Initial commit

1 files changed, 261 insertions, 0 deletions

diff --git a/pkg/proto/maskexpr/mskexpand.x b/pkg/proto/maskexpr/mskexpand.x
new file mode 100644
index 00000000..5fb6cc9d
--- /dev/null
+++ b/pkg/proto/maskexpr/mskexpand.x
@@ -0,0 +1,261 @@
+include <ctotok.h>
+include <ctype.h>
+include "gettok.h"
+
+# Some definitions.
+
+# Default symbol table size limits.
+define	DEF_LENINDEX	97
+define	DEF_LENSTAB	1024
+define	DEF_LENSBUF	8192
+
+# Expression database symbol.
+define	LEN_SYM		2
+define	SYM_TEXT	Memi[$1]
+define	SYM_NARGS	Memi[$1+1]
+
+# Argument list symbol
+define	LEN_ARGSYM	1
+define	ARGNO		Memi[$1]
+
+
+# ME_GETEXPRDB -- Read the expression database into a symbol table.  The
+# input file has the following structure:
+#
+#	<symbol>['(' arg-list ')'][':'|'=']	replacement-text
+#		
+# Symbols must be at the beginning of a line.  The expression text is
+# terminated by a nonempty, noncomment line with no leading whitespace.
+
+pointer procedure me_getexprdb (fname)
+
+char	fname[ARB]		#I file to be read
+
+pointer	sym, sp, lbuf, st, a_st, ip, symname, tokbuf, text
+int	tok, fd, line, nargs, op, token, buflen, offset, stpos, n
+pointer	stopen(), stenter()
+int	open(), getlline(), ctotok(), stpstr()
+errchk	open, getlline, stopen, stenter, me_puttok
+
+define	skip_ 91
+
+begin
+	call smark (sp)
+	call salloc (lbuf, SZ_COMMAND, TY_CHAR)
+	call salloc (text, SZ_COMMAND, TY_CHAR)
+	call salloc (tokbuf, SZ_COMMAND, TY_CHAR)
+	call salloc (symname, SZ_FNAME, TY_CHAR)
+
+	fd = open (fname, READ_ONLY, TEXT_FILE)
+	st = stopen ("imexpr", DEF_LENINDEX, DEF_LENSTAB, DEF_LENSBUF)
+	a_st = stopen ("args", DEF_LENINDEX, DEF_LENSTAB, DEF_LENSBUF)
+	line = 0
+
+	while (getlline (fd, Memc[lbuf], SZ_COMMAND) != EOF) {
+	    line = line + 1
+	    ip = lbuf
+
+	    # Skip comments and blank lines.
+	    while (IS_WHITE(Memc[ip]))
+		ip = ip + 1
+	    if (Memc[ip] == '\n' || Memc[ip] == '#')
+		next
+	
+	    # Get symbol name.
+	    if (ctotok (Memc,ip,Memc[symname],SZ_FNAME) != TOK_IDENTIFIER) {
+		call eprintf ("exprdb: expected identifier at line %d\n")
+		    call pargi (line)
+skip_		while (getlline (fd, Memc[lbuf], SZ_COMMAND) != EOF) {
+		    line = line + 1
+		    if (Memc[lbuf] == '\n')
+			break
+		}
+	    }
+
+	    call stmark (a_st, stpos)
+
+	    # Check for the optional argument-symbol list.  Allow only a
+	    # single space between the symbol name and its argument list,
+	    # otherwise we can't tell the difference between an argument
+	    # list and the parenthesized expression which follows.
+
+	    if (Memc[ip] == ' ')
+		ip = ip + 1
+
+	    if (Memc[ip] == '(') {
+		ip = ip + 1
+		n = 0
+		repeat {
+		    tok = ctotok (Memc, ip, Memc[tokbuf], SZ_FNAME)
+		    if (tok == TOK_IDENTIFIER) {
+			sym = stenter (a_st, Memc[tokbuf], LEN_ARGSYM)
+			n = n + 1
+			ARGNO(sym) = n
+		    } else if (Memc[tokbuf] == ',') {
+			;
+		    } else if (Memc[tokbuf] != ')') {
+			call eprintf ("exprdb: bad arglist at line %d\n")
+			    call pargi (line)
+			call stfree (a_st, stpos)
+			goto skip_
+		    }
+		} until (Memc[tokbuf] == ')')
+	    }
+
+	    # Check for the optional ":" or "=".
+	    while (IS_WHITE(Memc[ip]))
+		ip = ip + 1
+	    if (Memc[ip] == ':' || Memc[ip] == '=')
+		ip = ip + 1
+
+	    # Accumulate the expression text.
+	    buflen = SZ_COMMAND
+	    op = 1
+	    
+	    repeat {
+		repeat {
+		    token = ctotok (Memc, ip, Memc[tokbuf], SZ_COMMAND)
+		    if (Memc[tokbuf] == '#')
+			break
+		    else if (token != TOK_EOS && token != TOK_NEWLINE)
+			call me_puttok (a_st, text, op, buflen, Memc[tokbuf])
+		} until (token == TOK_EOS)
+
+		if (getlline (fd, Memc[lbuf], SZ_COMMAND) == EOF)
+		    break
+		else
+		    line = line + 1
+
+		for (ip=lbuf;  IS_WHITE(Memc[ip]);  ip=ip+1)
+		    ;
+		if (ip == lbuf) {
+		    call ungetline (fd, Memc[lbuf])
+		    line = line - 1
+		    break
+		}
+	    }
+
+	    # Free any argument list symbols.
+	    call stfree (a_st, stpos)
+
+	    # Scan the expression text and count the number of $N arguments.
+	    nargs = 0
+	    for (ip=text;  Memc[ip] != EOS;  ip=ip+1)
+		if (Memc[ip] == '$' && IS_DIGIT(Memc[ip+1])) {
+		    nargs = max (nargs, TO_INTEG(Memc[ip+1]))
+		    ip = ip + 1
+		}
+
+	    # Enter symbol in table.
+	    sym = stenter (st, Memc[symname], LEN_SYM)
+	    offset = stpstr (st, Memc[text], 0)
+	    SYM_TEXT(sym) = offset
+	    SYM_NARGS(sym) = nargs
+	}
+
+	call stclose (a_st)
+	call sfree (sp)
+
+	return (st)
+end
+
+
+# ME_PUTTOK -- Append a token string to a text buffer.
+
+procedure me_puttok (a_st, text, op, buflen, token)
+
+pointer	a_st			#I argument-symbol table
+pointer	text			#U text buffer
+int	op			#U output pointer
+int	buflen			#U buffer length, chars
+char	token[ARB]		#I token string
+
+pointer	sym
+int	ip, ch1, ch2
+pointer	stfind()
+errchk	realloc
+
+begin
+	# Replace any symbolic arguments by "$N".
+	if (a_st != NULL && IS_ALPHA(token[1])) {
+	    sym = stfind (a_st, token)
+	    if (sym != NULL) {
+		token[1] = '$'
+		token[2] = TO_DIGIT(ARGNO(sym))
+		token[3] = EOS
+	    }
+	}
+
+	# Append the token string to the text buffer.
+	for (ip=1;  token[ip] != EOS;  ip=ip+1) {
+	    if (op + 1 > buflen) {
+		buflen = buflen + SZ_COMMAND
+		call realloc (text, buflen, TY_CHAR)
+	    }
+
+	    # The following is necessary because ctotok parses tokens such as
+	    # "$N", "==", "!=", etc.  as two tokens.  We need to rejoin these
+	    # characters to make one token.
+
+	    if (op > 1 && token[ip+1] == EOS) {
+		ch1 = Memc[text+op-3]
+		ch2 = token[ip]
+
+		if (ch1 == '$' && IS_DIGIT(ch2))
+		    op = op - 1
+		else if (ch1 == '*' && ch2 == '*')
+		    op = op - 1
+		else if (ch1 == '/' && ch2 == '/')
+		    op = op - 1
+		else if (ch1 == '<' && ch2 == '=')
+		    op = op - 1
+		else if (ch1 == '>' && ch2 == '=')
+		    op = op - 1
+		else if (ch1 == '=' && ch2 == '=')
+		    op = op - 1
+		else if (ch1 == '!' && ch2 == '=')
+		    op = op - 1
+		else if (ch1 == '?' && ch2 == '=')
+		    op = op - 1
+		else if (ch1 == '&' && ch2 == '&')
+		    op = op - 1
+		else if (ch1 == '|' && ch2 == '|')
+		    op = op - 1
+	    }
+
+	    Memc[text+op-1] = token[ip]
+	    op = op + 1
+	}
+
+	# Append a space to ensure that tokens are delimited.
+	Memc[text+op-1] = ' '
+	op = op + 1
+
+	Memc[text+op-1] = EOS
+end
+
+
+# ME_EXPANDTEXT -- Scan an expression, performing macro substitution on the
+# contents and returning a fully expanded string.
+
+pointer procedure me_expandtext (st, expr)
+
+pointer	st			#I symbol table (macros)
+char	expr[ARB]		#I input expression
+
+pointer	buf, gt
+int	buflen, nchars
+int	locpr(), gt_expand()
+pointer	gt_opentext()
+extern	me_gsym()
+
+begin
+	buflen = SZ_COMMAND
+	call malloc (buf, buflen, TY_CHAR)
+
+	gt = gt_opentext (expr, locpr(me_gsym), st, 0, GT_NOFILE)
+	nchars = gt_expand (gt, buf, buflen)
+	call gt_close (gt)
+
+	return (buf)
+end