Expand references to number registers in exactly the same way as

references to user-defined strings.  While here, make number registers
signed int, like in groff.

Inspired by NetBSD roff.c rev. 1.8 and read.c rev. 1.7
written by Christos Zoulas on March 21, 2013, but implemented
in a completely different way, without hacking into read.c,
where this functionality really doesn't belong.

1 files changed, 52 insertions, 31 deletions

diff --git a/roff.c b/roff.c
index a33baa2d..56733186 100644
--- a/roff.c
+++ b/roff.c
@@ -97,11 +97,10 @@ struct	roffkv {
 
 /*
  * A single number register as part of a singly-linked list.
- * Registers are assumed to be unsigned ints for now.
  */
 struct	roffreg {
 	struct roffstr	 key;
-	unsigned int	 u;
+	int		 val;
 	struct roffreg	*next;
 };
 
@@ -186,6 +185,8 @@ static	void		 roff_free1(struct roff *);
 static	void		 roff_freereg(struct roffreg *);
 static	void		 roff_freestr(struct roffkv *);
 static	char		*roff_getname(struct roff *, char **, int, int);
+static	int		 roff_getregn(const struct roff *,
+				const char *, size_t);
 static	const char	*roff_getstrn(const struct roff *, 
 				const char *, size_t);
 static	enum rofferr	 roff_it(ROFF_ARGS);
@@ -480,22 +481,23 @@ roff_alloc(enum mparset type, struct mparse *parse)
 }
 
 /*
- * Pre-filter each and every line for reserved words (one beginning with
- * `\*', e.g., `\*(ab').  These must be handled before the actual line
- * is processed. 
- * This also checks the syntax of regular escapes.
+ * In the current line, expand user-defined strings ("\*")
+ * and references to number registers ("\n").
+ * Also check the syntax of other escape sequences.
  */
 static enum rofferr
 roff_res(struct roff *r, char **bufp, size_t *szp, int ln, int pos)
 {
-	enum mandoc_esc	 esc;
+	char		 ubuf[12]; /* buffer to print the number */
 	const char	*stesc;	/* start of an escape sequence ('\\') */
 	const char	*stnam;	/* start of the name, after "[(*" */
 	const char	*cp;	/* end of the name, e.g. before ']' */
 	const char	*res;	/* the string to be substituted */
-	int		 i, maxl, expand_count;
-	size_t		 nsz;
-	char		*n;
+	char		*nbuf;	/* new buffer to copy bufp to */
+	size_t		 nsz;	/* size of the new buffer */
+	size_t		 maxl;  /* expected length of the escape name */
+	size_t		 naml;	/* actual length of the escape name */
+	int		 expand_count;	/* to avoid infinite loops */
 
 	expand_count = 0;
 
@@ -505,7 +507,7 @@ again:
 		stesc = cp++;
 
 		/*
-		 * The second character must be an asterisk.
+		 * The second character must be an asterisk or an n.
 		 * If it isn't, skip it anyway:  It is escaped,
 		 * so it can't start another escape sequence.
 		 */
@@ -513,12 +515,16 @@ again:
 		if ('\0' == *cp)
 			return(ROFF_CONT);
 
-		if ('*' != *cp) {
-			res = cp;
-			esc = mandoc_escape(&cp, NULL, NULL);
-			if (ESCAPE_ERROR != esc)
+		switch (*cp) {
+		case ('*'):
+			res = NULL;
+			break;
+		case ('n'):
+			res = ubuf;
+			break;
+		default:
+			if (ESCAPE_ERROR != mandoc_escape(&cp, NULL, NULL))
 				continue;
-			cp = res;
 			mandoc_msg
 				(MANDOCERR_BADESCAPE, r->parse, 
 				 ln, (int)(stesc - *bufp), NULL);
@@ -529,7 +535,7 @@ again:
 
 		/*
 		 * The third character decides the length
-		 * of the name of the string.
+		 * of the name of the string or register.
 		 * Save a pointer to the name.
 		 */
 
@@ -552,7 +558,7 @@ again:
 
 		/* Advance to the end of the name. */
 
-		for (i = 0; 0 == maxl || i < maxl; i++, cp++) {
+		for (naml = 0; 0 == maxl || naml < maxl; naml++, cp++) {
 			if ('\0' == *cp) {
 				mandoc_msg
 					(MANDOCERR_BADESCAPE, 
@@ -569,7 +575,11 @@ again:
 		 * undefined, resume searching for escapes.
 		 */
 
-		res = roff_getstrn(r, stnam, (size_t)i);
+		if (NULL == res)
+			res = roff_getstrn(r, stnam, naml);
+		else
+			snprintf(ubuf, sizeof(ubuf), "%d",
+			    roff_getregn(r, stnam, naml));
 
 		if (NULL == res) {
 			mandoc_msg
@@ -583,15 +593,15 @@ again:
 		pos = stesc - *bufp;
 
 		nsz = *szp + strlen(res) + 1;
-		n = mandoc_malloc(nsz);
+		nbuf = mandoc_malloc(nsz);
 
-		strlcpy(n, *bufp, (size_t)(stesc - *bufp + 1));
-		strlcat(n, res, nsz);
-		strlcat(n, cp + (maxl ? 0 : 1), nsz);
+		strlcpy(nbuf, *bufp, (size_t)(stesc - *bufp + 1));
+		strlcat(nbuf, res, nsz);
+		strlcat(nbuf, cp + (maxl ? 0 : 1), nsz);
 
 		free(*bufp);
 
-		*bufp = n;
+		*bufp = nbuf;
 		*szp = nsz;
 
 		if (EXPAND_LIMIT >= ++expand_count)
@@ -1263,7 +1273,7 @@ roff_ds(ROFF_ARGS)
 }
 
 void
-roff_setreg(struct roff *r, const char *name, unsigned int val)
+roff_setreg(struct roff *r, const char *name, int val)
 {
 	struct roffreg	*reg;
 
@@ -1282,17 +1292,30 @@ roff_setreg(struct roff *r, const char *name, unsigned int val)
 		r->regtab = reg;
 	}
 
-	reg->u = val;
+	reg->val = val;
 }
 
-unsigned int
+int
 roff_getreg(const struct roff *r, const char *name)
 {
 	struct roffreg	*reg;
 
 	for (reg = r->regtab; reg; reg = reg->next)
 		if (0 == strcmp(name, reg->key.p))
-			return(reg->u);
+			return(reg->val);
+
+	return(0);
+}
+
+static int
+roff_getregn(const struct roff *r, const char *name, size_t len)
+{
+	struct roffreg	*reg;
+
+	for (reg = r->regtab; reg; reg = reg->next)
+		if (len == reg->key.sz &&
+		    0 == strncmp(name, reg->key.p, len))
+			return(reg->val);
 
 	return(0);
 }
@@ -1322,10 +1345,8 @@ roff_nr(ROFF_ARGS)
 	key = roff_getname(r, &val, ln, pos);
 
 	iv = mandoc_strntoi(val, strlen(val), 10);
-	if (0 > iv)
-		iv = 0;
 
-	roff_setreg(r, key, (unsigned)iv);
+	roff_setreg(r, key, iv);
 
 	return(ROFF_IGN);
 }