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/*
* 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_ */
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