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99 lines
2.3 KiB
C++
99 lines
2.3 KiB
C++
/*
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* \brief Inline filesystem
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* \author Norman Feske
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* \date 2014-04-14
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*
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* This file system allows the content of a file being specified as the content
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* of its config node.
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*/
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/*
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* Copyright (C) 2014 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _INCLUDE__VFS__INLINE_FILE_SYSTEM_H_
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#define _INCLUDE__VFS__INLINE_FILE_SYSTEM_H_
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#include <vfs/file_system.h>
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namespace Vfs { class Inline_file_system; }
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class Vfs::Inline_file_system : public Single_file_system
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{
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private:
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char const * const _base;
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file_size const _size;
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public:
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Inline_file_system(Xml_node config)
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:
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Single_file_system(NODE_TYPE_FILE, name(), config),
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_base(config.content_base()),
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_size(config.content_size())
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{ }
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static char const *name() { return "inline"; }
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/********************************
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** File I/O service interface **
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********************************/
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Stat_result stat(char const *path, Stat &out) override
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{
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Stat_result result = Single_file_system::stat(path, out);
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out.size = _size;
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return result;
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}
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/********************************
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** File I/O service interface **
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********************************/
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Write_result write(Vfs_handle *, char const *, file_size,
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file_size &count_out) override
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{
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count_out = 0;
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return WRITE_ERR_INVALID;
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}
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Read_result read(Vfs_handle *vfs_handle, char *dst, file_size count,
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file_size &out_count) override
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{
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/* file read limit is the size of the dataspace */
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file_size const max_size = _size;
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/* current read offset */
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file_size const read_offset = vfs_handle->seek();
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/* maximum read offset, clamped to dataspace size */
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file_size const end_offset = min(count + read_offset, max_size);
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/* source address within the dataspace */
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char const *src = _base + read_offset;
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/* check if end of file is reached */
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if (read_offset >= end_offset) {
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out_count = 0;
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return READ_OK;
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}
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/* copy-out bytes from ROM dataspace */
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file_size const num_bytes = end_offset - read_offset;
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memcpy(dst, src, num_bytes);
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out_count = num_bytes;
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return READ_OK;
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}
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};
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#endif /* _INCLUDE__VFS__INLINE_FILE_SYSTEM_H_ */
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