/*
 * Copyright 2014 Garrett D'Amore <garrett@damore.org>
 * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 1989, 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.
 * 4. 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 <err.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <alloca.h>
#include <ctype.h>
#include <locale.h>
#include <note.h>

#define warnx1(a, b, c)         warnx(a)
#define warnx2(a, b, c)         warnx(a, b)
#define warnx3(a, b, c)         warnx(a, b, c)

#define PTRDIFF(x, y)   ((uintptr_t)(x) - (uintptr_t)(y))

#define _(x)    gettext(x)

#define PF(f, func) do {                                                \
        char *b = NULL;                                                 \
        if (havewidth)                                                  \
                if (haveprec)                                           \
                        (void) asprintf(&b, f, fieldwidth, precision, func); \
                else                                                    \
                        (void) asprintf(&b, f, fieldwidth, func);       \
        else if (haveprec)                                              \
                (void) asprintf(&b, f, precision, func);                \
        else                                                            \
                (void) asprintf(&b, f, func);                           \
        if (b) {                                                        \
                (void) fputs(b, stdout);                                \
                free(b);                                                \
        }                                                               \
_NOTE(CONSTCOND) } while (0)

static int       asciicode(void);
static char     *doformat(char *, int *);
static int       escape(char *, int, size_t *);
static int       getchr(void);
static int       getfloating(long double *, int);
static int       getint(int *);
static int       getnum(intmax_t *, uintmax_t *, int);
static const char
                *getstr(void);
static char     *mknum(char *, char);
static void      usage(void);

static const char digits[] = "0123456789";

static int  myargc;
static char **myargv;
static char **gargv;
static char **maxargv;

int
main(int argc, char *argv[])
{
        size_t len;
        int end, rval;
        char *format, *fmt, *start;

        (void) setlocale(LC_ALL, "");

        argv++;
        argc--;

        /*
         * POSIX says: Standard utilities that do not accept options,
         * but that do accept operands, shall recognize "--" as a
         * first argument to be discarded.
         */
        if (argc && strcmp(argv[0], "--") == 0) {
                argc--;
                argv++;
        }

        if (argc < 1) {
                usage();
                return (1);
        }

        /*
         * Basic algorithm is to scan the format string for conversion
         * specifications -- once one is found, find out if the field
         * width or precision is a '*'; if it is, gather up value.  Note,
         * format strings are reused as necessary to use up the provided
         * arguments, arguments of zero/null string are provided to use
         * up the format string.
         */
        fmt = format = *argv;
        (void) escape(fmt, 1, &len);    /* backslash interpretation */
        rval = end = 0;
        gargv = ++argv;

        for (;;) {
                maxargv = gargv;

                myargv = gargv;
                for (myargc = 0; gargv[myargc]; myargc++)
                        /* nop */;
                start = fmt;
                while (fmt < format + len) {
                        if (fmt[0] == '%') {
                                (void) fwrite(start, 1, PTRDIFF(fmt, start),
                                    stdout);
                                if (fmt[1] == '%') {
                                        /* %% prints a % */
                                        (void) putchar('%');
                                        fmt += 2;
                                } else {
                                        fmt = doformat(fmt, &rval);
                                        if (fmt == NULL)
                                                return (1);
                                        end = 0;
                                }
                                start = fmt;
                        } else
                                fmt++;
                        if (gargv > maxargv)
                                maxargv = gargv;
                }
                gargv = maxargv;

                if (end == 1) {
                        warnx1(_("missing format character"), NULL, NULL);
                        return (1);
                }
                (void) fwrite(start, 1, PTRDIFF(fmt, start), stdout);
                if (!*gargv)
                        return (rval);
                /* Restart at the beginning of the format string. */
                fmt = format;
                end = 1;
        }
        /* NOTREACHED */
}


static char *
doformat(char *fmt, int *rval)
{
        static const char skip1[] = "#'-+ 0";
        int fieldwidth, haveprec, havewidth, mod_ldbl, precision;
        char convch, nextch;
        char *start;
        char **fargv;
        char *dptr;
        int l;

        start = alloca(strlen(fmt) + 1);

        dptr = start;
        *dptr++ = '%';
        *dptr = 0;

        fmt++;

        /* look for "n$" field index specifier */
        l = strspn(fmt, digits);
        if ((l > 0) && (fmt[l] == '$')) {
                int idx = atoi(fmt);
                if (idx <= myargc) {
                        gargv = &myargv[idx - 1];
                } else {
                        gargv = &myargv[myargc];
                }
                if (gargv > maxargv) {
                        maxargv = gargv;
                }
                fmt += l + 1;

                /* save format argument */
                fargv = gargv;
        } else {
                fargv = NULL;
        }

        /* skip to field width */
        while (*fmt && strchr(skip1, *fmt) != NULL) {
                *dptr++ = *fmt++;
                *dptr = 0;
        }


        if (*fmt == '*') {

                fmt++;
                l = strspn(fmt, digits);
                if ((l > 0) && (fmt[l] == '$')) {
                        int idx = atoi(fmt);
                        if (fargv == NULL) {
                                warnx1(_("incomplete use of n$"), NULL, NULL);
                                return (NULL);
                        }
                        if (idx <= myargc) {
                                gargv = &myargv[idx - 1];
                        } else {
                                gargv = &myargv[myargc];
                        }
                        fmt += l + 1;
                } else if (fargv != NULL) {
                        warnx1(_("incomplete use of n$"), NULL, NULL);
                        return (NULL);
                }

                if (getint(&fieldwidth))
                        return (NULL);
                if (gargv > maxargv) {
                        maxargv = gargv;
                }
                havewidth = 1;

                *dptr++ = '*';
                *dptr = 0;
        } else {
                havewidth = 0;

                /* skip to possible '.', get following precision */
                while (isdigit(*fmt)) {
                        *dptr++ = *fmt++;
                        *dptr = 0;
                }
        }

        if (*fmt == '.') {
                /* precision present? */
                fmt++;
                *dptr++ = '.';

                if (*fmt == '*') {

                        fmt++;
                        l = strspn(fmt, digits);
                        if ((l > 0) && (fmt[l] == '$')) {
                                int idx = atoi(fmt);
                                if (fargv == NULL) {
                                        warnx1(_("incomplete use of n$"),
                                            NULL, NULL);
                                        return (NULL);
                                }
                                if (idx <= myargc) {
                                        gargv = &myargv[idx - 1];
                                } else {
                                        gargv = &myargv[myargc];
                                }
                                fmt += l + 1;
                        } else if (fargv != NULL) {
                                warnx1(_("incomplete use of n$"), NULL, NULL);
                                return (NULL);
                        }

                        if (getint(&precision))
                                return (NULL);
                        if (gargv > maxargv) {
                                maxargv = gargv;
                        }
                        haveprec = 1;
                        *dptr++ = '*';
                        *dptr = 0;
                } else {
                        haveprec = 0;

                        /* skip to conversion char */
                        while (isdigit(*fmt)) {
                                *dptr++ = *fmt++;
                                *dptr = 0;
                        }
                }
        } else
                haveprec = 0;
        if (!*fmt) {
                warnx1(_("missing format character"), NULL, NULL);
                return (NULL);
        }
        *dptr++ = *fmt;
        *dptr = 0;

        /*
         * Look for a length modifier.  POSIX doesn't have these, so
         * we only support them for floating-point conversions, which
         * are extensions.  This is useful because the L modifier can
         * be used to gain extra range and precision, while omitting
         * it is more likely to produce consistent results on different
         * architectures.  This is not so important for integers
         * because overflow is the only bad thing that can happen to
         * them, but consider the command  printf %a 1.1
         */
        if (*fmt == 'L') {
                mod_ldbl = 1;
                fmt++;
                if (!strchr("aAeEfFgG", *fmt)) {
                        warnx2(_("bad modifier L for %%%c"), *fmt, NULL);
                        return (NULL);
                }
        } else {
                mod_ldbl = 0;
        }

        /* save the current arg offset, and set to the format arg */
        if (fargv != NULL) {
                gargv = fargv;
        }

        convch = *fmt;
        nextch = *++fmt;

        *fmt = '\0';
        switch (convch) {
        case 'b': {
                size_t len;
                char *p;
                int getout;

                p = strdup(getstr());
                if (p == NULL) {
                        warnx2("%s", strerror(ENOMEM), NULL);
                        return (NULL);
                }
                getout = escape(p, 0, &len);
                (void) fputs(p, stdout);
                free(p);

                if (getout)
                        exit(*rval);
                break;
        }
        case 'c': {
                char p;

                p = getchr();
                PF(start, p);
                break;
        }
        case 's': {
                const char *p;

                p = getstr();
                PF(start, p);
                break;
        }
        case 'd': case 'i': case 'o': case 'u': case 'x': case 'X': {
                char *f;
                intmax_t val;
                uintmax_t uval;
                int signedconv;

                signedconv = (convch == 'd' || convch == 'i');
                if ((f = mknum(start, convch)) == NULL)
                        return (NULL);
                if (getnum(&val, &uval, signedconv))
                        *rval = 1;
                if (signedconv)
                        PF(f, val);
                else
                        PF(f, uval);
                break;
        }
        case 'e': case 'E':
        case 'f': case 'F':
        case 'g': case 'G':
        case 'a': case 'A': {
                long double p;

                if (getfloating(&p, mod_ldbl))
                        *rval = 1;
                if (mod_ldbl)
                        PF(start, p);
                else
                        PF(start, (double)p);
                break;
        }
        default:
                warnx2(_("illegal format character %c"), convch, NULL);
                return (NULL);
        }
        *fmt = nextch;

        /* return the gargv to the next element */
        return (fmt);
}

static char *
mknum(char *str, char ch)
{
        static char *copy;
        static size_t copy_size;
        char *newcopy;
        size_t len, newlen;

        len = strlen(str) + 2;
        if (len > copy_size) {
                newlen = ((len + 1023) >> 10) << 10;
                if ((newcopy = realloc(copy, newlen)) == NULL) {
                        warnx2("%s", strerror(ENOMEM), NULL);
                        return (NULL);
                }
                copy = newcopy;
                copy_size = newlen;
        }

        (void) memmove(copy, str, len - 3);
        copy[len - 3] = 'j';
        copy[len - 2] = ch;
        copy[len - 1] = '\0';
        return (copy);
}

static int
escape(char *fmt, int percent, size_t *len)
{
        char *save, *store, c;
        int value;

        for (save = store = fmt; ((c = *fmt) != 0); ++fmt, ++store) {
                if (c != '\\') {
                        *store = c;
                        continue;
                }
                switch (*++fmt) {
                case '\0':              /* EOS, user error */
                        *store = '\\';
                        *++store = '\0';
                        *len = PTRDIFF(store, save);
                        return (0);
                case '\\':              /* backslash */
                case '\'':              /* single quote */
                        *store = *fmt;
                        break;
                case 'a':               /* bell/alert */
                        *store = '\a';
                        break;
                case 'b':               /* backspace */
                        *store = '\b';
                        break;
                case 'c':
                        if (!percent) {
                                *store = '\0';
                                *len = PTRDIFF(store, save);
                                return (1);
                        }
                        *store = 'c';
                        break;
                case 'f':               /* form-feed */
                        *store = '\f';
                        break;
                case 'n':               /* newline */
                        *store = '\n';
                        break;
                case 'r':               /* carriage-return */
                        *store = '\r';
                        break;
                case 't':               /* horizontal tab */
                        *store = '\t';
                        break;
                case 'v':               /* vertical tab */
                        *store = '\v';
                        break;
                                        /* octal constant */
                case '0': case '1': case '2': case '3':
                case '4': case '5': case '6': case '7':
                        c = (!percent && *fmt == '0') ? 4 : 3;
                        for (value = 0;
                            c-- && *fmt >= '0' && *fmt <= '7'; ++fmt) {
                                value <<= 3;
                                value += *fmt - '0';
                        }
                        --fmt;
                        if (percent && value == '%') {
                                *store++ = '%';
                                *store = '%';
                        } else
                                *store = (char)value;
                        break;
                default:
                        *store = *fmt;
                        break;
                }
        }
        *store = '\0';
        *len = PTRDIFF(store, save);
        return (0);
}

static int
getchr(void)
{
        if (!*gargv)
                return ('\0');
        return ((int)**gargv++);
}

static const char *
getstr(void)
{
        if (!*gargv)
                return ("");
        return (*gargv++);
}

static int
getint(int *ip)
{
        intmax_t val;
        uintmax_t uval;
        int rval;

        if (getnum(&val, &uval, 1))
                return (1);
        rval = 0;
        if (val < INT_MIN || val > INT_MAX) {
                warnx3("%s: %s", *gargv, strerror(ERANGE));
                rval = 1;
        }
        *ip = (int)val;
        return (rval);
}

static int
getnum(intmax_t *ip, uintmax_t *uip, int signedconv)
{
        char *ep;
        int rval;

        if (!*gargv) {
                *ip = *uip = 0;
                return (0);
        }
        if (**gargv == '"' || **gargv == '\'') {
                if (signedconv)
                        *ip = asciicode();
                else
                        *uip = asciicode();
                return (0);
        }
        rval = 0;
        errno = 0;
        if (signedconv)
                *ip = strtoimax(*gargv, &ep, 0);
        else
                *uip = strtoumax(*gargv, &ep, 0);
        if (ep == *gargv) {
                warnx2(_("%s: expected numeric value"), *gargv, NULL);
                rval = 1;
        } else if (*ep != '\0') {
                warnx2(_("%s: not completely converted"), *gargv, NULL);
                rval = 1;
        }
        if (errno == ERANGE) {
                warnx3("%s: %s", *gargv, strerror(ERANGE));
                rval = 1;
        }
        ++gargv;
        return (rval);
}

static int
getfloating(long double *dp, int mod_ldbl)
{
        char *ep;
        int rval;

        if (!*gargv) {
                *dp = 0.0;
                return (0);
        }
        if (**gargv == '"' || **gargv == '\'') {
                *dp = asciicode();
                return (0);
        }
        rval = 0;
        errno = 0;
        if (mod_ldbl)
                *dp = strtold(*gargv, &ep);
        else
                *dp = strtod(*gargv, &ep);
        if (ep == *gargv) {
                warnx2(_("%s: expected numeric value"), *gargv, NULL);
                rval = 1;
        } else if (*ep != '\0') {
                warnx2(_("%s: not completely converted"), *gargv, NULL);
                rval = 1;
        }
        if (errno == ERANGE) {
                warnx3("%s: %s", *gargv, strerror(ERANGE));
                rval = 1;
        }
        ++gargv;
        return (rval);
}

static int
asciicode(void)
{
        int ch;

        ch = **gargv;
        if (ch == '\'' || ch == '"')
                ch = (*gargv)[1];
        ++gargv;
        return (ch);
}

static void
usage(void)
{
        (void) fprintf(stderr, _("usage: printf format [arguments ...]\n"));
}