/*      $NetBSD: snprintb.c,v 1.51 2026/03/14 14:25:46 rillig Exp $     */

/*-
 * Copyright (c) 2002, 2024 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.
 */

#ifndef _STANDALONE
# ifndef _KERNEL

#  if HAVE_NBTOOL_CONFIG_H
#   include "nbtool_config.h"
#  endif

#  include <sys/cdefs.h>
#  if defined(LIBC_SCCS)
__RCSID("$NetBSD: snprintb.c,v 1.51 2026/03/14 14:25:46 rillig Exp $");
#  endif

#  include <sys/types.h>
#  include <inttypes.h>
#  include <stdio.h>
#  include <string.h>
#  include <util.h>
#  include <errno.h>
# else /* ! _KERNEL */
#  include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: snprintb.c,v 1.51 2026/03/14 14:25:46 rillig Exp $");
#  include <sys/param.h>
#  include <sys/inttypes.h>
#  include <sys/systm.h>
#  include <lib/libkern/libkern.h>
# endif /* ! _KERNEL */

# ifndef HAVE_SNPRINTB_M
typedef struct {
        char *const buf;
        size_t const bufsize;
        const char *bitfmt;
        uint64_t const val;
        size_t const line_max;

        char num_fmt[5];
        size_t total_len;
        size_t line_pos;
        size_t comma_pos;
        int in_angle_brackets;
} state;

static void
store(state *s, char c)
{
        if (s->total_len < s->bufsize)
                s->buf[s->total_len] = c;
        s->total_len++;
}

static int
store_num(state *s, const char *fmt, uintmax_t num)
{
        int num_len = s->total_len < s->bufsize
            ? snprintf(s->buf + s->total_len, s->bufsize - s->total_len,
                fmt, num)
            : snprintf(NULL, 0, fmt, num);
        if (num_len > 0)
                s->total_len += num_len;
        return num_len;
}

static void
store_eol(state *s)
{
        if (s->total_len - s->line_pos > s->line_max) {
                s->total_len = s->line_pos + s->line_max - 1;
                store(s, '#');
        }
        store(s, '\0');
        s->line_pos = s->total_len;
        s->comma_pos = 0;
        s->in_angle_brackets = 0;
}

static void
store_delimiter(state *s)
{
        if (s->in_angle_brackets) {
                s->comma_pos = s->total_len;
                store(s, ',');
        } else {
                store(s, '<');
                s->in_angle_brackets = 1;
        }
}

static void
maybe_wrap_line(state *s, const char *bitfmt)
{
        if (s->line_max > 0
            && s->comma_pos > 0
            && s->total_len - s->line_pos >= s->line_max) {
                s->total_len = s->comma_pos;
                store(s, '>');
                store_eol(s);
                store_num(s, s->num_fmt, s->val);
                s->bitfmt = bitfmt;
        }
}

static int
old_style(state *s)
{
        while (*s->bitfmt != '\0') {
                const char *cur_bitfmt = s->bitfmt;
                uint8_t bit = *s->bitfmt;
                if (bit > 32)
                        return -1;
                if ((uint8_t)cur_bitfmt[1] <= 32)
                        return -1;
                if (s->val & (1U << (bit - 1))) {
                        store_delimiter(s);
                        while ((uint8_t)*++s->bitfmt > 32)
                                store(s, *s->bitfmt);
                        maybe_wrap_line(s, cur_bitfmt);
                } else
                        while ((uint8_t)*++s->bitfmt > 32)
                                continue;
        }
        return 0;
}

static int
new_style(state *s)
{
        uint8_t field_kind = 0; // 0 or 'f' or 'F'
        uint64_t field = 0;     // valid if field_kind != '\0'
        int matched = 1;
        const char *prev_bitfmt = s->bitfmt;
        while (*s->bitfmt != '\0') {
                const char *cur_bitfmt = s->bitfmt;
                uint8_t kind = cur_bitfmt[0];
                switch (kind) {
                case 'b':
                        field_kind = 0;
                        prev_bitfmt = cur_bitfmt;
                        uint8_t b_bit = cur_bitfmt[1];
                        if (b_bit >= 64)
                                return -1;
                        if (cur_bitfmt[2] == '\0')
                                return -1;
                        s->bitfmt += 2;
                        if (((s->val >> b_bit) & 1) == 0)
                                goto skip_description;
                        store_delimiter(s);
                        while (*s->bitfmt++ != '\0')
                                store(s, s->bitfmt[-1]);
                        maybe_wrap_line(s, cur_bitfmt);
                        break;
                case 'f':
                case 'F':
                        field_kind = kind;
                        prev_bitfmt = cur_bitfmt;
                        matched = 0;
                        uint8_t f_lsb = cur_bitfmt[1];
                        if (f_lsb >= 64)
                                return -1;
                        uint8_t f_width = cur_bitfmt[2];
                        if (f_width > 64)
                                return -1;
                        if (kind == 'f' && cur_bitfmt[3] == '\0')
                                return -1;
                        field = s->val >> f_lsb;
                        if (f_width < 64)
                                field &= ((uint64_t) 1 << f_width) - 1;
                        s->bitfmt += 3;
                        store_delimiter(s);
                        if (kind == 'F')
                                goto skip_description;
                        while (*s->bitfmt++ != '\0')
                                store(s, s->bitfmt[-1]);
                        store(s, '=');
                        store_num(s, s->num_fmt, field);
                        maybe_wrap_line(s, cur_bitfmt);
                        break;
                case '=':
                case ':':
                        s->bitfmt += 2;
                        if (field_kind == 0)
                                return -1;
                        uint8_t cmp = cur_bitfmt[1];
                        if (cur_bitfmt[2] == '\0')
                                return -1;
                        if (field != cmp)
                                goto skip_description;
                        matched = 1;
                        if (kind == '=')
                                store(s, '=');
                        while (*s->bitfmt++ != '\0')
                                store(s, s->bitfmt[-1]);
                        maybe_wrap_line(s, prev_bitfmt);
                        break;
                case '*':
                        if (field_kind == 0)
                                return -1;
                        if (cur_bitfmt[1] == '\0')
                                return -1;
                        s->bitfmt++;
                        if (matched)
                                goto skip_description;
                        matched = 1;
                        if (store_num(s, s->bitfmt, field) < 0)
                                return -1;
                        maybe_wrap_line(s, prev_bitfmt);
                        goto skip_description;
                default:
                        return -1;
                skip_description:
                        while (*s->bitfmt++ != '\0')
                                continue;
                        break;
                }
        }
        return 0;
}

static void
finish_buffer(state *s)
{
        if (s->line_max > 0) {
                store_eol(s);
                store(s, '\0');
                if (s->total_len <= s->bufsize)
                        return;
                if (s->bufsize >= 3)
                        s->buf[s->bufsize - 3] = '#';
                if (s->bufsize >= 2)
                        s->buf[s->bufsize - 2] = '\0';
                if (s->bufsize >= 1)
                        s->buf[s->bufsize - 1] = '\0';
        } else {
                store(s, '\0');
                if (s->total_len <= s->bufsize)
                        return;
                if (s->bufsize >= 2)
                        s->buf[s->bufsize - 2] = '#';
                if (s->bufsize >= 1)
                        s->buf[s->bufsize - 1] = '\0';
        }
}

int
snprintb_m(char *buf, size_t bufsize, const char *bitfmt, uint64_t val,
           size_t line_max)
{
        int old = *bitfmt != '\177';
        if (!old)
                bitfmt++;

        state s = {
                .buf = buf,
                .bufsize = bufsize,
                .bitfmt = bitfmt,
                .val = val,
                .line_max = line_max,
        };
        int had_error = 0;

        switch (*s.bitfmt++) {
        case 8:
                memcpy(s.num_fmt, "%#jo", 4);
                break;
        case 10:
                memcpy(s.num_fmt, "%ju", 4);
                break;
        case 16:
                memcpy(s.num_fmt, "%#jx", 4);
                break;
        default:
                goto had_error;
        }

        store_num(&s, s.num_fmt, val);

        if ((old ? old_style(&s) : new_style(&s)) < 0) {
had_error:
#ifndef _KERNEL
                errno = EINVAL;
#endif
                had_error = 1;
                store(&s, '#');
        } else if (s.in_angle_brackets)
                store(&s, '>');
        finish_buffer(&s);
        return had_error ? -1 : (int)(s.total_len - 1);
}

int
snprintb(char *buf, size_t bufsize, const char *bitfmt, uint64_t val)
{
        return snprintb_m(buf, bufsize, bitfmt, val, 0);
}
# endif /* ! HAVE_SNPRINTB_M */
#endif /* ! _STANDALONE */