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/**
* @file large_fd_set.h
*
* @brief Macro's and functions for manipulation of large file descriptor sets.
*/
#ifndef LARGE_FD_SET_H
#define LARGE_FD_SET_H
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/types.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#if defined(HAVE_WINSOCK_H) && !defined(_WINSOCKAPI_) && !defined(_WINSOCK_H)
#error <winsock.h> or <winsock2.h> must have been included before this file.
#endif
#ifdef __cplusplus
extern "C" {
#endif
/**
* Add socket fd to the set *fdset if not yet present.
* Enlarges the set if necessary.
*/
#define NETSNMP_LARGE_FD_SET(fd, fdset) \
netsnmp_large_fd_setfd(fd, fdset)
/**
* Remove socket fd from the set *fdset.
* Do nothing if fd is not present in *fdset.
* Do nothing if fd >= fdset->lfs_setsize.
*/
#define NETSNMP_LARGE_FD_CLR(fd, fdset) \
netsnmp_large_fd_clr(fd, fdset)
/**
* Test whether set *fdset contains socket fd.
* Evaluates to zero (false) if fd >= fdset->lfs_setsize.
*/
#define NETSNMP_LARGE_FD_ISSET(fd, fdset) \
netsnmp_large_fd_is_set(fd, fdset)
#if !defined(cygwin) && defined(HAVE_WINSOCK_H)
/**
* Number of bytes needed to store a number of file descriptors as a
* struct fd_set.
*/
#define NETSNMP_FD_SET_BYTES(setsize) \
(sizeof(fd_set) + ((setsize) - FD_SETSIZE) * sizeof(SOCKET))
/** Remove all sockets from the set *fdset. */
#define NETSNMP_LARGE_FD_ZERO(fdset) \
do { (fdset)->lfs_setptr->fd_count = 0; } while(0)
NETSNMP_IMPORT
void netsnmp_large_fd_setfd( SOCKET fd, netsnmp_large_fd_set *fdset);
NETSNMP_IMPORT
void netsnmp_large_fd_clr( SOCKET fd, netsnmp_large_fd_set *fdset);
NETSNMP_IMPORT
int netsnmp_large_fd_is_set(SOCKET fd, netsnmp_large_fd_set *fdset);
#else
/**
* Size of a single element of the array with file descriptor bitmasks.
*
* According to SUSv2, this array must have the name fds_bits. See also
* <a href="http://www.opengroup.org/onlinepubs/007908775/xsh/systime.h.html">The Single UNIX Specification, Version 2, <sys/time.h></a>.
*/
#define NETSNMP_FD_MASK_SIZE sizeof(((fd_set*)0)->fds_bits[0])
/** Number of bits in one element of the fd_set.fds_bits array. */
#define NETSNMP_BITS_PER_FD_MASK (8 * NETSNMP_FD_MASK_SIZE)
/** Number of elements needed for the fds_bits array. */
#define NETSNMP_FD_SET_ELEM_COUNT(setsize) \
(setsize + NETSNMP_BITS_PER_FD_MASK - 1) / NETSNMP_BITS_PER_FD_MASK
/**
* Number of bytes needed to store a number of file descriptors as a
* struct fd_set.
*/
#define NETSNMP_FD_SET_BYTES(setsize) \
(sizeof(fd_set) + NETSNMP_FD_SET_ELEM_COUNT((setsize) - FD_SETSIZE) \
* NETSNMP_FD_MASK_SIZE)
/** Remove all file descriptors from the set *fdset. */
#define NETSNMP_LARGE_FD_ZERO(fdset) \
do { \
memset((fdset)->lfs_setptr, 0, \
NETSNMP_FD_SET_BYTES((fdset)->lfs_setsize)); \
} while (0)
void netsnmp_large_fd_setfd( int fd, netsnmp_large_fd_set *fdset);
void netsnmp_large_fd_clr( int fd, netsnmp_large_fd_set *fdset);
int netsnmp_large_fd_is_set(int fd, netsnmp_large_fd_set *fdset);
#endif
/**
* Initialize a netsnmp_large_fd_set structure.
*
* Note: this function only initializes the lfs_setsize and lfs_setptr
* members of netsnmp_large_fd_set, not the file descriptor set itself.
* The file descriptor set must be initialized separately, e.g. via
* NETSNMP_LARGE_FD_CLR().
*/
NETSNMP_IMPORT
void netsnmp_large_fd_set_init( netsnmp_large_fd_set *fdset, int setsize);
/**
* Modify the size of a file descriptor set and preserve the first
* min(fdset->lfs_setsize, setsize) file descriptors.
*
* Returns 1 upon success or 0 if memory allocation failed.
*/
int netsnmp_large_fd_set_resize( netsnmp_large_fd_set *fdset, int setsize);
/**
* Synchronous I/O multiplexing for large file descriptor sets.
*
* On POSIX systems, any file descriptor set with size below numfds will be
* resized before invoking select().
*
* @see See also select(2) for more information.
*/
NETSNMP_IMPORT
int netsnmp_large_fd_set_select(int numfds, netsnmp_large_fd_set *readfds,
netsnmp_large_fd_set *writefds,
netsnmp_large_fd_set *exceptfds,
struct timeval *timeout);
/** Deallocate the memory allocated by netsnmp_large_fd_set_init. */
NETSNMP_IMPORT
void netsnmp_large_fd_set_cleanup(netsnmp_large_fd_set *fdset);
/**
* Copy an fd_set to a netsnmp_large_fd_set structure.
*
* @note dst must have been initialized before this function is called.
*/
void netsnmp_copy_fd_set_to_large_fd_set(netsnmp_large_fd_set *dst,
const fd_set *src);
/**
* Copy a netsnmp_large_fd_set structure into an fd_set.
*
* @return 0 upon success, -1 when copying fails because *src is too large to
* fit into *dst.
*/
int netsnmp_copy_large_fd_set_to_fd_set( fd_set *dst,
const netsnmp_large_fd_set *src);
#ifdef __cplusplus
}
#endif
#endif /* LARGE_FD_SET_H */
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