[project @ 1998-12-02 13:17:09 by simonm]

Move 4.01 onto the main trunk.

1 files changed, 92 insertions, 0 deletions

diff --git a/ghc/lib/std/cbits/inputReady.c b/ghc/lib/std/cbits/inputReady.c
new file mode 100644
index 0000000000..cea179018a
--- /dev/null
+++ b/ghc/lib/std/cbits/inputReady.c
@@ -0,0 +1,92 @@
+/* 
+ * (c) The GRASP/AQUA Project, Glasgow University, 1994-1998
+ *
+ * $Id: inputReady.c,v 1.3 1998/12/02 13:27:42 simonm Exp $
+ *
+ * hReady Runtime Support
+ */
+
+/* select and supporting types is not */
+#ifndef _AIX
+#define NON_POSIX_SOURCE  
+#endif
+
+#include "Rts.h"
+#include "stgio.h"
+
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#ifdef _AIX 
+/* this is included from sys/types.h only if _BSD is defined. */
+/* Since it is not, I include it here. - andre */
+#include <sys/select.h>
+#endif
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+/*
+ * inputReady(ptr, msecs) checks to see whether input is available
+ * on the file object 'ptr', timing out after (approx.) 'msec' milliseconds.
+ * Input meaning 'can I safely read at least a *character* from this file
+ * object without blocking?'
+ * 
+ * If the file object has a non-empty buffer, the test is trivial. If not,
+ * we select() on the (readable) file descriptor.
+ *
+ * Notice that for file descriptors connected to ttys in non-canonical mode
+ * (i.e., it's buffered), inputReady will not return true until a *complete
+ * line* can be read.
+ */
+
+StgInt
+inputReady(ptr, msecs)
+StgForeignPtr ptr;
+StgInt msecs;
+{
+    IOFileObject* fo = (IOFileObject*)ptr;
+    int c, fd, maxfd, ready;
+    fd_set rfd;
+    struct timeval tv;
+
+    if ( FILEOBJ_IS_EOF(fo) )
+	return 0;
+
+    if ( !FILEOBJ_BUFFER_EMPTY(fo) ) {
+	   /* Don't look any further, there's stuff in the buffer */
+	   return 1;
+    }
+
+    fd = fo->fd;
+
+    /* Now try to get a character */
+    FD_ZERO(&rfd);
+    FD_SET(fd, &rfd);
+    /* select() will consider the descriptor set in the range of 0 to (maxfd-1) */
+    maxfd = fd + 1;
+    tv.tv_sec  = msecs / 1000;
+    tv.tv_usec = msecs % 1000;
+    while ((ready = select(maxfd, &rfd, NULL, NULL, &tv)) < 0 ) {
+      if (errno != EINTR ) {
+		cvtErrno();
+		stdErrno();
+                ready = -1;
+      		break;
+      }
+   }
+
+    /* 1 => Input ready, 0 => time expired  (-1 error) */
+    return (ready);
+
+}