xferbuf.h

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#ifndef _IPXE_XFERBUF_H
#define _IPXE_XFERBUF_H

/** @file
 *
 * Data transfer buffer
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <ipxe/iobuf.h>
#include <ipxe/uaccess.h>
#include <ipxe/interface.h>
#include <ipxe/xfer.h>

/** A data transfer buffer */
struct xfer_buffer {
        /** Data */
        void *data;
        /** Size of data */
        size_t len;
        /** Current offset within data */
        size_t pos;
        /** Data transfer buffer operations */
        struct xfer_buffer_operations *op;
};

/** Data transfer buffer operations */
struct xfer_buffer_operations {
        /** Reallocate data buffer
         *
         * @v xferbuf           Data transfer buffer
         * @v len               New length (or zero to free buffer)
         * @ret rc              Return status code
         */
        int ( * realloc ) ( struct xfer_buffer *xferbuf, size_t len );
        /** Write data to buffer
         *
         * @v xferbuf           Data transfer buffer
         * @v offset            Starting offset
         * @v data              Data to write
         * @v len               Length of data
         *
         * This call is simply a wrapper for the appropriate
         * memcpy()-like operation: the caller is responsible for
         * ensuring that the write does not exceed the buffer length.
         */
        void ( * write ) ( struct xfer_buffer *xferbuf, size_t offset,
                           const void *data, size_t len );
        /** Read data from buffer
         *
         * @v xferbuf           Data transfer buffer
         * @v offset            Starting offset
         * @v data              Data to read
         * @v len               Length of data
         *
         * This call is simply a wrapper for the appropriate
         * memcpy()-like operation: the caller is responsible for
         * ensuring that the read does not exceed the buffer length.
         */
        void ( * read ) ( struct xfer_buffer *xferbuf, size_t offset,
                          void *data, size_t len );
};

extern struct xfer_buffer_operations xferbuf_malloc_operations;
extern struct xfer_buffer_operations xferbuf_umalloc_operations;

/**
 * Initialise malloc()-based data transfer buffer
 *
 * @v xferbuf           Data transfer buffer
 */
static inline __attribute__ (( always_inline )) void
xferbuf_malloc_init ( struct xfer_buffer *xferbuf ) {
        xferbuf->op = &xferbuf_malloc_operations;
}

/**
 * Initialise umalloc()-based data transfer buffer
 *
 * @v xferbuf           Data transfer buffer
 * @v data              User pointer
 */
static inline __attribute__ (( always_inline )) void
xferbuf_umalloc_init ( struct xfer_buffer *xferbuf, userptr_t *data ) {
        xferbuf->data = data;
        xferbuf->op = &xferbuf_umalloc_operations;
}

extern void xferbuf_free ( struct xfer_buffer *xferbuf );
extern int xferbuf_write ( struct xfer_buffer *xferbuf, size_t offset,
                           const void *data, size_t len );
extern int xferbuf_read ( struct xfer_buffer *xferbuf, size_t offset,
                          void *data, size_t len );
extern int xferbuf_deliver ( struct xfer_buffer *xferbuf,
                             struct io_buffer *iobuf,
                             struct xfer_metadata *meta );

extern struct xfer_buffer * xfer_buffer ( struct interface *intf );
#define xfer_buffer_TYPE( object_type ) \
        typeof ( struct xfer_buffer * ( object_type ) )

#endif /* _IPXE_XFERBUF_H */