1 files changed, 88 insertions, 0 deletions
diff --git a/src/libs/uio/fileblock.h b/src/libs/uio/fileblock.h
new file mode 100644
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+++ b/src/libs/uio/fileblock.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2003  Serge van den Boom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ * Nota bene: later versions of the GNU General Public License do not apply
+ * to this program.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#ifndef LIBS_UIO_FILEBLOCK_H_
+#define LIBS_UIO_FILEBLOCK_H_
+
+typedef struct uio_FileBlock uio_FileBlock;
+
+#include "io.h"
+#include "uioport.h"
+
+#include <sys/types.h>
+
+#define uio_FB_USAGE_FORWARD  1
+#define uio_FB_USAGE_BACKWARD 2
+#define uio_FB_USAGE_MASK  (uio_FB_USAGE_FORWARD | uio_FB_USAGE_BACKWARD)
+
+#ifdef uio_INTERNAL_FILEBLOCK
+
+// A fileblock represents a contiguous block of data from a file.
+// It's purpose is to avoid needless copying of data, while enabling
+// buffering.
+
+struct uio_FileBlock {
+	uio_Handle *handle;
+	int flags;
+			// See above for uio_FB_USAGE_FORWARD, uio_FB_USAGE_BACKWARD.
+#define uio_FB_USE_MMAP       4
+	off_t offset;
+			// Offset to the start of the block in the file.
+	size_t blockSize;
+			// Size of the block of data represented by this FileBlock.
+	char *buffer;
+			// either allocated buffer, or buffer to mmap'ed area.
+	size_t bufSize;
+			// Size of the buffer.
+	off_t bufOffset;
+			// Offset of the start of the buffer into the block.
+	size_t bufFill;
+			// Part of 'buffer' which is in use.
+	size_t readAheadBufSize;
+			// Try to read up to this many bytes at a time, even when less
+			// is immediately needed.
+};
+// INV: The FileBlock represents 'fileData[offset..(offset + blockSize - 1)]'
+// where 'fileData' is the contents of the file.
+// INV: If buf != NULL then:
+//     bufFill <= bufSize
+//     bufFill <= blockSize
+//     buffer[0..bufFill - 1] == fileData[
+//             (offset + bufOffset)..(offset + bufOffset + bufFill - 1)]
+
+
+#endif  /* uio_INTERNAL_FILEBLOCK */
+
+uio_FileBlock *uio_openFileBlock(uio_Handle *handle);
+uio_FileBlock *uio_openFileBlock2(uio_Handle *handle, off_t offset,
+		size_t size);
+ssize_t uio_accessFileBlock(uio_FileBlock *block, off_t offset, size_t length,
+		char **buffer);
+int uio_copyFileBlock(uio_FileBlock *block, off_t offset, char *buffer,
+		size_t length);
+int uio_closeFileBlock(uio_FileBlock *block);
+#define uio_FB_READAHEAD_BUFSIZE_MAX ((size_t) -1)
+void uio_setFileBlockUsageHint(uio_FileBlock *block, int usage,
+		size_t readAheadBufSize);
+void uio_clearFileBlockBuffers(uio_FileBlock *block);
+
+#endif  /* LIBS_UIO_FILEBLOCK_H_ */
+
+