--- /dev/null
+#ifndef _IPXE_IOBUF_H
+#define _IPXE_IOBUF_H
+
+/** @file
+ *
+ * I/O buffers
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <assert.h>
+#include <ipxe/list.h>
+
+/**
+ * Minimum I/O buffer length
+ *
+ * alloc_iob() will round up the allocated length to this size if
+ * necessary. This is used on behalf of hardware that is not capable
+ * of auto-padding.
+ */
+#define IOB_ZLEN 64
+
+/**
+ * A persistent I/O buffer
+ *
+ * This data structure encapsulates a long-lived I/O buffer. The
+ * buffer may be passed between multiple owners, queued for possible
+ * retransmission, etc.
+ */
+struct io_buffer {
+ /** List of which this buffer is a member
+ *
+ * The list must belong to the current owner of the buffer.
+ * Different owners may maintain different lists (e.g. a
+ * retransmission list for TCP).
+ */
+ struct list_head list;
+
+ /** Start of the buffer */
+ void *head;
+ /** Start of data */
+ void *data;
+ /** End of data */
+ void *tail;
+ /** End of the buffer */
+ void *end;
+};
+
+/**
+ * Reserve space at start of I/O buffer
+ *
+ * @v iobuf I/O buffer
+ * @v len Length to reserve
+ * @ret data Pointer to new start of buffer
+ */
+static inline void * iob_reserve ( struct io_buffer *iobuf, size_t len ) {
+ iobuf->data += len;
+ iobuf->tail += len;
+ return iobuf->data;
+}
+#define iob_reserve( iobuf, len ) ( { \
+ void *__result; \
+ __result = iob_reserve ( (iobuf), (len) ); \
+ assert ( (iobuf)->tail <= (iobuf)->end ); \
+ __result; } )
+
+/**
+ * Add data to start of I/O buffer
+ *
+ * @v iobuf I/O buffer
+ * @v len Length to add
+ * @ret data Pointer to new start of buffer
+ */
+static inline void * iob_push ( struct io_buffer *iobuf, size_t len ) {
+ iobuf->data -= len;
+ return iobuf->data;
+}
+#define iob_push( iobuf, len ) ( { \
+ void *__result; \
+ __result = iob_push ( (iobuf), (len) ); \
+ assert ( (iobuf)->data >= (iobuf)->head ); \
+ __result; } )
+
+/**
+ * Remove data from start of I/O buffer
+ *
+ * @v iobuf I/O buffer
+ * @v len Length to remove
+ * @ret data Pointer to new start of buffer
+ */
+static inline void * iob_pull ( struct io_buffer *iobuf, size_t len ) {
+ iobuf->data += len;
+ assert ( iobuf->data <= iobuf->tail );
+ return iobuf->data;
+}
+#define iob_pull( iobuf, len ) ( { \
+ void *__result; \
+ __result = iob_pull ( (iobuf), (len) ); \
+ assert ( (iobuf)->data <= (iobuf)->tail ); \
+ __result; } )
+
+/**
+ * Add data to end of I/O buffer
+ *
+ * @v iobuf I/O buffer
+ * @v len Length to add
+ * @ret data Pointer to newly added space
+ */
+static inline void * iob_put ( struct io_buffer *iobuf, size_t len ) {
+ void *old_tail = iobuf->tail;
+ iobuf->tail += len;
+ return old_tail;
+}
+#define iob_put( iobuf, len ) ( { \
+ void *__result; \
+ __result = iob_put ( (iobuf), (len) ); \
+ assert ( (iobuf)->tail <= (iobuf)->end ); \
+ __result; } )
+
+/**
+ * Remove data from end of I/O buffer
+ *
+ * @v iobuf I/O buffer
+ * @v len Length to remove
+ */
+static inline void iob_unput ( struct io_buffer *iobuf, size_t len ) {
+ iobuf->tail -= len;
+}
+#define iob_unput( iobuf, len ) do { \
+ iob_unput ( (iobuf), (len) ); \
+ assert ( (iobuf)->tail >= (iobuf)->data ); \
+ } while ( 0 )
+
+/**
+ * Empty an I/O buffer
+ *
+ * @v iobuf I/O buffer
+ */
+static inline void iob_empty ( struct io_buffer *iobuf ) {
+ iobuf->tail = iobuf->data;
+}
+
+/**
+ * Calculate length of data in an I/O buffer
+ *
+ * @v iobuf I/O buffer
+ * @ret len Length of data in buffer
+ */
+static inline size_t iob_len ( struct io_buffer *iobuf ) {
+ return ( iobuf->tail - iobuf->data );
+}
+
+/**
+ * Calculate available space at start of an I/O buffer
+ *
+ * @v iobuf I/O buffer
+ * @ret len Length of data available at start of buffer
+ */
+static inline size_t iob_headroom ( struct io_buffer *iobuf ) {
+ return ( iobuf->data - iobuf->head );
+}
+
+/**
+ * Calculate available space at end of an I/O buffer
+ *
+ * @v iobuf I/O buffer
+ * @ret len Length of data available at end of buffer
+ */
+static inline size_t iob_tailroom ( struct io_buffer *iobuf ) {
+ return ( iobuf->end - iobuf->tail );
+}
+
+/**
+ * Create a temporary I/O buffer
+ *
+ * @v iobuf I/O buffer
+ * @v data Data buffer
+ * @v len Length of data
+ * @v max_len Length of buffer
+ *
+ * It is sometimes useful to use the iob_xxx() methods on temporary
+ * data buffers.
+ */
+static inline void iob_populate ( struct io_buffer *iobuf,
+ void *data, size_t len, size_t max_len ) {
+ iobuf->head = iobuf->data = data;
+ iobuf->tail = ( data + len );
+ iobuf->end = ( data + max_len );
+}
+
+/**
+ * Disown an I/O buffer
+ *
+ * @v iobuf I/O buffer
+ *
+ * There are many functions that take ownership of the I/O buffer they
+ * are passed as a parameter. The caller should not retain a pointer
+ * to the I/O buffer. Use iob_disown() to automatically nullify the
+ * caller's pointer, e.g.:
+ *
+ * xfer_deliver_iob ( xfer, iob_disown ( iobuf ) );
+ *
+ * This will ensure that iobuf is set to NULL for any code after the
+ * call to xfer_deliver_iob().
+ */
+#define iob_disown( iobuf ) ( { \
+ struct io_buffer *__iobuf = (iobuf); \
+ (iobuf) = NULL; \
+ __iobuf; } )
+
+extern struct io_buffer * __malloc alloc_iob_raw ( size_t len, size_t align,
+ size_t offset );
+extern struct io_buffer * __malloc alloc_iob ( size_t len );
+extern void free_iob ( struct io_buffer *iobuf );
+extern void iob_pad ( struct io_buffer *iobuf, size_t min_len );
+extern int iob_ensure_headroom ( struct io_buffer *iobuf, size_t len );
+extern struct io_buffer * iob_concatenate ( struct list_head *list );
+
+#endif /* _IPXE_IOBUF_H */
Code Review / kvmfornfv.git / blobdiff