[project @ 1998-08-14 12:42:01 by sof]

Beefed up IO stub functions to not have to rely on stdio any longer

1 files changed, 78 insertions, 0 deletions

diff --git a/ghc/lib/std/cbits/fileObject.h b/ghc/lib/std/cbits/fileObject.h
new file mode 100644
index 0000000000..f41e8fdcad
--- /dev/null
+++ b/ghc/lib/std/cbits/fileObject.h
@@ -0,0 +1,78 @@
+#ifndef FILEOBJECT_H
+#define FILEOBJECT_H
+
+/* a good idea? */
+#include <stdio.h>
+
+/*
+  IOFileObjects are used as part of the IO.Handle
+  implementation, ensuring that when handles are
+  finalised, buffers are flushed and FILE* objects
+  are closed (we really should be using file descriptors
+  here..)
+  
+ */
+
+typedef struct _IOFileObject {
+   int     fd;
+   void*   buf;
+   int     bufWPtr;  /* points to next position to write,
+   			  bufRPtr >= bufWPtr <= bufSize.
+			  
+			For read-only files, bufWPtr = bufSize
+
+			bufWPtr = 0 => buffer is empty.
+
+		     */
+   int     bufRPtr;  /* points to the next char to read 
+   			  -1 >= bufRPtr <= bufWPtr 
+			  
+		        For write-only files, bufRPtr = 0
+
+			bufRPtr == -1 => buffer is empty.
+		     */
+   int     bufSize;
+   int     flags;
+   struct _IOFileObject*   connectedTo;
+} IOFileObject;
+
+#define FILEOBJ_FLUSH    1
+#define FILEOBJ_LB       2
+#define FILEOBJ_BB       4
+#define FILEOBJ_EOF      8
+#define FILEOBJ_READ    16
+#define FILEOBJ_WRITE   32
+#define FILEOBJ_STD     64
+#define FILEOBJ_NONBLOCKING_IO 128
+/* The next two flags are used for RW file objects only.
+   They indicate whether the last operation was a read or a write.
+   (Need this info to determine whether a RW file object's
+    buffer should be flushed before doing a subsequent
+    read or write).
+*/
+#define FILEOBJ_RW_READ 256
+#define FILEOBJ_RW_WRITE 512
+
+#define FILEOBJ_IS_EOF(x)     ((x)->flags & FILEOBJ_EOF)
+#define FILEOBJ_SET_EOF(x)    ((x)->flags |= FILEOBJ_EOF)
+#define FILEOBJ_CLEAR_EOF(x)  ((x)->flags &= ~FILEOBJ_EOF)
+#define FILEOBJ_CLEAR_ERR(x)  FILEOBJ_CLEAR_EOF(x)
+
+#define FILEOBJ_BLOCKED_READ   -5
+#define FILEOBJ_BLOCKED_WRITE  -6
+#define FILEOBJ_BLOCKED_CONN_WRITE  -7
+
+#define FILEOBJ_UNBUFFERED(x)     (!((x)->flags & FILEOBJ_LB) && !((x)->flags & FILEOBJ_BB))
+#define FILEOBJ_LINEBUFFERED(x)   ((x)->flags & FILEOBJ_LB)
+#define FILEOBJ_BLOCKBUFFERED(x)  ((x)->flags & FILEOBJ_BB)
+#define FILEOBJ_BUFFER_FULL(x)    ((x)->bufWPtr >= (x)->bufSize)
+#define FILEOBJ_BUFFER_EMPTY(x)   ((x)->bufRPtr == (x)->bufWPtr)
+#define FILEOBJ_HAS_PUSHBACKS(x)  ((x)->buf != NULL && (x)->bufRPtr >= 0 && (x)->bufRPtr < (x)->bufWPtr)
+#define FILEOBJ_READABLE(x)       ((x)->flags & FILEOBJ_READ)
+#define FILEOBJ_WRITEABLE(x)      ((x)->flags & FILEOBJ_WRITE)
+#define FILEOBJ_JUST_READ(x)      ((x)->flags & FILEOBJ_RW_READ)
+#define FILEOBJ_JUST_WRITTEN(x)   ((x)->flags & FILEOBJ_RW_WRITE)
+#define FILEOBJ_NEEDS_FLUSHING(x) (!FILEOBJ_BUFFER_EMPTY(x))
+#define FILEOBJ_RW(x)		  (FILEOBJ_READABLE(x) && FILEOBJ_WRITEABLE(x))
+
+#endif /* FILEOBJECT_H */