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1 files changed, 58 insertions, 0 deletions

diff --git a/sys/qpoe/qpexdel.x b/sys/qpoe/qpexdel.x
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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	<mach.h>
+include	"qpex.h"
+
+# QPEX_DELETE -- Delete any previously compiled expression terms for the
+# event attribute with the given offset and datatype.  Only terms up to and
+# including ET_LAST are affected (allowing deletion while compiling additional
+# terms).
+
+procedure qpex_delete (ex, et_last, offset, dtype)
+
+pointer	ex			#I QPEX descriptor
+pointer	et_last			#I last expression term to be edited
+int	offset			#I typed offset of attribute in event struct
+int	dtype			#I datatype of attribute
+
+pointer	et, ip
+int	ninstr, i
+
+begin
+	if (et_last == NULL)
+	    return
+
+	for (et=EX_ETHEAD(ex);  et != NULL;  et=ET_NEXT(et)) {
+	    # Skip over already deleted terms or terms for other attributes.
+	    if (ET_DELETED(et) == YES)
+		next
+	    else if (ET_ATTOFF(et) != offset || ET_ATTTYPE(et) != dtype)
+		next
+
+	    # Physically and logically delete the term.  Edit the program
+	    # buffer and replace the compiled sequence of instructions by
+	    # a GOTO followed by a series of NO-OPs.
+
+	    ip = ET_PROGPTR(et)
+	    ninstr = ET_NINSTR(et)
+
+	    OPCODE(ip) = GOTO
+	    IARG1(ip)  = ip + ninstr * LEN_INSTRUCTION
+	    IARG2(ip)  = NULL
+	    IARG3(ip)  = NULL
+
+	    do i = 2, ninstr {
+		ip = ET_PROGPTR(et) + (i-1) * LEN_INSTRUCTION
+		OPCODE(ip) = NOP
+		IARG1(ip)  = NULL
+		IARG2(ip)  = NULL
+		IARG3(ip)  = NULL
+	    }
+
+	    # Flag the eterm as deleted.
+	    ET_DELETED(et) = YES
+
+	    if (et == et_last)
+		break
+	}
+end