include/linux/seq_buf.h

   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  */
  18 struct seq_buf {
  19         char                    *buffer;
  20         size_t                  size;
  21         size_t                  len;
  22         loff_t                  readpos;
  23 };
  24
  25 static inline void seq_buf_clear(struct seq_buf *s)
  26 {
  27         s->len = 0;
  28         s->readpos = 0;
  29 }
  30
  31 static inline void
  32 seq_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  */
  43 static inline bool
  44 seq_buf_has_overflowed(struct seq_buf *s)
  45 {
  46         return s->len > s->size;
  47 }
  48
  49 static inline void
  50 seq_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  */
  58 static inline unsigned int
  59 seq_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? */
  68 static 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  */
  81 static 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  */
 103 static 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
 114 extern __printf(2, 3)
 115 int seq_buf_printf(struct seq_buf *s, const char *fmt, ...);
 116 extern __printf(2, 0)
 117 int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args);
 118 extern int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s);
 119 extern int seq_buf_to_user(struct seq_buf *s, char __user *ubuf,
 120                            int cnt);
 121 extern int seq_buf_puts(struct seq_buf *s, const char *str);
 122 extern int seq_buf_putc(struct seq_buf *s, unsigned char c);
 123 extern int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len);
 124 extern int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
 125                               unsigned int len);
 126 extern int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc);
 127
 128 #ifdef CONFIG_BINARY_PRINTF
 129 extern int
 130 seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary);
 131 #endif
 132
 133 #endif /* _LINUX_SEQ_BUF_H */