From: Ben Gras <ben@minix3.org>
Date: Wed, 6 Jul 2005 07:22:21 +0000 (+0000)
Subject: Changed FD_* select() fd set manipulation functions to macros. Also
X-Git-Tag: v3.1.0~644
X-Git-Url: http://zhaoyanbai.com/repos/%22../static/howto.html?a=commitdiff_plain;h=1adcfcdf1c955d268f5e931b83af8ce4428a3b67;p=minix.git

Changed FD_* select() fd set manipulation functions to macros. Also
made FD_SETSIZE pre-#include-definable, with OPEN_MAX as default if unset.
---

diff --git a/include/sys/select.h b/include/sys/select.h
index 8517124b6..96f7cc015 100755
--- a/include/sys/select.h
+++ b/include/sys/select.h
@@ -5,6 +5,7 @@
 #include <sys/time.h>
 #include <sys/types.h>
 #include <limits.h>
+#include <string.h>
 
 /* Use this datatype as basic storage unit in fd_set */
 typedef u32_t _fdsetword;	
@@ -12,11 +13,17 @@ typedef u32_t _fdsetword;
 /* This many bits fit in an fd_set word. */
 #define _FDSETBITSPERWORD	(sizeof(_fdsetword)*8)
 
-/* We want to store OPEN_MAX fd bits. */
-#define _FDSETWORDS	((OPEN_MAX+_FDSETBITSPERWORD-1)/_FDSETBITSPERWORD)
+/* Bit manipulation macros */
+#define _FD_BITMASK(b)	(1L << ((b) % _FDSETBITSPERWORD))
+#define _FD_BITWORD(b)	((b)/_FDSETBITSPERWORD)
 
-/* This means we can store all of OPEN_MAX. */
+/* Default FD_SETSIZE is OPEN_MAX. */
+#ifndef FD_SETSIZE
 #define FD_SETSIZE		OPEN_MAX
+#endif
+
+/* We want to store FD_SETSIZE bits. */
+#define _FDSETWORDS	((FD_SETSIZE+_FDSETBITSPERWORD-1)/_FDSETBITSPERWORD)
 
 typedef struct {
 	_fdsetword	_fdsetval[_FDSETWORDS];
@@ -24,10 +31,10 @@ typedef struct {
 
 _PROTOTYPE( int select, (int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *timeout) );
 
-_PROTOTYPE( void FD_CLR, (int fd, fd_set *fdset));
-_PROTOTYPE( int FD_ISSET, (int fd, fd_set *fdset));
-_PROTOTYPE( void FD_SET, (int fd, fd_set *fdset));
-_PROTOTYPE( void FD_ZERO, (fd_set *fdset));
+#define FD_ZERO(s) do { memset((s), sizeof(s), 0); } while(0)
+#define FD_SET(f, s) do { (s)->_fdsetval[_FD_BITWORD(f)] |= _FD_BITMASK(f); } while(0)
+#define FD_CLR(f, s) do { (s)->_fdsetval[_FD_BITWORD(f)] &= ~(_FD_BITMASK(f)); } while(0)
+#define FD_ISSET(f, s) ((s)->_fdsetval[_FD_BITWORD(f)] & _FD_BITMASK(f))
 
 /* possible select() operation types; read, write, errors */
 /* (FS/driver internal use only) */
diff --git a/lib/posix/_select.c b/lib/posix/_select.c
index 4b86d1c97..7d46e6de7 100755
--- a/lib/posix/_select.c
+++ b/lib/posix/_select.c
@@ -18,38 +18,3 @@ PUBLIC int select(int nfds,
   return (_syscall(FS, SELECT, &m));
 }
 
-#define FD_BITMASK(b)	(1L << ((b) % _FDSETBITSPERWORD))
-#define FD_BITWORD(b)	((b)/_FDSETBITSPERWORD)
-
-PUBLIC void FD_CLR(int fd, fd_set *fdset)
-{
-	if(fd < 0 || fd >= FD_SETSIZE) return;
-	fdset->_fdsetval[FD_BITWORD(fd)] &= ~(FD_BITMASK(fd));
-	return;
-}
-
-PUBLIC int FD_ISSET(int fd, fd_set *fdset)
-{
-	if(fd < 0 || fd >= FD_SETSIZE)
-		return 0;
-	if(fdset->_fdsetval[FD_BITWORD(fd)] & FD_BITMASK(fd))
-		return 1;
-	return 0;
-}
-
-PUBLIC void FD_SET(int fd, fd_set *fdset)
-{
-	if(fd < 0 || fd >= FD_SETSIZE)
-		return;
-	fdset->_fdsetval[FD_BITWORD(fd)] |= FD_BITMASK(fd);
-	return;
-}
-
-PUBLIC void FD_ZERO(fd_set *fdset)
-{
-	int i;
-	for(i = 0; i < _FDSETWORDS; i++)
-		fdset->_fdsetval[i] = 0;
-	return;
-}
-