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 software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * As a special exception, the Free Software Foundation gives permission
+ * for additional uses of the text contained in its release of GUILE.
+ *
+ * The exception is that, if you link the GUILE library with other files
+ * to produce an executable, this does not by itself cause the
+ * resulting executable to be covered by the GNU General Public License.
+ * Your use of that executable is in no way restricted on account of
+ * linking the GUILE library code into it.
+ *
+ * This exception does not however invalidate any other reasons why
+ * the executable file might be covered by the GNU General Public License.
+ *
+ * This exception applies only to the code released by the
+ * Free Software Foundation under the name GUILE.  If you copy
+ * code from other Free Software Foundation releases into a copy of
+ * GUILE, as the General Public License permits, the exception does
+ * not apply to the code that you add in this way.  To avoid misleading
+ * anyone as to the status of such modified files, you must delete
+ * this exception notice from them.
+ *
+ * If you write modifications of your own for GUILE, it is your choice
+ * whether to permit this exception to apply to your modifications.
+ * If you do not wish that, delete this exception notice.  
+ */
+
+
+#include <stdio.h>
+#include "_scm.h"
+
+
+/* {Arbiters}
+ *
+ * These procedures implement synchronization primitives.  Processors
+ * with an atomic test-and-set instruction can use it here (and not
+ * SCM_DEFER_INTS). 
+ */
+
+static long scm_tc16_arbiter;
+
+#ifdef __STDC__
+static int 
+prinarb (SCM exp, SCM port, int writing)
+#else
+static int 
+prinarb (exp, port, writing)
+     SCM exp;
+     SCM port;
+     int writing;
+#endif
+{
+  scm_gen_puts (scm_regular_string, "#<arbiter ", port);
+  if (SCM_CAR (exp) & (1L << 16))
+    scm_gen_puts (scm_regular_string, "locked ", port);
+  scm_iprin1 (SCM_CDR (exp), port, writing);
+  scm_gen_putc ('>', port);
+  return !0;
+}
+
+static scm_smobfuns arbsmob =
+{
+  scm_markcdr, scm_free0, prinarb, 0
+};
+
+SCM_PROC(s_make_arbiter, "make-arbiter", 1, 0, 0, scm_make_arbiter);
+#ifdef __STDC__
+SCM 
+scm_make_arbiter (SCM name)
+#else
+SCM 
+scm_make_arbiter (name)
+     SCM name;
+#endif
+{
+  register SCM z;
+  SCM_NEWCELL (z);
+  SCM_CDR (z) = name;
+  SCM_CAR (z) = scm_tc16_arbiter;
+  return z;
+}
+
+SCM_PROC(s_try_arbiter, "try-arbiter", 1, 0, 0, scm_try_arbiter);
+#ifdef __STDC__
+SCM 
+scm_try_arbiter (SCM arb)
+#else
+SCM 
+scm_try_arbiter (arb)
+     SCM arb;
+#endif
+{
+  SCM_ASSERT ((SCM_TYP16 (arb) == scm_tc16_arbiter), arb, SCM_ARG1, s_try_arbiter);
+  SCM_DEFER_INTS;
+  if (SCM_CAR (arb) & (1L << 16))
+    arb = SCM_BOOL_F;
+  else
+    {
+      SCM_CAR (arb) = scm_tc16_arbiter | (1L << 16);
+      arb = SCM_BOOL_T;
+    }
+  SCM_ALLOW_INTS;
+  return arb;
+}
+
+
+SCM_PROC(s_release_arbiter, "release-arbiter", 1, 0, 0, scm_release_arbiter);
+#ifdef __STDC__
+SCM 
+scm_release_arbiter (SCM arb)
+#else
+SCM 
+scm_release_arbiter (arb)
+     SCM arb;
+#endif
+{
+  SCM_ASSERT ((SCM_TYP16 (arb) == scm_tc16_arbiter), arb, SCM_ARG1, s_release_arbiter);
+  if (!(SCM_CAR (arb) & (1L << 16)))
+    return SCM_BOOL_F;
+  SCM_CAR (arb) = scm_tc16_arbiter;
+  return SCM_BOOL_T;
+}
+
+
+#ifdef __STDC__
+void
+scm_init_arbiters (void)
+#else
+void
+scm_init_arbiters ()
+#endif
+{
+  scm_tc16_arbiter = scm_newsmob (&arbsmob);
+#include "arbiters.x"
+}
+