-/* Circular Buffer */
-
-/*
- * edge_buf_alloc
- *
- * Allocate a circular buffer and all associated memory.
- */
-
-static struct edge_buf *edge_buf_alloc(unsigned int size)
-{
- struct edge_buf *eb;
-
-
- if (size == 0)
- return NULL;
-
- eb = kmalloc(sizeof(struct edge_buf), GFP_KERNEL);
- if (eb == NULL)
- return NULL;
-
- eb->buf_buf = kmalloc(size, GFP_KERNEL);
- if (eb->buf_buf == NULL) {
- kfree(eb);
- return NULL;
- }
-
- eb->buf_size = size;
- eb->buf_get = eb->buf_put = eb->buf_buf;
-
- return eb;
-}
-
-
-/*
- * edge_buf_free
- *
- * Free the buffer and all associated memory.
- */
-
-static void edge_buf_free(struct edge_buf *eb)
-{
- if (eb) {
- kfree(eb->buf_buf);
- kfree(eb);
- }
-}
-
-
-/*
- * edge_buf_clear
- *
- * Clear out all data in the circular buffer.
- */
-
-static void edge_buf_clear(struct edge_buf *eb)
-{
- if (eb != NULL)
- eb->buf_get = eb->buf_put;
- /* equivalent to a get of all data available */
-}
-
-
-/*
- * edge_buf_data_avail
- *
- * Return the number of bytes of data available in the circular
- * buffer.
- */
-
-static unsigned int edge_buf_data_avail(struct edge_buf *eb)
-{
- if (eb == NULL)
- return 0;
- return ((eb->buf_size + eb->buf_put - eb->buf_get) % eb->buf_size);
-}
-
-
-/*
- * edge_buf_space_avail
- *
- * Return the number of bytes of space available in the circular
- * buffer.
- */
-
-static unsigned int edge_buf_space_avail(struct edge_buf *eb)
-{
- if (eb == NULL)
- return 0;
- return ((eb->buf_size + eb->buf_get - eb->buf_put - 1) % eb->buf_size);
-}
-
-
-/*
- * edge_buf_put
- *
- * Copy data data from a user buffer and put it into the circular buffer.
- * Restrict to the amount of space available.
- *
- * Return the number of bytes copied.
- */
-
-static unsigned int edge_buf_put(struct edge_buf *eb, const char *buf,
- unsigned int count)
-{
- unsigned int len;
-
-
- if (eb == NULL)
- return 0;
-
- len = edge_buf_space_avail(eb);
- if (count > len)
- count = len;
-
- if (count == 0)
- return 0;
-
- len = eb->buf_buf + eb->buf_size - eb->buf_put;
- if (count > len) {
- memcpy(eb->buf_put, buf, len);
- memcpy(eb->buf_buf, buf+len, count - len);
- eb->buf_put = eb->buf_buf + count - len;
- } else {
- memcpy(eb->buf_put, buf, count);
- if (count < len)
- eb->buf_put += count;
- else /* count == len */
- eb->buf_put = eb->buf_buf;
- }
-
- return count;
-}
-
-
-/*
- * edge_buf_get
- *
- * Get data from the circular buffer and copy to the given buffer.
- * Restrict to the amount of data available.
- *
- * Return the number of bytes copied.
- */
-
-static unsigned int edge_buf_get(struct edge_buf *eb, char *buf,
- unsigned int count)
-{
- unsigned int len;
-
-
- if (eb == NULL)
- return 0;
-
- len = edge_buf_data_avail(eb);
- if (count > len)
- count = len;
-
- if (count == 0)
- return 0;
-
- len = eb->buf_buf + eb->buf_size - eb->buf_get;
- if (count > len) {
- memcpy(buf, eb->buf_get, len);
- memcpy(buf+len, eb->buf_buf, count - len);
- eb->buf_get = eb->buf_buf + count - len;
- } else {
- memcpy(buf, eb->buf_get, count);
- if (count < len)
- eb->buf_get += count;
- else /* count == len */
- eb->buf_get = eb->buf_buf;
- }
-
- return count;
-}
-
-