1 // String manipulation functions.
2 //
3 // Copyright (C) 2008-2013 Kevin O'Connor <kevin@koconnor.net>
4 //
5 // This file may be distributed under the terms of the GNU LGPLv3 license.
6
7 #include "stacks.h" // yield
8 #include "string.h" // memcpy
9 #include "farptr.h" // SET_SEG
10
11
12 /****************************************************************
13 * String ops
14 ****************************************************************/
15
16 // Sum the bytes in the specified area.
17 u8
checksum_far(u16 buf_seg,void * buf_far,u32 len)18 checksum_far(u16 buf_seg, void *buf_far, u32 len)
19 {
20 SET_SEG(ES, buf_seg);
21 u32 i;
22 u8 sum = 0;
23 for (i=0; i<len; i++)
24 sum += GET_VAR(ES, ((u8*)buf_far)[i]);
25 return sum;
26 }
27
28 u8
checksum(void * buf,u32 len)29 checksum(void *buf, u32 len)
30 {
31 return checksum_far(GET_SEG(SS), buf, len);
32 }
33
34 size_t
strlen(const char * s)35 strlen(const char *s)
36 {
37 if (__builtin_constant_p(s))
38 return __builtin_strlen(s);
39 const char *p = s;
40 while (*p)
41 p++;
42 return p-s;
43 }
44
45 // Compare two areas of memory.
46 int
memcmp(const void * s1,const void * s2,size_t n)47 memcmp(const void *s1, const void *s2, size_t n)
48 {
49 while (n) {
50 if (*(u8*)s1 != *(u8*)s2)
51 return *(u8*)s1 < *(u8*)s2 ? -1 : 1;
52 s1++;
53 s2++;
54 n--;
55 }
56 return 0;
57 }
58
59 // Compare two strings.
60 int
strcmp(const char * s1,const char * s2)61 strcmp(const char *s1, const char *s2)
62 {
63 for (;;) {
64 if (*s1 != *s2)
65 return *s1 < *s2 ? -1 : 1;
66 if (! *s1)
67 return 0;
68 s1++;
69 s2++;
70 }
71 }
72
73 inline void
memset_far(u16 d_seg,void * d_far,u8 c,size_t len)74 memset_far(u16 d_seg, void *d_far, u8 c, size_t len)
75 {
76 d_far = MAKE_FLATPTR(d_seg, (u32)d_far);
77 memset(d_far, c, len);
78 }
79
80 inline void
memset16_far(u16 d_seg,void * s,u16 c,size_t n)81 memset16_far(u16 d_seg, void *s, u16 c, size_t n)
82 {
83 s = MAKE_FLATPTR(d_seg, (u32)s);
84 while (n)
85 ((u16 *)s)[--n] = c;
86 }
87
88 void *
memset(void * s,int c,size_t n)89 memset(void *s, int c, size_t n)
90 {
91 while (n)
92 ((char *)s)[--n] = c;
93 return s;
94 }
95
memset_fl(void * ptr,u8 val,size_t size)96 void memset_fl(void *ptr, u8 val, size_t size)
97 {
98 memset(ptr, val, size);
99 }
100
101 inline void
memcpy_far(u16 d_seg,void * d,u16 s_seg,const void * s,size_t n)102 memcpy_far(u16 d_seg, void *d, u16 s_seg, const void *s, size_t n)
103 {
104 d = MAKE_FLATPTR(d_seg, (u32)d);
105 s = MAKE_FLATPTR(s_seg, (u32)s);
106 while (n) {
107 --n;
108 ((char *)d)[n] = ((char *)s)[n];
109 }
110 }
111
112 inline void
memcpy_fl(void * d_fl,const void * s_fl,size_t len)113 memcpy_fl(void *d_fl, const void *s_fl, size_t len)
114 {
115 memcpy(d_fl, s_fl, len);
116 }
117
118 void *
119 #undef memcpy
memcpy(void * d1,const void * s1,size_t len)120 memcpy(void *d1, const void *s1, size_t len)
121 {
122 memcpy_far(0, d1, 0, s1, len);
123 return d1;
124 }
125
126 void
iomemcpy(void * d,const void * s,u32 len)127 iomemcpy(void *d, const void *s, u32 len)
128 {
129 memcpy(d, s, len);
130 }
131
132 void *
memmove(void * d,const void * s,size_t len)133 memmove(void *d, const void *s, size_t len)
134 {
135 if (s >= d)
136 return memcpy(d, s, len);
137
138 d += len-1;
139 s += len-1;
140 while (len--) {
141 *(char*)d = *(char*)s;
142 d--;
143 s--;
144 }
145
146 return d;
147 }
148
149 // Copy a string - truncating it if necessary.
150 char *
strtcpy(char * dest,const char * src,size_t len)151 strtcpy(char *dest, const char *src, size_t len)
152 {
153 char *d = dest;
154 while (--len && *src != '\0')
155 *d++ = *src++;
156 *d = '\0';
157 return dest;
158 }
159
160 // locate first occurrence of character c in the string s
161 char *
strchr(const char * s,int c)162 strchr(const char *s, int c)
163 {
164 for (; *s; s++)
165 if (*s == c)
166 return (char*)s;
167 return NULL;
168 }
169
170 // Remove any trailing blank characters (spaces, new lines, carriage returns)
171 char *
nullTrailingSpace(char * buf)172 nullTrailingSpace(char *buf)
173 {
174 int len = strlen(buf);
175 char *end = &buf[len-1];
176 while (end >= buf && *end <= ' ')
177 *(end--) = '\0';
178 while (*buf && *buf <= ' ')
179 buf++;
180 return buf;
181 }
182