/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <ctype.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <time.h>
#include "pathnames.h"
#include "extern.h"

#define STANDARD 0
#define ALTERNATE 1

/*
 * Vfontedpr.
 *
 * Dave Presotto 1/12/81 (adapted from an earlier version by Bill Joy)
 *
 */

#define STRLEN 10               /* length of strings introducing things */
#define PNAMELEN 40             /* length of a function/procedure name */
#define PSMAX 20                /* size of procedure name stacking */

static int       iskw(char *);
static bool      isproc(char *);
static void      putKcp(char *, char *, bool);
static void      putScp(char *);
static void      putcp(int);
static int       tabs(char *, char *);
static int       width(char *, char *);

/*
 *      The state variables
 */

static bool     filter = false; /* act as a filter (like eqn) */
static bool     inchr;          /* in a string constant */
static bool     incomm;         /* in a comment of the primary type */
static bool     idx = false;    /* form an index */
static bool     instr;          /* in a string constant */
static bool     nokeyw = false; /* no keywords being flagged */
static bool     pass = false;   /*
                                 * when acting as a filter, pass indicates
                                 * whether we are currently processing
                                 * input.
                                 */

static int      blklevel;       /* current nesting level */
static int      comtype;        /* type of comment */
static char *   defsfile[2] = { _PATH_VGRINDEFS, 0 };
                                /* name of language definitions file */
static int      margin;
static int      plstack[PSMAX]; /* the procedure nesting level stack */
static char     pname[BUFSIZ+1];
static bool  prccont;   /* continue last procedure */
static int      psptr;          /* the stack index of the current procedure */
static char     pstack[PSMAX][PNAMELEN+1];      /* the procedure name stack */

/*
 *      The language specific globals
 */

char    *l_acmbeg;              /* string introducing a comment */
char    *l_acmend;              /* string ending a comment */
char    *l_blkbeg;              /* string beginning of a block */
char    *l_blkend;              /* string ending a block */
char    *l_chrbeg;              /* delimiter for character constant */
char    *l_chrend;              /* delimiter for character constant */
char    *l_combeg;              /* string introducing a comment */
char    *l_comend;              /* string ending a comment */
char     l_escape;              /* character used to  escape characters */
char    *l_keywds[BUFSIZ/2];    /* keyword table address */
char    *l_nocom;               /* regexp for non-comments */
char    *l_prcbeg;              /* regular expr for procedure begin */
char    *l_strbeg;              /* delimiter for string constant */
char    *l_strend;              /* delimiter for string constant */
bool     l_toplex;              /* procedures only defined at top lex level */
const char *language = "c";     /* the language indicator */

#define ps(x)   printf("%s", x)
static char minus[] = "-";
static char minusn[] = "-n";

int
main(int argc, char **argv)
{
    const char *fname = "";
    struct stat stbuf;
    char buf[BUFSIZ];
    char *defs;
    int needbp = 0;

    argc--, argv++;
    do {
        char *cp;
        int i;

        if (argc > 0) {
            if (!strcmp(argv[0], "-h")) {
                if (argc == 1) {
                    printf("'ds =H\n");
                    argc = 0;
                    goto rest;
                }
                printf("'ds =H %s\n", argv[1]);
                argc--, argv++;
                argc--, argv++;
                if (argc > 0)
                    continue;
                goto rest;
            }

            /* act as a filter like eqn */
            if (!strcmp(argv[0], "-f")) {
                filter = true;
                argv[0] = argv[argc-1];
                argv[argc-1] = minus;
                continue;
            }

            /* take input from the standard place */
            if (!strcmp(argv[0], "-")) {
                argc = 0;
                goto rest;
            }

            /* build an index */
            if (!strcmp(argv[0], "-x")) {
                idx = true;
                argv[0] = minusn;
            }

            /* indicate no keywords */
            if (!strcmp(argv[0], "-n")) {
                nokeyw = true;
                argc--, argv++;
                continue;
            }

            /* specify the font size */
            if (!strncmp(argv[0], "-s", 2)) {
                i = 0;
                cp = argv[0] + 2;
                while (*cp)
                    i = i * 10 + (*cp++ - '0');
                printf("'ps %d\n'vs %d\n", i, i+1);
                argc--, argv++;
                continue;
            }

            /* specify the language */
            if (!strncmp(argv[0], "-l", 2)) {
                language = argv[0]+2;
                argc--, argv++;
                continue;
            }

            /* specify the language description file */
            if (!strncmp(argv[0], "-d", 2)) {
                defsfile[0] = argv[1];
                argc--, argv++;
                argc--, argv++;
                continue;
            }

            /* open the file for input */
            if (freopen(argv[0], "r", stdin) == NULL)
                err(1, "%s", argv[0]);
            if (idx)
                printf("'ta 4i 4.25i 5.5iR\n'in .5i\n");
            fname = argv[0];
            argc--, argv++;
        }
    rest:

        /*
         *  get the  language definition from the defs file
         */
        i = cgetent(&defs, defsfile, language);
        if (i == -1) {
            fprintf (stderr, "no entry for language %s\n", language);
            exit(0);
        } else  if (i == -2) { fprintf(stderr,
            "cannot find vgrindefs file %s\n", defsfile[0]);
            exit(0);
        } else if (i == -3) { fprintf(stderr,
            "potential reference loop detected in vgrindefs file %s\n",
            defsfile[0]);
            exit(0);
        }
        if (cgetustr(defs, "kw", &cp) == -1)
            nokeyw = true;
        else  {
            char **cpp;

            cpp = l_keywds;
            while (*cp) {
                while (*cp == ' ' || *cp =='\t')
                    *cp++ = '\0';
                if (*cp)
                    *cpp++ = cp;
                while (*cp != ' ' && *cp  != '\t' && *cp)
                    cp++;
            }
            *cpp = NULL;
        }
        cgetustr(defs, "pb", &cp);
        l_prcbeg = convexp(cp);
        cgetustr(defs, "cb", &cp);
        l_combeg = convexp(cp);
        cgetustr(defs, "ce", &cp);
        l_comend = convexp(cp);
        cgetustr(defs, "ab", &cp);
        l_acmbeg = convexp(cp);
        cgetustr(defs, "ae", &cp);
        l_acmend = convexp(cp);
        cgetustr(defs, "sb", &cp);
        l_strbeg = convexp(cp);
        cgetustr(defs, "se", &cp);
        l_strend = convexp(cp);
        cgetustr(defs, "bb", &cp);
        l_blkbeg = convexp(cp);
        cgetustr(defs, "be", &cp);
        l_blkend = convexp(cp);
        cgetustr(defs, "lb", &cp);
        l_chrbeg = convexp(cp);
        cgetustr(defs, "le", &cp);
        l_chrend = convexp(cp);
        if (cgetustr(defs, "nc", &cp) >= 0)
                l_nocom = convexp(cp);
        l_escape = '\\';
        l_onecase = (cgetcap(defs, "oc", ':') != NULL);
        l_toplex = (cgetcap(defs, "tl", ':') != NULL);

        /* initialize the program */

        incomm = false;
        instr = false;
        inchr = false;
        _escaped = false;
        blklevel = 0;
        for (psptr=0; psptr<PSMAX; psptr++) {
            pstack[psptr][0] = '\0';
            plstack[psptr] = 0;
        }
        psptr = -1;
        ps("'-F\n");
        if (!filter) {
            printf(".ds =F %s\n", fname);
            ps("'wh 0 vH\n");
            ps("'wh -1i vF\n");
        }
        if (needbp) {
            needbp = 0;
            printf(".()\n");
            printf(".bp\n");
        }
        if (!filter) {
            fstat(fileno(stdin), &stbuf);
            cp = ctime(&stbuf.st_mtime);
            cp[16] = '\0';
            cp[24] = '\0';
            printf(".ds =M %s %s\n", cp+4, cp+20);
        }

        /*
         *      MAIN LOOP!!!
         */
        while (fgets(buf, sizeof buf, stdin) != NULL) {
            if (buf[0] == '\f') {
                printf(".bp\n");
            }
            if (buf[0] == '.') {
                printf("%s", buf);
                if (!strncmp (buf+1, "vS", 2))
                    pass = true;
                if (!strncmp (buf+1, "vE", 2))
                    pass = false;
                continue;
            }
            prccont = false;
            if (!filter || pass)
                putScp(buf);
            else
                printf("%s", buf);
            if (prccont && (psptr >= 0)) {
                ps("'FC ");
                ps(pstack[psptr]);
                ps("\n");
            }
#ifdef DEBUG
            printf ("com %o str %o chr %o ptr %d\n", incomm, instr, inchr, psptr);
#endif
            margin = 0;
        }
        needbp = 1;
    } while (argc > 0);
    exit(0);
}

#define isidchr(c) (isalnum(c) || (c) == '_')

static void
putScp(char *os)
{
    register char *s = os;              /* pointer to unmatched string */
    char dummy[BUFSIZ];                 /* dummy to be used by expmatch */
    char *comptr;                       /* end of a comment delimiter */
    char *acmptr;                       /* end of a comment delimiter */
    char *strptr;                       /* end of a string delimiter */
    char *chrptr;                       /* end of a character const delimiter */
    char *blksptr;                      /* end of a lexical block start */
    char *blkeptr;                      /* end of a lexical block end */
    char *nocomptr;                     /* end of a non-comment delimiter */

    s_start = os;                       /* remember the start for expmatch */
    _escaped = false;
    if (nokeyw || incomm || instr)
        goto skip;
    if (isproc(s)) {
        ps("'FN ");
        ps(pname);
        ps("\n");
        if (psptr < PSMAX) {
            ++psptr;
            strncpy (pstack[psptr], pname, PNAMELEN);
            pstack[psptr][PNAMELEN] = '\0';
            plstack[psptr] = blklevel;
        }
    }
skip:
    do {
        /* check for string, comment, blockstart, etc */
        if (!incomm && !instr && !inchr) {

            blkeptr = expmatch(s, l_blkend, dummy);
            blksptr = expmatch(s, l_blkbeg, dummy);
            comptr = expmatch(s, l_combeg, dummy);
            acmptr = expmatch(s, l_acmbeg, dummy);
            strptr = expmatch(s, l_strbeg, dummy);
            chrptr = expmatch(s, l_chrbeg, dummy);
            nocomptr = expmatch (s, l_nocom, dummy);

            /* start of non-comment? */
            if (nocomptr != NULL)
                if ((nocomptr <= comptr || comptr == NULL)
                  && (nocomptr <= acmptr || acmptr == NULL)) {
                    /* continue after non-comment */
                    putKcp (s, nocomptr-1, false);
                    s = nocomptr;
                    continue;
                }

            /* start of a comment? */
            if (comptr != NULL)
                if ((comptr < strptr || strptr == NULL)
                  && (comptr < acmptr || acmptr == NULL)
                  && (comptr < chrptr || chrptr == NULL)
                  && (comptr < blksptr || blksptr == NULL)
                  && (comptr < blkeptr || blkeptr == NULL)) {
                    putKcp(s, comptr-1, false);
                    s = comptr;
                    incomm = true;
                    comtype = STANDARD;
                    if (s != os)
                        ps("\\c");
                    ps("\\c\n'+C\n");
                    continue;
                }

            /* start of a comment? */
            if (acmptr != NULL)
                if ((acmptr < strptr || strptr == NULL)
                  && (acmptr < chrptr || chrptr == NULL)
                  && (acmptr < blksptr || blksptr == NULL)
                  && (acmptr < blkeptr || blkeptr == NULL)) {
                    putKcp(s, acmptr-1, false);
                    s = acmptr;
                    incomm = true;
                    comtype = ALTERNATE;
                    if (s != os)
                        ps("\\c");
                    ps("\\c\n'+C\n");
                    continue;
                }

            /* start of a string? */
            if (strptr != NULL)
                if ((strptr < chrptr || chrptr == NULL)
                  && (strptr < blksptr || blksptr == NULL)
                  && (strptr < blkeptr || blkeptr == NULL)) {
                    putKcp(s, strptr-1, false);
                    s = strptr;
                    instr = true;
                    continue;
                }

            /* start of a character string? */
            if (chrptr != NULL)
                if ((chrptr < blksptr || blksptr == NULL)
                  && (chrptr < blkeptr || blkeptr == NULL)) {
                    putKcp(s, chrptr-1, false);
                    s = chrptr;
                    inchr = true;
                    continue;
                }

            /* end of a lexical block */
            if (blkeptr != NULL) {
                if (blkeptr < blksptr || blksptr == NULL) {
                    putKcp(s, blkeptr - 1, false);
                    s = blkeptr;
                    if (blklevel > 0 /* sanity */)
                            blklevel--;
                    if (psptr >= 0 && plstack[psptr] >= blklevel) {

                        /* end of current procedure */
                        if (s != os)
                            ps("\\c");
                        ps("\\c\n'-F\n");
                        blklevel = plstack[psptr];

                        /* see if we should print the last proc name */
                        if (--psptr >= 0)
                            prccont = true;
                        else
                            psptr = -1;
                    }
                    continue;
                }
            }

            /* start of a lexical block */
            if (blksptr != NULL) {
                putKcp(s, blksptr - 1, false);
                s = blksptr;
                blklevel++;
                continue;
            }

        /* check for end of comment */
        } else if (incomm) {
            comptr = expmatch(s, l_comend, dummy);
            acmptr = expmatch(s, l_acmend, dummy);
            if (((comtype == STANDARD) && (comptr != NULL)) ||
                ((comtype == ALTERNATE) && (acmptr != NULL))) {
                if (comtype == STANDARD) {
                    putKcp(s, comptr-1, true);
                    s = comptr;
                } else {
                    putKcp(s, acmptr-1, true);
                    s = acmptr;
                }
                incomm = false;
                ps("\\c\n'-C\n");
                continue;
            } else {
                putKcp(s, s + strlen(s) -1, true);
                s = s + strlen(s);
                continue;
            }

        /* check for end of string */
        } else if (instr) {
            if ((strptr = expmatch(s, l_strend, dummy)) != NULL) {
                putKcp(s, strptr-1, true);
                s = strptr;
                instr = false;
                continue;
            } else {
                putKcp(s, s+strlen(s)-1, true);
                s = s + strlen(s);
                continue;
            }

        /* check for end of character string */
        } else if (inchr) {
            if ((chrptr = expmatch(s, l_chrend, dummy)) != NULL) {
                putKcp(s, chrptr-1, true);
                s = chrptr;
                inchr = false;
                continue;
            } else {
                putKcp(s, s+strlen(s)-1, true);
                s = s + strlen(s);
                continue;
            }
        }

        /* print out the line */
        putKcp(s, s + strlen(s) -1, false);
        s = s + strlen(s);
    } while (*s);
}

/*
 * start: start of string to write
 * end: end of string to write
 * force: true if we should force nokeyw
 */
static void
putKcp(char *start, char *end, bool force)
{
    int i;
    int xfld = 0;

    while (start <= end) {
        if (idx) {
            if (*start == ' ' || *start == '\t') {
                if (xfld == 0)
                    printf("\001");
                printf("\t");
                xfld = 1;
                while (*start == ' ' || *start == '\t')
                    start++;
                continue;
            }
        }

        /* take care of nice tab stops */
        if (*start == '\t') {
            while (*start == '\t')
                start++;
            i = tabs(s_start, start) - margin / 8;
            printf("\\h'|%dn'", i * 10 + 1 - margin % 8);
            continue;
        }

        if (!nokeyw && !force)
            if ((*start == '#' || isidchr(*start))
            && (start == s_start || !isidchr(start[-1]))) {
                i = iskw(start);
                if (i > 0) {
                    ps("\\*(+K");
                    do
                        putcp((unsigned char)*start++);
                    while (--i > 0);
                    ps("\\*(-K");
                    continue;
                }
            }

        putcp((unsigned char)*start++);
    }
}


static int
tabs(char *s, char *os)
{

    return (width(s, os) / 8);
}

static int
width(register char *s, register char *os)
{
        register int i = 0;

        while (s < os) {
                if (*s == '\t') {
                        i = (i + 8) &~ 7;
                        s++;
                        continue;
                }
                if (*s < ' ')
                        i += 2;
                else
                        i++;
                s++;
        }
        return (i);
}

static void
putcp(register int c)
{

        switch(c) {

        case 0:
                break;

        case '\f':
                break;

        case '\r':
                break;

        case '{':
                ps("\\*(+K{\\*(-K");
                break;

        case '}':
                ps("\\*(+K}\\*(-K");
                break;

        case '\\':
                ps("\\e");
                break;

        case '_':
                ps("\\*_");
                break;

        case '-':
                ps("\\*-");
                break;

        case '`':
                ps("\\`");
                break;

        case '\'':
                ps("\\'");
                break;

        case '.':
                ps("\\&.");
                break;

        case '*':
                ps("\\fI*\\fP");
                break;

        case '/':
                ps("\\fI\\h'\\w' 'u-\\w'/'u'/\\fP");
                break;

        default:
                if (c < 040)
                        putchar('^'), c |= '@';
        case '\t':
        case '\n':
                putchar(c);
        }
}

/*
 *      look for a process beginning on this line
 */
static bool
isproc(char *s)
{
    pname[0] = '\0';
    if (!l_toplex || blklevel == 0)
        if (expmatch(s, l_prcbeg, pname) != NULL) {
            return (true);
        }
    return (false);
}


/*  iskw -      check to see if the next word is a keyword
 */

static int
iskw(register char *s)
{
        register char **ss = l_keywds;
        register int i = 1;
        register char *cp = s;

        while (++cp, isidchr(*cp))
                i++;
        while ((cp = *ss++))
                if (!STRNCMP(s,cp,i) && !isidchr(cp[i]))
                        return (i);
        return (0);
}