用C代码实现上述功能
时间: 2024-02-28 22:52:03 浏览: 25
以下是用C代码实现上述功能的一个简单示例:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_DIR_ENTRIES 100
#define MAX_FILE_SIZE 1024
typedef struct {
int id;
int is_dir;
char name[256];
int parent_id;
int child_id;
} DirEntry;
typedef struct {
int id;
char name[256];
int size;
char* data;
} File;
typedef struct {
int id;
char name[256];
int parent_id;
int num_entries;
DirEntry entries[MAX_DIR_ENTRIES];
} Dir;
Dir root_dir;
Dir user_dir;
File* open_files[MAX_DIR_ENTRIES];
int next_dir_id = 1;
int next_file_id = 1;
int next_fd = 1;
int get_entry_index_by_name(Dir* dir, char* name) {
int i;
for (i = 0; i < dir->num_entries; i++) {
if (strcmp(dir->entries[i].name, name) == 0) {
return i;
}
}
return -1;
}
void init_root_dir() {
root_dir.id = 0;
strcpy(root_dir.name, "/");
root_dir.parent_id = -1;
root_dir.num_entries = 0;
}
void init_user_dir() {
user_dir.id = next_dir_id++;
strcpy(user_dir.name, "user");
user_dir.parent_id = root_dir.id;
user_dir.num_entries = 0;
root_dir.entries[root_dir.num_entries++] = (DirEntry) {user_dir.id, 1, user_dir.name, user_dir.parent_id, user_dir.child_id};
}
void create_dir(char* name, int is_user_dir) {
Dir* parent_dir = is_user_dir ? &user_dir : &root_dir;
int entry_index = get_entry_index_by_name(parent_dir, name);
if (entry_index != -1) {
printf("Directory already exists.\n");
return;
}
Dir new_dir = {next_dir_id++, name, parent_dir->id, 0};
parent_dir->entries[parent_dir->num_entries++] = (DirEntry) {new_dir.id, 1, new_dir.name, new_dir.parent_id, new_dir.child_id};
}
void delete_dir(char* name, int is_user_dir) {
Dir* parent_dir = is_user_dir ? &user_dir : &root_dir;
int entry_index = get_entry_index_by_name(parent_dir, name);
if (entry_index == -1) {
printf("Directory not found.\n");
return;
}
DirEntry entry = parent_dir->entries[entry_index];
if (!entry.is_dir) {
printf("Not a directory.\n");
return;
}
int i;
for (i = 0; i < parent_dir->num_entries; i++) {
if (parent_dir->entries[i].parent_id == entry.id) {
printf("Directory not empty.\n");
return;
}
}
for (i = entry_index; i < parent_dir->num_entries - 1; i++) {
parent_dir->entries[i] = parent_dir->entries[i + 1];
}
parent_dir->num_entries--;
}
int open_file(char* name, int is_user_dir) {
Dir* parent_dir = is_user_dir ? &user_dir : &root_dir;
int entry_index = get_entry_index_by_name(parent_dir, name);
if (entry_index == -1) {
printf("File not found.\n");
return -1;
}
DirEntry entry = parent_dir->entries[entry_index];
if (entry.is_dir) {
printf("Not a file.\n");
return -1;
}
File* file = (File*) malloc(sizeof(File));
file->id = next_file_id++;
strcpy(file->name, name);
file->size = 0;
file->data = (char*) malloc(MAX_FILE_SIZE);
open_files[next_fd++] = file;
return next_fd - 1;
}
void close_file(int fd) {
File* file = open_files[fd];
free(file->data);
free(file);
open_files[fd] = NULL;
}
int read_file(int fd, char* buffer, int size) {
File* file = open_files[fd];
if (file == NULL) {
printf("File not open.\n");
return -1;
}
if (size > file->size) {
size = file->size;
}
strncpy(buffer, file->data, size);
return size;
}
int write_file(int fd, char* data, int size) {
File* file = open_files[fd];
if (file == NULL) {
printf("File not open.\n");
return -1;
}
if (file->size + size > MAX_FILE_SIZE) {
printf("File too large.\n");
return -1;
}
strncat(file->data, data, size);
file->size += size;
return size;
}
int main() {
init_root_dir();
init_user_dir();
create_dir("test", 0);
create_dir("test2", 1);
int fd = open_file("test.txt", 0);
write_file(fd, "Hello world!", 12);
close_file(fd);
fd = open_file("test.txt", 0);
char buffer[1024];
read_file(fd, buffer, 1024);
printf("%s\n", buffer);
close_file(fd);
delete_dir("test2", 1);
delete_dir("test", 0);
return 0;
}
```
这个示例实现了创建目录、删除目录、打开文件、读取文件、写入文件和关闭文件等功能,但是还有很多细节需要完善和优化。
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