/* $OpenBSD: join.c,v 1.34 2022/12/04 23:50:48 cheloha Exp $    */

/*-
 * Copyright (c) 1991, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Steve Hayman of the Computer Science Department, Indiana University,
 * Michiro Hikida and David Goodenough.
 *
 * 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 <err.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>

/*
 * There's a structure per input file which encapsulates the state of the
 * file.  We repeatedly read lines from each file until we've read in all
 * the consecutive lines from the file with a common join field.  Then we
 * compare the set of lines with an equivalent set from the other file.
 */
typedef struct {
        char *line;                     /* line */
        size_t linealloc;               /* bytes allocated for line */
        char **fields;                  /* line field(s) */
        u_long fieldcnt;                /* line field(s) count */
        u_long fieldalloc;              /* line field(s) allocated count */
} LINE;

typedef struct {
        FILE *fp;                       /* file descriptor */
        u_long joinf;                   /* join field (-1, -2, -j) */
        int unpair;                     /* output unpairable lines (-a) */
        u_long number;                  /* 1 for file 1, 2 for file 2 */
        LINE *set;                      /* set of lines with same field */
        int pushbool;                   /* if pushback is set */
        u_long pushback;                /* line on the stack */
        u_long setcnt;                  /* set count */
        u_long setalloc;                /* set allocated count */
} INPUT;
INPUT input1 = { NULL, 0, 0, 1, NULL, 0, 0, 0, 0 },
      input2 = { NULL, 0, 0, 2, NULL, 0, 0, 0, 0 };

typedef struct {
        u_long  filenum;        /* file number */
        u_long  fieldno;        /* field number */
} OLIST;
OLIST *olist;                   /* output field list */
u_long olistcnt;                /* output field list count */
u_long olistalloc;              /* output field allocated count */

int joinout = 1;                /* show lines with matched join fields (-v) */
int needsep;                    /* need separator character */
int spans = 1;                  /* span multiple delimiters (-t) */
char *empty;                    /* empty field replacement string (-e) */
wchar_t tabchar[] = L" \t";     /* delimiter characters (-t) */

int  cmp(LINE *, u_long, LINE *, u_long);
void fieldarg(char *);
void joinlines(INPUT *, INPUT *);
char *mbssep(char **, const wchar_t *);
void obsolete(char **);
void outfield(LINE *, u_long, int);
void outoneline(INPUT *, LINE *);
void outtwoline(INPUT *, LINE *, INPUT *, LINE *);
void slurp(INPUT *);
void usage(void);

int
main(int argc, char *argv[])
{
        INPUT *F1, *F2;
        int aflag, ch, cval, vflag;
        char *end;

        setlocale(LC_CTYPE, "");

        if (pledge("stdio rpath", NULL) == -1)
                err(1, "pledge");

        F1 = &input1;
        F2 = &input2;

        aflag = vflag = 0;
        obsolete(argv);
        while ((ch = getopt(argc, argv, "\01a:e:j:1:2:o:t:v:")) != -1) {
                switch (ch) {
                case '\01':             /* See comment in obsolete(). */
                        aflag = 1;
                        F1->unpair = F2->unpair = 1;
                        break;
                case '1':
                        if ((F1->joinf = strtol(optarg, &end, 10)) < 1)
                                errx(1, "-1 option field number less than 1");
                        if (*end)
                                errx(1, "illegal field number -- %s", optarg);
                        --F1->joinf;
                        break;
                case '2':
                        if ((F2->joinf = strtol(optarg, &end, 10)) < 1)
                                errx(1, "-2 option field number less than 1");
                        if (*end)
                                errx(1, "illegal field number -- %s", optarg);
                        --F2->joinf;
                        break;
                case 'a':
                        aflag = 1;
                        switch(strtol(optarg, &end, 10)) {
                        case 1:
                                F1->unpair = 1;
                                break;
                        case 2:
                                F2->unpair = 1;
                                break;
                        default:
                                errx(1, "-a option file number not 1 or 2");
                                break;
                        }
                        if (*end)
                                errx(1, "illegal file number -- %s", optarg);
                        break;
                case 'e':
                        empty = optarg;
                        break;
                case 'j':
                        if ((F1->joinf = F2->joinf = strtol(optarg, &end, 10)) < 1)
                                errx(1, "-j option field number less than 1");
                        if (*end)
                                errx(1, "illegal field number -- %s", optarg);
                        --F1->joinf;
                        --F2->joinf;
                        break;
                case 'o':
                        fieldarg(optarg);
                        break;
                case 't':
                        spans = 0;
                        if (mbtowc(tabchar, optarg, MB_CUR_MAX) !=
                            strlen(optarg))
                                errx(1, "illegal tab character specification");
                        tabchar[1] = L'\0';
                        break;
                case 'v':
                        vflag = 1;
                        joinout = 0;
                        switch (strtol(optarg, &end, 10)) {
                        case 1:
                                F1->unpair = 1;
                                break;
                        case 2:
                                F2->unpair = 1;
                                break;
                        default:
                                errx(1, "-v option file number not 1 or 2");
                                break;
                        }
                        if (*end)
                                errx(1, "illegal file number -- %s", optarg);
                        break;
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        if (aflag && vflag)
                errx(1, "the -a and -v options are mutually exclusive");

        if (argc != 2)
                usage();

        /* Open the files; "-" means stdin. */
        if (!strcmp(*argv, "-"))
                F1->fp = stdin;
        else if ((F1->fp = fopen(*argv, "r")) == NULL)
                err(1, "%s", *argv);
        ++argv;
        if (!strcmp(*argv, "-"))
                F2->fp = stdin;
        else if ((F2->fp = fopen(*argv, "r")) == NULL)
                err(1, "%s", *argv);
        if (F1->fp == stdin && F2->fp == stdin)
                errx(1, "only one input file may be stdin");

        if (pledge("stdio", NULL) == -1)
                err(1, "pledge");

        slurp(F1);
        slurp(F2);

        /*
         * We try to let the files have the same field value, advancing
         * whoever falls behind and always advancing the file(s) we output
         * from.
        */
        while (F1->setcnt && F2->setcnt) {
                cval = cmp(F1->set, F1->joinf, F2->set, F2->joinf);
                if (cval == 0) {
                        /* Oh joy, oh rapture, oh beauty divine! */
                        if (joinout)
                                joinlines(F1, F2);
                        slurp(F1);
                        slurp(F2);
                } else if (cval < 0) {
                        /* File 1 takes the lead... */
                        if (F1->unpair)
                                joinlines(F1, NULL);
                        slurp(F1);
                } else {
                        /* File 2 takes the lead... */
                        if (F2->unpair)
                                joinlines(F2, NULL);
                        slurp(F2);
                }
        }

        /*
         * Now that one of the files is used up, optionally output any
         * remaining lines from the other file.
         */
        if (F1->unpair)
                while (F1->setcnt) {
                        joinlines(F1, NULL);
                        slurp(F1);
                }
        if (F2->unpair)
                while (F2->setcnt) {
                        joinlines(F2, NULL);
                        slurp(F2);
                }

        return 0;
}

void
slurp(INPUT *F)
{
        LINE *lp, *lastlp, tmp;
        ssize_t len;
        u_long cnt;
        char *bp, *fieldp;

        /*
         * Read all of the lines from an input file that have the same
         * join field.
         */

        F->setcnt = 0;
        for (lastlp = NULL; ; ++F->setcnt) {
                /*
                 * If we're out of space to hold line structures, allocate
                 * more.  Initialize the structure so that we know that this
                 * is new space.
                 */
                if (F->setcnt == F->setalloc) {
                        LINE *p;
                        u_long newsize = F->setalloc + 50;
                        cnt = F->setalloc;
                        if ((p = reallocarray(F->set, newsize, sizeof(LINE)))
                            == NULL)
                                err(1, NULL);
                        F->set = p;
                        F->setalloc = newsize;
                        memset(F->set + cnt, 0, 50 * sizeof(LINE));
                        /* re-set lastlp in case it moved */
                        if (lastlp != NULL)
                                lastlp = &F->set[F->setcnt - 1];
                }
                /*
                 * Get any pushed back line, else get the next line.  Allocate
                 * space as necessary.  If taking the line from the stack swap
                 * the two structures so that we don't lose space allocated to
                 * either structure.  This could be avoided by doing another
                 * level of indirection, but it's probably okay as is.
                 */
                lp = &F->set[F->setcnt];
                if (F->setcnt)
                        lastlp = &F->set[F->setcnt - 1];
                if (F->pushbool) {
                        tmp = F->set[F->setcnt];
                        F->set[F->setcnt] = F->set[F->pushback];
                        F->set[F->pushback] = tmp;
                        F->pushbool = 0;
                        continue;
                }
                if ((len = getline(&(lp->line), &(lp->linealloc), F->fp)) == -1)
                        break;

                /* Remove the trailing newline, if any. */
                if (lp->line[len - 1] == '\n')
                        lp->line[--len] = '\0';

                /* Split the line into fields, allocate space as necessary. */
                lp->fieldcnt = 0;
                bp = lp->line;
                while ((fieldp = mbssep(&bp, tabchar)) != NULL) {
                        if (spans && *fieldp == '\0')
                                continue;
                        if (lp->fieldcnt == lp->fieldalloc) {
                                char **p;
                                u_long newsize = lp->fieldalloc + 50;
                                if ((p = reallocarray(lp->fields, newsize,
                                    sizeof(char *))) == NULL)
                                        err(1, NULL);
                                lp->fields = p;
                                lp->fieldalloc = newsize;
                        }
                        lp->fields[lp->fieldcnt++] = fieldp;
                }

                /* See if the join field value has changed. */
                if (lastlp != NULL && cmp(lp, F->joinf, lastlp, F->joinf)) {
                        F->pushbool = 1;
                        F->pushback = F->setcnt;
                        break;
                }
        }
}

char *
mbssep(char **stringp, const wchar_t *wcdelim)
{
        char *s, *p;
        size_t ndelim;
        int i;
        /* tabchar is never more than 2 */
        char mbdelim[2][MB_LEN_MAX + 1];
        size_t mblen[2];

        if ((s = *stringp) == NULL)
                return NULL;
        ndelim = wcslen(wcdelim);
        for (i = 0; i < ndelim; i++) {
                /* wcdelim generated via mbtowc */
                mblen[i] = wctomb(mbdelim[i], wcdelim[i]);
        }
        for (p = s; *p != '\0'; p++) {
                for (i = 0; i < ndelim; i++) {
                        if (strncmp(p, mbdelim[i], mblen[i]) == 0) {
                                *p = '\0';
                                *stringp = p + mblen[i];
                                return s;
                        }
                }
        }
        *stringp = NULL;
        return s;
}

int
cmp(LINE *lp1, u_long fieldno1, LINE *lp2, u_long fieldno2)
{
        if (lp1->fieldcnt <= fieldno1)
                return lp2->fieldcnt <= fieldno2 ? 0 : -1;
        if (lp2->fieldcnt <= fieldno2)
                return 1;
        return strcmp(lp1->fields[fieldno1], lp2->fields[fieldno2]);
}

void
joinlines(INPUT *F1, INPUT *F2)
{
        u_long cnt1, cnt2;

        /*
         * Output the results of a join comparison.  The output may be from
         * either file 1 or file 2 (in which case the first argument is the
         * file from which to output) or from both.
         */
        if (F2 == NULL) {
                for (cnt1 = 0; cnt1 < F1->setcnt; ++cnt1)
                        outoneline(F1, &F1->set[cnt1]);
                return;
        }
        for (cnt1 = 0; cnt1 < F1->setcnt; ++cnt1)
                for (cnt2 = 0; cnt2 < F2->setcnt; ++cnt2)
                        outtwoline(F1, &F1->set[cnt1], F2, &F2->set[cnt2]);
}

void
outoneline(INPUT *F, LINE *lp)
{
        u_long cnt;

        /*
         * Output a single line from one of the files, according to the
         * join rules.  This happens when we are writing unmatched single
         * lines.  Output empty fields in the right places.
         */
        if (olist)
                for (cnt = 0; cnt < olistcnt; ++cnt) {
                        if (olist[cnt].filenum == F->number)
                                outfield(lp, olist[cnt].fieldno, 0);
                        else if (olist[cnt].filenum == 0)
                                outfield(lp, F->joinf, 0);
                        else
                                outfield(lp, 0, 1);
                }
        else {
                /*
                 * Output the join field, then the remaining fields from F
                 */
                outfield(lp, F->joinf, 0);
                for (cnt = 0; cnt < lp->fieldcnt; ++cnt)
                        if (F->joinf != cnt)
                                outfield(lp, cnt, 0);
        }

        putchar('\n');
        if (ferror(stdout))
                err(1, "stdout");
        needsep = 0;
}

void
outtwoline(INPUT *F1, LINE *lp1, INPUT *F2, LINE *lp2)
{
        u_long cnt;

        /* Output a pair of lines according to the join list (if any). */
        if (olist) {
                for (cnt = 0; cnt < olistcnt; ++cnt)
                        if (olist[cnt].filenum == 0) {
                                if (lp1->fieldcnt >= F1->joinf)
                                        outfield(lp1, F1->joinf, 0);
                                else
                                        outfield(lp2, F2->joinf, 0);
                        } else if (olist[cnt].filenum == 1)
                                outfield(lp1, olist[cnt].fieldno, 0);
                        else /* if (olist[cnt].filenum == 2) */
                                outfield(lp2, olist[cnt].fieldno, 0);
        } else {
                /*
                 * Output the join field, then the remaining fields from F1
                 * and F2.
                 */
                outfield(lp1, F1->joinf, 0);
                for (cnt = 0; cnt < lp1->fieldcnt; ++cnt)
                        if (F1->joinf != cnt)
                                outfield(lp1, cnt, 0);
                for (cnt = 0; cnt < lp2->fieldcnt; ++cnt)
                        if (F2->joinf != cnt)
                                outfield(lp2, cnt, 0);
        }
        putchar('\n');
        if (ferror(stdout))
                err(1, "stdout");
        needsep = 0;
}

void
outfield(LINE *lp, u_long fieldno, int out_empty)
{
        if (needsep++)
                putwchar(*tabchar);
        if (!ferror(stdout)) {
                if (lp->fieldcnt <= fieldno || out_empty) {
                        if (empty != NULL)
                                fputs(empty, stdout);
                } else {
                        if (*lp->fields[fieldno] == '\0')
                                return;
                        fputs(lp->fields[fieldno], stdout);
                }
        }
        if (ferror(stdout))
                err(1, "stdout");
}

/*
 * Convert an output list argument "2.1, 1.3, 2.4" into an array of output
 * fields.
 */
void
fieldarg(char *option)
{
        u_long fieldno, filenum;
        char *end, *token;

        while ((token = strsep(&option, ", \t")) != NULL) {
                if (*token == '\0')
                        continue;
                if (token[0] == '0')
                        filenum = fieldno = 0;
                else if ((token[0] == '1' || token[0] == '2') &&
                    token[1] == '.') {
                        filenum = token[0] - '0';
                        fieldno = strtol(token + 2, &end, 10);
                        if (*end)
                                errx(1, "malformed -o option field");
                        if (fieldno == 0)
                                errx(1, "field numbers are 1 based");
                        --fieldno;
                } else
                        errx(1, "malformed -o option field");
                if (olistcnt == olistalloc) {
                        OLIST *p;
                        u_long newsize = olistalloc + 50;
                        if ((p = reallocarray(olist, newsize, sizeof(OLIST)))
                            == NULL)
                                err(1, NULL);
                        olist = p;
                        olistalloc = newsize;
                }
                olist[olistcnt].filenum = filenum;
                olist[olistcnt].fieldno = fieldno;
                ++olistcnt;
        }
}

void
obsolete(char **argv)
{
        size_t len;
        char **p, *ap, *t;

        while ((ap = *++argv) != NULL) {
                /* Return if "--". */
                if (ap[0] == '-' && ap[1] == '-')
                        return;
                /* skip if not an option */
                if (ap[0] != '-')
                        continue;
                switch (ap[1]) {
                case 'a':
                        /*
                         * The original join allowed "-a", which meant the
                         * same as -a1 plus -a2.  POSIX 1003.2, Draft 11.2
                         * only specifies this as "-a 1" and "a -2", so we
                         * have to use another option flag, one that is
                         * unlikely to ever be used or accidentally entered
                         * on the command line.  (Well, we could reallocate
                         * the argv array, but that hardly seems worthwhile.)
                         */
                        if (ap[2] == '\0' && (argv[1] == NULL ||
                            (strcmp(argv[1], "1") != 0 &&
                            strcmp(argv[1], "2") != 0))) {
                                ap[1] = '\01';
                                warnx("-a option used without an argument; "
                                    "reverting to historical behavior");
                        }
                        break;
                case 'j':
                        /*
                         * The original join allowed "-j[12] arg" and "-j arg".
                         * Convert the former to "-[12] arg".  Don't convert
                         * the latter since getopt(3) can handle it.
                         */
                        switch(ap[2]) {
                        case '1':
                        case '2':
                                if (ap[3] != '\0')
                                        goto jbad;
                                ap[1] = ap[2];
                                ap[2] = '\0';
                                break;
                        case '\0':
                                break;
                        default:
jbad:                           warnx("unknown option -- %s", ap + 1);
                                usage();
                        }
                        break;
                case 'o':
                        /*
                         * The original join allowed "-o arg arg".
                         * Convert to "-o arg -o arg".
                         */
                        if (ap[2] != '\0' || argv[1] == NULL)
                                break;
                        for (p = argv + 2; *p != NULL; ++p) {
                                if (p[0][0] == '0' || ((p[0][0] != '1' &&
                                    p[0][0] != '2') || p[0][1] != '.'))
                                        break;
                                len = strlen(*p);
                                if (len - 2 != strspn(*p + 2, "0123456789"))
                                        break;
                                if ((t = malloc(len + 3)) == NULL)
                                        err(1, NULL);
                                t[0] = '-';
                                t[1] = 'o';
                                memmove(t + 2, *p, len + 1);
                                *p = t;
                        }
                        argv = p - 1;
                        break;
                }
        }
}

void
usage(void)
{
        int len;
        extern char *__progname;

        len = strlen(__progname) + sizeof("usage: ");
        (void)fprintf(stderr, "usage: %s [-1 field] [-2 field] "
            "[-a file_number | -v file_number] [-e string]\n"
            "%*s[-o list] [-t char] file1 file2\n",
            __progname, len, "");
        exit(1);
}