LXR linux/include/linux/seq

   1#ifndef _LINUX_SEQ_BUF_H
   2#define _LINUX_SEQ_BUF_H
   3
   4#include <linux/fs.h>
   5
   6/*
   7 * Trace sequences are used to allow a function to call several other functions
   8 * to create a string of data to use.
   9 */
  10
  11/**
  12 * seq_buf - seq buffer structure
  13 * @buffer:     pointer to the buffer
  14 * @size:       size of the buffer
  15 * @len:        the amount of data inside the buffer
  16 * @readpos:    The next position to read in the buffer.
  17 */
  18struct seq_buf {
  19        char                    *buffer;
  20        size_t                  size;
  21        size_t                  len;
  22        loff_t                  readpos;
  23};
  24
  25static inline void seq_buf_clear(struct seq_buf *s)
  26{
  27        s->len = 0;
  28        s->readpos = 0;
  29}
  30
  31static inline void
  32seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size)
  33{
  34        s->buffer = buf;
  35        s->size = size;
  36        seq_buf_clear(s);
  37}
  38
  39/*
  40 * seq_buf have a buffer that might overflow. When this happens
  41 * the len and size are set to be equal.
  42 */
  43static inline bool
  44seq_buf_has_overflowed(struct seq_buf *s)
  45{
  46        return s->len > s->size;
  47}
  48
  49static inline void
  50seq_buf_set_overflow(struct seq_buf *s)
  51{
  52        s->len = s->size + 1;
  53}
  54
  55/*
  56 * How much buffer is left on the seq_buf?
  57 */
  58static inline unsigned int
  59seq_buf_buffer_left(struct seq_buf *s)
  60{
  61        if (seq_buf_has_overflowed(s))
  62                return 0;
  63
  64        return s->size - s->len;
  65}
  66
  67/* How much buffer was written? */
  68static inline unsigned int seq_buf_used(struct seq_buf *s)
  69{
  70        return min(s->len, s->size);
  71}
  72
  73/**
  74 * seq_buf_get_buf - get buffer to write arbitrary data to
  75 * @s: the seq_buf handle
  76 * @bufp: the beginning of the buffer is stored here
  77 *
  78 * Return the number of bytes available in the buffer, or zero if
  79 * there's no space.
  80 */
  81static inline size_t seq_buf_get_buf(struct seq_buf *s, char **bufp)
  82{
  83        WARN_ON(s->len > s->size + 1);
  84
  85        if (s->len < s->size) {
  86                *bufp = s->buffer + s->len;
  87                return s->size - s->len;
  88        }
  89
  90        *bufp = NULL;
  91        return 0;
  92}
  93
  94/**
  95 * seq_buf_commit - commit data to the buffer
  96 * @s: the seq_buf handle
  97 * @num: the number of bytes to commit
  98 *
  99 * Commit @num bytes of data written to a buffer previously acquired
 100 * by seq_buf_get.  To signal an error condition, or that the data
 101 * didn't fit in the available space, pass a negative @num value.
 102 */
 103static inline void seq_buf_commit(struct seq_buf *s, int num)
 104{
 105        if (num < 0) {
 106                seq_buf_set_overflow(s);
 107        } else {
 108                /* num must be negative on overflow */
 109                BUG_ON(s->len + num > s->size);
 110                s->len += num;
 111        }
 112}
 113
 114extern __printf(2, 3)
 115int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
 116extern __printf(2, 0)
 117int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
 118extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
 119extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
 120                           int cnt);
 121extern int seq_buf_puts(struct seq_buf *s, const char *str);
 122extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
 123extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
 124extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
 125                              unsigned int len);
 126extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
 127
 128#ifdef CONFIG_BINARY_PRINTF
 129extern int
 130seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
 131#endif
 132
 133#endif /* _LINUX_SEQ_BUF_H */
 134