// Copyright 2015 The Chromium OS Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef _BSDIFF_FILE_INTERFACE_H_
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#define _BSDIFF_FILE_INTERFACE_H_
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#include <sys/types.h>
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#include <stddef.h>
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#include <stdint.h>
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#include "bsdiff/common.h"
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static_assert(sizeof(off_t) == sizeof(int64_t),
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"off_t must be a 64-bit number, use -D_FILE_OFFSET_BITS=64");
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namespace bsdiff {
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class BSDIFF_EXPORT FileInterface {
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public:
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virtual ~FileInterface() = default;
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// Reads synchronously from the current file position up to |count| bytes into
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// the passed |buf| buffer. On success, stores in |bytes_read| how many bytes
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// were actually read from the file. In case of error returns false. This
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// method may read less than |count| bytes even if there's no error. If the
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// end of file is reached, 0 bytes will be read and this methods returns true.
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virtual bool Read(void* buf, size_t count, size_t* bytes_read) = 0;
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// Writes synchronously up to |count| bytes from to passed |buf| buffer to
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// the file. On success, stores in |bytes_written| how many bytes
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// were actually written to the file. This method may write less than |count|
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// bytes and return successfully, or even write 0 bytes if there's no more
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// space left on the device. Returns whether the write succeeded.
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virtual bool Write(const void* buf, size_t count, size_t* bytes_written) = 0;
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// Change the current file position to |pos| bytes from the beginning of the
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// file. Return whether the seek succeeded.
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virtual bool Seek(off_t pos) = 0;
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// Closes the file and flushes any cached data. Returns whether the close
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// succeeded.
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virtual bool Close() = 0;
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// Compute the size of the file and store it in |size|. Returns whether it
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// computed the size successfully.
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virtual bool GetSize(uint64_t* size) = 0;
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protected:
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FileInterface() = default;
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};
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} // namespace bsdiff
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#endif // _BSDIFF_FILE_INTERFACE_H_
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