X-Git-Url: http://git.tdb.fi/?p=libs%2Fcore.git;a=blobdiff_plain;f=source%2Fio%2Fslice.cpp;h=63df62f29f841d164d5c52e7f80506c16a5a128f;hp=423c1a6c8cae85e73c2f6e15e9733786b31d700e;hb=970a9aee41d1e0b7aecdd972583e7396433a739f;hpb=eedad559456b8e62ed3b9bd9e8253e5f8bcc02d6

diff --git a/source/io/slice.cpp b/source/io/slice.cpp
index 423c1a6..63df62f 100644
--- a/source/io/slice.cpp
+++ b/source/io/slice.cpp
@@ -16,6 +16,7 @@ Slice::Slice(Seekable &b, SeekOffset s, SeekOffset l):
 	if(s<0 || l<0)
 		throw invalid_argument("Slice");
 
+	Base::Synchronize sync(below);
 	mode = below.get_mode()&M_RDWR;
 	below.signal_flush_required.connect(sigc::mem_fun(this, &Slice::flush));
 }
@@ -30,9 +31,14 @@ unsigned Slice::prepare_op(unsigned size, Mode m)
 	check_access(m);
 
 	if(sync_position)
-		seek(position, S_BEG);
-
-	SeekOffset remaining = start_offset+length-position;
+	{
+		SeekOffset pos = below.seek(start_offset+position, S_BEG)-start_offset;
+		if(pos!=position)
+			throw runtime_error("failed to restore position");
+		sync_position = false;
+	}
+
+	SeekOffset remaining = length-position;
 	if(size>remaining)
 		size = remaining;
 	if(!size && m==M_READ)
@@ -43,6 +49,7 @@ unsigned Slice::prepare_op(unsigned size, Mode m)
 
 unsigned Slice::do_write(const char *data, unsigned size)
 {
+	Base::Synchronize sync(below);
 	size = prepare_op(size, M_WRITE);
 	if(!size)
 		return 0;
@@ -54,6 +61,7 @@ unsigned Slice::do_write(const char *data, unsigned size)
 
 unsigned Slice::do_read(char *data, unsigned size)
 {
+	Base::Synchronize sync(below);
 	size = prepare_op(size, M_READ);
 	if(!size)
 		return 0;
@@ -67,6 +75,7 @@ unsigned Slice::do_read(char *data, unsigned size)
 
 unsigned Slice::put(char c)
 {
+	Base::Synchronize sync(below);
 	if(!prepare_op(1, M_WRITE))
 		return 0;
 
@@ -77,6 +86,7 @@ unsigned Slice::put(char c)
 
 int Slice::get()
 {
+	Base::Synchronize sync(below);
 	if(!prepare_op(1, M_READ))
 		return 0;
 
@@ -90,12 +100,14 @@ int Slice::get()
 
 SeekOffset Slice::seek(SeekOffset off, SeekType type)
 {
-	if(type==S_BEG)
-		off += start_offset;
-	else if(type==S_CUR)
+	Base::Synchronize sync(below);
+	off += start_offset;
+	if(type==S_CUR)
 		off += position;
 	else if(type==S_END)
-		off += start_offset+length;
+		off += length;
+	else if(type!=S_BEG)
+		throw invalid_argument("Slice::seek");
 
 	if(off<start_offset || off>start_offset+length)
 		throw bad_seek(off, type);