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File: [cvsweb.bsd.lv] / mandoc / roff.c (download)

Revision 1.178, Sat Jul 13 12:52:07 2013 UTC (7 years, 11 months ago) by schwarze
Branch: MAIN
CVS Tags: VERSION_1_12_2
Changes since 1.177: +58 -11 lines

Rudimentary implementation of the .it request (input line trap).
As with any low-level roff request involving subtle interactions
with macro internals, this implementation is not exact, but it
does handle the simplest cases.

This request occurs in man(7) code generated from DocBook,
for example mysql(1) and yasm_arch(7).
Thanks to brad@ for reporting the issue back in January 2011.

/*	$Id: roff.c,v 1.178 2013/07/13 12:52:07 schwarze Exp $ */
/*
 * Copyright (c) 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2010, 2011, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "mandoc.h"
#include "libroff.h"
#include "libmandoc.h"

/* Maximum number of nested if-else conditionals. */
#define	RSTACK_MAX	128

/* Maximum number of string expansions per line, to break infinite loops. */
#define	EXPAND_LIMIT	1000

enum	rofft {
	ROFF_ad,
	ROFF_am,
	ROFF_ami,
	ROFF_am1,
	ROFF_cc,
	ROFF_de,
	ROFF_dei,
	ROFF_de1,
	ROFF_ds,
	ROFF_el,
	ROFF_hy,
	ROFF_ie,
	ROFF_if,
	ROFF_ig,
	ROFF_it,
	ROFF_ne,
	ROFF_nh,
	ROFF_nr,
	ROFF_ns,
	ROFF_ps,
	ROFF_rm,
	ROFF_so,
	ROFF_ta,
	ROFF_tr,
	ROFF_Dd,
	ROFF_TH,
	ROFF_TS,
	ROFF_TE,
	ROFF_T_,
	ROFF_EQ,
	ROFF_EN,
	ROFF_cblock,
	ROFF_ccond,
	ROFF_USERDEF,
	ROFF_MAX
};

enum	roffrule {
	ROFFRULE_ALLOW,
	ROFFRULE_DENY
};

/*
 * A single register entity.  If "set" is zero, the value of the
 * register should be the default one, which is per-register.
 * Registers are assumed to be unsigned ints for now.
 */
struct	reg {
	int		 set; /* whether set or not */
	unsigned int	 u; /* unsigned integer */
};

/*
 * An incredibly-simple string buffer.
 */
struct	roffstr {
	char		*p; /* nil-terminated buffer */
	size_t		 sz; /* saved strlen(p) */
};

/*
 * A key-value roffstr pair as part of a singly-linked list.
 */
struct	roffkv {
	struct roffstr	 key;
	struct roffstr	 val;
	struct roffkv	*next; /* next in list */
};

struct	roff {
	enum mparset	 parsetype; /* requested parse type */
	struct mparse	*parse; /* parse point */
	struct roffnode	*last; /* leaf of stack */
	enum roffrule	 rstack[RSTACK_MAX]; /* stack of !`ie' rules */
	char		 control; /* control character */
	int		 rstackpos; /* position in rstack */
	struct reg	 regs[REG__MAX];
	struct roffkv	*strtab; /* user-defined strings & macros */
	struct roffkv	*xmbtab; /* multi-byte trans table (`tr') */
	struct roffstr	*xtab; /* single-byte trans table (`tr') */
	const char	*current_string; /* value of last called user macro */
	struct tbl_node	*first_tbl; /* first table parsed */
	struct tbl_node	*last_tbl; /* last table parsed */
	struct tbl_node	*tbl; /* current table being parsed */
	struct eqn_node	*last_eqn; /* last equation parsed */
	struct eqn_node	*first_eqn; /* first equation parsed */
	struct eqn_node	*eqn; /* current equation being parsed */
};

struct	roffnode {
	enum rofft	 tok; /* type of node */
	struct roffnode	*parent; /* up one in stack */
	int		 line; /* parse line */
	int		 col; /* parse col */
	char		*name; /* node name, e.g. macro name */
	char		*end; /* end-rules: custom token */
	int		 endspan; /* end-rules: next-line or infty */
	enum roffrule	 rule; /* current evaluation rule */
};

#define	ROFF_ARGS	 struct roff *r, /* parse ctx */ \
			 enum rofft tok, /* tok of macro */ \
		 	 char **bufp, /* input buffer */ \
			 size_t *szp, /* size of input buffer */ \
			 int ln, /* parse line */ \
			 int ppos, /* original pos in buffer */ \
			 int pos, /* current pos in buffer */ \
			 int *offs /* reset offset of buffer data */

typedef	enum rofferr (*roffproc)(ROFF_ARGS);

struct	roffmac {
	const char	*name; /* macro name */
	roffproc	 proc; /* process new macro */
	roffproc	 text; /* process as child text of macro */
	roffproc	 sub; /* process as child of macro */
	int		 flags;
#define	ROFFMAC_STRUCT	(1 << 0) /* always interpret */
	struct roffmac	*next;
};

struct	predef {
	const char	*name; /* predefined input name */
	const char	*str; /* replacement symbol */
};

#define	PREDEF(__name, __str) \
	{ (__name), (__str) },

static	enum rofft	 roffhash_find(const char *, size_t);
static	void		 roffhash_init(void);
static	void		 roffnode_cleanscope(struct roff *);
static	void		 roffnode_pop(struct roff *);
static	void		 roffnode_push(struct roff *, enum rofft,
				const char *, int, int);
static	enum rofferr	 roff_block(ROFF_ARGS);
static	enum rofferr	 roff_block_text(ROFF_ARGS);
static	enum rofferr	 roff_block_sub(ROFF_ARGS);
static	enum rofferr	 roff_cblock(ROFF_ARGS);
static	enum rofferr	 roff_cc(ROFF_ARGS);
static	enum rofferr	 roff_ccond(ROFF_ARGS);
static	enum rofferr	 roff_cond(ROFF_ARGS);
static	enum rofferr	 roff_cond_text(ROFF_ARGS);
static	enum rofferr	 roff_cond_sub(ROFF_ARGS);
static	enum rofferr	 roff_ds(ROFF_ARGS);
static	enum roffrule	 roff_evalcond(const char *, int *);
static	void		 roff_free1(struct roff *);
static	void		 roff_freestr(struct roffkv *);
static	char		*roff_getname(struct roff *, char **, int, int);
static	const char	*roff_getstrn(const struct roff *, 
				const char *, size_t);
static	enum rofferr	 roff_it(ROFF_ARGS);
static	enum rofferr	 roff_line_ignore(ROFF_ARGS);
static	enum rofferr	 roff_nr(ROFF_ARGS);
static	void		 roff_openeqn(struct roff *, const char *,
				int, int, const char *);
static	enum rofft	 roff_parse(struct roff *, const char *, int *);
static	enum rofferr	 roff_parsetext(char **, size_t *, int, int *);
static	enum rofferr	 roff_res(struct roff *, 
				char **, size_t *, int, int);
static	enum rofferr	 roff_rm(ROFF_ARGS);
static	void		 roff_setstr(struct roff *,
				const char *, const char *, int);
static	void		 roff_setstrn(struct roffkv **, const char *, 
				size_t, const char *, size_t, int);
static	enum rofferr	 roff_so(ROFF_ARGS);
static	enum rofferr	 roff_tr(ROFF_ARGS);
static	enum rofferr	 roff_Dd(ROFF_ARGS);
static	enum rofferr	 roff_TH(ROFF_ARGS);
static	enum rofferr	 roff_TE(ROFF_ARGS);
static	enum rofferr	 roff_TS(ROFF_ARGS);
static	enum rofferr	 roff_EQ(ROFF_ARGS);
static	enum rofferr	 roff_EN(ROFF_ARGS);
static	enum rofferr	 roff_T_(ROFF_ARGS);
static	enum rofferr	 roff_userdef(ROFF_ARGS);

/* See roffhash_find() */

#define	ASCII_HI	 126
#define	ASCII_LO	 33
#define	HASHWIDTH	(ASCII_HI - ASCII_LO + 1)

static	struct roffmac	*hash[HASHWIDTH];

static	struct roffmac	 roffs[ROFF_MAX] = {
	{ "ad", roff_line_ignore, NULL, NULL, 0, NULL },
	{ "am", roff_block, roff_block_text, roff_block_sub, 0, NULL },
	{ "ami", roff_block, roff_block_text, roff_block_sub, 0, NULL },
	{ "am1", roff_block, roff_block_text, roff_block_sub, 0, NULL },
	{ "cc", roff_cc, NULL, NULL, 0, NULL },
	{ "de", roff_block, roff_block_text, roff_block_sub, 0, NULL },
	{ "dei", roff_block, roff_block_text, roff_block_sub, 0, NULL },
	{ "de1", roff_block, roff_block_text, roff_block_sub, 0, NULL },
	{ "ds", roff_ds, NULL, NULL, 0, NULL },
	{ "el", roff_cond, roff_cond_text, roff_cond_sub, ROFFMAC_STRUCT, NULL },
	{ "hy", roff_line_ignore, NULL, NULL, 0, NULL },
	{ "ie", roff_cond, roff_cond_text, roff_cond_sub, ROFFMAC_STRUCT, NULL },
	{ "if", roff_cond, roff_cond_text, roff_cond_sub, ROFFMAC_STRUCT, NULL },
	{ "ig", roff_block, roff_block_text, roff_block_sub, 0, NULL },
	{ "it", roff_it, NULL, NULL, 0, NULL },
	{ "ne", roff_line_ignore, NULL, NULL, 0, NULL },
	{ "nh", roff_line_ignore, NULL, NULL, 0, NULL },
	{ "nr", roff_nr, NULL, NULL, 0, NULL },
	{ "ns", roff_line_ignore, NULL, NULL, 0, NULL },
	{ "ps", roff_line_ignore, NULL, NULL, 0, NULL },
	{ "rm", roff_rm, NULL, NULL, 0, NULL },
	{ "so", roff_so, NULL, NULL, 0, NULL },
	{ "ta", roff_line_ignore, NULL, NULL, 0, NULL },
	{ "tr", roff_tr, NULL, NULL, 0, NULL },
	{ "Dd", roff_Dd, NULL, NULL, 0, NULL },
	{ "TH", roff_TH, NULL, NULL, 0, NULL },
	{ "TS", roff_TS, NULL, NULL, 0, NULL },
	{ "TE", roff_TE, NULL, NULL, 0, NULL },
	{ "T&", roff_T_, NULL, NULL, 0, NULL },
	{ "EQ", roff_EQ, NULL, NULL, 0, NULL },
	{ "EN", roff_EN, NULL, NULL, 0, NULL },
	{ ".", roff_cblock, NULL, NULL, 0, NULL },
	{ "\\}", roff_ccond, NULL, NULL, 0, NULL },
	{ NULL, roff_userdef, NULL, NULL, 0, NULL },
};

const	char *const __mdoc_reserved[] = {
	"Ac", "Ad", "An", "Ao", "Ap", "Aq", "Ar", "At",
	"Bc", "Bd", "Bf", "Bk", "Bl", "Bo", "Bq",
	"Brc", "Bro", "Brq", "Bsx", "Bt", "Bx",
	"Cd", "Cm", "Db", "Dc", "Dd", "Dl", "Do", "Dq",
	"Ds", "Dt", "Dv", "Dx", "D1",
	"Ec", "Ed", "Ef", "Ek", "El", "Em", "em",
	"En", "Eo", "Eq", "Er", "Es", "Ev", "Ex",
	"Fa", "Fc", "Fd", "Fl", "Fn", "Fo", "Fr", "Ft", "Fx",
	"Hf", "Ic", "In", "It", "Lb", "Li", "Lk", "Lp", "LP",
	"Me", "Ms", "Mt", "Nd", "Nm", "No", "Ns", "Nx",
	"Oc", "Oo", "Op", "Os", "Ot", "Ox",
	"Pa", "Pc", "Pf", "Po", "Pp", "PP", "pp", "Pq",
	"Qc", "Ql", "Qo", "Qq", "Or", "Rd", "Re", "Rs", "Rv",
	"Sc", "Sf", "Sh", "SH", "Sm", "So", "Sq",
	"Ss", "St", "Sx", "Sy",
	"Ta", "Tn", "Ud", "Ux", "Va", "Vt", "Xc", "Xo", "Xr",
	"%A", "%B", "%D", "%I", "%J", "%N", "%O",
	"%P", "%Q", "%R", "%T", "%U", "%V",
	NULL
};

const	char *const __man_reserved[] = {
	"AT", "B", "BI", "BR", "BT", "DE", "DS", "DT",
	"EE", "EN", "EQ", "EX", "HF", "HP", "I", "IB", "IP", "IR",
	"LP", "ME", "MT", "OP", "P", "PD", "PP", "PT",
	"R", "RB", "RE", "RI", "RS", "SB", "SH", "SM", "SS", "SY",
	"TE", "TH", "TP", "TQ", "TS", "T&", "UC", "UE", "UR", "YS",
	NULL
};

/* Array of injected predefined strings. */
#define	PREDEFS_MAX	 38
static	const struct predef predefs[PREDEFS_MAX] = {
#include "predefs.in"
};

/* See roffhash_find() */
#define	ROFF_HASH(p)	(p[0] - ASCII_LO)

static	int	 roffit_lines;  /* number of lines to delay */
static	char	*roffit_macro;  /* nil-terminated macro line */

static void
roffhash_init(void)
{
	struct roffmac	 *n;
	int		  buc, i;

	for (i = 0; i < (int)ROFF_USERDEF; i++) {
		assert(roffs[i].name[0] >= ASCII_LO);
		assert(roffs[i].name[0] <= ASCII_HI);

		buc = ROFF_HASH(roffs[i].name);

		if (NULL != (n = hash[buc])) {
			for ( ; n->next; n = n->next)
				/* Do nothing. */ ;
			n->next = &roffs[i];
		} else
			hash[buc] = &roffs[i];
	}
}

/*
 * Look up a roff token by its name.  Returns ROFF_MAX if no macro by
 * the nil-terminated string name could be found.
 */
static enum rofft
roffhash_find(const char *p, size_t s)
{
	int		 buc;
	struct roffmac	*n;

	/*
	 * libroff has an extremely simple hashtable, for the time
	 * being, which simply keys on the first character, which must
	 * be printable, then walks a chain.  It works well enough until
	 * optimised.
	 */

	if (p[0] < ASCII_LO || p[0] > ASCII_HI)
		return(ROFF_MAX);

	buc = ROFF_HASH(p);

	if (NULL == (n = hash[buc]))
		return(ROFF_MAX);
	for ( ; n; n = n->next)
		if (0 == strncmp(n->name, p, s) && '\0' == n->name[(int)s])
			return((enum rofft)(n - roffs));

	return(ROFF_MAX);
}


/*
 * Pop the current node off of the stack of roff instructions currently
 * pending.
 */
static void
roffnode_pop(struct roff *r)
{
	struct roffnode	*p;

	assert(r->last);
	p = r->last; 

	r->last = r->last->parent;
	free(p->name);
	free(p->end);
	free(p);
}


/*
 * Push a roff node onto the instruction stack.  This must later be
 * removed with roffnode_pop().
 */
static void
roffnode_push(struct roff *r, enum rofft tok, const char *name,
		int line, int col)
{
	struct roffnode	*p;

	p = mandoc_calloc(1, sizeof(struct roffnode));
	p->tok = tok;
	if (name)
		p->name = mandoc_strdup(name);
	p->parent = r->last;
	p->line = line;
	p->col = col;
	p->rule = p->parent ? p->parent->rule : ROFFRULE_DENY;

	r->last = p;
}


static void
roff_free1(struct roff *r)
{
	struct tbl_node	*tbl;
	struct eqn_node	*e;
	int		 i;

	while (NULL != (tbl = r->first_tbl)) {
		r->first_tbl = tbl->next;
		tbl_free(tbl);
	}

	r->first_tbl = r->last_tbl = r->tbl = NULL;

	while (NULL != (e = r->first_eqn)) {
		r->first_eqn = e->next;
		eqn_free(e);
	}

	r->first_eqn = r->last_eqn = r->eqn = NULL;

	while (r->last)
		roffnode_pop(r);

	roff_freestr(r->strtab);
	roff_freestr(r->xmbtab);

	r->strtab = r->xmbtab = NULL;

	if (r->xtab)
		for (i = 0; i < 128; i++)
			free(r->xtab[i].p);

	free(r->xtab);
	r->xtab = NULL;
}

void
roff_reset(struct roff *r)
{
	int		 i;

	roff_free1(r);

	r->control = 0;
	memset(&r->regs, 0, sizeof(struct reg) * REG__MAX);

	for (i = 0; i < PREDEFS_MAX; i++) 
		roff_setstr(r, predefs[i].name, predefs[i].str, 0);
}


void
roff_free(struct roff *r)
{

	roff_free1(r);
	free(r);
}


struct roff *
roff_alloc(enum mparset type, struct mparse *parse)
{
	struct roff	*r;
	int		 i;

	r = mandoc_calloc(1, sizeof(struct roff));
	r->parsetype = type;
	r->parse = parse;
	r->rstackpos = -1;
	
	roffhash_init();

	for (i = 0; i < PREDEFS_MAX; i++) 
		roff_setstr(r, predefs[i].name, predefs[i].str, 0);

	return(r);
}

/*
 * 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.
 */
static enum rofferr
roff_res(struct roff *r, char **bufp, size_t *szp, int ln, int pos)
{
	enum mandoc_esc	 esc;
	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;

	expand_count = 0;

again:
	cp = *bufp + pos;
	while (NULL != (cp = strchr(cp, '\\'))) {
		stesc = cp++;

		/*
		 * The second character must be an asterisk.
		 * If it isn't, skip it anyway:  It is escaped,
		 * so it can't start another escape sequence.
		 */

		if ('\0' == *cp)
			return(ROFF_CONT);

		if ('*' != *cp) {
			res = cp;
			esc = mandoc_escape(&cp, NULL, NULL);
			if (ESCAPE_ERROR != esc)
				continue;
			cp = res;
			mandoc_msg
				(MANDOCERR_BADESCAPE, r->parse, 
				 ln, (int)(stesc - *bufp), NULL);
			return(ROFF_CONT);
		}

		cp++;

		/*
		 * The third character decides the length
		 * of the name of the string.
		 * Save a pointer to the name.
		 */

		switch (*cp) {
		case ('\0'):
			return(ROFF_CONT);
		case ('('):
			cp++;
			maxl = 2;
			break;
		case ('['):
			cp++;
			maxl = 0;
			break;
		default:
			maxl = 1;
			break;
		}
		stnam = cp;

		/* Advance to the end of the name. */

		for (i = 0; 0 == maxl || i < maxl; i++, cp++) {
			if ('\0' == *cp) {
				mandoc_msg
					(MANDOCERR_BADESCAPE, 
					 r->parse, ln, 
					 (int)(stesc - *bufp), NULL);
				return(ROFF_CONT);
			}
			if (0 == maxl && ']' == *cp)
				break;
		}

		/*
		 * Retrieve the replacement string; if it is
		 * undefined, resume searching for escapes.
		 */

		res = roff_getstrn(r, stnam, (size_t)i);

		if (NULL == res) {
			mandoc_msg
				(MANDOCERR_BADESCAPE, r->parse, 
				 ln, (int)(stesc - *bufp), NULL);
			res = "";
		}

		/* Replace the escape sequence by the string. */

		pos = stesc - *bufp;

		nsz = *szp + strlen(res) + 1;
		n = mandoc_malloc(nsz);

		strlcpy(n, *bufp, (size_t)(stesc - *bufp + 1));
		strlcat(n, res, nsz);
		strlcat(n, cp + (maxl ? 0 : 1), nsz);

		free(*bufp);

		*bufp = n;
		*szp = nsz;

		if (EXPAND_LIMIT >= ++expand_count)
			goto again;

		/* Just leave the string unexpanded. */
		mandoc_msg(MANDOCERR_ROFFLOOP, r->parse, ln, pos, NULL);
		return(ROFF_IGN);
	}
	return(ROFF_CONT);
}

/*
 * Process text streams:
 * Convert all breakable hyphens into ASCII_HYPH.
 * Decrement and spring input line trap.
 */
static enum rofferr
roff_parsetext(char **bufp, size_t *szp, int pos, int *offs)
{
	size_t		 sz;
	const char	*start;
	char		*p;
	int		 isz;
	enum mandoc_esc	 esc;

	start = p = *bufp + pos;

	while ('\0' != *p) {
		sz = strcspn(p, "-\\");
		p += sz;

		if ('\0' == *p)
			break;

		if ('\\' == *p) {
			/* Skip over escapes. */
			p++;
			esc = mandoc_escape
				((const char **)&p, NULL, NULL);
			if (ESCAPE_ERROR == esc)
				break;
			continue;
		} else if (p == start) {
			p++;
			continue;
		}

		if (isalpha((unsigned char)p[-1]) &&
		    isalpha((unsigned char)p[1]))
			*p = ASCII_HYPH;
		p++;
	}

	/* Spring the input line trap. */
	if (1 == roffit_lines) {
		isz = asprintf(&p, "%s\n.%s", *bufp, roffit_macro);
		if (-1 == isz) {
			perror(NULL);
			exit((int)MANDOCLEVEL_SYSERR);
		}
		free(*bufp);
		*bufp = p;
		*szp = isz + 1;
		*offs = 0;
		free(roffit_macro);
		roffit_lines = 0;
		return(ROFF_REPARSE);
	} else if (1 < roffit_lines)
		--roffit_lines;
	return(ROFF_CONT);
}

enum rofferr
roff_parseln(struct roff *r, int ln, char **bufp, 
		size_t *szp, int pos, int *offs)
{
	enum rofft	 t;
	enum rofferr	 e;
	int		 ppos, ctl;

	/*
	 * Run the reserved-word filter only if we have some reserved
	 * words to fill in.
	 */

	e = roff_res(r, bufp, szp, ln, pos);
	if (ROFF_IGN == e)
		return(e);
	assert(ROFF_CONT == e);

	ppos = pos;
	ctl = roff_getcontrol(r, *bufp, &pos);

	/*
	 * First, if a scope is open and we're not a macro, pass the
	 * text through the macro's filter.  If a scope isn't open and
	 * we're not a macro, just let it through.
	 * Finally, if there's an equation scope open, divert it into it
	 * no matter our state.
	 */

	if (r->last && ! ctl) {
		t = r->last->tok;
		assert(roffs[t].text);
		e = (*roffs[t].text)
			(r, t, bufp, szp, ln, pos, pos, offs);
		assert(ROFF_IGN == e || ROFF_CONT == e);
		if (ROFF_CONT != e)
			return(e);
		if (r->eqn)
			return(eqn_read(&r->eqn, ln, *bufp, pos, offs));
		if (r->tbl)
			return(tbl_read(r->tbl, ln, *bufp, pos));
		return(roff_parsetext(bufp, szp, pos, offs));
	} else if ( ! ctl) {
		if (r->eqn)
			return(eqn_read(&r->eqn, ln, *bufp, pos, offs));
		if (r->tbl)
			return(tbl_read(r->tbl, ln, *bufp, pos));
		return(roff_parsetext(bufp, szp, pos, offs));
	} else if (r->eqn)
		return(eqn_read(&r->eqn, ln, *bufp, ppos, offs));

	/*
	 * If a scope is open, go to the child handler for that macro,
	 * as it may want to preprocess before doing anything with it.
	 * Don't do so if an equation is open.
	 */

	if (r->last) {
		t = r->last->tok;
		assert(roffs[t].sub);
		return((*roffs[t].sub)
				(r, t, bufp, szp, 
				 ln, ppos, pos, offs));
	}

	/*
	 * Lastly, as we've no scope open, try to look up and execute
	 * the new macro.  If no macro is found, simply return and let
	 * the compilers handle it.
	 */

	if (ROFF_MAX == (t = roff_parse(r, *bufp, &pos)))
		return(ROFF_CONT);

	assert(roffs[t].proc);
	return((*roffs[t].proc)
			(r, t, bufp, szp, 
			 ln, ppos, pos, offs));
}


void
roff_endparse(struct roff *r)
{

	if (r->last)
		mandoc_msg(MANDOCERR_SCOPEEXIT, r->parse,
				r->last->line, r->last->col, NULL);

	if (r->eqn) {
		mandoc_msg(MANDOCERR_SCOPEEXIT, r->parse, 
				r->eqn->eqn.ln, r->eqn->eqn.pos, NULL);
		eqn_end(&r->eqn);
	}

	if (r->tbl) {
		mandoc_msg(MANDOCERR_SCOPEEXIT, r->parse, 
				r->tbl->line, r->tbl->pos, NULL);
		tbl_end(&r->tbl);
	}
}

/*
 * Parse a roff node's type from the input buffer.  This must be in the
 * form of ".foo xxx" in the usual way.
 */
static enum rofft
roff_parse(struct roff *r, const char *buf, int *pos)
{
	const char	*mac;
	size_t		 maclen;
	enum rofft	 t;

	if ('\0' == buf[*pos] || '"' == buf[*pos] || 
			'\t' == buf[*pos] || ' ' == buf[*pos])
		return(ROFF_MAX);

	/*
	 * We stop the macro parse at an escape, tab, space, or nil.
	 * However, `\}' is also a valid macro, so make sure we don't
	 * clobber it by seeing the `\' as the end of token.
	 */

	mac = buf + *pos;
	maclen = strcspn(mac + 1, " \\\t\0") + 1;

	t = (r->current_string = roff_getstrn(r, mac, maclen))
	    ? ROFF_USERDEF : roffhash_find(mac, maclen);

	*pos += (int)maclen;

	while (buf[*pos] && ' ' == buf[*pos])
		(*pos)++;

	return(t);
}

/* ARGSUSED */
static enum rofferr
roff_cblock(ROFF_ARGS)
{

	/*
	 * A block-close `..' should only be invoked as a child of an
	 * ignore macro, otherwise raise a warning and just ignore it.
	 */

	if (NULL == r->last) {
		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
		return(ROFF_IGN);
	}

	switch (r->last->tok) {
	case (ROFF_am):
		/* FALLTHROUGH */
	case (ROFF_ami):
		/* FALLTHROUGH */
	case (ROFF_am1):
		/* FALLTHROUGH */
	case (ROFF_de):
		/* ROFF_de1 is remapped to ROFF_de in roff_block(). */
		/* FALLTHROUGH */
	case (ROFF_dei):
		/* FALLTHROUGH */
	case (ROFF_ig):
		break;
	default:
		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
		return(ROFF_IGN);
	}

	if ((*bufp)[pos])
		mandoc_msg(MANDOCERR_ARGSLOST, r->parse, ln, pos, NULL);

	roffnode_pop(r);
	roffnode_cleanscope(r);
	return(ROFF_IGN);

}


static void
roffnode_cleanscope(struct roff *r)
{

	while (r->last) {
		if (--r->last->endspan != 0)
			break;
		roffnode_pop(r);
	}
}


/* ARGSUSED */
static enum rofferr
roff_ccond(ROFF_ARGS)
{

	if (NULL == r->last) {
		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
		return(ROFF_IGN);
	}

	switch (r->last->tok) {
	case (ROFF_el):
		/* FALLTHROUGH */
	case (ROFF_ie):
		/* FALLTHROUGH */
	case (ROFF_if):
		break;
	default:
		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
		return(ROFF_IGN);
	}

	if (r->last->endspan > -1) {
		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
		return(ROFF_IGN);
	}

	if ((*bufp)[pos])
		mandoc_msg(MANDOCERR_ARGSLOST, r->parse, ln, pos, NULL);

	roffnode_pop(r);
	roffnode_cleanscope(r);
	return(ROFF_IGN);
}


/* ARGSUSED */
static enum rofferr
roff_block(ROFF_ARGS)
{
	int		sv;
	size_t		sz;
	char		*name;

	name = NULL;

	if (ROFF_ig != tok) {
		if ('\0' == (*bufp)[pos]) {
			mandoc_msg(MANDOCERR_NOARGS, r->parse, ln, ppos, NULL);
			return(ROFF_IGN);
		}

		/*
		 * Re-write `de1', since we don't really care about
		 * groff's strange compatibility mode, into `de'.
		 */

		if (ROFF_de1 == tok)
			tok = ROFF_de;
		if (ROFF_de == tok)
			name = *bufp + pos;
		else
			mandoc_msg(MANDOCERR_REQUEST, r->parse, ln, ppos,
			    roffs[tok].name);

		while ((*bufp)[pos] && ! isspace((unsigned char)(*bufp)[pos]))
			pos++;

		while (isspace((unsigned char)(*bufp)[pos]))
			(*bufp)[pos++] = '\0';
	}

	roffnode_push(r, tok, name, ln, ppos);

	/*
	 * At the beginning of a `de' macro, clear the existing string
	 * with the same name, if there is one.  New content will be
	 * added from roff_block_text() in multiline mode.
	 */

	if (ROFF_de == tok)
		roff_setstr(r, name, "", 0);

	if ('\0' == (*bufp)[pos])
		return(ROFF_IGN);

	/* If present, process the custom end-of-line marker. */

	sv = pos;
	while ((*bufp)[pos] && ! isspace((unsigned char)(*bufp)[pos]))
		pos++;

	/*
	 * Note: groff does NOT like escape characters in the input.
	 * Instead of detecting this, we're just going to let it fly and
	 * to hell with it.
	 */

	assert(pos > sv);
	sz = (size_t)(pos - sv);

	if (1 == sz && '.' == (*bufp)[sv])
		return(ROFF_IGN);

	r->last->end = mandoc_malloc(sz + 1);

	memcpy(r->last->end, *bufp + sv, sz);
	r->last->end[(int)sz] = '\0';

	if ((*bufp)[pos])
		mandoc_msg(MANDOCERR_ARGSLOST, r->parse, ln, pos, NULL);

	return(ROFF_IGN);
}


/* ARGSUSED */
static enum rofferr
roff_block_sub(ROFF_ARGS)
{
	enum rofft	t;
	int		i, j;

	/*
	 * First check whether a custom macro exists at this level.  If
	 * it does, then check against it.  This is some of groff's
	 * stranger behaviours.  If we encountered a custom end-scope
	 * tag and that tag also happens to be a "real" macro, then we
	 * need to try interpreting it again as a real macro.  If it's
	 * not, then return ignore.  Else continue.
	 */

	if (r->last->end) {
		for (i = pos, j = 0; r->last->end[j]; j++, i++)
			if ((*bufp)[i] != r->last->end[j])
				break;

		if ('\0' == r->last->end[j] && 
				('\0' == (*bufp)[i] ||
				 ' ' == (*bufp)[i] ||
				 '\t' == (*bufp)[i])) {
			roffnode_pop(r);
			roffnode_cleanscope(r);

			while (' ' == (*bufp)[i] || '\t' == (*bufp)[i])
				i++;

			pos = i;
			if (ROFF_MAX != roff_parse(r, *bufp, &pos))
				return(ROFF_RERUN);
			return(ROFF_IGN);
		}
	}

	/*
	 * If we have no custom end-query or lookup failed, then try
	 * pulling it out of the hashtable.
	 */

	t = roff_parse(r, *bufp, &pos);

	/*
	 * Macros other than block-end are only significant
	 * in `de' blocks; elsewhere, simply throw them away.
	 */
	if (ROFF_cblock != t) {
		if (ROFF_de == tok)
			roff_setstr(r, r->last->name, *bufp + ppos, 1);
		return(ROFF_IGN);
	}

	assert(roffs[t].proc);
	return((*roffs[t].proc)(r, t, bufp, szp, 
				ln, ppos, pos, offs));
}


/* ARGSUSED */
static enum rofferr
roff_block_text(ROFF_ARGS)
{

	if (ROFF_de == tok)
		roff_setstr(r, r->last->name, *bufp + pos, 1);

	return(ROFF_IGN);
}


/* ARGSUSED */
static enum rofferr
roff_cond_sub(ROFF_ARGS)
{
	enum rofft	 t;
	enum roffrule	 rr;
	char		*ep;

	rr = r->last->rule;
	roffnode_cleanscope(r);
	t = roff_parse(r, *bufp, &pos);

	/*
	 * Fully handle known macros when they are structurally
	 * required or when the conditional evaluated to true.
	 */

	if ((ROFF_MAX != t) &&
	    (ROFF_ccond == t || ROFFRULE_ALLOW == rr ||
	     ROFFMAC_STRUCT & roffs[t].flags)) {
		assert(roffs[t].proc);
		return((*roffs[t].proc)(r, t, bufp, szp,
					ln, ppos, pos, offs));
	}

	/* Always check for the closing delimiter `\}'. */

	ep = &(*bufp)[pos];
	while (NULL != (ep = strchr(ep, '\\'))) {
		if ('}' != *(++ep))
			continue;

		/*
		 * If we're at the end of line, then just chop
		 * off the \} and resize the buffer.
		 * If we aren't, then convert it to spaces.
		 */

		if ('\0' == *(ep + 1)) {
			*--ep = '\0';
			*szp -= 2;
		} else
			*(ep - 1) = *ep = ' ';

		roff_ccond(r, ROFF_ccond, bufp, szp, 
				ln, pos, pos + 2, offs);
		break;
	}
	return(ROFFRULE_DENY == rr ? ROFF_IGN : ROFF_CONT);
}

/* ARGSUSED */
static enum rofferr
roff_cond_text(ROFF_ARGS)
{
	char		*ep;
	enum roffrule	 rr;

	rr = r->last->rule;
	roffnode_cleanscope(r);

	ep = &(*bufp)[pos];
	for ( ; NULL != (ep = strchr(ep, '\\')); ep++) {
		ep++;
		if ('}' != *ep)
			continue;
		*ep = '&';
		roff_ccond(r, ROFF_ccond, bufp, szp, 
				ln, pos, pos + 2, offs);
	}
	return(ROFFRULE_DENY == rr ? ROFF_IGN : ROFF_CONT);
}

static enum roffrule
roff_evalcond(const char *v, int *pos)
{

	switch (v[*pos]) {
	case ('n'):
		(*pos)++;
		return(ROFFRULE_ALLOW);
	case ('e'):
		/* FALLTHROUGH */
	case ('o'):
		/* FALLTHROUGH */
	case ('t'):
		(*pos)++;
		return(ROFFRULE_DENY);
	default:
		break;
	}

	while (v[*pos] && ' ' != v[*pos])
		(*pos)++;
	return(ROFFRULE_DENY);
}

/* ARGSUSED */
static enum rofferr
roff_line_ignore(ROFF_ARGS)
{

	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_cond(ROFF_ARGS)
{

	roffnode_push(r, tok, NULL, ln, ppos);

	/* 
	 * An `.el' has no conditional body: it will consume the value
	 * of the current rstack entry set in prior `ie' calls or
	 * defaults to DENY.  
	 *
	 * If we're not an `el', however, then evaluate the conditional.
	 */

	r->last->rule = ROFF_el == tok ?
		(r->rstackpos < 0 ? 
		 ROFFRULE_DENY : r->rstack[r->rstackpos--]) :
		roff_evalcond(*bufp, &pos);

	/*
	 * An if-else will put the NEGATION of the current evaluated
	 * conditional into the stack of rules.
	 */

	if (ROFF_ie == tok) {
		if (r->rstackpos == RSTACK_MAX - 1) {
			mandoc_msg(MANDOCERR_MEM, 
				r->parse, ln, ppos, NULL);
			return(ROFF_ERR);
		}
		r->rstack[++r->rstackpos] = 
			ROFFRULE_DENY == r->last->rule ?
			ROFFRULE_ALLOW : ROFFRULE_DENY;
	}

	/* If the parent has false as its rule, then so do we. */

	if (r->last->parent && ROFFRULE_DENY == r->last->parent->rule)
		r->last->rule = ROFFRULE_DENY;

	/*
	 * Determine scope.
	 * If there is nothing on the line after the conditional,
	 * not even whitespace, use next-line scope.
	 */

	if ('\0' == (*bufp)[pos]) {
		r->last->endspan = 2;
		goto out;
	}

	while (' ' == (*bufp)[pos])
		pos++;

	/* An opening brace requests multiline scope. */

	if ('\\' == (*bufp)[pos] && '{' == (*bufp)[pos + 1]) {
		r->last->endspan = -1;
		pos += 2;
		goto out;
	} 

	/*
	 * Anything else following the conditional causes
	 * single-line scope.  Warn if the scope contains
	 * nothing but trailing whitespace.
	 */

	if ('\0' == (*bufp)[pos])
		mandoc_msg(MANDOCERR_NOARGS, r->parse, ln, ppos, NULL);

	r->last->endspan = 1;

out:
	*offs = pos;
	return(ROFF_RERUN);
}


/* ARGSUSED */
static enum rofferr
roff_ds(ROFF_ARGS)
{
	char		*name, *string;

	/*
	 * A symbol is named by the first word following the macro
	 * invocation up to a space.  Its value is anything after the
	 * name's trailing whitespace and optional double-quote.  Thus,
	 *
	 *  [.ds foo "bar  "     ]
	 *
	 * will have `bar  "     ' as its value.
	 */

	string = *bufp + pos;
	name = roff_getname(r, &string, ln, pos);
	if ('\0' == *name)
		return(ROFF_IGN);

	/* Read past initial double-quote. */
	if ('"' == *string)
		string++;

	/* The rest is the value. */
	roff_setstr(r, name, string, 0);
	return(ROFF_IGN);
}

int
roff_regisset(const struct roff *r, enum regs reg)
{

	return(r->regs[(int)reg].set);
}

unsigned int
roff_regget(const struct roff *r, enum regs reg)
{

	return(r->regs[(int)reg].u);
}

void
roff_regunset(struct roff *r, enum regs reg)
{

	r->regs[(int)reg].set = 0;
}

/* ARGSUSED */
static enum rofferr
roff_nr(ROFF_ARGS)
{
	const char	*key;
	char		*val;
	int		 iv;

	val = *bufp + pos;
	key = roff_getname(r, &val, ln, pos);

	if (0 == strcmp(key, "nS")) {
		r->regs[(int)REG_nS].set = 1;
		if ((iv = mandoc_strntoi(val, strlen(val), 10)) >= 0)
			r->regs[(int)REG_nS].u = (unsigned)iv;
		else
			r->regs[(int)REG_nS].u = 0u;
	}

	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_rm(ROFF_ARGS)
{
	const char	 *name;
	char		 *cp;

	cp = *bufp + pos;
	while ('\0' != *cp) {
		name = roff_getname(r, &cp, ln, (int)(cp - *bufp));
		if ('\0' != *name)
			roff_setstr(r, name, NULL, 0);
	}
	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_it(ROFF_ARGS)
{
	char		*cp;
	size_t		 len;
	int		 iv;

	/* Parse the number of lines. */
	cp = *bufp + pos;
	len = strcspn(cp, " \t");
	cp[len] = '\0';
	if ((iv = mandoc_strntoi(cp, len, 10)) <= 0) {
		mandoc_msg(MANDOCERR_NUMERIC, r->parse,
				ln, ppos, *bufp + 1);
		return(ROFF_IGN);
	}
	cp += len + 1;

	/* Arm the input line trap. */
	roffit_lines = iv;
	roffit_macro = mandoc_strdup(cp);
	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_Dd(ROFF_ARGS)
{
	const char *const	*cp;

	if (MPARSE_MDOC != r->parsetype)
		for (cp = __mdoc_reserved; *cp; cp++)
			roff_setstr(r, *cp, NULL, 0);

	return(ROFF_CONT);
}

/* ARGSUSED */
static enum rofferr
roff_TH(ROFF_ARGS)
{
	const char *const	*cp;

	if (MPARSE_MDOC != r->parsetype)
		for (cp = __man_reserved; *cp; cp++)
			roff_setstr(r, *cp, NULL, 0);

	return(ROFF_CONT);
}

/* ARGSUSED */
static enum rofferr
roff_TE(ROFF_ARGS)
{

	if (NULL == r->tbl)
		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
	else
		tbl_end(&r->tbl);

	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_T_(ROFF_ARGS)
{

	if (NULL == r->tbl)
		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
	else
		tbl_restart(ppos, ln, r->tbl);

	return(ROFF_IGN);
}

#if 0
static int
roff_closeeqn(struct roff *r)
{

	return(r->eqn && ROFF_EQN == eqn_end(&r->eqn) ? 1 : 0);
}
#endif

static void
roff_openeqn(struct roff *r, const char *name, int line, 
		int offs, const char *buf)
{
	struct eqn_node *e;
	int		 poff;

	assert(NULL == r->eqn);
	e = eqn_alloc(name, offs, line, r->parse);

	if (r->last_eqn)
		r->last_eqn->next = e;
	else
		r->first_eqn = r->last_eqn = e;

	r->eqn = r->last_eqn = e;

	if (buf) {
		poff = 0;
		eqn_read(&r->eqn, line, buf, offs, &poff);
	}
}

/* ARGSUSED */
static enum rofferr
roff_EQ(ROFF_ARGS)
{

	roff_openeqn(r, *bufp + pos, ln, ppos, NULL);
	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_EN(ROFF_ARGS)
{

	mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_TS(ROFF_ARGS)
{
	struct tbl_node	*tbl;

	if (r->tbl) {
		mandoc_msg(MANDOCERR_SCOPEBROKEN, r->parse, ln, ppos, NULL);
		tbl_end(&r->tbl);
	}

	tbl = tbl_alloc(ppos, ln, r->parse);

	if (r->last_tbl)
		r->last_tbl->next = tbl;
	else
		r->first_tbl = r->last_tbl = tbl;

	r->tbl = r->last_tbl = tbl;
	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_cc(ROFF_ARGS)
{
	const char	*p;

	p = *bufp + pos;

	if ('\0' == *p || '.' == (r->control = *p++))
		r->control = 0;

	if ('\0' != *p)
		mandoc_msg(MANDOCERR_ARGCOUNT, r->parse, ln, ppos, NULL);

	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_tr(ROFF_ARGS)
{
	const char	*p, *first, *second;
	size_t		 fsz, ssz;
	enum mandoc_esc	 esc;

	p = *bufp + pos;

	if ('\0' == *p) {
		mandoc_msg(MANDOCERR_ARGCOUNT, r->parse, ln, ppos, NULL);
		return(ROFF_IGN);
	}

	while ('\0' != *p) {
		fsz = ssz = 1;

		first = p++;
		if ('\\' == *first) {
			esc = mandoc_escape(&p, NULL, NULL);
			if (ESCAPE_ERROR == esc) {
				mandoc_msg
					(MANDOCERR_BADESCAPE, r->parse, 
					 ln, (int)(p - *bufp), NULL);
				return(ROFF_IGN);
			}
			fsz = (size_t)(p - first);
		}

		second = p++;
		if ('\\' == *second) {
			esc = mandoc_escape(&p, NULL, NULL);
			if (ESCAPE_ERROR == esc) {
				mandoc_msg
					(MANDOCERR_BADESCAPE, r->parse, 
					 ln, (int)(p - *bufp), NULL);
				return(ROFF_IGN);
			}
			ssz = (size_t)(p - second);
		} else if ('\0' == *second) {
			mandoc_msg(MANDOCERR_ARGCOUNT, r->parse, 
					ln, (int)(p - *bufp), NULL);
			second = " ";
			p--;
		}

		if (fsz > 1) {
			roff_setstrn(&r->xmbtab, first, 
					fsz, second, ssz, 0);
			continue;
		}

		if (NULL == r->xtab)
			r->xtab = mandoc_calloc
				(128, sizeof(struct roffstr));

		free(r->xtab[(int)*first].p);
		r->xtab[(int)*first].p = mandoc_strndup(second, ssz);
		r->xtab[(int)*first].sz = ssz;
	}

	return(ROFF_IGN);
}

/* ARGSUSED */
static enum rofferr
roff_so(ROFF_ARGS)
{
	char *name;

	mandoc_msg(MANDOCERR_SO, r->parse, ln, ppos, NULL);

	/*
	 * Handle `so'.  Be EXTREMELY careful, as we shouldn't be
	 * opening anything that's not in our cwd or anything beneath
	 * it.  Thus, explicitly disallow traversing up the file-system
	 * or using absolute paths.
	 */

	name = *bufp + pos;
	if ('/' == *name || strstr(name, "../") || strstr(name, "/..")) {
		mandoc_msg(MANDOCERR_SOPATH, r->parse, ln, pos, NULL);
		return(ROFF_ERR);
	}

	*offs = pos;
	return(ROFF_SO);
}

/* ARGSUSED */
static enum rofferr
roff_userdef(ROFF_ARGS)
{
	const char	 *arg[9];
	char		 *cp, *n1, *n2;
	int		  i;

	/*
	 * Collect pointers to macro argument strings
	 * and null-terminate them.
	 */
	cp = *bufp + pos;
	for (i = 0; i < 9; i++)
		arg[i] = '\0' == *cp ? "" :
		    mandoc_getarg(r->parse, &cp, ln, &pos);

	/*
	 * Expand macro arguments.
	 */
	*szp = 0;
	n1 = cp = mandoc_strdup(r->current_string);
	while (NULL != (cp = strstr(cp, "\\$"))) {
		i = cp[2] - '1';
		if (0 > i || 8 < i) {
			/* Not an argument invocation. */
			cp += 2;
			continue;
		}

		*szp = strlen(n1) - 3 + strlen(arg[i]) + 1;
		n2 = mandoc_malloc(*szp);

		strlcpy(n2, n1, (size_t)(cp - n1 + 1));
		strlcat(n2, arg[i], *szp);
		strlcat(n2, cp + 3, *szp);

		cp = n2 + (cp - n1);
		free(n1);
		n1 = n2;
	}

	/*
	 * Replace the macro invocation
	 * by the expanded macro.
	 */
	free(*bufp);
	*bufp = n1;
	if (0 == *szp)
		*szp = strlen(*bufp) + 1;

	return(*szp > 1 && '\n' == (*bufp)[(int)*szp - 2] ?
	   ROFF_REPARSE : ROFF_APPEND);
}

static char *
roff_getname(struct roff *r, char **cpp, int ln, int pos)
{
	char	 *name, *cp;

	name = *cpp;
	if ('\0' == *name)
		return(name);

	/* Read until end of name. */
	for (cp = name; '\0' != *cp && ' ' != *cp; cp++) {
		if ('\\' != *cp)
			continue;
		cp++;
		if ('\\' == *cp)
			continue;
		mandoc_msg(MANDOCERR_NAMESC, r->parse, ln, pos, NULL);
		*cp = '\0';
		name = cp;
	}

	/* Nil-terminate name. */
	if ('\0' != *cp)
		*(cp++) = '\0';

	/* Read past spaces. */
	while (' ' == *cp)
		cp++;

	*cpp = cp;
	return(name);
}

/*
 * Store *string into the user-defined string called *name.
 * In multiline mode, append to an existing entry and append '\n';
 * else replace the existing entry, if there is one.
 * To clear an existing entry, call with (*r, *name, NULL, 0).
 */
static void
roff_setstr(struct roff *r, const char *name, const char *string,
	int multiline)
{

	roff_setstrn(&r->strtab, name, strlen(name), string,
			string ? strlen(string) : 0, multiline);
}

static void
roff_setstrn(struct roffkv **r, const char *name, size_t namesz,
		const char *string, size_t stringsz, int multiline)
{
	struct roffkv	*n;
	char		*c;
	int		 i;
	size_t		 oldch, newch;

	/* Search for an existing string with the same name. */
	n = *r;

	while (n && strcmp(name, n->key.p))
		n = n->next;

	if (NULL == n) {
		/* Create a new string table entry. */
		n = mandoc_malloc(sizeof(struct roffkv));
		n->key.p = mandoc_strndup(name, namesz);
		n->key.sz = namesz;
		n->val.p = NULL;
		n->val.sz = 0;
		n->next = *r;
		*r = n;
	} else if (0 == multiline) {
		/* In multiline mode, append; else replace. */
		free(n->val.p);
		n->val.p = NULL;
		n->val.sz = 0;
	}

	if (NULL == string)
		return;

	/*
	 * One additional byte for the '\n' in multiline mode,
	 * and one for the terminating '\0'.
	 */
	newch = stringsz + (multiline ? 2u : 1u);

	if (NULL == n->val.p) {
		n->val.p = mandoc_malloc(newch);
		*n->val.p = '\0';
		oldch = 0;
	} else {
		oldch = n->val.sz;
		n->val.p = mandoc_realloc(n->val.p, oldch + newch);
	}

	/* Skip existing content in the destination buffer. */
	c = n->val.p + (int)oldch;

	/* Append new content to the destination buffer. */
	i = 0;
	while (i < (int)stringsz) {
		/*
		 * Rudimentary roff copy mode:
		 * Handle escaped backslashes.
		 */
		if ('\\' == string[i] && '\\' == string[i + 1])
			i++;
		*c++ = string[i++];
	}

	/* Append terminating bytes. */
	if (multiline)
		*c++ = '\n';

	*c = '\0';
	n->val.sz = (int)(c - n->val.p);
}

static const char *
roff_getstrn(const struct roff *r, const char *name, size_t len)
{
	const struct roffkv *n;

	for (n = r->strtab; n; n = n->next)
		if (0 == strncmp(name, n->key.p, len) && 
				'\0' == n->key.p[(int)len])
			return(n->val.p);

	return(NULL);
}

static void
roff_freestr(struct roffkv *r)
{
	struct roffkv	 *n, *nn;

	for (n = r; n; n = nn) {
		free(n->key.p);
		free(n->val.p);
		nn = n->next;
		free(n);
	}
}

const struct tbl_span *
roff_span(const struct roff *r)
{
	
	return(r->tbl ? tbl_span(r->tbl) : NULL);
}

const struct eqn *
roff_eqn(const struct roff *r)
{
	
	return(r->last_eqn ? &r->last_eqn->eqn : NULL);
}

/*
 * Duplicate an input string, making the appropriate character
 * conversations (as stipulated by `tr') along the way.
 * Returns a heap-allocated string with all the replacements made.
 */
char *
roff_strdup(const struct roff *r, const char *p)
{
	const struct roffkv *cp;
	char		*res;
	const char	*pp;
	size_t		 ssz, sz;
	enum mandoc_esc	 esc;

	if (NULL == r->xmbtab && NULL == r->xtab)
		return(mandoc_strdup(p));
	else if ('\0' == *p)
		return(mandoc_strdup(""));

	/*
	 * Step through each character looking for term matches
	 * (remember that a `tr' can be invoked with an escape, which is
	 * a glyph but the escape is multi-character).
	 * We only do this if the character hash has been initialised
	 * and the string is >0 length.
	 */

	res = NULL;
	ssz = 0;

	while ('\0' != *p) {
		if ('\\' != *p && r->xtab && r->xtab[(int)*p].p) {
			sz = r->xtab[(int)*p].sz;
			res = mandoc_realloc(res, ssz + sz + 1);
			memcpy(res + ssz, r->xtab[(int)*p].p, sz);
			ssz += sz;
			p++;
			continue;
		} else if ('\\' != *p) {
			res = mandoc_realloc(res, ssz + 2);
			res[ssz++] = *p++;
			continue;
		}

		/* Search for term matches. */
		for (cp = r->xmbtab; cp; cp = cp->next)
			if (0 == strncmp(p, cp->key.p, cp->key.sz))
				break;

		if (NULL != cp) {
			/*
			 * A match has been found.
			 * Append the match to the array and move
			 * forward by its keysize.
			 */
			res = mandoc_realloc
				(res, ssz + cp->val.sz + 1);
			memcpy(res + ssz, cp->val.p, cp->val.sz);
			ssz += cp->val.sz;
			p += (int)cp->key.sz;
			continue;
		}

		/*
		 * Handle escapes carefully: we need to copy
		 * over just the escape itself, or else we might
		 * do replacements within the escape itself.
		 * Make sure to pass along the bogus string.
		 */
		pp = p++;
		esc = mandoc_escape(&p, NULL, NULL);
		if (ESCAPE_ERROR == esc) {
			sz = strlen(pp);
			res = mandoc_realloc(res, ssz + sz + 1);
			memcpy(res + ssz, pp, sz);
			break;
		}
		/* 
		 * We bail out on bad escapes. 
		 * No need to warn: we already did so when
		 * roff_res() was called.
		 */
		sz = (int)(p - pp);
		res = mandoc_realloc(res, ssz + sz + 1);
		memcpy(res + ssz, pp, sz);
		ssz += sz;
	}

	res[(int)ssz] = '\0';
	return(res);
}

/*
 * Find out whether a line is a macro line or not.  
 * If it is, adjust the current position and return one; if it isn't,
 * return zero and don't change the current position.
 * If the control character has been set with `.cc', then let that grain
 * precedence.
 * This is slighly contrary to groff, where using the non-breaking
 * control character when `cc' has been invoked will cause the
 * non-breaking macro contents to be printed verbatim.
 */
int
roff_getcontrol(const struct roff *r, const char *cp, int *ppos)
{
	int		pos;

	pos = *ppos;

	if (0 != r->control && cp[pos] == r->control)
		pos++;
	else if (0 != r->control)
		return(0);
	else if ('\\' == cp[pos] && '.' == cp[pos + 1])
		pos += 2;
	else if ('.' == cp[pos] || '\'' == cp[pos])
		pos++;
	else
		return(0);

	while (' ' == cp[pos] || '\t' == cp[pos])
		pos++;

	*ppos = pos;
	return(1);
}