/*
 * Copyright (c) 2025-2026 The FreeBSD Foundation
 * Copyright (c) 2025-2026 Jean-Sébastien Pédron <dumbbell@FreeBSD.org>
 *
 * This software was developed by Jean-Sébastien Pédron under sponsorship
 * from the FreeBSD Foundation.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#ifndef _LINUXKPI_LINUX_SEQ_BUF_H_
#define _LINUXKPI_LINUX_SEQ_BUF_H_

#include <linux/bug.h>
#include <linux/minmax.h>
#include <linux/seq_file.h>
#include <linux/types.h>

struct seq_buf {
        char    *buffer;
        size_t   size;
        size_t   len;
};

#define DECLARE_SEQ_BUF(NAME, SIZE)                     \
        struct seq_buf NAME = {                         \
                .buffer = (char[SIZE]) { 0 },           \
                .size = SIZE,                           \
        }

static inline void
seq_buf_clear(struct seq_buf *s)
{
        s->len = 0;
        if (s->size > 0)
                s->buffer[0] = '\0';
}

static inline void
seq_buf_set_overflow(struct seq_buf *s)
{
        s->len = s->size + 1;
}

static inline bool
seq_buf_has_overflowed(struct seq_buf *s)
{
        return (s->len > s->size);
}

static inline bool
seq_buf_buffer_left(struct seq_buf *s)
{
        if (seq_buf_has_overflowed(s))
                return (0);

        return (s->size - s->len);
}

#define seq_buf_init(s, buf, size) linuxkpi_seq_buf_init((s), (buf), (size))
void linuxkpi_seq_buf_init(struct seq_buf *s, char *buf, unsigned int size);

#define seq_buf_printf(s, f, ...) linuxkpi_seq_buf_printf((s), (f), __VA_ARGS__)
int linuxkpi_seq_buf_printf(struct seq_buf *s, const char *fmt, ...) \
    __printflike(2, 3);

#define seq_buf_vprintf(s, f, a) linuxkpi_seq_buf_vprintf((s), (f), (a))
int linuxkpi_seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);

#define seq_buf_str(s) linuxkpi_seq_buf_str((s))
const char * linuxkpi_seq_buf_str(struct seq_buf *s);

#endif