From fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 Mon Sep 17 00:00:00 2001
From: Joseph Hunkeler <jhunkeler@gmail.com>
Date: Wed, 8 Jul 2015 20:46:52 -0400
Subject: Initial commit

---
 sys/symtab/stfindall.x | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 sys/symtab/stfindall.x

(limited to 'sys/symtab/stfindall.x')

diff --git a/sys/symtab/stfindall.x b/sys/symtab/stfindall.x
new file mode 100644
index 00000000..d0477c5a
--- /dev/null
+++ b/sys/symtab/stfindall.x
@@ -0,0 +1,81 @@
+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+include	"symtab.h"
+
+# STFINDALL -- Search the symbol table for the named key and return an array
+# of symstruct pointers to all symbols with the given key.  The array is
+# ordered with the most recently entered symbols at the beginning.  The number
+# of symbols found is returned as the function value.
+
+int procedure stfindall (stp, key, symbols, max_symbols)
+
+pointer	stp			# symbol table descriptor
+char	key[ARB]		# symbol name
+pointer	symbols[max_symbols]	# pointers to the symstructs
+int	max_symbols
+
+long	sum
+char	first_char
+int	head, ip, nsym, thread
+pointer	el, cp, stab, sbuf
+
+begin
+	# When a symbol is entered in the table a flag is set in the ST_ASCII
+	# array to flag that the symbol table contains at least one key
+	# beginning with that character.  If the flag is not set we can thus
+	# determine very quickly that the symbol is not present.  This is
+	# important for applications such as mapping identifiers for macro
+	# expansion, where most macros have upper case keys but most program
+	# identifiers have lower case keys.  (Subtle note: since the first
+	# element of ST_ASCII is for ascii value 0=EOS, the following also
+	# serves to detect null keys).
+
+	if (ST_ASCII(stp,key[1]) == 0)
+	    return (NULL)
+
+	# Hash the key onto a thread in the index.
+	sum = 0
+	do ip = 1, MAX_HASHCHARS {
+	    if (key[ip] == EOS)
+		break
+	    sum = sum + (sum + key[ip])
+	}
+
+	thread = mod (sum, ST_INDEXLEN(stp))
+	head = Memi[ST_INDEX(stp)+thread]
+
+	# If thread is not empty search down it for the named key and return
+	# pointers to all occurrences of the symbol.
+
+	nsym = 0
+
+	if (head != NULL && max_symbols > 0) {
+	    first_char = key[1]
+	    sbuf = ST_SBUFP(stp)
+	    stab = ST_STABP(stp)
+
+	    for (el=stab+head;  el > stab;  el=stab+E_NEXTHASH(el)) {
+		cp = sbuf + E_KEY(el)
+		if (Memc[cp] != first_char)
+		    next
+
+		# If the first character of the key matches compare the full
+		# string and output a symstruct pointer if we have a match.
+
+		do ip = 1, MAX_SZKEY {
+		    if (key[ip] != Memc[cp])
+			break
+		    if (key[ip] == EOS) {
+			nsym = nsym + 1
+			symbols[nsym] = E_USERFIELDS(el)
+			if (nsym >= max_symbols)
+			    return (max_symbols)
+			break
+		    }
+		    cp = cp + 1
+		}
+	    }
+	}
+
+	return (nsym)
+end
-- 
cgit