/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */


/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved. The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Copyright (c) 2018, Joyent, Inc.
 */

/*
 * checknr: check an nroff/troff input file for matching macro calls.
 * we also attempt to match size and font changes, but only the embedded
 * kind.  These must end in \s0 and \fP resp.  Maybe more sophistication
 * later but for now think of these restrictions as contributions to
 * structured typesetting.
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <locale.h>

#define MAXSTK  100     /* Stack size */
static  int     maxstk;
#define MAXBR   100     /* Max number of bracket pairs known */
#define MAXCMDS 500     /* Max number of commands known */

/*
 * The stack on which we remember what we've seen so far.
 */
static struct stkstr {
        int opno;       /* number of opening bracket */
        int pl;         /* '+', '-', ' ' for \s, 1 for \f, 0 for .ft */
        int parm;       /* parm to size, font, etc */
        int lno;        /* line number the thing came in in */
} *stk;
static int stktop;

/*
 * The kinds of opening and closing brackets.
 */
static struct brstr {
        char *opbr;
        char *clbr;
} br[MAXBR] = {
        /* A few bare bones troff commands */
#define SZ      0
        "sz",   "sz",   /* also \s */
#define FT      1
        "ft",   "ft",   /* also \f */
        /* the -mm package */
        "AL",   "LE",
        "AS",   "AE",
        "BL",   "LE",
        "BS",   "BE",
        "DF",   "DE",
        "DL",   "LE",
        "DS",   "DE",
        "FS",   "FE",
        "ML",   "LE",
        "NS",   "NE",
        "RL",   "LE",
        "VL",   "LE",
        /* the -ms package */
        "AB",   "AE",
        "BD",   "DE",
        "CD",   "DE",
        "DS",   "DE",
        "FS",   "FE",
        "ID",   "DE",
        "KF",   "KE",
        "KS",   "KE",
        "LD",   "DE",
        "LG",   "NL",
        "QS",   "QE",
        "RS",   "RE",
        "SM",   "NL",
        "XA",   "XE",
        "XS",   "XE",
        /* The -me package */
        "(b",   ")b",
        "(c",   ")c",
        "(d",   ")d",
        "(f",   ")f",
        "(l",   ")l",
        "(q",   ")q",
        "(x",   ")x",
        "(z",   ")z",
        /* Things needed by preprocessors */
        "EQ",   "EN",
        "TS",   "TE",
        /* Refer */
        "[",    "]",
        0,      0
};

/*
 * All commands known to nroff, plus macro packages.
 * Used so we can complain about unrecognized commands.
 */
static char *knowncmds[MAXCMDS] = {
"$c", "$f", "$h", "$p", "$s", "(b", "(c", "(d", "(f", "(l", "(q", "(t",
"(x", "(z", ")b", ")c", ")d", ")f", ")l", ")q", ")t", ")x", ")z", "++",
"+c", "1C", "1c", "2C", "2c", "@(", "@)", "@C", "@D", "@F", "@I", "@M",
"@c", "@e", "@f", "@h", "@m", "@n", "@o", "@p", "@r", "@t", "@z", "AB",
"AE", "AF", "AI", "AL", "AM", "AS", "AT", "AU", "AX", "B",  "B1", "B2",
"BD", "BE", "BG", "BL", "BS", "BT", "BX", "C1", "C2", "CD", "CM", "CT",
"D",  "DA", "DE", "DF", "DL", "DS", "DT", "EC", "EF", "EG", "EH", "EM",
"EN", "EQ", "EX", "FA", "FD", "FE", "FG", "FJ", "FK", "FL", "FN", "FO",
"FQ", "FS", "FV", "FX", "H",  "HC", "HD", "HM", "HO", "HU", "I",  "ID",
"IE", "IH", "IM", "IP", "IX", "IZ", "KD", "KE", "KF", "KQ", "KS", "LB",
"LC", "LD", "LE", "LG", "LI", "LP", "MC", "ME", "MF", "MH", "ML", "MR",
"MT", "ND", "NE", "NH", "NL", "NP", "NS", "OF", "OH", "OK", "OP", "P",
"P1", "PF", "PH", "PP", "PT", "PX", "PY", "QE", "QP", "QS", "R",  "RA",
"RC", "RE", "RL", "RP", "RQ", "RS", "RT", "S",  "S0", "S2", "S3", "SA",
"SG", "SH", "SK", "SM", "SP", "SY", "T&", "TA", "TB", "TC", "TD", "TE",
"TH", "TL", "TM", "TP", "TQ", "TR", "TS", "TX", "UL", "US", "UX", "VL",
"WC", "WH", "XA", "XD", "XE", "XF", "XK", "XP", "XS", "[",  "[-", "[0",
"[1", "[2", "[3", "[4", "[5", "[<", "[>", "[]", "]",  "]-", "]<", "]>",
"][", "ab", "ac", "ad", "af", "am", "ar", "as", "b",  "ba", "bc", "bd",
"bi", "bl", "bp", "br", "bx", "c.", "c2", "cc", "ce", "cf", "ch", "cs",
"ct", "cu", "da", "de", "di", "dl", "dn", "ds", "dt", "dw", "dy", "ec",
"ef", "eh", "el", "em", "eo", "ep", "ev", "ex", "fc", "fi", "fl", "fo",
"fp", "ft", "fz", "hc", "he", "hl", "hp", "ht", "hw", "hx", "hy", "i",
"ie", "if", "ig", "in", "ip", "it", "ix", "lc", "lg", "li", "ll", "ln",
"lo", "lp", "ls", "lt", "m1", "m2", "m3", "m4", "mc", "mk", "mo", "n1",
"n2", "na", "ne", "nf", "nh", "nl", "nm", "nn", "np", "nr", "ns", "nx",
"of", "oh", "os", "pa", "pc", "pi", "pl", "pm", "pn", "po", "pp", "ps",
"q",  "r",  "rb", "rd", "re", "rm", "rn", "ro", "rr", "rs", "rt", "sb",
"sc", "sh", "sk", "so", "sp", "ss", "st", "sv", "sz", "ta", "tc", "th",
"ti", "tl", "tm", "tp", "tr", "u",  "uf", "uh", "ul", "vs", "wh", "xp",
"yr", 0
};

static  int     lineno;         /* current line number in input file */
static  char    line[256];      /* the current line */
static  char    *cfilename;     /* name of current file */
static  int     nfiles;         /* number of files to process */
static  int     fflag;          /* -f: ignore \f */
static  int     sflag;          /* -s: ignore \s */
static  int     ncmds;          /* size of knowncmds */
static  int     slot;           /* slot in knowncmds found by binsrch */

static void growstk();
static void usage();
static void process(FILE *f);
static void complain(int i);
static void prop(int i);
static void chkcmd(char *line, char *mac);
static void nomatch(char *mac);
static int eq(char *s1, char *s2);
static void pe(int lineno);
static void checkknown(char *mac);
static void addcmd(char *line);
static void addmac(char *mac);
static int binsrch(char *mac);

static void
growstk()
{
        stktop++;
        if (stktop >= maxstk) {
                maxstk *= 2;
                stk = (struct stkstr *)realloc(stk,
                    sizeof (struct stkstr) * maxstk);
        }
}

int
main(argc, argv)
int argc;
char **argv;
{
        FILE *f;
        int i;
        char *cp;
        char b1[4];

        (void) setlocale(LC_ALL, "");
#if !defined(TEXT_DOMAIN)
#define TEXT_DOMAIN     "SYS_TEST"
#endif
        (void) textdomain(TEXT_DOMAIN);
        stk = (struct stkstr *)calloc(100, sizeof (struct stkstr));
        maxstk = 100;
        /* Figure out how many known commands there are */
        while (knowncmds[ncmds])
                ncmds++;
        while (argc > 1 && argv[1][0] == '-') {
                switch (argv[1][1]) {

                /* -a: add pairs of macros */
                case 'a':
                        i = strlen(argv[1]) - 2;
                        if (i % 6 != 0)
                                usage();
                        /* look for empty macro slots */
                        for (i = 0; br[i].opbr; i++)
                                ;
                        for (cp = argv[1]+3; cp[-1]; cp += 6) {
                                br[i].opbr = malloc(3);
                                (void) strncpy(br[i].opbr, cp, 2);
                                br[i].clbr = malloc(3);
                                (void) strncpy(br[i].clbr, cp+3, 2);
                                /* knows pairs are also known cmds */
                                addmac(br[i].opbr);
                                addmac(br[i].clbr);
                                i++;
                        }
                        break;

                /* -c: add known commands */
                case 'c':
                        i = strlen(argv[1]) - 2;
                        if (i % 3 != 0)
                                usage();
                        for (cp = argv[1]+3; cp[-1]; cp += 3) {
                                if (cp[2] && cp[2] != '.')
                                        usage();
                                (void) strncpy(b1, cp, 2);
                                addmac(b1);
                        }
                        break;

                /* -f: ignore font changes */
                case 'f':
                        fflag = 1;
                        break;

                /* -s: ignore size changes */
                case 's':
                        sflag = 1;
                        break;
                default:
                        usage();
                }
                argc--; argv++;
        }

        nfiles = argc - 1;

        if (nfiles > 0) {
                for (i = 1; i < argc; i++) {
                        cfilename = argv[i];
                        f = fopen(cfilename, "r");
                        if (f == NULL) {
                                perror(cfilename);
                                exit(1);
                                }
                        else
                                process(f);
                }
        } else {
                cfilename = "stdin";
                process(stdin);
        }
        return (0);
}

static void
usage()
{
        (void) printf(gettext("Usage: \
checknr [ -fs ] [ -a.xx.yy.xx.yy...] [-c.xx.xx.xx...] [ filename .. ]\n"));
        exit(1);
}

static void
process(FILE *f)
{
        int i, n;
        char mac[5];    /* The current macro or nroff command */
        int pl;

        stktop = -1;
        for (lineno = 1; fgets(line, sizeof (line), f); lineno++) {
                if (line[0] == '.') {
                        /*
                         * find and isolate the macro/command name.
                         */
                        (void) strncpy(mac, line+1, 4);
                        if (isspace(mac[0])) {
                                pe(lineno);
                                (void) printf(gettext("Empty command\n"));
                        } else if (isspace(mac[1])) {
                                mac[1] = 0;
                        } else if (isspace(mac[2])) {
                                mac[2] = 0;
                        } else if (mac[0] != '\\' || mac[1] != '\"') {
                                pe(lineno);
                                (void) printf(gettext("Command too long\n"));
                        }

                        /*
                         * Is it a known command?
                         */
                        checkknown(mac);

                        /*
                         * Should we add it?
                         */
                        if (eq(mac, "de"))
                                addcmd(line);

                        chkcmd(line, mac);
                }

                /*
                 * At this point we process the line looking
                 * for \s and \f.
                 */
                for (i = 0; line[i]; i++)
                        if (line[i] == '\\' && (i == 0 || line[i-1] != '\\')) {
                                if (!sflag && line[++i] == 's') {
                                        pl = line[++i];
                                        if (isdigit(pl)) {
                                                n = pl - '0';
                                                pl = ' ';
                                        } else
                                                n = 0;
                                        while (isdigit(line[++i]))
                                                n = 10 * n + line[i] - '0';
                                        i--;
                                        if (n == 0) {
                                                if (stk[stktop].opno == SZ) {
                                                        stktop--;
                                                } else {
                                                        pe(lineno);
                                                        (void) printf(
                                                gettext("unmatched \\s0\n"));
                                                }
                                        } else {
                                                growstk();
                                                stk[stktop].opno = SZ;
                                                stk[stktop].pl = pl;
                                                stk[stktop].parm = n;
                                                stk[stktop].lno = lineno;
                                        }
                                } else if (!fflag && line[i] == 'f') {
                                        n = line[++i];
                                        if (n == 'P') {
                                                if (stk[stktop].opno == FT) {
                                                        stktop--;
                                                } else {
                                                        pe(lineno);
                                                        (void) printf(
                                                gettext("unmatched \\fP\n"));
                                                }
                                        } else {
                                                growstk();
                                                stk[stktop].opno = FT;
                                                stk[stktop].pl = 1;
                                                stk[stktop].parm = n;
                                                stk[stktop].lno = lineno;
                                        }
                                }
                        }
        }
        /*
         * We've hit the end and look at all this stuff that hasn't been
         * matched yet!  Complain, complain.
         */
        for (i = stktop; i >= 0; i--) {
                complain(i);
        }
}

static void
complain(int i)
{
        pe(stk[i].lno);
        (void) printf(gettext("Unmatched "));
        prop(i);
        (void) printf("\n");
}

static void
prop(int i)
{
        if (stk[i].pl == 0)
                (void) printf(".%s", br[stk[i].opno].opbr);
        else switch (stk[i].opno) {
        case SZ:
                (void) printf("\\s%c%d", stk[i].pl, stk[i].parm);
                break;
        case FT:
                (void) printf("\\f%c", stk[i].parm);
                break;
        default:
                (void) printf(gettext("Bug: stk[%d].opno = %d = .%s, .%s"),
                        i, stk[i].opno, br[stk[i].opno].opbr,
                        br[stk[i].opno].clbr);
        }
}

/* ARGSUSED */
static void
chkcmd(char *line, char *mac)
{
        int i;

        /*
         * Check to see if it matches top of stack.
         */
        if (stktop >= 0 && eq(mac, br[stk[stktop].opno].clbr))
                stktop--;       /* OK. Pop & forget */
        else {
                /* No. Maybe it's an opener */
                for (i = 0; br[i].opbr; i++) {
                        if (eq(mac, br[i].opbr)) {
                                /* Found. Push it. */
                                growstk();
                                stk[stktop].opno = i;
                                stk[stktop].pl = 0;
                                stk[stktop].parm = 0;
                                stk[stktop].lno = lineno;
                                break;
                        }
                        /*
                         * Maybe it's an unmatched closer.
                         * NOTE: this depends on the fact
                         * that none of the closers can be
                         * openers too.
                         */
                        if (eq(mac, br[i].clbr)) {
                                nomatch(mac);
                                break;
                        }
                }
        }
}

static void
nomatch(char *mac)
{
        int i, j;

        /*
         * Look for a match further down on stack
         * If we find one, it suggests that the stuff in
         * between is supposed to match itself.
         */
        for (j = stktop; j >= 0; j--)
                if (eq(mac, br[stk[j].opno].clbr)) {
                        /* Found.  Make a good diagnostic. */
                        if (j == stktop-2) {
                                /*
                                 * Check for special case \fx..\fR and don't
                                 * complain.
                                 */
                                if (stk[j+1].opno == FT &&
                                    stk[j+1].parm != 'R' &&
                                    stk[j+2].opno == FT &&
                                    stk[j+2].parm == 'R') {
                                        stktop = j -1;
                                        return;
                                }
                                /*
                                 * We have two unmatched frobs.  Chances are
                                 * they were intended to match, so we mention
                                 * them together.
                                 */
                                pe(stk[j+1].lno);
                                prop(j+1);
                                (void) printf(gettext(" does not match %d: "),
                                        stk[j+2].lno);
                                prop(j+2);
                                (void) printf("\n");
                        } else for (i = j+1; i <= stktop; i++) {
                                complain(i);
                        }
                        stktop = j-1;
                        return;
                }
        /* Didn't find one.  Throw this away. */
        pe(lineno);
        (void) printf(gettext("Unmatched .%s\n"), mac);
}

/* eq: are two strings equal? */
static int
eq(char *s1, char *s2)
{
        return (strcmp(s1, s2) == 0);
}

/* print the first part of an error message, given the line number */
static void
pe(int lineno)
{
        if (nfiles > 1)
                (void) printf("%s: ", cfilename);
        (void) printf("%d: ", lineno);
}

static void
checkknown(char *mac)
{

        if (eq(mac, "."))
                return;
        if (binsrch(mac) >= 0)
                return;
        if (mac[0] == '\\' && mac[1] == '"')    /* comments */
                return;

        pe(lineno);
        (void) printf(gettext("Unknown command: .%s\n"), mac);
}

/*
 * We have a .de xx line in "line".  Add xx to the list of known commands.
 */
static void
addcmd(char *line)
{
        char *mac;

        /* grab the macro being defined */
        mac = line+4;
        while (isspace(*mac))
                mac++;
        if (*mac == 0) {
                pe(lineno);
                (void) printf(gettext("illegal define: %s\n"), line);
                return;
        }
        mac[2] = 0;
        if (isspace(mac[1]) || mac[1] == '\\')
                mac[1] = 0;
        if (ncmds >= MAXCMDS) {
                (void) printf(gettext("Only %d known commands allowed\n"),
                    MAXCMDS);
                exit(1);
        }
        addmac(mac);
}

/*
 * Add mac to the list.  We should really have some kind of tree
 * structure here but this is a quick-and-dirty job and I just don't
 * have time to mess with it.  (I wonder if this will come back to haunt
 * me someday?)  Anyway, I claim that .de is fairly rare in user
 * nroff programs, and the loop below is pretty fast.
 */
static void
addmac(char *mac)
{
        char **src, **dest, **loc;

        if (binsrch(mac) >= 0) {        /* it's OK to redefine something */
#ifdef DEBUG
                (void) printf("binsrch(%s) -> already in table\n", mac);
#endif
                return;
        }
        /* binsrch sets slot as a side effect */
#ifdef DEBUG
printf("binsrch(%s) -> %d\n", mac, slot);
#endif
        loc = &knowncmds[slot];
        src = &knowncmds[ncmds-1];
        dest = src+1;
        while (dest > loc)
                *dest-- = *src--;
        *loc = malloc(3);
        (void) strcpy(*loc, mac);
        ncmds++;
#ifdef DEBUG
        (void) printf("after: %s %s %s %s %s, %d cmds\n",
            knowncmds[slot-2], knowncmds[slot-1], knowncmds[slot],
            knowncmds[slot+1], knowncmds[slot+2], ncmds);
#endif
}

/*
 * Do a binary search in knowncmds for mac.
 * If found, return the index.  If not, return -1.
 */
static int
binsrch(char *mac)
{
        char *p;        /* pointer to current cmd in list */
        int d;          /* difference if any */
        int mid;        /* mid point in binary search */
        int top, bot;   /* boundaries of bin search, inclusive */

        top = ncmds-1;
        bot = 0;
        while (top >= bot) {
                mid = (top+bot)/2;
                p = knowncmds[mid];
                d = p[0] - mac[0];
                if (d == 0)
                        d = p[1] - mac[1];
                if (d == 0)
                        return (mid);
                if (d < 0)
                        bot = mid + 1;
                else
                        top = mid - 1;
        }
        slot = bot;     /* place it would have gone */
        return (-1);
}