10 FILE_LICENCE ( GPL2_OR_LATER );
14 #include <ipxe/list.h>
17 * Minimum I/O buffer length
19 * alloc_iob() will round up the allocated length to this size if
20 * necessary. This is used on behalf of hardware that is not capable
26 * A persistent I/O buffer
28 * This data structure encapsulates a long-lived I/O buffer. The
29 * buffer may be passed between multiple owners, queued for possible
30 * retransmission, etc.
33 /** List of which this buffer is a member
35 * The list must belong to the current owner of the buffer.
36 * Different owners may maintain different lists (e.g. a
37 * retransmission list for TCP).
39 struct list_head list;
41 /** Start of the buffer */
47 /** End of the buffer */
52 * Reserve space at start of I/O buffer
55 * @v len Length to reserve
56 * @ret data Pointer to new start of buffer
58 static inline void * iob_reserve ( struct io_buffer *iobuf, size_t len ) {
63 #define iob_reserve( iobuf, len ) ( { \
65 __result = iob_reserve ( (iobuf), (len) ); \
66 assert ( (iobuf)->tail <= (iobuf)->end ); \
70 * Add data to start of I/O buffer
73 * @v len Length to add
74 * @ret data Pointer to new start of buffer
76 static inline void * iob_push ( struct io_buffer *iobuf, size_t len ) {
80 #define iob_push( iobuf, len ) ( { \
82 __result = iob_push ( (iobuf), (len) ); \
83 assert ( (iobuf)->data >= (iobuf)->head ); \
87 * Remove data from start of I/O buffer
90 * @v len Length to remove
91 * @ret data Pointer to new start of buffer
93 static inline void * iob_pull ( struct io_buffer *iobuf, size_t len ) {
95 assert ( iobuf->data <= iobuf->tail );
98 #define iob_pull( iobuf, len ) ( { \
100 __result = iob_pull ( (iobuf), (len) ); \
101 assert ( (iobuf)->data <= (iobuf)->tail ); \
105 * Add data to end of I/O buffer
107 * @v iobuf I/O buffer
108 * @v len Length to add
109 * @ret data Pointer to newly added space
111 static inline void * iob_put ( struct io_buffer *iobuf, size_t len ) {
112 void *old_tail = iobuf->tail;
116 #define iob_put( iobuf, len ) ( { \
118 __result = iob_put ( (iobuf), (len) ); \
119 assert ( (iobuf)->tail <= (iobuf)->end ); \
123 * Remove data from end of I/O buffer
125 * @v iobuf I/O buffer
126 * @v len Length to remove
128 static inline void iob_unput ( struct io_buffer *iobuf, size_t len ) {
131 #define iob_unput( iobuf, len ) do { \
132 iob_unput ( (iobuf), (len) ); \
133 assert ( (iobuf)->tail >= (iobuf)->data ); \
137 * Empty an I/O buffer
139 * @v iobuf I/O buffer
141 static inline void iob_empty ( struct io_buffer *iobuf ) {
142 iobuf->tail = iobuf->data;
146 * Calculate length of data in an I/O buffer
148 * @v iobuf I/O buffer
149 * @ret len Length of data in buffer
151 static inline size_t iob_len ( struct io_buffer *iobuf ) {
152 return ( iobuf->tail - iobuf->data );
156 * Calculate available space at start of an I/O buffer
158 * @v iobuf I/O buffer
159 * @ret len Length of data available at start of buffer
161 static inline size_t iob_headroom ( struct io_buffer *iobuf ) {
162 return ( iobuf->data - iobuf->head );
166 * Calculate available space at end of an I/O buffer
168 * @v iobuf I/O buffer
169 * @ret len Length of data available at end of buffer
171 static inline size_t iob_tailroom ( struct io_buffer *iobuf ) {
172 return ( iobuf->end - iobuf->tail );
176 * Create a temporary I/O buffer
178 * @v iobuf I/O buffer
179 * @v data Data buffer
180 * @v len Length of data
181 * @v max_len Length of buffer
183 * It is sometimes useful to use the iob_xxx() methods on temporary
186 static inline void iob_populate ( struct io_buffer *iobuf,
187 void *data, size_t len, size_t max_len ) {
188 iobuf->head = iobuf->data = data;
189 iobuf->tail = ( data + len );
190 iobuf->end = ( data + max_len );
194 * Disown an I/O buffer
196 * @v iobuf I/O buffer
198 * There are many functions that take ownership of the I/O buffer they
199 * are passed as a parameter. The caller should not retain a pointer
200 * to the I/O buffer. Use iob_disown() to automatically nullify the
201 * caller's pointer, e.g.:
203 * xfer_deliver_iob ( xfer, iob_disown ( iobuf ) );
205 * This will ensure that iobuf is set to NULL for any code after the
206 * call to xfer_deliver_iob().
208 #define iob_disown( iobuf ) ( { \
209 struct io_buffer *__iobuf = (iobuf); \
213 extern struct io_buffer * __malloc alloc_iob_raw ( size_t len, size_t align,
215 extern struct io_buffer * __malloc alloc_iob ( size_t len );
216 extern void free_iob ( struct io_buffer *iobuf );
217 extern void iob_pad ( struct io_buffer *iobuf, size_t min_len );
218 extern int iob_ensure_headroom ( struct io_buffer *iobuf, size_t len );
219 extern struct io_buffer * iob_concatenate ( struct list_head *list );
221 #endif /* _IPXE_IOBUF_H */