Sds为redis的字符串操作函数，主要依赖于Zmalloc，直接贴代码
Sds.h
View Code 1 #ifndef __SDS_H 2 #define __SDS_H 3 4 #include5 #include 6 7 typedef char *sds; 8 9 10 //可变长度结构体,sizeof(sdshdr)=811 struct sdshdr {12 int len;13 int free;14 char buf[];15 }; 16 17 sds sdsnewlen(const void *init, size_t initlen);18 sds sdsnew(const char *init);19 sds sdsempty();20 size_t sdslen(const sds s);21 sds sdsdup(const sds s);22 void sdsfree(sds s);23 size_t sdsavail(sds s);24 sds sdsgrowzero(sds s, size_t len);25 sds sdscatlen(sds s, void *t, size_t len);26 sds sdscat(sds s, char *t);27 sds sdscpylen(sds s, char *t, size_t len);28 sds sdscpy(sds s, char *t);29 30 sds sdscatvprintf(sds s, const char *fmt, va_list ap);31 #ifdef __GNUC__32 sds sdscatprintf(sds s, const char *fmt, ...)33 __attribute__((format(printf, 2, 3)));34 #else35 sds sdscatprintf(sds s, const char *fmt, ...);36 #endif37 38 sds sdstrim(sds s, const char *cset);39 sds sdsrange(sds s, int start, int end);40 void sdsupdatelen(sds s);41 int sdscmp(sds s1, sds s2);42 sds *sdssplitlen(char *s, int len, char *sep, int seplen, int *count);43 void sdsfreesplitres(sds *tokens, int count);44 void sdstolower(sds s);45 void sdstoupper(sds s);46 sds sdsfromlonglong(long long value);47 sds sdscatrepr(sds s, char *p, size_t len);48 sds *sdssplitargs(char *line, int *argc);49 50 #endif
Sds.c
View Code 1 //是否在内存申请失败时发出SIGABRT信号 2 #define SDS_ABORT_ON_OOM 3 4 #include "sds.h" 5 #include6 #include 7 #include 8 #include 9 #include "zmalloc.h" 10 11 12 //当内存申请失败时发出SIGABRT信号 13 static void sdsOomAbort(void) { 14 fprintf(stderr,"SDS: Out Of Memory (SDS_ABORT_ON_OOM defined)\n"); 15 abort(); 16 } 17 18 //初始化存储长度为initlen的sds结构体，返回sds中buf字段的指针 19 sds sdsnewlen(const void *init, size_t initlen) { 20 struct sdshdr *sh; 21 //8 + initlen + 1 = sizeof(int) + sizeof(int) + sizeof('\0') 22 sh = zmalloc(sizeof(struct sdshdr)+initlen+1); 23 #ifdef SDS_ABORT_ON_OOM 24 if (sh == NULL) sdsOomAbort(); 25 #else 26 if (sh == NULL) return NULL; 27 #endif 28 sh->len = initlen; 29 sh->free = 0; 30 if (initlen) { 31 if (init) memcpy(sh->buf, init, initlen); 32 else memset(sh->buf,0,initlen); 33 } 34 sh->buf[initlen] = '\0'; 35 return (char*)sh->buf; 36 } 37 38 //初始化一个字符串为空的sds中buf字段的指针 39 sds sdsempty(void) { 40 return sdsnewlen("",0); 41 } 42 43 //将一个char *转化成sds结构，得到sds中buf字段的指针 44 sds sdsnew(const char *init) { 45 size_t initlen = (init == NULL) ? 0 : strlen(init); 46 return sdsnewlen(init, initlen); 47 } 48 49 //根据buf的指针-8得到sds结构体的指针，得到len字段 50 size_t sdslen(const sds s) { 51 struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); 52 return sh->len; 53 } 54 55 //复制一个sds字符串 56 sds sdsdup(const sds s) { 57 return sdsnewlen(s, sdslen(s)); 58 } 59 60 //释放sds字符串所在的整个sdshdr的结构体的内存空间 61 void sdsfree(sds s) { 62 if (s == NULL) return; 63 zfree(s-sizeof(struct sdshdr)); 64 } 65 66 //得到sds结构的可用长度，即s->len - strlen(s->buff) 67 size_t sdsavail(sds s) { 68 struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); 69 return sh->free; 70 } 71 72 //当sds字符串操作后，更新sds结构体中的len信息 73 void sdsupdatelen(sds s) { 74 struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); 75 int reallen = strlen(s); 76 sh->free += (sh->len-reallen); 77 sh->len = reallen; 78 } 79 80 //另外在sds s串中申请长度为addlen长度的空间 81 static sds sdsMakeRoomFor(sds s, size_t addlen) { 82 struct sdshdr *sh, *newsh; 83 size_t free = sdsavail(s); 84 size_t len, newlen; 85 86 if (free >= addlen) return s; 87 len = sdslen(s); 88 sh = (void*) (s-(sizeof(struct sdshdr))); 89 newlen = (len+addlen)*2; //多申请些，以防止短时内再次申请 ? 有点不明白为什么这么做 90 newsh = zrealloc(sh, sizeof(struct sdshdr)+newlen+1); 91 #ifdef SDS_ABORT_ON_OOM 92 if (newsh == NULL) sdsOomAbort(); 93 #else 94 if (newsh == NULL) return NULL; 95 #endif 96 97 newsh->free = newlen - len; 98 return newsh->buf; 99 }100 101 /* Grow the sds to have the specified length. Bytes that were not part of102 * the original length of the sds will be set to zero. */103 //扩容s所能容纳的字符串的长度到len104 sds sdsgrowzero(sds s, size_t len) {105 struct sdshdr *sh = (void*)(s-(sizeof(struct sdshdr)));106 size_t totlen, curlen = sh->len;107 108 if (len <= curlen) return s; //如果当前长度已经满足，直接返回109 s = sdsMakeRoomFor(s,len-curlen);110 if (s == NULL) return NULL;111 112 /* Make sure added region doesn't contain garbage */113 sh = (void*)(s-(sizeof(struct sdshdr)));114 memset(s+curlen,0,(len-curlen+1)); /* also set trailing \0 byte */115 totlen = sh->len+sh->free;116 sh->len = len;117 sh->free = totlen-sh->len;118 return s;119 }120 121 //将t开头的长度为len的字符串接到s后边122 sds sdscatlen(sds s, void *t, size_t len) {123 struct sdshdr *sh;124 size_t curlen = sdslen(s);125 126 s = sdsMakeRoomFor(s,len);127 if (s == NULL) return NULL;128 sh = (void*) (s-(sizeof(struct sdshdr)));129 memcpy(s+curlen, t, len);130 sh->len = curlen+len;131 sh->free = sh->free-len;132 s[curlen+len] = '\0';133 return s;134 }135 136 //将t开头字符串接到s后边137 sds sdscat(sds s, char *t) {138 return sdscatlen(s, t, strlen(t));139 }140 141 //将t开头长度为len的字符串复制给s142 sds sdscpylen(sds s, char *t, size_t len) {143 struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr)));144 size_t totlen = sh->free+sh->len;145 146 if (totlen < len) {147 s = sdsMakeRoomFor(s,len-sh->len);148 if (s == NULL) return NULL;149 sh = (void*) (s-(sizeof(struct sdshdr)));150 totlen = sh->free+sh->len;151 }152 memcpy(s, t, len);153 s[len] = '\0';154 sh->len = len;155 sh->free = totlen-len;156 return s;157 }158 159 //将t开头的字符串复制给s160 sds sdscpy(sds s, char *t) {161 return sdscpylen(s, t, strlen(t));162 }163 164 165 //将fmt格式的字符串接到s后边166 sds sdscatvprintf(sds s, const char *fmt, va_list ap) {167 va_list cpy;168 char *buf, *t;169 size_t buflen = 16;170 171 while(1) {172 buf = zmalloc(buflen);173 #ifdef SDS_ABORT_ON_OOM174 if (buf == NULL) sdsOomAbort();175 #else176 if (buf == NULL) return NULL;177 #endif178 buf[buflen-2] = '\0';179 va_copy(cpy,ap);180 vsnprintf(buf, buflen, fmt, cpy);181 if (buf[buflen-2] != '\0') {182 zfree(buf);183 buflen *= 2;184 continue;185 }186 break;187 }188 t = sdscat(s, buf);189 zfree(buf);190 return t;191 }192 193 //将fmt格式的字符串接到s后边194 sds sdscatprintf(sds s, const char *fmt, ...) {195 va_list ap;196 char *t;197 va_start(ap, fmt);198 t = sdscatvprintf(s,fmt,ap);199 va_end(ap);200 return t;201 }202 203 //trim....移除s中头尾属于cset串中的字符204 sds sdstrim(sds s, const char *cset) {205 struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr)));206 char *start, *end, *sp, *ep;207 size_t len;208 209 sp = start = s;210 ep = end = s+sdslen(s)-1;211 while(sp <= end && strchr(cset, *sp)) sp++; //找到头尾212 while(ep > start && strchr(cset, *ep)) ep--;213 len = (sp > ep) ? 0 : ((ep-sp)+1);//计算trim后的长度214 if (sh->buf != sp) memmove(sh->buf, sp, len);215 sh->buf[len] = '\0';216 sh->free = sh->free+(sh->len-len);217 sh->len = len;218 return s;219 }220 221 //得到s的start开始，end结束的子串222 sds sdsrange(sds s, int start, int end) {223 struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr)));224 size_t newlen, len = sdslen(s);225 226 if (len == 0) return s;227 if (start < 0) {228 start = len+start;229 if (start < 0) start = 0;230 }231 if (end < 0) {232 end = len+end;233 if (end < 0) end = 0;234 }235 newlen = (start > end) ? 0 : (end-start)+1;236 if (newlen != 0) {237 if (start >= (signed)len) {238 newlen = 0;239 } else if (end >= (signed)len) {240 end = len-1;241 newlen = (start > end) ? 0 : (end-start)+1;242 }243 } else {244 start = 0;245 }246 if (start && newlen) memmove(sh->buf, sh->buf+start, newlen);247 sh->buf[newlen] = 0;248 sh->free = sh->free+(sh->len-newlen);249 sh->len = newlen;250 return s;251 }252 253 //将s中的字符全变成小写254 void sdstolower(sds s) {255 int len = sdslen(s), j;256 257 for (j = 0; j < len; j++) s[j] = tolower(s[j]);258 }259 260 //将s中的字符全变成大写261 void sdstoupper(sds s) {262 int len = sdslen(s), j;263 264 for (j = 0; j < len; j++) s[j] = toupper(s[j]);265 }266 267 //比较两个字符串268 int sdscmp(sds s1, sds s2) {269 size_t l1, l2, minlen;270 int cmp;271 272 l1 = sdslen(s1);273 l2 = sdslen(s2);274 minlen = (l1 < l2) ? l1 : l2;275 cmp = memcmp(s1,s2,minlen);276 if (cmp == 0) return l1-l2;277 return cmp;278 }279 280 //使用sep串作为分隔符，将s串分割，将数量放到count变量，返回sds数组第一个元素的指针281 /* Split 's' with separator in 'sep'. An array282 * of sds strings is returned. *count will be set283 * by reference to the number of tokens returned.284 *285 * On out of memory, zero length string, zero length286 * separator, NULL is returned.287 *288 * Note that 'sep' is able to split a string using289 * a multi-character separator. For example290 * sdssplit("foo_-_bar","_-_"); will return two291 * elements "foo" and "bar".292 *293 * This version of the function is binary-safe but294 * requires length arguments. sdssplit() is just the295 * same function but for zero-terminated strings.296 */297 sds *sdssplitlen(char *s, int len, char *sep, int seplen, int *count) {298 int elements = 0, slots = 5, start = 0, j;299 300 sds *tokens = zmalloc(sizeof(sds)*slots);301 #ifdef SDS_ABORT_ON_OOM302 if (tokens == NULL) sdsOomAbort();303 #endif304 if (seplen < 1 || len < 0 || tokens == NULL) return NULL;305 if (len == 0) {306 *count = 0;307 return tokens;308 }309 for (j = 0; j < (len-(seplen-1)); j++) {310 /* make sure there is room for the next element and the final one */311 if (slots < elements+2) {312 sds *newtokens;313 314 slots *= 2;315 newtokens = zrealloc(tokens,sizeof(sds)*slots);316 if (newtokens == NULL) {317 #ifdef SDS_ABORT_ON_OOM318 sdsOomAbort();319 #else320 goto cleanup;321 #endif322 }323 tokens = newtokens;324 }325 /* search the separator */326 if ((seplen == 1 && *(s+j) == sep[0]) || (memcmp(s+j,sep,seplen) == 0)) {327 tokens[elements] = sdsnewlen(s+start,j-start);328 if (tokens[elements] == NULL) {329 #ifdef SDS_ABORT_ON_OOM330 sdsOomAbort();331 #else332 goto cleanup;333 #endif334 }335 elements++;336 start = j+seplen;337 j = j+seplen-1; /* skip the separator */338 }339 }340 /* Add the final element. We are sure there is room in the tokens array. */341 tokens[elements] = sdsnewlen(s+start,len-start);342 if (tokens[elements] == NULL) {343 #ifdef SDS_ABORT_ON_OOM344 sdsOomAbort();345 #else346 goto cleanup;347 #endif348 }349 elements++;350 *count = elements;351 return tokens;352 353 #ifndef SDS_ABORT_ON_OOM354 cleanup:355 {356 int i;357 for (i = 0; i < elements; i++) sdsfree(tokens[i]);358 zfree(tokens);359 return NULL;360 }361 #endif362 }363 364 //释放tokens的内存365 void sdsfreesplitres(sds *tokens, int count) {366 if (!tokens) return;367 while(count--)368 sdsfree(tokens[count]);369 zfree(tokens);370 }371 372 //从long long转换成sds字符串373 sds sdsfromlonglong(long long value) {374 char buf[32], *p;375 unsigned long long v;376 377 v = (value < 0) ? -value : value;378 p = buf+31; /* point to the last character */379 do {380 *p-- = '0'+(v%10);381 v /= 10;382 } while(v);383 if (value < 0) *p-- = '-';384 p++;385 return sdsnewlen(p,32-(p-buf));386 }387 388 //将p串接到s后边，保留转义符389 sds sdscatrepr(sds s, char *p, size_t len) {390 s = sdscatlen(s,"\"",1);391 while(len--) {392 switch(*p) {393 case '\\':394 case '"':395 s = sdscatprintf(s,"\\%c",*p);396 break;397 case '\n': s = sdscatlen(s,"\\n",1); break;398 case '\r': s = sdscatlen(s,"\\r",1); break;399 case '\t': s = sdscatlen(s,"\\t",1); break;400 case '\a': s = sdscatlen(s,"\\a",1); break;401 case '\b': s = sdscatlen(s,"\\b",1); break;402 default:403 if (isprint(*p))404 s = sdscatprintf(s,"%c",*p);405 else406 s = sdscatprintf(s,"\\x%02x",(unsigned char)*p);407 break;408 }409 p++;410 }411 return sdscatlen(s,"\"",1);412 }413 414 //是否是十六进制数字415 /* Helper function for sdssplitargs() that returns non zero if 'c'416 * is a valid hex digit. */417 int is_hex_digit(char c) {418 return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') ||419 (c >= 'A' && c <= 'F');420 }421 422 //十六进制字符转成十进制423 /* Helper function for sdssplitargs() that converts an hex digit into an424 * integer from 0 to 15 */425 int hex_digit_to_int(char c) {426 switch(c) {427 case '0': return 0;428 case '1': return 1;429 case '2': return 2;430 case '3': return 3;431 case '4': return 4;432 case '5': return 5;433 case '6': return 6;434 case '7': return 7;435 case '8': return 8;436 case '9': return 9;437 case 'a': case 'A': return 10;438 case 'b': case 'B': return 11;439 case 'c': case 'C': return 12;440 case 'd': case 'D': return 13;441 case 'e': case 'E': return 14;442 case 'f': case 'F': return 15;443 default: return 0;444 }445 }446 447 /* Split a line into arguments, where every argument can be in the448 * following programming-language REPL-alike form:449 *450 * foo bar "newline are supported\n" and "\xff\x00otherstuff"451 *452 * The number of arguments is stored into *argc, and an array453 * of sds is returned. The caller should sdsfree() all the returned454 * strings and finally zfree() the array itself.455 *456 * Note that sdscatrepr() is able to convert back a string into457 * a quoted string in the same format sdssplitargs() is able to parse.458 */459 sds *sdssplitargs(char *line, int *argc) {460 char *p = line;461 char *current = NULL;462 char **vector = NULL;463 464 *argc = 0;465 while(1) {466 /* skip blanks */467 while(*p && isspace(*p)) p++;468 if (*p) {469 /* get a token */470 int inq=0; /* set to 1 if we are in "quotes" */471 int done=0;472 473 if (current == NULL) current = sdsempty();474 while(!done) {475 if (inq) {476 if (*p == '\\' && *(p+1) == 'x' &&477 is_hex_digit(*(p+2)) &&478 is_hex_digit(*(p+3)))479 {480 unsigned char byte;481 482 byte = (hex_digit_to_int(*(p+2))*16)+483 hex_digit_to_int(*(p+3));484 current = sdscatlen(current,(char*)&byte,1);485 p += 3;486 } else if (*p == '\\' && *(p+1)) {487 char c;488 489 p++;490 switch(*p) {491 case 'n': c = '\n'; break;492 case 'r': c = '\r'; break;493 case 't': c = '\t'; break;494 case 'b': c = '\b'; break;495 case 'a': c = '\a'; break;496 default: c = *p; break;497 }498 current = sdscatlen(current,&c,1);499 } else if (*p == '"') {500 /* closing quote must be followed by a space */501 if (*(p+1) && !isspace(*(p+1))) goto err;502 done=1;503 } else if (!*p) {504 /* unterminated quotes */505 goto err;506 } else {507 current = sdscatlen(current,p,1);508 }509 } else {510 switch(*p) {511 case ' ':512 case '\n':513 case '\r':514 case '\t':515 case '\0':516 done=1;517 break;518 case '"':519 inq=1;520 break;521 default:522 current = sdscatlen(current,p,1);523 break;524 }525 }526 if (*p) p++;527 }528 /* add the token to the vector */529 vector = zrealloc(vector,((*argc)+1)*sizeof(char*));530 vector[*argc] = current;531 (*argc)++;532 current = NULL;533 } else {534 return vector;535 }536 }537 538 err:539 while((*argc)--)540 sdsfree(vector[*argc]);541 zfree(vector);542 if (current) sdsfree(current);543 return NULL;544 }545 546 #ifdef SDS_TEST_MAIN547 #include 548 #include "testhelp.h"549 550 int main(void) {551 {552 sds x = sdsnew("foo"), y;553 554 test_cond("Create a string and obtain the length",555 sdslen(x) == 3 && memcmp(x,"foo\0",4) == 0)556 557 sdsfree(x);558 x = sdsnewlen("foo",2);559 test_cond("Create a string with specified length",560 sdslen(x) == 2 && memcmp(x,"fo\0",3) == 0)561 562 x = sdscat(x,"bar");563 test_cond("Strings concatenation",564 sdslen(x) == 5 && memcmp(x,"fobar\0",6) == 0);565 566 x = sdscpy(x,"a");567 test_cond("sdscpy() against an originally longer string",568 sdslen(x) == 1 && memcmp(x,"a\0",2) == 0)569 570 x = sdscpy(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk");571 test_cond("sdscpy() against an originally shorter string",572 sdslen(x) == 33 &&573 memcmp(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk\0",33) == 0)574 575 sdsfree(x);576 x = sdscatprintf(sdsempty(),"%d",123);577 test_cond("sdscatprintf() seems working in the base case",578 sdslen(x) == 3 && memcmp(x,"123\0",4) ==0)579 580 sdsfree(x);581 x = sdstrim(sdsnew("xxciaoyyy"),"xy");582 test_cond("sdstrim() correctly trims characters",583 sdslen(x) == 4 && memcmp(x,"ciao\0",5) == 0)584 585 y = sdsrange(sdsdup(x),1,1);586 test_cond("sdsrange(...,1,1)",587 sdslen(y) == 1 && memcmp(y,"i\0",2) == 0)588 589 sdsfree(y);590 y = sdsrange(sdsdup(x),1,-1);591 test_cond("sdsrange(...,1,-1)",592 sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0)593 594 sdsfree(y);595 y = sdsrange(sdsdup(x),-2,-1);596 test_cond("sdsrange(...,-2,-1)",597 sdslen(y) == 2 && memcmp(y,"ao\0",3) == 0)598 599 sdsfree(y);600 y = sdsrange(sdsdup(x),2,1);601 test_cond("sdsrange(...,2,1)",602 sdslen(y) == 0 && memcmp(y,"\0",1) == 0)603 604 sdsfree(y);605 y = sdsrange(sdsdup(x),1,100);606 test_cond("sdsrange(...,1,100)",607 sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0)608 609 sdsfree(y);610 y = sdsrange(sdsdup(x),100,100);611 test_cond("sdsrange(...,100,100)",612 sdslen(y) == 0 && memcmp(y,"\0",1) == 0)613 614 sdsfree(y);615 sdsfree(x);616 x = sdsnew("foo");617 y = sdsnew("foa");618 test_cond("sdscmp(foo,foa)", sdscmp(x,y) > 0)619 620 sdsfree(y);621 sdsfree(x);622 x = sdsnew("bar");623 y = sdsnew("bar");624 test_cond("sdscmp(bar,bar)", sdscmp(x,y) == 0)625 626 sdsfree(y);627 sdsfree(x);628 x = sdsnew("aar");629 y = sdsnew("bar");630 test_cond("sdscmp(bar,bar)", sdscmp(x,y) < 0)631 }632 test_report()633 }634 #endif
哦了，越看越费力，基础很差~路漫漫~加油