/*      $NetBSD: snprintb.c,v 1.22 2019/12/06 19:36:22 christos Exp $   */

/*-
 * Copyright (c) 2002 The NetBSD Foundation, Inc.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * snprintb: print an interpreted bitmask to a buffer
 *
 * => returns the length of the buffer that would be required to print the
 *    string minus the terminating NUL.
 */

#include <sys/types.h>
#include <errno.h>
#include <inttypes.h>
#include <libutil.h>
#include <stdio.h>

int
snprintb_m(char *buf, size_t buflen, const char *bitfmt, uint64_t val,
           size_t l_max)
{
        char *bp = buf, *s_bp = NULL;
        const char *c_fmt, *s_fmt = NULL, *cur_fmt;
        const char *sbase;
        int bit, ch, t_len, s_len = 0, l_len, f_len, v_len, sep;
        int restart = 0, matched = 1;
        uint64_t field;

        ch = *bitfmt++;
        switch (ch != '\177' ? ch : *bitfmt++) {
        case 8:
                sbase = "%#jo";
                break;
        case 10:
                sbase = "%ju";
                break;
        case 16:
                sbase = "%#jx";
                break;
        default:
                goto internal;
        }

        /* Reserve space for trailing blank line if needed */
        if (l_max > 0)
                buflen--;

        t_len = snprintf(bp, buflen, sbase, (uintmax_t)val);
        if (t_len < 0)
                goto internal;

        v_len = l_len = t_len;

        if ((size_t)t_len < buflen)
                bp += t_len;
        else
                bp += buflen - 1;

        /*
         * If the value we printed was 0 and we're using the old-style format,
         * we're done.
         */
        if ((val == 0) && (ch != '\177'))
                goto terminate;

#define STORE(c) do { l_len++;                                          \
                   if ((size_t)(++t_len) < buflen)                      \
                        *bp++ = (c);                                    \
                 } while ( /* CONSTCOND */ 0)

#define BACKUP  do { if (s_bp != NULL) {                                \
                        bp = s_bp; s_bp = NULL;                         \
                        t_len -= l_len - s_len;                         \
                        restart = 1;                                    \
                        bitfmt = s_fmt;                                 \
                  }                                                     \
                  STORE('>'); STORE('\0');                              \
                  if ((size_t)t_len < buflen)                           \
                        snprintf(bp, buflen - t_len, sbase, (uintmax_t)val);\
                  t_len += v_len; l_len = v_len; bp += v_len;           \
                } while ( /* CONSTCOND */ 0)

#define PUTSEP do {                                                     \
                        if (l_max > 0 && (size_t)l_len >= l_max) {      \
                                BACKUP;                                 \
                                STORE('<');                             \
                        } else {                                        \
                                /* Remember separator location */       \
                                if (l_max > 0 && sep != '<') {          \
                                        s_len = l_len;                  \
                                        s_bp  = bp;                     \
                                        s_fmt = cur_fmt;                \
                                }                                       \
                                STORE(sep);                             \
                                restart = 0;                            \
                        }                                               \
                } while ( /* CONSTCOND */ 0)

#define PUTCHR(c) do {                                                  \
                        if (l_max > 0 && (size_t)l_len >= (l_max - 1)) {\
                                BACKUP;                                 \
                                if (restart == 0)                       \
                                        STORE(c);                       \
                                else                                    \
                                        sep = '<';                      \
                        } else {                                        \
                                STORE(c);                               \
                                restart = 0;                            \
                        }                                               \
                } while ( /* CONSTCOND */ 0)

#define PUTS(s) while ((ch = *(s)++) != 0) {                            \
                        PUTCHR(ch);                                     \
                        if (restart)                                    \
                                break;                                  \
                }
#define FMTSTR(sb, f)                                                   \
        do {                                                            \
                f_len = snprintf(bp, buflen - t_len, sb, (uintmax_t)f); \
                if (f_len < 0)                                          \
                        goto internal;                                  \
                t_len += f_len;                                         \
                l_len += f_len;                                         \
                if ((size_t)t_len < buflen)                             \
                        bp += f_len;                                    \
        } while (/*CONSTCOND*/0)

        /*
         * Chris Torek's new bitmask format is identified by a leading \177
         */
        sep = '<';
        if (ch != '\177') {
                /* old (standard) format. */
                for (;(bit = *bitfmt) != 0;) {
                        cur_fmt = bitfmt++;
                        if (val & (1U << (bit - 1))) {
                                PUTSEP;
                                if (restart)
                                        continue;
                                sep = ',';
                                for (; (ch = *bitfmt) > ' '; ++bitfmt) {
                                        PUTCHR(ch); 
                                        if (restart)
                                                break;
                                }
                        } else
                                for (; *bitfmt > ' '; ++bitfmt)
                                        continue;
                }
        } else {
                /* new quad-capable format; also does fields. */
                field = val;
                while (c_fmt = bitfmt, (ch = *bitfmt++) != '\0') {
                        bit = *bitfmt++;        /* now 0-origin */
                        switch (ch) {
                        case 'b':
                                if (((unsigned int)(val >> bit) & 1) == 0)
                                        goto skip;
                                cur_fmt = c_fmt;
                                PUTSEP;
                                if (restart)
                                        break;
                                PUTS(bitfmt);
                                if (restart == 0)
                                        sep = ',';
                                break;
                        case 'f':
                        case 'F':
                                matched = 0;
                                cur_fmt = c_fmt;
                                f_len = *bitfmt++;      /* field length */
                                field = (val >> bit) &
                                            (((uint64_t)1 << f_len) - 1);
                                PUTSEP;
                                if (restart == 0)
                                        sep = ',';
                                if (ch == 'F') {        /* just extract */
                                        /* duplicate PUTS() effect on bitfmt */
                                        while (*bitfmt++ != '\0')
                                                continue;
                                        break;
                                }
                                if (restart == 0)
                                        PUTS(bitfmt);
                                if (restart == 0)
                                        PUTCHR('=');
                                if (restart == 0) {
                                        FMTSTR(sbase, field);
                                        if (l_max > 0 && (size_t)l_len > l_max)
                                                PUTCHR('#');
                                }
                                break;
                        case '=':
                        case ':':
                                /*
                                 * Here "bit" is actually a value instead,
                                 * to be compared against the last field.
                                 * This only works for values in [0..255],
                                 * of course.
                                 */
                                if ((int)field != bit)
                                        goto skip;
                                matched = 1;
                                if (ch == '=')
                                        PUTCHR('=');
                                PUTS(bitfmt);
                                break;
                        case '*':
                                bitfmt--;
                                if (!matched) {
                                        matched = 1;
                                        FMTSTR(bitfmt, field);
                                }
                                /*FALLTHROUGH*/
                        default:
                        skip:
                                while (*bitfmt++ != '\0')
                                        continue;
                                break;
                        }
                }
        }
        l_len++;
        if (sep != '<' && (size_t)(++t_len) < buflen)
                *bp++ = '>';
terminate:
        *bp++ = '\0';
        if (l_max != 0) {
                t_len++;
                *bp = '\0';
        }
        return t_len;
internal:
        errno = EINVAL;
        return -1;
}

int
snprintb(char *buf, size_t buflen, const char *bitfmt, uint64_t val)
{
        return snprintb_m(buf, buflen, bitfmt, val, 0);
}