1 #include <common/string.h>
2 #include <common/glib.h>
3
4 /**
5 * @brief 拷贝整个字符串
6 *
7 * @param dst 目标地址
8 * @param src 源地址
9 * @return char* 目标字符串
10 */
strcpy(char * dst,const char * src)11 char *strcpy(char *dst, const char *src)
12 {
13 while (*src)
14 {
15 *(dst++) = *(src++);
16 }
17 *dst = 0;
18
19 return dst;
20 }
21
strnlen(const char * src,unsigned long maxlen)22 long strnlen(const char *src, unsigned long maxlen)
23 {
24
25 if (src == NULL)
26 return 0;
27 register int __res = 0;
28 while (src[__res] != '\0' && __res < maxlen)
29 {
30 ++__res;
31 }
32 return __res;
33 }
34
35 /*
36 比较字符串 FirstPart and SecondPart
37 FirstPart = SecondPart => 0
38 FirstPart > SecondPart => 1
39 FirstPart < SecondPart => -1
40 */
41
strcmp(const char * FirstPart,const char * SecondPart)42 int strcmp(const char *FirstPart, const char *SecondPart)
43 {
44 register int __res;
45 __asm__ __volatile__("cld \n\t"
46 "1: \n\t"
47 "lodsb \n\t"
48 "scasb \n\t"
49 "jne 2f \n\t"
50 "testb %%al, %%al \n\t"
51 "jne 1b \n\t"
52 "xorl %%eax, %%eax \n\t"
53 "jmp 3f \n\t"
54 "2: \n\t"
55 "movl $1, %%eax \n\t"
56 "jl 3f \n\t"
57 "negl %%eax \n\t"
58 "3: \n\t"
59 : "=a"(__res)
60 : "D"(FirstPart), "S"(SecondPart)
61 :);
62 return __res;
63 }
64
strncpy(char * dst,const char * src,long count)65 char *strncpy(char *dst, const char *src, long count)
66 {
67 __asm__ __volatile__("cld \n\t"
68 "1: \n\t"
69 "decq %2 \n\t"
70 "js 2f \n\t"
71 "lodsb \n\t"
72 "stosb \n\t"
73 "testb %%al, %%al \n\t"
74 "jne 1b \n\t"
75 "rep \n\t"
76 "stosb \n\t"
77 "2: \n\t"
78 :
79 : "S"(src), "D"(dst), "c"(count)
80 : "ax", "memory");
81 return dst;
82 }
83
strncpy_from_user(char * dst,const char * src,unsigned long size)84 long strncpy_from_user(char *dst, const char *src, unsigned long size)
85 {
86 if (!verify_area((uint64_t)src, size))
87 return 0;
88
89 strncpy(dst, src, size);
90 return size;
91 }
92
93 /**
94 * @brief 测量来自用户空间的字符串的长度，会检验地址空间是否属于用户空间
95 * @param src
96 * @param maxlen
97 * @return long
98 */
strnlen_user(const char * src,unsigned long maxlen)99 long strnlen_user(const char *src, unsigned long maxlen)
100 {
101
102 unsigned long size = strlen(src);
103 // 地址不合法
104 if (!verify_area((uint64_t)src, size))
105 return 0;
106
107 return size <= maxlen ? size : maxlen;
108 }
109
110 /**
111 * @brief 拼接两个字符串（将src接到dest末尾）
112 *
113 * @param dest 目标串
114 * @param src 源串
115 * @return char*
116 */
strcat(char * dest,const char * src)117 char *strcat(char *dest, const char *src)
118 {
119 strcpy(dest + strlen(dest), src);
120 return dest;
121 }