Move c_src dirs back to toplevel

[bcachefs-tools-debian] / include / linux / seq_buf.h

diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
new file mode 100644 (file)
index 0000000..8c9c0dd
--- /dev/null
+++ b/include/linux/seq_buf.h
@@ -0,0 +1,153 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_SEQ_BUF_H
+#define _LINUX_SEQ_BUF_H
+
+#include <linux/kernel.h>
+#include <stdarg.h>
+#include <string.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, 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_terminate - Make sure buffer is nul terminated
+ * @s: the seq_buf descriptor to terminate.
+ *
+ * This makes sure that the buffer in @s is nul terminated and
+ * safe to read as a string.
+ *
+ * Note, if this is called when the buffer has overflowed, then
+ * the last byte of the buffer is zeroed, and the len will still
+ * point passed it.
+ *
+ * After this function is called, s->buffer is safe to use
+ * in string operations.
+ */
+static inline void seq_buf_terminate(struct seq_buf *s)
+{
+       if (WARN_ON(s->size == 0))
+               return;
+
+       if (seq_buf_buffer_left(s))
+               s->buffer[s->len] = 0;
+       else
+               s->buffer[s->size - 1] = 0;
+}
+
+/**
+ * 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_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);
+
+void seq_buf_human_readable_u64(struct seq_buf *, u64);
+
+#endif /* _LINUX_SEQ_BUF_H */