/* vi: set sw=4 ts=4: */
/*
 * Support code for the hexdump and od applets,
 * based on code from util-linux v 2.11l
 *
 * Copyright (c) 1989
 * The Regents of the University of California.  All rights reserved.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 *
 * Original copyright notice is retained at the end of this file.
 */
#include "libbb.h"
#include "dump.h"

#define F_IGNORE        0x01            /* %_A */
#define F_SETREP        0x02            /* rep count set, not default */
#define F_ADDRESS       0x001           /* print offset */
#define F_BPAD          0x002           /* blank pad */
#define F_C             0x004           /* %_c */
#define F_CHAR          0x008           /* %c */
#define F_DBL           0x010           /* %[EefGf] */
#define F_INT           0x020           /* %[di] */
#define F_P             0x040           /* %_p */
#define F_STR           0x080           /* %s */
#define F_U             0x100           /* %_u */
#define F_UINT          0x200           /* %[ouXx] */
#define F_TEXT          0x400           /* no conversions */

typedef struct priv_dumper_t {
        dumper_t pub;

        char **argv;
        FU *endfu;
        off_t savaddress;        /* saved address/offset in stream */
        off_t eaddress;          /* end address */
        int blocksize;
        smallint exitval;        /* final exit value */

        /* former statics */
        smallint next__done;
        smallint get__ateof; // = 1;
        unsigned char *get__curp;
        unsigned char *get__savp;
} priv_dumper_t;

static const char dot_flags_width_chars[] ALIGN1 = ".#-+ 0123456789";

static const char size_conv_str[] ALIGN1 =
"\x1\x4\x4\x4\x4\x4\x4\x8\x8\x8\x8\010cdiouxXeEfgG";

static const char int_convs[] ALIGN1 = "diouxX";

dumper_t* FAST_FUNC alloc_dumper(void)
{
        priv_dumper_t *dumper = xzalloc(sizeof(*dumper));
        dumper->pub.dump_length = -1;
        dumper->pub.dump_vflag = FIRST;
        dumper->get__ateof = 1;
        return &dumper->pub;
}

static NOINLINE int bb_dump_size(FS *fs)
{
        FU *fu;
        int bcnt, cur_size;
        char *fmt;
        const char *p;
        int prec;

        /* figure out the data block size needed for each format unit */
        for (cur_size = 0, fu = fs->nextfu; fu; fu = fu->nextfu) {
                if (fu->bcnt) {
                        cur_size += fu->bcnt * fu->reps;
                        continue;
                }
                for (bcnt = prec = 0, fmt = fu->fmt; *fmt; ++fmt) {
                        if (*fmt != '%')
                                continue;
                        /*
                         * skip any special chars -- save precision in
                         * case it's a %s format.
                         */
                        while (strchr(dot_flags_width_chars + 1, *++fmt))
                                continue;
                        if (*fmt == '.' && isdigit(*++fmt)) {
                                prec = atoi(fmt);
                                while (isdigit(*++fmt))
                                        continue;
                        }
                        p = strchr(size_conv_str + 12, *fmt);
                        if (!p) {
                                if (*fmt == 's') {
                                        bcnt += prec;
                                }
                                if (*fmt == '_') {
                                        ++fmt;
                                        if ((*fmt == 'c') || (*fmt == 'p') || (*fmt == 'u')) {
                                                bcnt += 1;
                                        }
                                }
                        } else {
                                bcnt += p[-12];
                        }
                }
                cur_size += bcnt * fu->reps;
        }
        return cur_size;
}

static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
{
        FU *fu;

        for (fu = fs->nextfu; fu; fu = fu->nextfu) {
                PR *pr;
                char *p1, *p2, *p3;
                char *fmtp;
                int nconv = 0;
                /*
                 * break each format unit into print units; each
                 * conversion character gets its own.
                 */
                for (fmtp = fu->fmt; *fmtp; ) {
                        unsigned len;
                        const char *prec;
                        const char *byte_count_str;

                        /* DBU:[dvae@cray.com] zalloc so that forward ptrs start out NULL */
                        pr = xzalloc(sizeof(*pr));
                        if (!fu->nextpr)
                                fu->nextpr = pr;

                        /* skip preceding text and up to the next % sign */
                        p1 = strchr(fmtp, '%');
                        if (!p1) { /* only text in the string */
                                pr->fmt = fmtp;
                                pr->flags = F_TEXT;
                                break;
                        }

                        /*
                         * get precision for %s -- if have a byte count, don't
                         * need it.
                         */
                        prec = NULL;
                        if (fu->bcnt) {
                                /* skip to conversion character */
                                while (strchr(dot_flags_width_chars, *++p1))
                                        continue;
                        } else {
                                /* skip any special chars, field width */
                                while (strchr(dot_flags_width_chars + 1, *++p1))
                                        continue;
                                if (*p1 == '.' && isdigit(*++p1)) {
                                        prec = p1;
                                        while (isdigit(*++p1))
                                                continue;
                                }
                        }

                        p2 = p1 + 1; /* set end pointer */

                        /*
                         * figure out the byte count for each conversion;
                         * rewrite the format as necessary, set up blank-
                         * padding for end of data.
                         */
                        if (*p1 == 'c') {
                                pr->flags = F_CHAR;
 DO_BYTE_COUNT_1:
                                byte_count_str = "\001";
 DO_BYTE_COUNT:
                                if (fu->bcnt) {
                                        for (;;) {
                                                if (fu->bcnt == *byte_count_str)
                                                        break;
                                                if (*++byte_count_str == 0)
                                                        bb_error_msg_and_die("bad byte count for conversion character %s", p1);
                                        }
                                }
                                /* Unlike the original, output the remainder of the format string. */
                                pr->bcnt = *byte_count_str;
                        } else
                        if (*p1 == 'l') { /* %ld etc */
                                const char *e;

                                ++p2;
                                ++p1;
 DO_INT_CONV:
                                e = strchr(int_convs, *p1); /* "diouxX"? */
                                if (!e)
                                        goto DO_BAD_CONV_CHAR;
                                pr->flags = F_INT;
                                if (e > int_convs + 1) /* not d or i? */
                                        pr->flags = F_UINT;
                                byte_count_str = "\004\002\001";
                                goto DO_BYTE_COUNT;
                        } else
                        if (strchr(int_convs, *p1)) { /* %d etc */
                                goto DO_INT_CONV;
                        } else
                        if (strchr("eEfgG", *p1)) { /* floating point */
                                pr->flags = F_DBL;
                                byte_count_str = "\010\004";
                                goto DO_BYTE_COUNT;
                        } else
                        if (*p1 == 's') {
                                pr->flags = F_STR;
                                pr->bcnt = fu->bcnt;
                                if (fu->bcnt == 0) {
                                        if (!prec)
                                                bb_simple_error_msg_and_die("%s needs precision or byte count");
                                        pr->bcnt = atoi(prec);
                                }
                        } else
                        if (*p1 == '_') {
                                p2++;  /* move past a in "%_a" */
                                switch (p1[1]) {
                                case 'A':       /* %_A[dox]: print address and the end */
                                        dumper->endfu = fu;
                                        fu->flags |= F_IGNORE;
                                        /* FALLTHROUGH */
                                case 'a':       /* %_a[dox]: current address */
                                        pr->flags = F_ADDRESS;
                                        p2++;  /* move past x in "%_ax" */
                                        if ((p1[2] != 'd') && (p1[2] != 'o') && (p1[2] != 'x')) {
                                                goto DO_BAD_CONV_CHAR;
                                        }
                                        *p1++ = 'l';
                                        *p1++ = 'l';
                                        break;
                                case 'c':       /* %_c: chars, \ooo, \n \r \t etc */
                                        pr->flags = F_C;
                                        /* *p1 = 'c';   set in conv_c */
                                        goto DO_BYTE_COUNT_1;
                                case 'p':       /* %_p: chars, dots for nonprintable */
                                        pr->flags = F_P;
                                        *p1 = 'c';
                                        goto DO_BYTE_COUNT_1;
                                case 'u':       /* %_p: chars, 'nul', 'esc' etc for nonprintable */
                                        pr->flags = F_U;
                                        /* *p1 = 'c';   set in conv_u */
                                        goto DO_BYTE_COUNT_1;
                                default:
                                        goto DO_BAD_CONV_CHAR;
                                }
                        } else {
 DO_BAD_CONV_CHAR:
                                bb_error_msg_and_die("bad conversion character %%%s", p1);
                        }

                        /*
                         * copy to PR format string, set conversion character
                         * pointer, update original.
                         */
                        len = (p1 - fmtp) + 1;
                        pr->fmt = xstrndup(fmtp, len);
                        /* DBU:[dave@cray.com] w/o this, trailing fmt text, space is lost.
                         * Skip subsequent text and up to the next % sign and tack the
                         * additional text onto fmt: eg. if fmt is "%x is a HEX number",
                         * we lose the " is a HEX number" part of fmt.
                         */
                        for (p3 = p2; *p3 && *p3 != '%'; p3++)
                                continue;
                        if ((p3 - p2) != 0) {
                                char *d;
                                pr->fmt = d = xrealloc(pr->fmt, len + (p3 - p2) + 1);
                                d += len;
                                do {
                                        *d++ = *p2++;
                                } while (p2 != p3);
                                *d = '\0';
                                /* now p2 = p3 */
                        }
                        pr->cchar = pr->fmt + len - 1; /* must be after realloc! */
                        fmtp = p2;

                        /* only one conversion character if byte count */
                        if (!(pr->flags & F_ADDRESS) && fu->bcnt && nconv++) {
                                bb_simple_error_msg_and_die("byte count with multiple conversion characters");
                        }
                }
                /*
                 * if format unit byte count not specified, figure it out
                 * so can adjust rep count later.
                 */
                if (fu->bcnt == 0)
                        for (pr = fu->nextpr; pr; pr = pr->nextpr)
                                fu->bcnt += pr->bcnt;
        }
        /*
         * if the format string interprets any data at all, and it's
         * not the same as the blocksize, and its last format unit
         * interprets any data at all, and has no iteration count,
         * repeat it as necessary.
         *
         * if rep count is greater than 1, no trailing whitespace
         * gets output from the last iteration of the format unit:
         * 2/1 "%02x " prints "XX XX", not "XX XX "
         * 2/1 "%02x\n" prints "XX\nXX", not "XX\nXX\n"
         */
        for (fu = fs->nextfu; fu; fu = fu->nextfu) {
                if (!fu->nextfu
                 && fs->bcnt < dumper->blocksize
                 && !(fu->flags & F_SETREP)
                 && fu->bcnt
                ) {
                        fu->reps += (dumper->blocksize - fs->bcnt) / fu->bcnt;
                }
                if (fu->reps > 1 && fu->nextpr) {
                        PR *pr;
                        char *p1, *p2;

                        for (pr = fu->nextpr;; pr = pr->nextpr)
                                if (!pr->nextpr)
                                        break;
                        p2 = NULL;
                        for (p1 = pr->fmt; *p1; ++p1)
                                p2 = isspace(*p1) ? p1 : NULL;
                        if (p2)
                                pr->nospace = p2;
                }
        }
}

static void do_skip(priv_dumper_t *dumper, const char *fname)
{
        struct stat sbuf;

        xfstat(STDIN_FILENO, &sbuf, fname);
        if (S_ISREG(sbuf.st_mode)
         && dumper->pub.dump_skip >= sbuf.st_size
        ) {
                /* If st_size is valid and pub.dump_skip >= st_size */
                dumper->pub.dump_skip -= sbuf.st_size;
                dumper->pub.address += sbuf.st_size;
                return;
        }
        if (fseeko(stdin, dumper->pub.dump_skip, SEEK_SET)) {
                bb_simple_perror_msg_and_die(fname);
        }
        dumper->pub.address += dumper->pub.dump_skip;
        dumper->savaddress = dumper->pub.address;
        dumper->pub.dump_skip = 0;
}

static NOINLINE int next(priv_dumper_t *dumper)
{
        for (;;) {
                const char *fname = *dumper->argv;

                if (fname) {
                        dumper->argv++;
                        if (NOT_LONE_DASH(fname)) {
                                if (!freopen(fname, "r", stdin)) {
                                        bb_simple_perror_msg(fname);
                                        dumper->exitval = 1;
                                        dumper->next__done = 1;
                                        continue;
                                }
                        }
                } else {
                        if (dumper->next__done)
                                return 0; /* no next file */
                }
                dumper->next__done = 1;
                if (dumper->pub.dump_skip)
                        do_skip(dumper, fname ? fname : "stdin");
                if (dumper->pub.dump_skip == 0)
                        return 1;
        }
        /* NOTREACHED */
}

static unsigned char *get(priv_dumper_t *dumper)
{
        int n;
        int need, nread;
        int blocksize = dumper->blocksize;

        if (!dumper->get__curp) {
                dumper->pub.address = (off_t)0; /*DBU:[dave@cray.com] initialize,initialize..*/
                dumper->get__curp = xmalloc(blocksize);
                dumper->get__savp = xzalloc(blocksize); /* need to be initialized */
        } else {
                unsigned char *tmp = dumper->get__curp;
                dumper->get__curp = dumper->get__savp;
                dumper->get__savp = tmp;
                dumper->savaddress += blocksize;
                dumper->pub.address = dumper->savaddress;
        }
        need = blocksize;
        nread = 0;
        while (1) {
                /*
                 * if read the right number of bytes, or at EOF for one file,
                 * and no other files are available, zero-pad the rest of the
                 * block and set the end flag.
                 */
                if (!dumper->pub.dump_length || (dumper->get__ateof && !next(dumper))) {
                        if (need == blocksize) {
                                return NULL;
                        }
                        if (dumper->pub.dump_vflag != ALL   /* not "show all"? */
                         && dumper->pub.dump_vflag != FIRST /* not first line? */
                         && memcmp(dumper->get__curp, dumper->get__savp, nread) == 0 /* same data? */
                        ) {
                                if (dumper->pub.dump_vflag != DUP) {
                                        puts("*");
                                }
                        }
                        memset(dumper->get__curp + nread, 0, need);
                        dumper->eaddress = dumper->pub.address + nread;
                        return dumper->get__curp;
                }
                n = fread(dumper->get__curp + nread, sizeof(unsigned char),
                                dumper->pub.dump_length == -1 ? need : MIN(dumper->pub.dump_length, need), stdin);
                if (n == 0) {
                        if (ferror(stdin)) {
                                bb_simple_perror_msg(dumper->argv[-1]);
                        }
                        dumper->get__ateof = 1;
                        continue;
                }
                dumper->get__ateof = 0;
                if (dumper->pub.dump_length != -1) {
                        dumper->pub.dump_length -= n;
                }
                need -= n;
                if (need == 0) {
                        if (dumper->pub.dump_vflag == ALL   /* "show all"? */
                         || dumper->pub.dump_vflag == FIRST /* first line? */
                         || memcmp(dumper->get__curp, dumper->get__savp, blocksize) != 0 /* not same data? */
                        ) {
                                if (dumper->pub.dump_vflag == DUP || dumper->pub.dump_vflag == FIRST) {
                                        dumper->pub.dump_vflag = WAIT;
                                }
                                return dumper->get__curp;
                        }
                        if (dumper->pub.dump_vflag == WAIT) {
                                puts("*");
                        }
                        dumper->pub.dump_vflag = DUP;
                        dumper->savaddress += blocksize;
                        dumper->pub.address = dumper->savaddress;
                        need = blocksize;
                        nread = 0;
                } else {
                        nread += n;
                }
        }
}

static void bpad(PR *pr)
{
        char *p1, *p2;

        /*
         * remove all conversion flags; '-' is the only one valid
         * with %s, and it's not useful here.
         */
        pr->flags = F_BPAD;
        *pr->cchar = 's';
        for (p1 = pr->fmt; *p1 != '%'; ++p1)
                continue;
        for (p2 = ++p1; *p1 && strchr(" -0+#", *p1); ++p1)
                if (pr->nospace)
                        pr->nospace--;
        while ((*p2++ = *p1++) != '\0')
                continue;
}

static const char conv_str[] ALIGN1 =
        "\0"  "\\""0""\0"
        "\007""\\""a""\0"  /* \a */
        "\b"  "\\""b""\0"
        "\f"  "\\""f""\0"
        "\n"  "\\""n""\0"
        "\r"  "\\""r""\0"
        "\t"  "\\""t""\0"
        "\v"  "\\""v""\0"
        ;

static void conv_c(PR *pr, unsigned char *p)
{
        const char *str = conv_str;

        do {
                if (*p == *str) {
                        ++str;
                        goto strpr; /* map e.g. '\n' to "\\n" */
                }
                str += 4;
        } while (*str);

        if (isprint_asciionly(*p)) {
                *pr->cchar = 'c';
                printf(pr->fmt, *p);
        } else {
                char buf[4];
                /* gcc-8.0.1 needs lots of casts to shut up */
                sprintf(buf, "%03o", (unsigned)(uint8_t)*p);
                str = buf;
 strpr:
                *pr->cchar = 's';
                printf(pr->fmt, str);
        }
}

static void conv_u(PR *pr, unsigned char *p)
{
        static const char list[] ALIGN1 =
                "nul\0soh\0stx\0etx\0eot\0enq\0ack\0bel\0"
                "bs\0_ht\0_lf\0_vt\0_ff\0_cr\0_so\0_si\0_"
                "dle\0dcl\0dc2\0dc3\0dc4\0nak\0syn\0etb\0"
                "can\0em\0_sub\0esc\0fs\0_gs\0_rs\0_us";

        /* od used nl, not lf */
        if (*p <= 0x1f) {
                *pr->cchar = 's';
                printf(pr->fmt, list + (4 * (int)*p));
        } else if (*p == 0x7f) {
                *pr->cchar = 's';
                printf(pr->fmt, "del");
        } else if (*p < 0x7f) { /* isprint() */
                *pr->cchar = 'c';
                printf(pr->fmt, *p);
        } else {
                *pr->cchar = 'x';
                printf(pr->fmt, (int) *p);
        }
}

static void display(priv_dumper_t* dumper)
{
        unsigned char *bp;
        unsigned char savech = '\0';

        while ((bp = get(dumper)) != NULL) {
                FS *fs;
                unsigned char *savebp;
                off_t saveaddress;

                fs = dumper->pub.fshead;
                savebp = bp;
                saveaddress = dumper->pub.address;
                for (; fs; fs = fs->nextfs, bp = savebp, dumper->pub.address = saveaddress) {
                        FU *fu;
                        for (fu = fs->nextfu; fu; fu = fu->nextfu) {
                                int cnt;
                                if (fu->flags & F_IGNORE) {
                                        break;
                                }
                                for (cnt = fu->reps; cnt; --cnt) {
                                        PR *pr;
                                        for (pr = fu->nextpr; pr; dumper->pub.address += pr->bcnt,
                                                                bp += pr->bcnt, pr = pr->nextpr) {
                                                if (dumper->eaddress
                                                 && dumper->pub.address >= dumper->eaddress
                                                ) {
                                                        if (dumper->pub.xxd_eofstring) {
                                                                /* xxd support: requested to not pad incomplete blocks */
                                                                fputs_stdout(dumper->pub.xxd_eofstring);
                                                                return;
                                                        }
                                                        if (!(pr->flags & (F_TEXT | F_BPAD)))
                                                                bpad(pr);
                                                }
                                                if (cnt == 1 && pr->nospace) {
                                                        savech = *pr->nospace;
                                                        *pr->nospace = '\0';
                                                }
                                                switch (pr->flags) {
                                                case F_ADDRESS:
                                                        printf(pr->fmt, (unsigned long long) dumper->pub.address + dumper->pub.xxd_displayoff);
                                                        break;
                                                case F_BPAD:
                                                        printf(pr->fmt, "");
                                                        break;
                                                case F_C:
                                                        conv_c(pr, bp);
                                                        break;
                                                case F_CHAR:
                                                        printf(pr->fmt, *bp);
                                                        break;
                                                case F_DBL: {
                                                        double dval;
                                                        float fval;

                                                        switch (pr->bcnt) {
                                                        case 4:
                                                                memcpy(&fval, bp, sizeof(fval));
                                                                printf(pr->fmt, fval);
                                                                break;
                                                        case 8:
                                                                memcpy(&dval, bp, sizeof(dval));
                                                                printf(pr->fmt, dval);
                                                                break;
                                                        }
                                                        break;
                                                }
                                                case F_INT: {
                                                        int ival;
                                                        short sval;

                                                        switch (pr->bcnt) {
                                                        case 1:
                                                                printf(pr->fmt, (int) *bp);
                                                                break;
                                                        case 2:
                                                                memcpy(&sval, bp, sizeof(sval));
                                                                printf(pr->fmt, (int) sval);
                                                                break;
                                                        case 4:
                                                                memcpy(&ival, bp, sizeof(ival));
                                                                printf(pr->fmt, ival);
                                                                break;
                                                        }
                                                        break;
                                                }
                                                case F_P:
                                                        printf(pr->fmt, isprint_asciionly(*bp) ? *bp : '.');
                                                        break;
                                                case F_STR:
                                                        printf(pr->fmt, (char *) bp);
                                                        break;
                                                case F_TEXT:
                                                        printf(pr->fmt);
                                                        break;
                                                case F_U:
                                                        conv_u(pr, bp);
                                                        break;
                                                case F_UINT: {
                                                        unsigned ival;
                                                        unsigned short sval;

                                                        switch (pr->bcnt) {
                                                        case 1:
                                                                printf(pr->fmt, (unsigned) *bp);
                                                                break;
                                                        case 2:
                                                                memcpy(&sval, bp, sizeof(sval));
                                                                printf(pr->fmt, (unsigned) sval);
                                                                break;
                                                        case 4:
                                                                memcpy(&ival, bp, sizeof(ival));
                                                                printf(pr->fmt, ival);
                                                                break;
                                                        }
                                                        break;
                                                }
                                                }
                                                if (cnt == 1 && pr->nospace) {
                                                        *pr->nospace = savech;
                                                }
                                        }
                                }
                        }
                }
        }

        if (dumper->endfu) {
                PR *pr;
                /*
                 * if eaddress not set, error or file size was multiple
                 * of blocksize, and no partial block ever found.
                 */
                if (!dumper->eaddress) {
                        if (!dumper->pub.address) {
                                return;
                        }
                        dumper->eaddress = dumper->pub.address;
                }
                for (pr = dumper->endfu->nextpr; pr; pr = pr->nextpr) {
                        switch (pr->flags) {
                        case F_ADDRESS:
                                printf(pr->fmt, (unsigned long long) dumper->eaddress + dumper->pub.xxd_displayoff);
                                break;
                        case F_TEXT:
                                printf(pr->fmt);
                                break;
                        }
                }
        }
}

#define dumper ((priv_dumper_t*)pub_dumper)
int FAST_FUNC bb_dump_dump(dumper_t *pub_dumper, char **argv)
{
        FS *tfs;
        int blocksize;

        /* figure out the data block size */
        blocksize = 0;
        tfs = dumper->pub.fshead;
        while (tfs) {
                tfs->bcnt = bb_dump_size(tfs);
                if (blocksize < tfs->bcnt) {
                        blocksize = tfs->bcnt;
                }
                tfs = tfs->nextfs;
        }
        dumper->blocksize = blocksize;

        /* rewrite the rules, do syntax checking */
        for (tfs = dumper->pub.fshead; tfs; tfs = tfs->nextfs) {
                rewrite(dumper, tfs);
        }

        dumper->argv = argv;
        display(dumper);

        return dumper->exitval;
}

void FAST_FUNC bb_dump_add(dumper_t* pub_dumper, const char *fmt)
{
        const char *p;
        FS *tfs;
        FU **nextfupp;

        /* start new linked list of format units */
        tfs = xzalloc(sizeof(FS)); /*DBU:[dave@cray.com] start out NULL */
        if (!dumper->pub.fshead) {
                dumper->pub.fshead = tfs;
        } else {
                FS *fslast = dumper->pub.fshead;
                while (fslast->nextfs)
                        fslast = fslast->nextfs;
                fslast->nextfs = tfs;
        }
        nextfupp = &tfs->nextfu;

        /* take the format string and break it up into format units */
        p = fmt;
        for (;;) {
                FU *tfu;
                const char *savep;

                p = skip_whitespace(p);
                if (*p == '\0') {
                        break;
                }

                /* allocate a new format unit and link it in */
                /* NOSTRICT */
                /* DBU:[dave@cray.com] zalloc so that forward pointers start out NULL */
                tfu = xzalloc(sizeof(FU));
                *nextfupp = tfu;
                nextfupp = &tfu->nextfu;
                tfu->reps = 1;

                /* if leading digit, repetition count */
                if (isdigit(*p)) {
                        for (savep = p; isdigit(*p); ++p)
                                continue;
                        if (!isspace(*p) && *p != '/') {
                                bb_error_msg_and_die("bad format {%s}", fmt);
                        }
                        /* may overwrite either white space or slash */
                        tfu->reps = atoi(savep);
                        tfu->flags = F_SETREP;
                        /* skip trailing white space */
                        p = skip_whitespace(++p);
                }

                /* skip slash and trailing white space */
                if (*p == '/') {
                        p = skip_whitespace(p + 1);
                }

                /* byte count */
                if (isdigit(*p)) {
// TODO: use bb_strtou
                        savep = p;
                        while (isdigit(*++p))
                                continue;
                        if (!isspace(*p)) {
                                bb_error_msg_and_die("bad format {%s}", fmt);
                        }
// Above check prohibits formats such as '/1"%02x"' - it requires space after 1.
// Other than this, formats can be pretty much jammed together:
// "%07_ax:"8/2 "%04x|""\n"
// but this space is required. The check *can* be removed, but
// keeping it to stay compat with util-linux hexdump.
                        tfu->bcnt = atoi(savep);
                        /* skip trailing white space */
                        p = skip_whitespace(p + 1);
                }

                /* format */
                if (*p != '"') {
                        bb_error_msg_and_die("bad format {%s}", fmt);
                }
                for (savep = ++p; *p != '"';) {
                        if (*p++ == '\0') {
                                bb_error_msg_and_die("bad format {%s}", fmt);
                        }
                }
                tfu->fmt = xstrndup(savep, p - savep);

                /* alphabetic escape sequences have to be done in place */
                strcpy_and_process_escape_sequences(tfu->fmt, tfu->fmt);
                /* unknown mappings are not changed: "\z" -> '\\' 'z' */
                /* trailing backslash, if any, is preserved */
#if 0
                char *p1;
                char *p2;
                p1 = tfu->fmt;
                for (p2 = p1;; ++p1, ++p2) {
                        *p2 = *p1;
                        if (*p1 == '\0')
                                break;

                        if (*p1 == '\\') {
                                const char *cs;

                                p1++;
                                *p2 = *p1;
                                if (*p1 == '\0') {
                                        /* "...\" trailing backslash. Eaten. */
                                        break;
                                }
                                cs = conv_str + 4; /* skip NUL element */
                                do {
                                        /* map e.g. "\n" -> '\n' */
                                        if (*p1 == cs[2]) {
                                                *p2 = cs[0];
                                                break;
                                        }
                                        cs += 4;
                                } while (*cs);
                                /* unknown mappings remove bkslash: "\z" -> 'z' */
                        }
                }
#endif

                p++;
        }
}

/*
 * Copyright (c) 1989 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.
 */