/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 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.
 */

/*
 * jot - print sequential or random data
 *
 * Author:  John Kunze, Office of Comp. Affairs, UCB
 */

#include <sys/capsicum.h>
#include <capsicum_helpers.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

/* Defaults */
#define REPS_DEF        100
#define BEGIN_DEF       1
#define ENDER_DEF       100
#define STEP_DEF        1

/* Flags of options that have been set */
#define HAVE_STEP       1
#define HAVE_ENDER      2
#define HAVE_BEGIN      4
#define HAVE_REPS       8

#define is_default(s)   (*(s) == 0 || strcmp((s), "-") == 0)

static bool     boring;
static int      prec = -1;
static bool     longdata;
static bool     intdata;
static bool     chardata;
static bool     nosign;
static const    char *sepstring = "\n";
static char     format[BUFSIZ];

static void     getformat(void);
static int      getprec(const char *);
static int      putdata(double, bool);
static void     usage(void);

int
main(int argc, char **argv)
{
        cap_rights_t rights;
        bool    have_format = false;
        bool    infinity = false;
        bool    nofinalnl = false;
        bool    randomize = false;
        bool    use_random = false;
        int     ch;
        int     mask = 0;
        int     n = 0;
        double  begin = BEGIN_DEF;
        double  divisor;
        double  ender = ENDER_DEF;
        double  s = STEP_DEF;
        double  x, y;
        long    i;
        long    reps = REPS_DEF;

        if (caph_limit_stdio() < 0)
                err(1, "unable to limit rights for stdio");
        cap_rights_init(&rights);
        if (caph_rights_limit(STDIN_FILENO, &rights) < 0)
                err(1, "unable to limit rights for stdin");

        /*
         * Cache NLS data, for strerror, for err(3), before entering capability
         * mode.
         */
        caph_cache_catpages();

        if (caph_enter() < 0)
                err(1, "unable to enter capability mode");

        while ((ch = getopt(argc, argv, "b:cnp:rs:w:")) != -1)
                switch (ch) {
                case 'b':
                        boring = true;
                        /* FALLTHROUGH */
                case 'w':
                        if (strlcpy(format, optarg, sizeof(format)) >=
                            sizeof(format))
                                errx(1, "-%c word too long", ch);
                        have_format = true;
                        break;
                case 'c':
                        chardata = true;
                        break;
                case 'n':
                        nofinalnl = true;
                        break;
                case 'p':
                        prec = atoi(optarg);
                        if (prec < 0)
                                errx(1, "bad precision value");
                        have_format = true;
                        break;
                case 'r':
                        randomize = true;
                        break;
                case 's':
                        sepstring = optarg;
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        switch (argc) { /* examine args right to left, falling thru cases */
        case 4:
                if (!is_default(argv[3])) {
                        if (!sscanf(argv[3], "%lf", &s))
                                errx(1, "bad s value: %s", argv[3]);
                        mask |= HAVE_STEP;
                        if (randomize)
                                use_random = true;
                }
                /* FALLTHROUGH */
        case 3:
                if (!is_default(argv[2])) {
                        if (!sscanf(argv[2], "%lf", &ender))
                                ender = argv[2][strlen(argv[2])-1];
                        mask |= HAVE_ENDER;
                        if (prec < 0)
                                n = getprec(argv[2]);
                }
                /* FALLTHROUGH */
        case 2:
                if (!is_default(argv[1])) {
                        if (!sscanf(argv[1], "%lf", &begin))
                                begin = argv[1][strlen(argv[1])-1];
                        mask |= HAVE_BEGIN;
                        if (prec < 0)
                                prec = getprec(argv[1]);
                        if (n > prec)           /* maximum precision */
                                prec = n;
                }
                /* FALLTHROUGH */
        case 1:
                if (!is_default(argv[0])) {
                        if (!sscanf(argv[0], "%ld", &reps))
                                errx(1, "bad reps value: %s", argv[0]);
                        mask |= HAVE_REPS;
                }
                break;
        case 0:
                usage();
        default:
                errx(1, "too many arguments.  What do you mean by %s?",
                    argv[4]);
        }
        getformat();

        if (prec == -1)
                prec = 0;

        while (mask)    /* 4 bit mask has 1's where last 4 args were given */
                switch (mask) { /* fill in the 0's by default or computation */
                case HAVE_STEP:
                case HAVE_ENDER:
                case HAVE_ENDER | HAVE_STEP:
                case HAVE_BEGIN:
                case HAVE_BEGIN | HAVE_STEP:
                        reps = REPS_DEF;
                        mask |= HAVE_REPS;
                        break;
                case HAVE_BEGIN | HAVE_ENDER:
                        s = ender > begin ? 1 : -1;
                        mask |= HAVE_STEP;
                        break;
                case HAVE_BEGIN | HAVE_ENDER | HAVE_STEP:
                        if (randomize)
                                reps = REPS_DEF;
                        else if (s == 0.0)
                                reps = 0;
                        else
                                reps = (ender - begin + s) / s;
                        if (reps <= 0)
                                errx(1, "impossible stepsize");
                        mask = 0;
                        break;
                case HAVE_REPS:
                case HAVE_REPS | HAVE_STEP:
                        begin = BEGIN_DEF;
                        mask |= HAVE_BEGIN;
                        break;
                case HAVE_REPS | HAVE_ENDER:
                        s = STEP_DEF;
                        mask = HAVE_REPS | HAVE_ENDER | HAVE_STEP;
                        break;
                case HAVE_REPS | HAVE_ENDER | HAVE_STEP:
                        if (randomize)
                                begin = BEGIN_DEF;
                        else if (reps == 0)
                                errx(1, "must specify begin if reps == 0");
                        begin = ender - reps * s + s;
                        mask = 0;
                        break;
                case HAVE_REPS | HAVE_BEGIN:
                        s = STEP_DEF;
                        mask = HAVE_REPS | HAVE_BEGIN | HAVE_STEP;
                        break;
                case HAVE_REPS | HAVE_BEGIN | HAVE_STEP:
                        if (randomize)
                                ender = ENDER_DEF;
                        else
                                ender = begin + reps * s - s;
                        mask = 0;
                        break;
                case HAVE_REPS | HAVE_BEGIN | HAVE_ENDER:
                        if (!randomize) {
                                if (reps == 0)
                                        errx(1, "infinite sequences cannot "
                                            "be bounded");
                                else if (reps == 1)
                                        s = 0.0;
                                else
                                        s = (ender - begin) / (reps - 1);
                        }
                        mask = 0;
                        break;
                case HAVE_REPS | HAVE_BEGIN | HAVE_ENDER | HAVE_STEP:
                        /* if reps given and implied, */
                        if (!randomize && s != 0.0) {
                                long t = (ender - begin + s) / s;
                                if (t <= 0)
                                        errx(1, "impossible stepsize");
                                if (t < reps)           /* take lesser */
                                        reps = t;
                        }
                        mask = 0;
                        break;
                default:
                        errx(1, "bad mask");
                }
        if (reps == 0)
                infinity = true;
        if (randomize) {
                if (use_random) {
                        srandom((unsigned long)s);
                        divisor = (double)INT32_MAX + 1;
                } else
                        divisor = (double)UINT32_MAX + 1;

                /*
                 * Attempt to DWIM when the user has specified an
                 * integer range within that of the random number
                 * generator: distribute the numbers equally in
                 * the range [begin .. ender].  Jot's default %.0f
                 * format would make the appearance of the first and
                 * last specified value half as likely as the rest.
                 */
                if (!have_format && prec == 0 &&
                    begin >= 0 && begin < divisor &&
                    ender >= 0 && ender < divisor) {
                        if (begin <= ender)
                                ender += 1;
                        else
                                begin += 1;
                        nosign = true;
                        intdata = true;
                        (void)strlcpy(format,
                            chardata ? "%c" : "%u", sizeof(format));
                }
                x = ender - begin;
                for (i = 1; i <= reps || infinity; i++) {
                        if (use_random)
                                y = random() / divisor;
                        else
                                y = arc4random() / divisor;
                        if (putdata(y * x + begin, !(reps - i)))
                                errx(1, "range error in conversion");
                }
        } else
                for (i = 1, x = begin; i <= reps || infinity; i++, x += s)
                        if (putdata(x, !(reps - i)))
                                errx(1, "range error in conversion");
        if (!nofinalnl)
                putchar('\n');
        exit(0);
}

/*
 * Send x to stdout using the specified format.
 * Last is  true if this is the set's last value.
 * Return 0 if OK, or a positive number if the number passed was
 * outside the range specified by the various flags.
 */
static int
putdata(double x, bool last)
{

        if (boring)
                printf("%s", format);
        else if (longdata && nosign) {
                if (x <= (double)ULONG_MAX && x >= (double)0)
                        printf(format, (unsigned long)x);
                else
                        return (1);
        } else if (longdata) {
                if (x <= (double)LONG_MAX && x >= (double)LONG_MIN)
                        printf(format, (long)x);
                else
                        return (1);
        } else if (chardata || (intdata && !nosign)) {
                if (x <= (double)INT_MAX && x >= (double)INT_MIN)
                        printf(format, (int)x);
                else
                        return (1);
        } else if (intdata) {
                if (x <= (double)UINT_MAX && x >= (double)0)
                        printf(format, (unsigned int)x);
                else
                        return (1);

        } else
                printf(format, x);
        if (!last)
                fputs(sepstring, stdout);

        return (0);
}

static void
usage(void)
{
        fprintf(stderr, "%s\n%s\n",
        "usage: jot [-cnr] [-b word] [-w word] [-s string] [-p precision]",
        "           [reps [begin [end [s]]]]");
        exit(1);
}

/* 
 * Return the number of digits following the number's decimal point.
 * Return 0 if no decimal point is found.
 */
static int
getprec(const char *str)
{
        const char      *p;
        const char      *q;

        for (p = str; *p; p++)
                if (*p == '.')
                        break;
        if (!*p)
                return (0);
        for (q = ++p; *p; p++)
                if (!isdigit((unsigned char)*p))
                        break;
        return (p - q);
}

/*
 * Set format, intdata, chardata, longdata, and nosign
 * based on the command line arguments.
 */
static void
getformat(void)
{
        char    *p, *p2;
        int dot, hash, space, sign, numbers = 0;
        size_t sz;

        if (boring)                             /* no need to bother */
                return;
        for (p = format; *p; p++)               /* look for '%' */
                if (*p == '%') {
                        if (p[1] == '%')
                                p++;            /* leave %% alone */
                        else
                                break;
                }
        sz = sizeof(format) - strlen(format) - 1;
        if (!*p && !chardata) {
                if (snprintf(p, sz, "%%.%df", prec) >= (int)sz)
                        errx(1, "-w word too long");
        } else if (!*p && chardata) {
                if (strlcpy(p, "%c", sz) >= sz)
                        errx(1, "-w word too long");
                intdata = true;
        } else if (!*(p+1)) {
                if (sz <= 0)
                        errx(1, "-w word too long");
                strcat(format, "%");            /* cannot end in single '%' */
        } else {
                /*
                 * Allow conversion format specifiers of the form
                 * %[#][ ][{+,-}][0-9]*[.[0-9]*]? where ? must be one of
                 * [l]{d,i,o,u,x} or {f,e,g,E,G,d,o,x,D,O,U,X,c,u}
                 */
                p2 = p++;
                dot = hash = space = sign = numbers = 0;
                while (!isalpha((unsigned char)*p)) {
                        if (isdigit((unsigned char)*p)) {
                                numbers++;
                                p++;
                        } else if ((*p == '#' && !(numbers|dot|sign|space|
                            hash++)) ||
                            (*p == ' ' && !(numbers|dot|space++)) ||
                            ((*p == '+' || *p == '-') && !(numbers|dot|sign++))
                            || (*p == '.' && !(dot++)))
                                p++;
                        else
                                goto fmt_broken;
                }
                if (*p == 'l') {
                        longdata = true;
                        if (*++p == 'l') {
                                if (p[1] != '\0')
                                        p++;
                                goto fmt_broken;
                        }
                }
                switch (*p) {
                case 'o': case 'u': case 'x': case 'X':
                        intdata = nosign = true;
                        break;
                case 'd': case 'i':
                        intdata = true;
                        break;
                case 'D':
                        if (!longdata) {
                                intdata = true;
                                break;
                        }
                case 'O': case 'U':
                        if (!longdata) {
                                intdata = nosign = true;
                                break;
                        }
                case 'c':
                        if (!(intdata | longdata)) {
                                chardata = true;
                                break;
                        }
                case 'h': case 'n': case 'p': case 'q': case 's': case 'L':
                case '$': case '*':
                        goto fmt_broken;
                case 'f': case 'e': case 'g': case 'E': case 'G':
                        if (!longdata)
                                break;
                        /* FALLTHROUGH */
                default:
fmt_broken:
                        *++p = '\0';
                        errx(1, "illegal or unsupported format '%s'", p2);
                        /* NOTREACHED */
                }
                while (*++p)
                        if (*p == '%' && *(p+1) && *(p+1) != '%')
                                errx(1, "too many conversions");
                        else if (*p == '%' && *(p+1) == '%')
                                p++;
                        else if (*p == '%' && !*(p+1)) {
                                if (strlcat(format, "%", sizeof(format)) >=
                                    sizeof(format))
                                        errx(1, "-w word too long");
                                break;
                        }
        }
}