sds和adlist一样，是redis的基础数据结构之一，是其为自身实现的字符串类型。A C dynamic strings library
sds.h
1
#ifndef __SDS_H
2
#define
__SDS_H
3
4
#define
SDS_MAX_PREALLOC (1024*1024) //字符串最大的预分配长度是1M
5
6
#include <sys/types.h>
7
#include <stdarg.h>
8
9
typedef
char
*
sds; //sds本身被typedef为char*，是后续绝大部分函数的参数（之一）
10
11
struct
sdshdr {
12
int
len;
13
int
free;
14
char
buf[];
15
}; //字符串的数据结构，记录了字符串长度、空闲字节，以及指向实际存储数据buf的指针
16
17
static
inline size_t sdslen(
const
sds s) {
18
struct
sdshdr *sh = (
void
*)(s-(
sizeof
(
struct
sdshdr)));
19
return
sh->
len;
20
} //尽管在不考虑typedef的前提下，但从函数参数来看，非引用/指针类型，但毕竟底层实现是char*，因此作者也将所有函数内不改变的参数标记为了const
//传的参数指向实际字符串，因此需要先取得数据结构头的位置，然后返回字符串长度；
21
22
static
inline size_t sdsavail(
const
sds s) {
23
struct
sdshdr *sh = (
void
*)(s-(
sizeof
(
struct
sdshdr)));
24
return
sh->
free;
25
} //同上，返回的是空闲字节数
26
27
sds sdsnewlen(
const
void
*
init, size_t initlen);
28
sds sdsnew(
const
char
*
init);
29
sds sdsempty(); //三个初始化函数
30
size_t sdslen(
const
sds s); //上述内联函数的函数声明
31
sds sdsdup(
const
sds s); //字符串复制函数
32
void
sdsfree(sds s);
33
size_t sdsavail(sds s);
34
sds sdsgrowzero(sds s, size_t len);
35
sds sdscatlen(sds s,
void
*
t, size_t len);
36
sds sdscat(sds s,
char
*
t);
37
sds sdscatsds(sds s, sds t);
38
sds sdscpylen(sds s,
char
*
t, size_t len);
39
sds sdscpy(sds s,
char
*
t);
40
41
sds sdscatvprintf(sds s,
const
char
*
fmt, va_list ap);
42
#ifdef __GNUC__
43
sds sdscatprintf(sds s,
const
char
*
fmt, ...)
44
__attribute__((format(printf,
2
,
3
)));
45
#else
46
sds sdscatprintf(sds s,
const
char
*
fmt, ...);
47
#endif //为啥这么写，没看懂。。非重点，暂且略过
48
49
sds sdstrim(sds s,
const
char
*
cset);
50
sds sdsrange(sds s,
int
start,
int
end);
51
void
sdsupdatelen(sds s);
52
void
sdsclear(sds s);
53
int
sdscmp(sds s1, sds s2);
54
sds *sdssplitlen(
char
*s,
int
len,
char
*sep,
int
seplen,
int
*
count);
55
void
sdsfreesplitres(sds *tokens,
int
count);
56
void
sdstolower(sds s);
57
void
sdstoupper(sds s);
58
sds sdsfromlonglong(
long
long
value);
59
sds sdscatrepr(sds s,
char
*
p, size_t len);
60
sds *sdssplitargs(
char
*line,
int
*
argc);
61
62
#endif
对libc的string.h库熟悉的同学，根据上述函数名也大概能猜出来函数的作用，就不一一写了，具体参见sds.c的实现部分。
sds.c
看似很长，但绝大部分代码都很通俗易懂，大家不要恐惧。
1
#define
SDS_ABORT_ON_OOM //在内存不够时的默认动作是终止进程（abort）
2
3
#include <stdio.h>
4
#include <stdlib.h>
5
#include <
string
.h>
6
#include <ctype.h>
7
#include
"
sds.h
"
8
#include
"
zmalloc.h
" //同样用na个简单封装的内存分配库
9
10
static
void
sdsOomAbort(
void
) {
11
fprintf(stderr,
"
SDS: Out Of Memory (SDS_ABORT_ON_OOM defined)\n
"
);
12
abort();
13
} //abort前作的唯一的善后工作是告诉大家自己是由于在SDS时内存不够挂掉的
14
15
sds sdsnewlen(
const
void
*
init, size_t initlen) {
16
struct
sdshdr *
sh;
17
18
sh = zmalloc(
sizeof
(
struct
sdshdr)+initlen+
1
); //所分配的长度是头的长度sizeof(struct sdshdr)+字符串长度initlen+‘\0’的一个字节
//注意这里的sizeof(struct sdshdr)长度为8，剩下的都直接存在了sh->buf上
19
#ifdef SDS_ABORT_ON_OOM
20
if
(sh ==
NULL) sdsOomAbort();
21
#else
22
if
(sh == NULL)
return
NULL; //如果没有定义SDS_ABORT_ON_OOM，简单的返回NULL
23
#endif
24
sh->len =
initlen;
25
sh->free =
0
; //创建字符串时free的长度是0
26
if
(initlen) {
27
if
(init) memcpy(sh->
buf, init, initlen); //若参数init不等于NULL,则拷贝initlen长度给sh->buf
28
else
memset(sh->buf,
0
,initlen); //否则这块缓冲区被赋值为0
29
}
30
sh->buf[initlen] =
'
\0
'
; //用'\0'为字符串结尾
31
return
(
char
*)sh->
buf; //返回的是实际字符串的指针
32
}
33
34
sds sdsempty(
void
) {
35
return
sdsnewlen(
""
,
0
); //注意""字符串常量并不代表空，但0表示空了
36
}
37
38
sds sdsnew(
const
char
*
init) {
39
size_t initlen = (init == NULL) ?
0
: strlen(init);
40
return
sdsnewlen(init, initlen);
41
}
42
43
sds sdsdup(
const
sds s) {
44
return
sdsnewlen(s, sdslen(s));
45
} //dup复制函数也是调用newlen实现的
46
47
void
sdsfree(sds s) {
48
if
(s == NULL)
return
;
49
zfree(s-
sizeof
(
struct
sdshdr));
50
} //释放链接要先找到sds的header
51
52
void
sdsupdatelen(sds s) {
53
struct
sdshdr *sh = (
void
*) (s-(
sizeof
(
struct
sdshdr)));
54
int
reallen =
strlen(s);
55
sh->free += (sh->len-
reallen);
56
sh->len =
reallen;
57
} //更新长度是更新header的len和free两个字段
58
59
void
sdsclear(sds s) {
60
struct
sdshdr *sh = (
void
*) (s-(
sizeof
(
struct
sdshdr)));
61
sh->free += sh->
len;
62
sh->len =
0
;
63
sh->buf[
0
] =
'
\0
'
;
64
} //将所有的len都给free，但并未释放内存空间
65
66
static
sds sdsMakeRoomFor(sds s, size_t addlen) {
67
struct
sdshdr *sh, *
newsh;
68
size_t free =
sdsavail(s);
69
size_t len, newlen;
70
71
if
(free >= addlen)
return
s; //如果剩余空间仍足够，则直接将传进来的参数s返回
72
len =
sdslen(s);
73
sh = (
void
*) (s-(
sizeof
(
struct
sdshdr)));
74
newlen = (len+
addlen);
75
if
(newlen <
SDS_MAX_PREALLOC)
76
newlen *=
2
;
77
else
78
newlen +=
SDS_MAX_PREALLOC; //在为newlen增加了addlen这么长的空余空间的同时，也在这次操作中额外申请了内存空间，当newlen小于系统定义的单次最大分配内存时，额外分配的长度是newlen，负责多分配SDS_MAX_PREALLOC这么大的空间。熟悉std::vector实现的同学对这种分配机制一定似曾相识。这里基于这样一种假设，这次make room的sds，也很有可能在不久的将来再次make room，所以预先分配了空间
79
newsh = zrealloc(sh,
sizeof
(
struct
sdshdr)+newlen+
1
); //realloc保证原来分配空间的数据会拷贝过去，但执行此操作后，sh指针就失效了
80
#ifdef SDS_ABORT_ON_OOM
81
if
(newsh ==
NULL) sdsOomAbort();
82
#else
83
if
(newsh == NULL)
return
NULL;
84
#endif
85
86
newsh->free = newlen -
len;
87
return
newsh->
buf;
88
}
89
90
/*
Grow the sds to have the specified length. Bytes that were not part of
91
* the original length of the sds will be set to zero.
*/
92
sds sdsgrowzero(sds s, size_t len) { //len是一个to 参数，表示增长到
93
struct
sdshdr *sh = (
void
*)(s-(
sizeof
(
struct
sdshdr)));
94
size_t totlen, curlen = sh->
len;
95
96
if
(len <= curlen)
return
s; //len比原sds还短，则直接返回
97
s = sdsMakeRoomFor(s,len-
curlen);
98
if
(s == NULL)
return
NULL; //只有可能在不abort时，才会返回NULL
99
100
/*
Make sure added region doesn't contain garbage
*/
101
sh = (
void
*)(s-(
sizeof
(
struct
sdshdr)));
102
memset(s+curlen,
0
,(len-curlen+
1
));
/*
also set trailing \0 byte
*/ //将len长度的字段都赋成0了，包括最有的'\0'也赋成0了
103
totlen = sh->len+sh->
free;
104
sh->len =
len;
105
sh->free = totlen-sh->
len;
106
return
s; //经过这个函数调用后，sds长度变成了len，只是有可能之前不足len长度的字符串被填成了0
107
}
108
109
sds sdscatlen(sds s,
void
*
t, size_t len) {
110
struct
sdshdr *
sh;
111
size_t curlen =
sdslen(s);
112
113
s =
sdsMakeRoomFor(s,len);
114
if
(s == NULL)
return
NULL;
115
sh = (
void
*) (s-(
sizeof
(
struct
sdshdr)));
116
memcpy(s+
curlen, t, len);
117
sh->len = curlen+
len;
118
sh->free = sh->free-
len;
119
s[curlen+len] =
'
\0
'
;
120
return
s;
121
}
122
123
sds sdscat(sds s,
char
*
t) {
124
return
sdscatlen(s, t, strlen(t));
125
}
126
127
sds sdscatsds(sds s, sds t) {
128
return
sdscatlen(s, t, sdslen(t));
129
}
130
131
sds sdscpylen(sds s,
char
*
t, size_t len) {
132
struct
sdshdr *sh = (
void
*) (s-(
sizeof
(
struct
sdshdr)));
133
size_t totlen = sh->free+sh->
len;
134
135
if
(totlen <
len) {
136
s = sdsMakeRoomFor(s,len-sh->
len);
137
if
(s == NULL)
return
NULL;
138
sh = (
void
*) (s-(
sizeof
(
struct
sdshdr)));
139
totlen = sh->free+sh->
len;
140
}
141
memcpy(s, t, len);
142
s[len] =
'
\0
'
;
143
sh->len =
len;
144
sh->free = totlen-
len;
145
return
s;
146
}
147
148
sds sdscpy(sds s,
char
*
t) {
149
return
sdscpylen(s, t, strlen(t));
150
}
151
下面这个函数的实现很有意思，因为类printf操作，事先并不知道源串长度，因此采用了一种类似启发式的方法，从16bytes开始，按照倍数递增的方法来猜测长度，猜测长度时，是在倒数第二个字节处打了个标记（'\0'）,然后判断操作前后是否保持一致来判断是否空间够的。好好看看while循环，其实挺有意思的。
152
sds sdscatvprintf(sds s,
const
char
*
fmt, va_list ap) {
153
va_list cpy;
154
char
*buf, *
t;
155
size_t buflen =
16
;
156
157
while
(
1
) {
158
buf =
zmalloc(buflen);
159
#ifdef SDS_ABORT_ON_OOM
160
if
(buf ==
NULL) sdsOomAbort();
161
#else
162
if
(buf == NULL)
return
NULL;
163
#endif
164
buf[buflen-
2
] =
'
\0
'
;
165
va_copy(cpy,ap);
166
vsnprintf(buf, buflen, fmt, cpy);
167
if
(buf[buflen-
2
] !=
'
\0
'
) {
168
zfree(buf);
169
buflen *=
2
;
170
continue
;
171
}
172
break
;
173
}
174
t =
sdscat(s, buf);
175
zfree(buf);
176
return
t;
177
}
178
179
sds sdscatprintf(sds s,
const
char
*
fmt, ...) {
180
va_list ap;
181
char
*
t;
182
va_start(ap, fmt);
183
t =
sdscatvprintf(s,fmt,ap);
184
va_end(ap);
185
return
t;
186
}
187
188
sds sdstrim(sds s,
const
char
*
cset) {
189
struct
sdshdr *sh = (
void
*) (s-(
sizeof
(
struct
sdshdr)));
190
char
*start, *end, *sp, *
ep; //sp == start pointer, ep == end pointer, sp,ep 是移动的，start end是静止的
191
size_t len;
192
193
sp = start =
s;
194
ep = end = s+sdslen(s)-
1
; //最后一个有意义的字节，非'\0'
195
while
(sp <= end && strchr(cset, *sp)) sp++
;
196
while
(ep > start && strchr(cset, *ep)) ep--
; //将头尾出现在字符串cset中的字符都删干净, *sp和*ep都是字符而非字符指针
197
len = (sp > ep) ?
0
: ((ep-sp)+
1
);
198
if
(sh->buf != sp) memmove(sh->
buf, sp, len); //因为sp和sh->buf指向的字符串有可能重叠，所以用了memmove
199
sh->buf[len] =
'
\0
'
;
200
sh->free = sh->free+(sh->len-
len);
201
sh->len =
len;
202
return
s; //删除特定空间后，并不释放内存，只是增大sh->free
203
}
204
205
sds sdsrange(sds s,
int
start,
int
end) {
206
struct
sdshdr *sh = (
void
*) (s-(
sizeof
(
struct
sdshdr)));
207
size_t newlen, len =
sdslen(s);
208
209
if
(len ==
0
)
return
s;
210
if
(start <
0
) {
211
start = len+
start;
212
if
(start <
0
) start =
0
;
213
}
214
if
(end <
0
) {
215
end = len+
end;
216
if
(end <
0
) end =
0
;
217
} //处理start和end为负值的情况
218
newlen = (start > end) ?
0
: (end-start)+
1
;
219
if
(newlen !=
0
) {
220
if
(start >=
(signed)len) {
221
newlen =
0
;
222
}
else
if
(end >=
(signed)len) {
223
end = len-
1
;
224
newlen = (start > end) ?
0
: (end-start)+
1
;
225
}
226
}
else
{
227
start =
0
;
228
}
229
if
(start && newlen) memmove(sh->buf, sh->buf+
start, newlen); //注意这个函数是在传进来的字符串上做操作的
230
sh->buf[newlen] =
0
;
231
sh->free = sh->free+(sh->len-
newlen);
232
sh->len =
newlen;
233
return
s;
234
}
235
236 void sdstolower(sds s) {
237 int len = sdslen(s), j;
238
239 for (j = 0; j < len; j++) s[j] = tolower(s[j]);
240 } //逐个字符变成小写
241
242 void sdstoupper(sds s) {
243 int len = sdslen(s), j;
244
245 for (j = 0; j < len; j++) s[j] = toupper(s[j]);
246 } //逐个字符变成大写
247
248 int sdscmp(sds s1, sds s2) {
249 size_t l1, l2, minlen;
250 int cmp;
251
252 l1 = sdslen(s1);
253 l2 = sdslen(s2);
254 minlen = (l1 < l2) ? l1 : l2;
255 cmp = memcmp(s1,s2,minlen);
256 if (cmp == 0) return l1-l2;
257 return cmp;
258 } //字符串比较，没啥好说的，只关注len，不关注free
259
260 /* Split 's' with separator in 'sep'. An array
261 * of sds strings is returned. *count will be set
262 * by reference to the number of tokens returned.
263 *
264 * On out of memory, zero length string, zero length
265 * separator, NULL is returned.
266 *
267 * Note that 'sep' is able to split a string using
268 * a multi-character separator. For example
269 * sdssplit("foo_-_bar","_-_"); will return two
270 * elements "foo" and "bar".
271 *
272 * This version of the function is binary-safe but
273 * requires length arguments. sdssplit() is just the
274 * same function but for zero-terminated strings. //其实作者根本就懒到没有在额外提供sdssplit，任何场景下都使用binary-safe的函数总是好的
275 */
276 sds *sdssplitlen(char *s, int len, char *sep, int seplen, int *count) {
277 int elements = 0, slots = 5, start = 0, j;
278 sds *tokens;
279
280 if (seplen < 1 || len < 0) return NULL;
281
282 tokens = zmalloc(sizeof(sds)*slots); //先假设有5个tokens供返回。在这个函数里返回值叫tokens,但在后续的sdssplitargs里返回值被起名为vector，而且类型一个是sds*，一个是char**，虽说是一样的，但其实还是改的一致比较好。按道理，一个这样的不算大（关键是逻辑简单）的源文件，作者没必要交给两个不同的人写啊
283 #ifdef SDS_ABORT_ON_OOM
284 if (tokens == NULL) sdsOomAbort();
285 #else
286 if (tokens == NULL) return NULL;
287 #endif
288
289 if (len == 0) {
290 *count = 0;
291 return tokens;
292 }
293 for (j = 0; j < (len-(seplen-1)); j++) {
294 /* make sure there is room for the next element and the final one */
295 if (slots < elements+2) {
296 sds *newtokens;
297
298 slots *= 2;
299 newtokens = zrealloc(tokens,sizeof(sds)*slots);
300 if (newtokens == NULL) {
301 #ifdef SDS_ABORT_ON_OOM
302 sdsOomAbort();
303 #else
304 goto cleanup;
305 #endif
306 }
307 tokens = newtokens;
308 }
309 /* search the separator */
310 if ((seplen == 1 && *(s+j) == sep[0]) || (memcmp(s+j,sep,seplen) == 0)) {
311 tokens[elements] = sdsnewlen(s+start,j-start);
312 if (tokens[elements] == NULL) {
313 #ifdef SDS_ABORT_ON_OOM
314 sdsOomAbort();
315 #else
316 goto cleanup;
317 #endif
318 }
319 elements++;
320 start = j+seplen;
321 j = j+seplen-1; /* skip the separator */
322 }
323 }
324 /* Add the final element. We are sure there is room in the tokens array. */
325 tokens[elements] = sdsnewlen(s+start,len-start);
326 if (tokens[elements] == NULL) {
327 #ifdef SDS_ABORT_ON_OOM
328 sdsOomAbort();
329 #else
330 goto cleanup;
331 #endif
332 }
333 elements++;
334 *count = elements;
335 return tokens;
336
337 #ifndef SDS_ABORT_ON_OOM
338 cleanup:
339 {
340 int i;
341 for (i = 0; i < elements; i++) sdsfree(tokens[i]);
342 zfree(tokens);
343 return NULL;
344 }
345 #endif
346 }
347
348 void sdsfreesplitres(sds *tokens, int count) {
349 if (!tokens) return;
350 while(count--)
351 sdsfree(tokens[count]);
352 zfree(tokens);
353 }
354
355
sds sdsfromlonglong(
long
long
value) {
356
char
buf[
32
], *
p;
357
unsigned
long
long
v;
358
359
v = (value <
0
) ? -
value : value;
360
p = buf+
31
;
/*
point to the last character
*/
361
do
{
362
*p-- =
'
0
'
+(v%
10
);
363
v /=
10
;
364
}
while
(v);
365
if
(value <
0
) *p-- =
'
-
'
;
366
p++
;
367
return
sdsnewlen(p,
32
-(p-
buf));
368
} //将long long转成字符串，没啥好说的
369
370
sds sdscatrepr(sds s,
char
*
p, size_t len) {
371
s = sdscatlen(s,
"
\"
"
,
1
);
372
while
(len--
) {
373
switch
(*
p) {
374
case
'
\\
'
:
375
case
'
"
'
:
376
s = sdscatprintf(s,
"
\\%c
"
,*
p);
377
break
;
378
case
'
\n
'
: s = sdscatlen(s,
"
\\n
"
,
2
);
break
;
379
case
'
\r
'
: s = sdscatlen(s,
"
\\r
"
,
2
);
break
;
380
case
'
\t
'
: s = sdscatlen(s,
"
\\t
"
,
2
);
break
;
381
case
'
\a
'
: s = sdscatlen(s,
"
\\a
"
,
2
);
break
;
382
case
'
\b
'
: s = sdscatlen(s,
"
\\b
"
,
2
);
break
;
383
default
:
384
if
(isprint(*
p))
385
s = sdscatprintf(s,
"
%c
"
,*
p);
386
else
387
s = sdscatprintf(s,
"
\\x%02x
"
,(unsigned
char
)*
p);
388
break
;
389
}
390
p++
;
391
}
392
return
sdscatlen(s,
"
\"
"
,
1
);
393
} //这个函数将参数p原封不动（做过处理的，是计算机认为合法的）保存在一个sds里，用于协议交换
394
395
/*
Helper function for sdssplitargs() that returns non zero if 'c'
396
* is a valid hex digit.
*/
397
int
is_hex_digit(
char
c) {
398
return
(c >=
'
0
'
&& c <=
'
9
'
) || (c >=
'
a
'
&& c <=
'
f
'
) ||
399
(c >=
'
A
'
&& c <=
'
F
'
);
400
}
401
402
/*
Helper function for sdssplitargs() that converts an hex digit into an
403
* integer from 0 to 15
*/
404
int
hex_digit_to_int(
char
c) {
405
switch
(c) {
406
case
'
0
'
:
return
0
;
407
case
'
1
'
:
return
1
;
408
case
'
2
'
:
return
2
;
409
case
'
3
'
:
return
3
;
410
case
'
4
'
:
return
4
;
411
case
'
5
'
:
return
5
;
412
case
'
6
'
:
return
6
;
413
case
'
7
'
:
return
7
;
414
case
'
8
'
:
return
8
;
415
case
'
9
'
:
return
9
;
416
case
'
a
'
:
case
'
A
'
:
return
10
;
417
case
'
b
'
:
case
'
B
'
:
return
11
;
418
case
'
c
'
:
case
'
C
'
:
return
12
;
419
case
'
d
'
:
case
'
D
'
:
return
13
;
420
case
'
e
'
:
case
'
E
'
:
return
14
;
421
case
'
f
'
:
case
'
F
'
:
return
15
;
422
default
:
return
0
;
423
}
424
}
425
426
/*
Split a line into arguments, where every argument can be in the
427
* following programming-language REPL-alike form:
428
*
429
* foo bar "newline are supported\n" and "\xff\x00otherstuff"
430
*
431
* The number of arguments is stored into *argc, and an array
432
* of sds is returned. The caller should sdsfree() all the returned
433
* strings and finally zfree() the array itself.
434
*
435
* Note that sdscatrepr() is able to convert back a string into
436
* a quoted string in the same format sdssplitargs() is able to parse.
437
*/
438
sds *sdssplitargs(
char
*line,
int
*
argc) {
439
char
*p =
line;
440
char
*current =
NULL;
441
char
**vector =
NULL;
442
443
*argc =
0
;
444
while
(
1
) {
445
/*
skip blanks
*/
446
while
(*p && isspace(*p)) p++
;
447
if
(*
p) {
448
/*
get a token
*/
449
int
inq=
0
;
/*
set to 1 if we are in "quotes"
*/
450
int
insq=
0
;
/*
set to 1 if we are in 'single quotes'
*/
451
int
done=
0
;
452
453
if
(current == NULL) current =
sdsempty();
454
while
(!
done) {
455
if
(inq) {
456
if
(*p ==
'
\\
'
&& *(p+
1
) ==
'
x
'
&&
457
is_hex_digit(*(p+
2
)) &&
458
is_hex_digit(*(p+
3
)))
459
{
460
unsigned
char
byte
;
461
462
byte
= (hex_digit_to_int(*(p+
2
))*
16
)+
463
hex_digit_to_int(*(p+
3
));
464
current = sdscatlen(current,(
char
*)&
byte
,
1
);
465
p +=
3
;
466
}
else
if
(*p ==
'
\\
'
&& *(p+
1
)) {
467
char
c;
468
469
p++
;
470
switch
(*
p) {
471
case
'
n
'
: c =
'
\n
'
;
break
;
472
case
'
r
'
: c =
'
\r
'
;
break
;
473
case
'
t
'
: c =
'
\t
'
;
break
;
474
case
'
b
'
: c =
'
\b
'
;
break
;
475
case
'
a
'
: c =
'
\a
'
;
break
;
476
default
: c = *p;
break
;
477
}
478
current = sdscatlen(current,&c,
1
);
479
}
else
if
(*p ==
'
"
'
) {
480
/*
closing quote must be followed by a space or
481
* nothing at all.
*/
482
if
(*(p+
1
) && !isspace(*(p+
1
)))
goto
err;
483
done=
1
;
484
}
else
if
(!*
p) {
485
/*
unterminated quotes
*/
486
goto
err;
487
}
else
{
488
current = sdscatlen(current,p,
1
);
489
}
490
}
else
if
(insq) {
491
if
(*p ==
'
\\
'
&& *(p+
1
) ==
'
\'
'
) {
492
p++
;
493
current = sdscatlen(current,
"
'
"
,
1
);
494
}
else
if
(*p ==
'
\'
'
) {
495
/*
closing quote must be followed by a space or
496
* nothing at all.
*/
497
if
(*(p+
1
) && !isspace(*(p+
1
)))
goto
err;
498
done=
1
;
499
}
else
if
(!*
p) {
500
/*
unterminated quotes
*/
501
goto
err;
502
}
else
{
503
current = sdscatlen(current,p,
1
);
504
}
505
}
else
{
506
switch
(*
p) {
507
case
'
'
:
508
case
'
\n
'
:
509
case
'
\r
'
:
510
case
'
\t
'
:
511
case
'
\0
'
:
512
done=
1
;
513
break
;
514
case
'
"
'
:
515
inq=
1
;
516
break
;
517
case
'
\'
'
:
518
insq=
1
;
519
break
;
520
default
:
521
current = sdscatlen(current,p,
1
);
522
break
;
523
}
524
}
525
if
(*p) p++
;
526
}
527
/*
add the token to the vector
*/
528
vector = zrealloc(vector,((*argc)+
1
)*
sizeof
(
char
*
));
529
vector[*argc] =
current;
530
(*argc)++
;
531
current =
NULL;
532
}
else
{
533
return
vector;
534
}
535
}
536
537
err:
538
while
((*argc)--
)
539
sdsfree(vector[*
argc]);
540
zfree(vector);
541
if
(current) sdsfree(current);
542
return
NULL;
543
} //解析参数，仔细看肯定能看懂的，但不好加注释。。
544
545 #ifdef SDS_TEST_MAIN
546 #include <stdio.h>
547 #include "testhelp.h" //testhelp是redis自带的一个tiny的做单元测试的框架，下篇日志里介绍
548
549 int main(void) {
550 {
551 sds x = sdsnew("foo"), y;
552
553 test_cond("Create a string and obtain the length",
554 sdslen(x) == 3 && memcmp(x,"foo\0",4) == 0)
555
556 sdsfree(x);
557 x = sdsnewlen("foo",2);
558 test_cond("Create a string with specified length",
559 sdslen(x) == 2 && memcmp(x,"fo\0",3) == 0)
560
561 x = sdscat(x,"bar");
562 test_cond("Strings concatenation",
563 sdslen(x) == 5 && memcmp(x,"fobar\0",6) == 0);
564
565 x = sdscpy(x,"a");
566 test_cond("sdscpy() against an originally longer string",
567 sdslen(x) == 1 && memcmp(x,"a\0",2) == 0)
568
569 x = sdscpy(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk");
570 test_cond("sdscpy() against an originally shorter string",
571 sdslen(x) == 33 &&
572 memcmp(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk\0",33) == 0) //^_^疑似笔误，不过测试还是可以通过的
573
574 sdsfree(x);
575 x = sdscatprintf(sdsempty(),"%d",123);
576 test_cond("sdscatprintf() seems working in the base case",
577 sdslen(x) == 3 && memcmp(x,"123\0",4) ==0)
578
579 sdsfree(x);
580 x = sdstrim(sdsnew("xxciaoyyy"),"xy");
581 test_cond("sdstrim() correctly trims characters",
582 sdslen(x) == 4 && memcmp(x,"ciao\0",5) == 0)
583
584 y = sdsrange(sdsdup(x),1,1);
585 test_cond("sdsrange(...,1,1)",
586 sdslen(y) == 1 && memcmp(y,"i\0",2) == 0)
587
588 sdsfree(y);
589 y = sdsrange(sdsdup(x),1,-1);
590 test_cond("sdsrange(...,1,-1)",
591 sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0)
592
593 sdsfree(y);
594 y = sdsrange(sdsdup(x),-2,-1);
595 test_cond("sdsrange(...,-2,-1)",
596 sdslen(y) == 2 && memcmp(y,"ao\0",3) == 0)
597
598 sdsfree(y);
599 y = sdsrange(sdsdup(x),2,1);
600 test_cond("sdsrange(...,2,1)",
601 sdslen(y) == 0 && memcmp(y,"\0",1) == 0)
602
603 sdsfree(y);
604 y = sdsrange(sdsdup(x),1,100);
605 test_cond("sdsrange(...,1,100)",
606 sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0)
607
608 sdsfree(y);
609 y = sdsrange(sdsdup(x),100,100);
610 test_cond("sdsrange(...,100,100)",
611 sdslen(y) == 0 && memcmp(y,"\0",1) == 0)
612
613 sdsfree(y);
614 sdsfree(x);
615 x = sdsnew("foo");
616 y = sdsnew("foa");
617 test_cond("sdscmp(foo,foa)", sdscmp(x,y) > 0)
618
619 sdsfree(y);
620 sdsfree(x);
621 x = sdsnew("bar");
622 y = sdsnew("bar");
623 test_cond("sdscmp(bar,bar)", sdscmp(x,y) == 0)
624
625 sdsfree(y);
626 sdsfree(x);
627 x = sdsnew("aar");
628 y = sdsnew("bar");
629 test_cond("sdscmp(bar,bar)", sdscmp(x,y) < 0)
630 }
631 test_report()
632 }
633 #endif
