FAT 文件系统模拟设计与实现：C语言程序模拟FAT16-编程知识

实验描述

利用标准C 语言，模拟实现 FAT 16文件系统，支持 FAT 文件系统格式的模拟磁盘卷及其中的目录与文件的存取操作，包括磁盘卷格式化、创建目录、改变当前目录、重命名目录、显示目录、删除目录、创建空文件、重命名文件、写文件、显示文件内容、删除文件。

用到的数据结构

路径存储，存储卷的名字和当前的目录，存储目录的起点和空闲块。当卷没有初始化即卷名字为空时可以实现报错
```
typedef struct {char filename[MAX_FILENAME_LENGTH];int start_block;int size;char data[MAX_FILE_SIZE];
} DirectoryEntry;
```

文件的数据结构，存储文件的起点和占用的块的大小，data存储文件内部的数据

typedef struct {char volume_name[MAX_FILENAME_LENGTH];int total_blocks;int free_blocks;DirectoryEntry* directory;char current_path[MAX_FILENAME_LENGTH];
} FileSystem;

磁盘使用模拟

分别用函数实现磁盘卷格式化、创建目录、改变当前目录、重命名目录、显示目录、删除目录、创建空文件、重命名文件、写文件、显示文件内容、删除文件。列表编号每个操作，输入对应的序号选择操作并且进行交互，遇到一些错误则会有提示，模拟结束可以选择退出的操作。

运行示例

卷的初始化：输入卷名字和空间大小，即磁盘的格式化

创建目录user1

进入目录user1，此处若没有写对目录名字则会报错

创建新文件story

查看目录

写文件story，需要在此处输入有效的文件名

查看文件story，需要在此处输入有效的文件名

完整程序

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_FILENAME_LENGTH 16
#define MAX_FILE_SIZE 1024typedef struct {char filename[MAX_FILENAME_LENGTH];int start_block;int size;char data[MAX_FILE_SIZE];
} DirectoryEntry;typedef struct {char volume_name[MAX_FILENAME_LENGTH];int total_blocks;int free_blocks;DirectoryEntry* directory;char current_path[MAX_FILENAME_LENGTH];
} FileSystem;FileSystem fs;void formatDisk() {printf("Enter volume name: ");scanf("%s", fs.volume_name);printf("Enter total number of blocks: ");scanf("%d", &fs.total_blocks);fs.free_blocks = fs.total_blocks;fs.directory = (DirectoryEntry*)malloc(sizeof(DirectoryEntry) * fs.total_blocks);for (int i = 0; i < fs.total_blocks; i++) {strcpy(fs.directory[i].filename, "");fs.directory[i].start_block = -1;fs.directory[i].size = 0;}strcpy(fs.current_path, "/");printf("Disk formatted successfully.\n");
}void createDirectory() {char dirname[MAX_FILENAME_LENGTH];printf("Enter directory name: ");scanf("%s", dirname);for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, "") == 0) {strcpy(fs.directory[i].filename, dirname);fs.directory[i].start_block = -1;fs.directory[i].size = 0;printf("Directory created successfully.\n");return;}}printf("No free space for directory creation.\n");
}void changeDirectory() {char dirname[MAX_FILENAME_LENGTH];printf("Enter directory name: ");scanf("%s", dirname);for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, dirname) == 0) {strcat(fs.current_path, dirname);strcat(fs.current_path, "/");printf("Directory changed to '%s'.\n", fs.current_path);return;}}printf("Directory '%s' not found.\n", dirname);
}void renameDirectory() {char oldname[MAX_FILENAME_LENGTH], newname[MAX_FILENAME_LENGTH];printf("Enter old directory name: ");scanf("%s", oldname);printf("Enter new directory name: ");scanf("%s", newname);for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, oldname) == 0) {strcpy(fs.directory[i].filename, newname);printf("Directory renamed successfully.\n");return;}}printf("Directory '%s' not found.\n", oldname);
}void displayDirectory() {printf("Current Disk: %s\n", fs.volume_name);printf("Current Path: %s\n", fs.current_path);printf("Directory listing:\n");for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, "") != 0) {printf("- %s\n", fs.directory[i].filename);}}
}void deleteDirectory() {char dirname[MAX_FILENAME_LENGTH];printf("Enter directory name: ");scanf("%s", dirname);for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, dirname) == 0) {strcpy(fs.directory[i].filename, "");printf("Directory deleted successfully.\n");return;}}printf("Directory '%s' not found.\n", dirname);
}void createFile() {char filename[MAX_FILENAME_LENGTH];printf("Enter file name: ");scanf("%s", filename);for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, "") == 0) {strcpy(fs.directory[i].filename, filename);fs.directory[i].start_block = i;fs.directory[i].size = 0;fs.directory[i].data[0] = '\0'; fs.free_blocks--;printf("File created successfully.\n");return;}}printf("No free space for file creation.\n");
}void renameFile() {char oldname[MAX_FILENAME_LENGTH], newname[MAX_FILENAME_LENGTH];printf("Enter old file name: ");scanf("%s", oldname);printf("Enter new file name: ");scanf("%s", newname);for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, oldname) == 0) {strcpy(fs.directory[i].filename, newname);printf("File renamed successfully.\n");return;}}printf("File '%s' not found.\n", oldname);
}void writeFile() {char filename[MAX_FILENAME_LENGTH];printf("Enter file name: ");scanf("%s", filename);for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, filename) == 0) {int block_index = fs.directory[i].start_block;if (block_index == -1) {printf("File '%s' not found.\n", filename);return;}printf("Enter file content:\n");char content[MAX_FILE_SIZE];scanf("%s", content);strcpy(fs.current_path, filename);fs.directory[i].size = strlen(content);strcpy(fs.directory[i].data, content); printf("File '%s' written successfully.\n", filename);return;}}printf("File '%s' not found.\n", filename);
}void displayFileContent() {char filename[MAX_FILENAME_LENGTH];printf("Enter file name: ");scanf("%s", filename);for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, filename) == 0) {printf("Content of file '%s':\n%s\n", filename, fs.directory[i].data);return;}}printf("File '%s' not found.\n", filename);
}void deleteFile() {char filename[MAX_FILENAME_LENGTH];printf("Enter file name: ");scanf("%s", filename);for (int i = 0; i < fs.total_blocks; i++) {if (strcmp(fs.directory[i].filename, filename) == 0) {strcpy(fs.directory[i].filename, "");fs.directory[i].start_block = -1;fs.directory[i].size = 0;fs.free_blocks++;printf("File deleted successfully.\n");return;}}printf("File '%s' not found.\n", filename);
}int main() {int choice;printf("----------------------------------- FAT16 File System ----------------------------------\n");printf("1. Format Disk         2. Create Directory    3. Change Directory    4. Rename Directory\n");printf("5. Display Directory   6. Delete Directory    7. Create File         8. Rename File\n");printf("9. Write File         10. Display File       11. Delete File         0. Exit\n");do {printf("\nCurrent Disk: %s   Current Path: %s\n", fs.volume_name, fs.current_path);  printf("Enter your choice: ");scanf("%d", &choice);switch (choice) {case 1: formatDisk(); break;case 2: createDirectory(); break;case 3: changeDirectory(); break;case 4: renameDirectory(); break;case 5: displayDirectory(); break;case 6: deleteDirectory(); break;case 7: createFile(); break;case 8: renameFile(); break;case 9: writeFile(); break;case 10: displayFileContent(); break;case 11: deleteFile(); break;case 0: break;default: printf("Invalid choice.\n");}} while (choice != 0);free(fs.directory);return 0;
}