1 files changed, 110 insertions, 0 deletions
diff --git a/usr.bin/doscmd/dispatch.h b/usr.bin/doscmd/dispatch.h
new file mode 100644
index 0000000000000..59620f1593125
--- /dev/null
+++ b/usr.bin/doscmd/dispatch.h
@@ -0,0 +1,110 @@
+/*
+** Copyright (c) 1996
+**	Michael Smith.  All rights reserved.
+**
+** Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions
+** are met:
+** 1. Redistributions of source code must retain the above copyright
+**    notice, this list of conditions and the following disclaimer.
+** 2. Redistributions in binary form must reproduce the above copyright
+**    notice, this list of conditions and the following disclaimer in the
+**    documentation and/or other materials provided with the distribution.
+**
+** THIS SOFTWARE IS PROVIDED BY Michael Smith ``AS IS'' AND
+** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+** ARE DISCLAIMED.  IN NO EVENT SHALL Michael Smith BE LIABLE
+** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+** SUCH DAMAGE.
+**
+** $Id: dispatch.h,v 1.3 1996/09/22 05:52:56 miff Exp $
+*/
+
+/*
+** Interrupt dispatcher assistants.
+*/
+
+
+/*
+** Declare a static, initialised array of these, with one
+** entry per function/subfunction.
+**
+** The last element should be a dummy with a 'func' of -1
+*/
+struct intfunc_table 
+{
+    int		func;				/* interrupt function number */
+    int		subfunc;			/* subfunction number */
+    int		(* handler)(regcontext_t *REGS);/* handling function */
+    const char	*desc;				/* textual description */
+};
+#define IFT_NOSUBFUNC	-1
+
+
+/*
+** Declare a static array of 256 integers to use as a fast lookup 
+** into the table of handlers.
+**
+** Call this function to initialise the lookup.  Note that the table
+** must be arranged with all handlers for a given function together, and
+** that the handler listed with IFT_NOSUBFUNC should be last.
+*/
+static inline void
+intfunc_init(struct intfunc_table table[], int index[])
+{
+    int		hn;
+
+    for (hn = 0; hn < 256; hn++)		/* initialise all no-handler state */
+	index[hn] = -1;				/* default to no handler */
+
+    for (hn = 0; table[hn].func >= 0; hn++)	/* walk list of handlers and add references */
+	if (index[table[hn].func] == -1 )	/* reference first handler */
+	    index[table[hn].func] = hn;
+}
+
+/*
+** Call this to get an index matching the function/subfunction 
+** described by (sc), or -1 if none exist
+*/
+static inline int
+intfunc_find(struct intfunc_table table[], int index[], int func, int subfunc)
+{
+    int	ent = index[func];				/* look for handler */
+    
+    while ((ent >= 0) &&				/* scan entries for function */
+	   (table[ent].func == func)) {
+
+	if ((table[ent].subfunc == IFT_NOSUBFUNC) ||	/* handles all */
+	    (table[ent].subfunc == subfunc)) {		/* handles this one */
+	    return(ent);
+	}
+	ent++;
+    }
+    return(-1);
+}
+
+/*
+** A slower lookup for a set of function handlers, but one that requires
+** no initialisation calls.
+** Again, handlers with IFT_NOSUBFUNC should be listed after any with
+** specific subfunction values.
+*/
+static inline int
+intfunc_search(struct intfunc_table table[], int func, int subfunc)
+{
+    int		ent;
+
+    for (ent = 0; table[ent].func >= 0; ent++)
+	if ((table[ent].func == func) &&	/* matches required function */
+	    ((table[ent].subfunc == IFT_NOSUBFUNC) || table[ent].subfunc == subfunc))
+	    return(ent);
+    return(-1);
+}
+
+