/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef _LINUX_SEQ_BUF_H
  #define _LINUX_SEQ_BUF_H
  
  #include <linux/fs.h>
  
  /*
   * Trace sequences are used to allow a function to call several other functions
   * to create a string of data to use.
   */
  
  /**
   * seq_buf - seq buffer structure
   * @buffer:	pointer to the buffer
   * @size:	size of the buffer
   * @len:	the amount of data inside the buffer
   * @readpos:	The next position to read in the buffer.
   */
  struct seq_buf {

  	char			*buffer;
  	size_t			size;
  	size_t			len;
  	loff_t			readpos;

  };

  static inline void seq_buf_clear(struct seq_buf *s)
  {
  	s->len = 0;
  	s->readpos = 0;
  }

  static inline void
  seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
  {
  	s->buffer = buf;
  	s->size = size;

  	seq_buf_clear(s);

  }
  
  /*
   * seq_buf have a buffer that might overflow. When this happens
   * the len and size are set to be equal.
   */
  static inline bool
  seq_buf_has_overflowed(struct seq_buf *s)
  {

  	return s->len > s->size;

  }
  
  static inline void
  seq_buf_set_overflow(struct seq_buf *s)
  {

  	s->len = s->size + 1;

  }
  
  /*
   * How much buffer is left on the seq_buf?
   */
  static inline unsigned int
  seq_buf_buffer_left(struct seq_buf *s)
  {
  	if (seq_buf_has_overflowed(s))
  		return 0;

  	return s->size - s->len;

  }

  /* How much buffer was written? */
  static inline unsigned int seq_buf_used(struct seq_buf *s)
  {
  	return min(s->len, s->size);
  }

  /**
   * seq_buf_get_buf - get buffer to write arbitrary data to
   * @s: the seq_buf handle
   * @bufp: the beginning of the buffer is stored here
   *
   * Return the number of bytes available in the buffer, or zero if
   * there's no space.
   */
  static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
  {
  	WARN_ON(s->len > s->size + 1);
  
  	if (s->len < s->size) {
  		*bufp = s->buffer + s->len;
  		return s->size - s->len;
  	}
  
  	*bufp = NULL;
  	return 0;
  }
  
  /**
   * seq_buf_commit - commit data to the buffer
   * @s: the seq_buf handle
   * @num: the number of bytes to commit
   *
   * Commit @num bytes of data written to a buffer previously acquired
   * by seq_buf_get.  To signal an error condition, or that the data
   * didn't fit in the available space, pass a negative @num value.
   */
  static inline void seq_buf_commit(struct seq_buf *s, int num)
  {
  	if (num < 0) {
  		seq_buf_set_overflow(s);
  	} else {
  		/* num must be negative on overflow */
  		BUG_ON(s->len + num > s->size);
  		s->len += num;
  	}
  }

  extern __printf(2, 3)
  int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
  extern __printf(2, 0)
  int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);

  extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
  extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
  			   int cnt);
  extern int seq_buf_puts(struct seq_buf *s, const char *str);
  extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
  extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
  extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
  			      unsigned int len);

  extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);

  #ifdef CONFIG_BINARY_PRINTF
  extern int
  seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
  #endif

  #endif /* _LINUX_SEQ_BUF_H */