目录
思维导图
准备工作
对控制参数的处置
一共有 7 个可选参数，分别是-a、-l、-R、-t、-r、-i、-s，这些参数可以互相自由组合，因而可以设计一种机制，就是直接把它们全部用循环一次性做或运算，得到一个参数标志Vec。
// 标志: -a、-l、-R、-t、-r、-i、-s 参数(向量分量)
#define a 0b1000000
#define l 0b0100000
#define R 0b0010000
#define t 0b0001000
#define r 0b0000100
#define I 0b0000010
#define s 0b0000001
// 向量
int Vec = 0;而 Vec 可以使用全局变量，这样可以防止写函数时不时地给函数参数参与地址参数，使得更加代码整洁，更直观。
对dir参数的处置
同理，仍然可以设计一个全局容器，不时地把 dirname 扔进去：
char* dirname[4096 * 128];
int dirlen = 0;而对于 filename 也是一样的，但在每次遍历一个dir 之前，就得filename 容器做重置处置：
char* filenames[4096 * 128];
int file_cnt = 0;
函数实现
void tags_cal(int argc, char* argv[]) {
for (int i = 1; i < argc; i++) {
if (argv[0] !=
'-') { // 只接受以'-'开头的参数,其它参数要么错误,要么是文件夹名称或文件名
char* tempdirname = (char*)malloc(sizeof(char) * 4096);
strcpy(tempdirname, argv);
dirname[dirlen++] = tempdirname;
} else {
int len = strlen(argv);
for (int j = 1; j < len; j++) {
switch (argv[j]) {
case 'a':
Vec |= a;
break;
case 'l':
Vec |= l;
break;
case 'R':
Vec |= R;
break;
case 't':
Vec |= t;
break;
case 'r':
Vec |= r;
break;
case 'i':
Vec |= I;
break;
case 's':
Vec |= s;
break;
default:
fprintf(stderr, "%c参数错误!\n", argv[j]);
break;
}
}
}
}
if (dirlen == 0) {
dirlen = 1;
char* tempdirname = (char*)malloc(sizeof(char) * 2048);
strcpy(tempdirname, ".");
dirname[0] = tempdirname;
}
}这里需要注意的是，假设dirlen == 0，说明我们的命令并没有加参数，默认是对当前文件夹停止操作，因而需要重新对 dirlen赋值为 1，然后把 dirname[0]置为"."。
实现
我们上一步胜利得到了，dirnname、dirlen，这样就可以逐个dirname停止处置了！
void do_myls() {
for (int i = 0; i < dirlen; i++) {
if (do_name(dirname) == -1) {
continue;
}
// 且自动字典排序
if ((Vec & t) == t) { // 时间排序
do_t(filenames);
}
if ((Vec & r) == r) { // 逆序
do_r(filenames, file_cnt);
}
printf("当前途径:\"%s\"\n", dirname);
int tag = 0; // 换行
for (int j = 0; j < file_cnt; j++) {
// 拼凑文件名
char path[4096] = {0};
strcpy(path, dirname);
int len = strlen(dirname);
strcpy(&path[len], "/");
strcpy(&path[len + 1], filenames[j]);
tag++;
if ((Vec & a) == 0) {
if ((strcmp(filenames[j], ".") == 0 ||
strcmp(filenames[j], "..") == 0) ||
filenames[j][0] == '.') {
continue;
}
}
struct stat info;
stat(path, &info); // 拉进 info
if (S_ISDIR(info.st_mode) && ((Vec & R) == R)) {
// 假设是目录,那就直接拉进 dirnames:"dirname/filename"
char* tempdirname = (char*)malloc(sizeof(char) * 4096);
strcpy(tempdirname, dirname);
int len = strlen(tempdirname);
strcpy(&tempdirname[len], "/");
strcpy(&tempdirname[len + 1], filenames[j]);
dirname[dirlen++] = tempdirname;
}
if ((Vec & I) == I) {
do_i(path);
}
if ((Vec & s) == s) {
do_s(path);
}
if ((Vec & l) == 0) {
if (S_ISDIR(info.st_mode)) // 判断是否为目录
{
printf(GREEN "%s\t" NONE, filenames[j]);
} else {
printf(BLUE "%s\t" NONE, filenames[j]);
}
}
if ((Vec & l) == l) {
void mode_to_letters();
char modestr[11];
mode_to_letters(info.st_mode, modestr);
printf("%s ", modestr);
printf("%4d ", (int)info.st_nlink);
printf("%-8s ", uid_to_name(info.st_uid));
printf("%-8s ", gid_to_name(info.st_gid));
printf("%8ld ", (long)info.st_size);
printf("%.12s ", ctime(&info.st_mtime));
if (S_ISDIR(info.st_mode)) // 判断是否为目录
{
printf(GREEN "%s\t" NONE, filenames[j]);
} else {
printf(BLUE "%s\t" NONE, filenames[j]);
}
printf("\n");
}
if ((tag % 5 == 0) && ((Vec & l) == 0)) {
printf("\n");
}
}
// 清空容器
for (int k = 0; k < file_cnt; k++) {
memset(filenames[k], 4096, '\0');
}
file_cnt = 0;
}
}这里最关键的就是对-R参数的处置，因为我们的整体框架并不适宜做函数的递归，因而我们可以在判断某个 filename是一个 dir 之后，就可以把它参与到 dirname 中，并且把 dirlen++，这样就在逻辑上实现了遍历，这里也充沛利用了全局变量的优势：牵一发而动全身。
struct stat info;
stat(path, &info); // 拉进 info
if (S_ISDIR(info.st_mode) && ((Vec & R) == R)) {
// 假设是目录,那就直接拉进 dirnames:"dirname/filename"
char* tempdirname = (char*)malloc(sizeof(char) * 4096);
strcpy(tempdirname, dirname);
int len = strlen(tempdirname);
strcpy(&tempdirname[len], "/");
strcpy(&tempdirname[len + 1], filenames[j]);
dirname[dirlen++] = tempdirname;
}而其它的功能性函数实现起来就很简单了，就不负担了。
完好代码
#include <dirent.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
// 标志: -a、-l、-R、-t、-r、-i、-s 参数(向量分量)
#define a 0b1000000
#define l 0b0100000
#define R 0b0010000
#define t 0b0001000
#define r 0b0000100
#define I 0b0000010
#define s 0b0000001
// 颜色宏
#define NONE "\033[m"
#define GREEN "\033[0;32;32m"
#define BLUE "\033[0;32;34m"
// 函数声明
void tags_cal(int argc, char* argv[]);
void restored_ls(struct dirent* cur_item);
void sort(char** filenames, int start, int end);
void do_r(char** filenames, int file_cnt);
int partition(char** filenames, int start, int end);
void swap(char** s1, char** s2);
int compare(char* s1, char* s2);
char* uid_to_name(uid_t);
char* gid_to_name(gid_t);
void mode_to_letters(int, char[]);
char* uid_to_name(uid_t);
// ********函数声明********
void do_i(char filename[]);
void do_s(char filename[]);
int do_name(char dirname[]);
void do_myls();
void do_t(char** filenames);
int Vec = 0;
char* dirname[4096 * 128];
int dirlen = 0;
char* filenames[4096 * 128];
int file_cnt = 0;
int main(int argc, char* argv[]) {
tags_cal(argc, argv);
do_myls();
return 0;
}
void do_myls() {
for (int i = 0; i < dirlen; i++) {
if (do_name(dirname) == -1) {
continue;
}
// 且自动字典排序
if ((Vec & t) == t) { // 时间排序
do_t(filenames);
}
if ((Vec & r) == r) { // 逆序
do_r(filenames, file_cnt);
}
printf("当前途径:\"%s\"\n", dirname);
int tag = 0; // 换行
for (int j = 0; j < file_cnt; j++) {
// 拼凑文件名
char path[4096] = {0};
strcpy(path, dirname);
int len = strlen(dirname);
strcpy(&path[len], "/");
strcpy(&path[len + 1], filenames[j]);
tag++;
if ((Vec & a) == 0) {
if ((strcmp(filenames[j], ".") == 0 ||
strcmp(filenames[j], "..") == 0) ||
filenames[j][0] == '.') {
continue;
}
}
struct stat info;
stat(path, &info); // 拉进 info
if (S_ISDIR(info.st_mode) && ((Vec & R) == R)) {
// 假设是目录,那就直接拉进 dirnames:"dirname/filename"
char* tempdirname = (char*)malloc(sizeof(char) * 4096);
strcpy(tempdirname, dirname);
int len = strlen(tempdirname);
strcpy(&tempdirname[len], "/");
strcpy(&tempdirname[len + 1], filenames[j]);
dirname[dirlen++] = tempdirname;
}
if ((Vec & I) == I) {
do_i(path);
}
if ((Vec & s) == s) {
do_s(path);
}
if ((Vec & l) == 0) {
if (S_ISDIR(info.st_mode)) // 判断是否为目录
{
printf(GREEN "%s\t" NONE, filenames[j]);
} else {
printf(BLUE "%s\t" NONE, filenames[j]);
}
}
if ((Vec & l) == l) {
void mode_to_letters();
char modestr[11];
mode_to_letters(info.st_mode, modestr);
printf("%s ", modestr);
printf("%4d ", (int)info.st_nlink);
printf("%-8s ", uid_to_name(info.st_uid));
printf("%-8s ", gid_to_name(info.st_gid));
printf("%8ld ", (long)info.st_size);
printf("%.12s ", ctime(&info.st_mtime));
if (S_ISDIR(info.st_mode)) // 判断是否为目录
{
printf(GREEN "%s\t" NONE, filenames[j]);
} else {
printf(BLUE "%s\t" NONE, filenames[j]);
}
printf("\n");
}
if ((tag % 5 == 0) && ((Vec & l) == 0)) {
printf("\n");
}
}
// 清空容器
for (int k = 0; k < file_cnt; k++) {
memset(filenames[k], 4096, '\0');
}
file_cnt = 0;
}
}
void tags_cal(int argc, char* argv[]) {
for (int i = 1; i < argc; i++) {
if (argv[0] !=
'-') { // 只接受以'-'开头的参数,其它参数要么错误,要么是文件夹名称或文件名
char* tempdirname = (char*)malloc(sizeof(char) * 4096);
strcpy(tempdirname, argv);
dirname[dirlen++] = tempdirname;
} else {
int len = strlen(argv);
for (int j = 1; j < len; j++) {
switch (argv[j]) {
case 'a':
Vec |= a;
break;
case 'l':
Vec |= l;
break;
case 'R':
Vec |= R;
break;
case 't':
Vec |= t;
break;
case 'r':
Vec |= r;
break;
case 'i':
Vec |= I;
break;
case 's':
Vec |= s;
break;
default:
fprintf(stderr, "%c参数错误!\n", argv[j]);
break;
}
}
}
}
if (dirlen == 0) {
dirlen = 1;
char* tempdirname = (char*)malloc(sizeof(char) * 2048);
strcpy(tempdirname, ".");
dirname[0] = tempdirname;
}
}
void do_i(char filename[]) {
struct stat info;
if (stat(filename, &info) == -1)
perror(filename);
printf("%llu\t", info.st_ino);
}
void do_s(char filename[]) {
struct stat info;
if (stat(filename, &info) == -1)
perror(filename);
printf("%4llu\t", info.st_size / 4096 * 4 + (info.st_size % 4096 ? 4 : 0));
}
int do_name(char dirname[]) {
int i = 0;
int len = 0;
DIR* dir_ptr;
struct dirent* direntp;
if ((dir_ptr = opendir(dirname)) == NULL) {
fprintf(stderr, "权限不够,cannot open: %s\n", dirname);
return -1;
} else {
while ((direntp = readdir(dir_ptr))) {
restored_ls(direntp);
}
sort(filenames, 0, file_cnt - 1);
}
printf("\n");
closedir(dir_ptr);
return 1;
}
void sort(char** filenames, int start, int end) {
if (start < end) {
int position = partition(filenames, start, end);
sort(filenames, start, position - 1);
sort(filenames, position + 1, end);
}
}
int partition(char** filenames, int start, int end) {
if (!filenames)
return -1;
char* privot = filenames[start];
while (start < end) {
while (start < end && compare(privot, filenames[end]) < 0)
--end;
swap(&filenames[start], &filenames[end]);
while (start < end && compare(privot, filenames[start]) >= 0)
++start;
swap(&filenames[start], &filenames[end]);
}
return start;
}
void swap(char** s1, char** s2) {
char* tmp = *s1;
*s1 = *s2;
*s2 = tmp;
}
int compare(char* s1, char* s2) {
if (*s1 == '.')
s1++;
if (*s2 == '.')
s2++;
while (*s1 && *s2 && *s1 == *s2) {
++s1;
++s2;
if (*s1 == '.')
s1++;
if (*s2 == '.')
s2++;
}
return *s1 - *s2;
}
void restored_ls(struct dirent* cur_item) {
char* result = (char*)malloc(sizeof(char) * 4096);
strcpy(result, cur_item->d_name);
filenames[file_cnt++] = result;
}
void mode_to_letters(int mode, char str[]) {
strcpy(str, "----------");
if (S_ISDIR(mode))
str[0] = 'd';
if (S_ISCHR(mode))
str[0] = 'c';
if (S_ISBLK(mode))
str[0] = 'b';
if (mode & S_IRUSR)
str[1] = 'r';
if (mode & S_IWUSR)
str[2] = 'w';
if (mode & S_IXUSR)
str[3] = 'x';
if (mode & S_IRGRP)
str[4] = 'r';
if (mode & S_IWGRP)
str[5] = 'w';
if (mode & S_IXGRP)
str[6] = 'x';
if (mode & S_IROTH)
str[7] = 'r';
if (mode & S_IWOTH)
str[8] = 'w';
if (mode & S_IXOTH)
str[9] = 'x';
}
char* gid_to_name(gid_t gid) {
struct group *getgrgid(), *grp_ptr;
static char numstr[10];
if ((grp_ptr = getgrgid(gid)) == NULL) {
sprintf(numstr, "%d", gid);
return numstr;
} else {
return grp_ptr->gr_name;
}
}
char* uid_to_name(gid_t uid) {
struct passwd* getpwuid();
struct passwd* pw_ptr;
static char numstr[10];
if ((pw_ptr = getpwuid(uid)) == NULL) {
sprintf(numstr, "%d", uid);
return numstr;
} else {
return pw_ptr->pw_name;
}
}
void do_t(char** filenames) {
char temp[2048] = {0};
struct stat info1;
struct stat info2;
for (int i = 0; i < file_cnt - 1; i++) {
for (int j = i + 1; j < file_cnt; j++) {
stat(filenames, &info1);
stat(filenames[j], &info2);
if (info1.st_mtime < info2.st_mtime) {
strcpy(temp, filenames);
strcpy(filenames, filenames[j]);
strcpy(filenames[j], temp);
}
}
}
}
void do_r(char** arr, int file_cnt) {
// 只需要修改指针
char left = 0;
char right = file_cnt - 1;
char temp;
while (left < right) {
char* temp = arr[left];
arr[left] = arr[right];
arr[right] = temp;
left++;
right--;
}
}
总结
这个 myls的难点在于整个系统的设计，比如参数怎么处置，怎么根据参数输出相应的信息。而函数的实现就比较简单。
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