130 lines
3.3 KiB
C++
130 lines
3.3 KiB
C++
#include "rawdisk.h"
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class SuperBlock{
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public:
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static off_t getFreeListHead(){
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char buffer[512] = {0};
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rawdisk_read(0, buffer);
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off_t t = 0;
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for (int j = 0; j < 8; j++)
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t = t | (((off_t)buffer[j])<<(8*j));
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return t;
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}
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static void writeFreeListHead(){
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char buffer[512] = {0};
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for (int j = 0; j < 8; j++){
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buffer[j] = t & (((off_t)1<<(8*j))-1);
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t >>= 8;
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}
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rawdisk_write(0, buffer);
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}
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};
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class INode{
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// direct datablocks
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off_t blocks[48];
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// indirect address
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off_t single_indirect, double_indirect, triple_indirect;
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// other
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off_t uid;
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off_t gid;
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off_t permissions;
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off_t size;
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public:
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void read_get_byte(off_t &t, int ¤t_pos, char *buffer){
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t = 0;
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for (int j = 0; j < 8; j++)
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t = t | (((off_t)buffer[j+current_pos])<<(8*j));
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current_pos += 8;
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}
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void inode_construct(off_t blockNumber){
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char buffer[512] = {0};
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rawdisk_read(blockNumber, buffer);
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int current_pos = 0;
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// initialize blocks
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for (int i = 0; i < 48; i++){
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read_get_byte(block[i], current_pos, buffer);
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}
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read_get_byte(single_indirect, current_pos, buffer);
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read_get_byte(double_indirect, current_pos, buffer);
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read_get_byte(triple_indirect, current_pos, buffer);
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read_get_byte(uid, current_pos, buffer);
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read_get_byte(gid, current_pos, buffer);
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read_get_byte(permissions, current_pos, buffer);
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read_get_byte(size, current_pos, buffer);
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}
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void write_get_byte(off_t t, int ¤t_pos, char *buffer){
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for (int j = 0; j < 8; j++){
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buffer[j+current_pos] = t & (((off_t)1<<(8*j))-1);
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t >>= 8;
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}
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current_pos += 8;
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}
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void inode_save(off_t blockNumber){
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char buffer[512] = {0};
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int current_pos = 0;
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for (int i = 0; i < 48; i++){
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write_get_byte(block[i], current_pos, buffer);
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}
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write_get_byte(single_indirect, current_pos, buffer);
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write_get_byte(double_indirect, current_pos, buffer);
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write_get_byte(triple_indirect, current_pos, buffer);
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write_get_byte(uid, current_pos, buffer);
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write_get_byte(gid, current_pos, buffer);
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write_get_byte(permissions, current_pos, buffer);
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write_get_byte(size, current_pos, buffer);
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rawdisk_write(bloackNumber, buffer);
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}
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// allowcate 1 datablock and add to the end of the file
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off_t datablock_allocate(){
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//do we need to check dynamic?
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//find a free data block
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off_t freeListHead = SuperBlock::getFreeListHead();
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for (freeListHead)
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//add the data block to blocks, single, double, triple
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//return the block number
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}
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// deallocate 1 datablock from the end of the file
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void datablock_deallocate(){
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}
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}
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class INodeOperation{
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// free list head is at super block (0): first 8 bytes
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public:
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// allocate an inode and return the number of the inode
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// the i-th inode is in the i-th block
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off_t inode_allocate(){
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//return inode number
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}
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//
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void inode_free(off_t iNodeNumber){
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}
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//ignore for now
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void inode_read(){
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}
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void inode_write(){
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}
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} |