@@ -36,10 +36,11 @@
 #import "OFDictionary.h"
 #import "OFDataArray.h"
 #import "OFLocalization.h"
 
 #import "OFInitializationFailedException.h"
+#import "OFNotOpenException.h"
 #import "OFOutOfRangeException.h"
 #import "OFReadFailedException.h"
 #import "OFWriteFailedException.h"
 
 #ifdef OF_WINDOWS
@@ -436,11 +437,11 @@
 #ifndef OF_WINDOWS
 	if (_readPipe[0] == -1)
 #else
 	if (_readPipe[0] == NULL)
 #endif
-		return true;
+		@throw [OFNotOpenException exceptionWithObject: self];
 
 	return _atEndOfStream;
 }
 
 - (size_t)lowlevelReadIntoBuffer: (void *)buffer
@@ -447,13 +448,12 @@
 			  length: (size_t)length
 {
 #ifndef OF_WINDOWS
 	ssize_t ret;
 
-	if (_readPipe[0] == -1 || _atEndOfStream)
-		@throw [OFReadFailedException exceptionWithObject: self
-						  requestedLength: length];
+	if (_readPipe[0] == -1)
+		@throw [OFNotOpenException exceptionWithObject: self];
 
 	if ((ret = read(_readPipe[0], buffer, length)) < 0)
 		@throw [OFReadFailedException exceptionWithObject: self
 						  requestedLength: length
 							    errNo: errno];
@@ -461,13 +461,12 @@
 	DWORD ret;
 
 	if (length > UINT32_MAX)
 		@throw [OFOutOfRangeException exception];
 
-	if (_readPipe[0] == NULL || _atEndOfStream)
-		@throw [OFReadFailedException exceptionWithObject: self
-						  requestedLength: length];
+	if (_readPipe[0] == NULL)
+		@throw [OFNotOpenException exceptionWithObject: self];
 
 	if (!ReadFile(_readPipe[0], buffer, (DWORD)length, &ret, NULL)) {
 		if (GetLastError() == ERROR_BROKEN_PIPE) {
 			_atEndOfStream = true;
 			return 0;
@@ -486,13 +485,12 @@
 
 - (void)lowlevelWriteBuffer: (const void *)buffer
 		     length: (size_t)length
 {
 #ifndef OF_WINDOWS
-	if (_writePipe[1] == -1 || _atEndOfStream)
-		@throw [OFWriteFailedException exceptionWithObject: self
-						   requestedLength: length];
+	if (_writePipe[1] == -1)
+		@throw [OFNotOpenException exceptionWithObject: self];
 
 	if (length > SSIZE_MAX)
 		@throw [OFOutOfRangeException exception];
 
 	if (write(_writePipe[1], buffer, length) != (ssize_t)length)
@@ -503,13 +501,12 @@
 	DWORD ret;
 
 	if (length > UINT32_MAX)
 		@throw [OFOutOfRangeException exception];
 
-	if (_writePipe[1] == NULL || _atEndOfStream)
-		@throw [OFWriteFailedException exceptionWithObject: self
-						   requestedLength: length];
+	if (_writePipe[1] == NULL)
+		@throw [OFNotOpenException exceptionWithObject: self];
 
 	if (!WriteFile(_writePipe[1], buffer, (DWORD)length, &ret, NULL) ||
 	    ret != (DWORD)length) {
 		int errNo = 0;