327 lines
9.7 KiB
C
327 lines
9.7 KiB
C
#include "../include/fat16.h"
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#include "../include/memory.h"
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#include "../include/disk.h"
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void read_root_dir_sector1(struct File *root_entries) {
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read_disk(SECTOR_NUM_OF_ROOT_DIR_START, 1, (unsigned int) root_entries);
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}
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void save_root_dir_sector1(struct File *root_entries) {
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write_disk(SECTOR_NUM_OF_ROOT_DIR_START, 1, (unsigned int) root_entries);
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}
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void read_one_cluster(unsigned short clustno, unsigned int memory_addrress) {
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read_disk(clustno + SECTOR_CLUSTER_BALANCE, 1, memory_addrress);
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}
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int read_root_dir(struct File *file_infos) {
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struct File *root_entries = (struct File *) kmalloc(SECTOR_SIZE);
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read_root_dir_sector1(root_entries);
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int n = 0; // 记录文件数
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for (int i = 0; i < MAX_FILE_NUM; i++) {
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if (root_entries[i].name[0] == 0) {
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break;
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}
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if (root_entries[i].name[0] != 0xe5) {
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file_infos[n] = root_entries[i];
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n++;
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}
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}
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kfree(root_entries);
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return n;
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}
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void get_fat1(unsigned short *fat1) {
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read_disk(SECTOR_NUM_OF_FAT1_START, FAT1_SECTORS, (unsigned int) fat1); // 将FAT1全部读取到内存中。
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}
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void save_fat1(unsigned short *fat1) {
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write_disk(SECTOR_NUM_OF_FAT1_START, FAT1_SECTORS, (unsigned int) fat1); // 将FAT1全部写回到内存中。
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}
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void get_file_all_clustnos(unsigned short first_clustno, unsigned short *clustnos) {
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unsigned short *fat1 = kmalloc(FAT1_SECTORS * SECTOR_SIZE);
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get_fat1(fat1);
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*clustnos = first_clustno;
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while (1) {
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unsigned short clustno = *(fat1 + *clustnos);
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clustnos++;
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*clustnos = clustno;
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if (clustno >= 0xfff8) // 大于等于0xfff8表示文件的最后一个簇
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{
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break;
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}
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}
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kfree(fat1);
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}
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void read_file(struct File *file, void *file_addr) {
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if (file->size == 0) {
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return;
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}
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int cluster_count = (file->size + 511) / 512;
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unsigned short *clustnos = kmalloc(cluster_count * 2);
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get_file_all_clustnos(file->clustno, clustnos);
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for (int i = 0; i < cluster_count; i++) {
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read_one_cluster(clustnos[i], (unsigned int) file_addr);
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file_addr += 512;
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}
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kfree(clustnos);
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}
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void check_name_or_ext(char *str, int len) {
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for (int i = 0; i < len; i++) {
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if (str[i] == 0) {
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str[i] = ' ';
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} else if ('a' <= str[i] && str[i] <= 'z') {
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str[i] -= 0x20;
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}
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}
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}
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void check_name_and_ext(char *name, char *ext) {
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check_name_or_ext(name, 8);
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check_name_or_ext(ext, 3);
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}
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void analyse_fullname(char *fullname, char *name, char *ext) {
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int ext_dot_index = -1;
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for (int i = 11; i >= 0; i--) {
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if (fullname[i] == '.') {
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ext_dot_index = i;
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}
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}
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if (ext_dot_index == -1) // 没有后缀名的情况
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{
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memcpy(name, fullname, 8);
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memset(ext, ' ', 3);
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} else if (ext_dot_index == 0) // 没有文件名的情况
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{
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memset(name, ' ', 8);
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memcpy(ext, fullname + 1, 3);
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} else {
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memcpy(name, fullname, ext_dot_index);
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memcpy(ext, fullname + ext_dot_index + 1, 3);
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}
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check_name_and_ext(name, ext);
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}
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int find_file(char *name, char *ext, struct File *const file) {
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struct File *root_entries = kmalloc(SECTOR_SIZE);
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read_root_dir_sector1(root_entries);
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int isfind = 0;
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for (int i = 0; i < MAX_FILE_NUM; i++) {
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if (memcmp(root_entries[i].name, name, 8) == 0 && memcmp(root_entries[i].ext, ext, 3) == 0) {
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if (file != 0) {
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*file = root_entries[i];
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}
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isfind = 1;
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}
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}
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kfree(root_entries);
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return isfind;
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}
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struct File *create_dir(char *fullname) {
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char name[8] = {0};
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char ext[3] = {0};
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analyse_fullname(fullname, name, ext);
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int isfind = find_file(name, ext, 0);
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if (isfind) {
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return 0; //文件已存在。
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}
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struct File *file = (struct File *) kmalloc(32);
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memcpy(file->name, name, 8);
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memcpy(file->ext, " ", 3);
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file->type = 0x10;
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file->time = 0;
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file->date = 0;
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file->clustno = 0;
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file->size = 0;
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struct File *root_entries = kmalloc(SECTOR_SIZE);
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read_root_dir_sector1(root_entries);
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for (int i = 0; i < MAX_FILE_NUM; i++) {
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if (root_entries[i].name[0] == 0 || root_entries[i].name[0] == 0xe5) { //找一个空闲的文件项存放。
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root_entries[i] = *file;
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break;
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}
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}
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save_root_dir_sector1(root_entries);
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kfree(root_entries);
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return file;
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}
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struct File *create_file(char *fullname) {
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char name[8] = {0};
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char ext[3] = {0};
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analyse_fullname(fullname, name, ext);
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int isfind = find_file(name, ext, 0);
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if (isfind) {
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return 0; //文件已存在。
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}
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struct File *file = (struct File *) kmalloc(32);
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memcpy(file->name, name, 8);
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memcpy(file->ext, ext, 3);
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file->type = 0x20;
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file->time = 0;
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file->date = 0;
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file->clustno = 0;
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file->size = 0;
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struct File *root_entries = kmalloc(SECTOR_SIZE);
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read_root_dir_sector1(root_entries);
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for (int i = 0; i < MAX_FILE_NUM; i++) {
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if (root_entries[i].name[0] == 0 || root_entries[i].name[0] == 0xe5) { //找一个空闲的文件项存放。
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root_entries[i] = *file;
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break;
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}
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}
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save_root_dir_sector1(root_entries);
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kfree(root_entries);
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//open_file_task(file);
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kfree(name);
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kfree(ext);
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return file;
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}
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struct File *open_file(char *fullname) {
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char name[8] = {0};
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char ext[3] = {0};
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analyse_fullname(fullname, name, ext);
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struct File *file = (struct File *) kmalloc(32);
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int isfind = find_file(name, ext, file);
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if (!isfind) {
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kfree(file);
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file = 0;
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} else {
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//set_opened_file(file);
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}
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return file;
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}
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void alter_file_name(struct File *file, char *new_fullname) {
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char new_name[8] = {0};
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char new_ext[3] = {0};
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analyse_fullname(new_fullname, new_name, new_ext);
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struct File *root_entries = kmalloc(SECTOR_SIZE);
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read_root_dir_sector1(root_entries);
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for (int i = 0; i < MAX_FILE_NUM; i++) {
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if (memcmp(root_entries[i].name, file->name, 8) == 0 && memcmp(root_entries[i].ext, file->ext, 3) == 0) {
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memcpy(root_entries[i].name, new_name, 8);
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memcpy(root_entries[i].ext, new_ext, 3);
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}
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}
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save_root_dir_sector1(root_entries);
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kfree(root_entries);
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}
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void alter_dir_entry(struct File *file) {
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struct File *root_entries = kmalloc(SECTOR_SIZE);
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read_root_dir_sector1(root_entries);
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for (int i = 0; i < MAX_FILE_NUM; i++) {
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if (memcmp(root_entries[i].name, file->name, 8) == 0 && memcmp(root_entries[i].ext, file->ext, 3) == 0) {
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root_entries[i] = *file;
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}
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}
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save_root_dir_sector1(root_entries);
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kfree(root_entries);
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}
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void save_file(struct File *file, char *content) {
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unsigned int file_size = strlen(content); //内容大小
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if (file_size == 0 && file->size == 0) {
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return;
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}
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file->size = file_size;
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int sector_num = (file_size + 511) / 512; //将要占用的扇区数
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unsigned short *fat1 = kmalloc(FAT1_SECTORS * SECTOR_SIZE);
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get_fat1(fat1);
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unsigned short clustno = file->clustno;
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unsigned short next_clustno;
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if (file->clustno == 0) //第一次写入
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{
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clustno = 2; //可用簇号从2开始
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while (1) {
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if (*(fat1 + clustno) == 0) //空闲簇号
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{
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file->clustno = clustno; //分配起始簇号
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break;
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} else {
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clustno++;
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}
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}
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}
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int i = 0;
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while (1) {
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write_disk(SECTOR_CLUSTER_BALANCE + clustno, 1, (unsigned int) content);
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if (i == sector_num - 1) { //已写完最后一扇区。
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break;
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}
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i++;
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content += 512;
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next_clustno = *(fat1 + clustno);
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if (next_clustno == 0 || next_clustno >= 0xfff8) { //寻找下一个可用簇号
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next_clustno = clustno + 1;
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while (1) {
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if (*(fat1 + next_clustno) == 0) {
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*(fat1 + clustno) = next_clustno;
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break;
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} else {
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next_clustno++;
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}
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}
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}
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clustno = next_clustno;
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}
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next_clustno = *(fat1 + clustno);
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*(fat1 + clustno) = 0xffff; //0xfff8~0xffff表示文件结束，没有下一个簇了。
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//如果本次写入的内容比上次的少，上次用过的簇号本次用不完，以下将剩下的簇号清零处理。
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if (1 < next_clustno && next_clustno < 0xfff0) {
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while (1) {
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clustno = next_clustno;
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next_clustno = *(fat1 + clustno);
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*(fat1 + clustno) = 0;
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if (next_clustno >= 0xfff8) {
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break;
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}
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}
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}
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alter_dir_entry(file);
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save_fat1(fat1);
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kfree(fat1);
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}
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void delete_file(struct File *file) {
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//1.标记目录项为已删除。
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struct File *root_entries = kmalloc(SECTOR_SIZE);
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read_root_dir_sector1(root_entries);
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for (int i = 0; i < MAX_FILE_NUM; i++) {
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if (memcmp(root_entries[i].name, file->name, 8) == 0 && memcmp(root_entries[i].ext, file->ext, 3) == 0) {
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root_entries[i].name[0] = 0xe5;
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break;
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}
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}
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save_root_dir_sector1(root_entries);
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kfree(root_entries);
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if (file->clustno == 0) {
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return;
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}
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unsigned short *fat1 = kmalloc(FAT1_SECTORS * SECTOR_SIZE);
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get_fat1(fat1);
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unsigned short clustno = file->clustno;
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unsigned short next_clustno = 0;
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while (1) {
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next_clustno = *(fat1 + clustno);
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*(fat1 + clustno) = 0;
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if (next_clustno >= 0xfff8) {
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break;
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}
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clustno = next_clustno;
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}
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save_fat1(fat1);
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kfree(fat1);
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} |