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#define SDS_ABORT_ON_OOM#include "sds.h"#include#include #include #include #include #include "zmalloc.h"
//内存出错函数**封装的一个报错函数static void sdsOomAbort(void) { //发生内存错误时向标准输出设备输出出错信息 fprintf(stderr,"SDS: Out Of Memory (SDS_ABORT_ON_OOM defined)\n"); abort();//出错时直接终止程序} //新建一个字符串，并将其初始化，初始化时，取init字符串中initlen个字符sds sdsnewlen(const void *init, size_t initlen) { struct sdshdr *sh; //创建字符串存储空间，多创建一个1，是因为C语言中的字符串 //均有一个\0结束符 sh = zmalloc(sizeof(struct sdshdr)+initlen+1);#ifdef SDS_ABORT_ON_OOM //如果内存分配失败的情况下，直接终止程序的运行 if (sh == NULL) sdsOomAbort();#else //如果内存分配失败的情况下，返回NULL if (sh == NULL) return NULL;#endif //记录内存空间的实际使用量 sh->len = initlen; //记录内存空间的余下多少 sh->free = 0; if (initlen) { //如果设置了init的情况下，复制initlen个字符 if (init) memcpy(sh->buf, init, initlen); //否则将内存全部置为0 else memset(sh->buf,0,initlen); } //结尾字符,C语言中字符串均以\0结尾 sh->buf[initlen] = '\0'; return (char*)sh->buf;}//生成一个空字符串,调用newlen()函数，开辟0个长度sds sdsempty(void) { return sdsnewlen("",0);}/* * 生成一个新字符串 * init表字生成新字符串时要拷贝进来的东西 * 计算传进来的字符串长度，然后调用sdsnewlen()函数 */sds sdsnew(const char *init) { size_t initlen = (init == NULL) ? 0 : strlen(init); //传入 init的值，init的长度 //返回的是 //返回sdshdr这个结构体的return (char*)sh->buf;字符串长度 return sdsnewlen(init, initlen);} /* * 获取字符串的长度 * 字符串的长度是存放在sdshdr结构中的len里面 */size_t sdslen(const sds s) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); return sh->len;}/* * 对字符串进行复制 */sds sdsdup(const sds s) { return sdsnewlen(s, sdslen(s));}/* * 释放字符串 */void sdsfree(sds s) { if (s == NULL) return; zfree(s-sizeof(struct sdshdr));}/* * 返回字符串中还有多少空间可以使用 */size_t sdsavail(sds s) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); return sh->free;}/* * 更新字符串的长度 */void sdsupdatelen(sds s) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); int reallen = strlen(s); sh->free += (sh->len-reallen); sh->len = reallen;}/* * 给字符串增加长度 */static sds sdsMakeRoomFor(sds s, size_t addlen) { struct sdshdr *sh, *newsh; size_t free = sdsavail(s); size_t len, newlen; //如果余下空间还足够的话 if (free >= addlen) return s; len = sdslen(s); sh = (void*) (s-(sizeof(struct sdshdr))); newlen = (len+addlen)*2; newsh = zrealloc(sh, sizeof(struct sdshdr)+newlen+1); //内存分配失败的情况下进行处理#ifdef SDS_ABORT_ON_OOM if (newsh == NULL) sdsOomAbort();#else if (newsh == NULL) return NULL;#endif //新的余下空间 newsh->free = newlen - len; return newsh->buf;} //进行字符串的拼接操作sds sdscatlen(sds s, void *t, size_t len) { struct sdshdr *sh; size_t curlen = sdslen(s); s = sdsMakeRoomFor(s,len); if (s == NULL) return NULL; sh = (void*) (s-(sizeof(struct sdshdr))); memcpy(s+curlen, t, len); sh->len = curlen+len; sh->free = sh->free-len; s[curlen+len] = '\0'; return s;}//同样进行字符串的拼接操作sds sdscat(sds s, char *t) { return sdscatlen(s, t, strlen(t));}//进行字符串的copy,会覆盖掉原字符串sds sdscpylen(sds s, char *t, size_t len) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); //字符串s代表的字符串的总共长度 size_t totlen = sh->free+sh->len; if (totlen < len) { s = sdsMakeRoomFor(s,len-totlen); if (s == NULL) return NULL; sh = (void*) (s-(sizeof(struct sdshdr))); totlen = sh->free+sh->len; } memcpy(s, t, len); s[len] = '\0'; sh->len = len; sh->free = totlen-len; return s;}//同样也是进行字符串的copy//也会覆盖掉原字符串sds sdscpy(sds s, char *t) { return sdscpylen(s, t, strlen(t));}//格式化拼接字符串sds sdscatprintf(sds s, const char *fmt, ...) { va_list ap; char *buf, *t; size_t buflen = 32; while(1) { buf = zmalloc(buflen);#ifdef SDS_ABORT_ON_OOM if (buf == NULL) sdsOomAbort();#else if (buf == NULL) return NULL;#endif buf[buflen-2] = '\0'; //c语言中的可变参数的循环遍历 va_start(ap, fmt); vsnprintf(buf, buflen, fmt, ap); va_end(ap); if (buf[buflen-2] != '\0') { zfree(buf); buflen *= 2; continue; } break; } //对字符串进行拼接 t = sdscat(s, buf); zfree(buf); return t;} //字符串中去掉首尾包含cset里的字符sds sdstrim(sds s, const char *cset) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); char *start, *end, *sp, *ep; size_t len; //字符串的开始位置 sp = start = s; //字符串的结束位置 ep = end = s+sdslen(s)-1; //查看字符串cset中首次出现字符*sp的位置 while(sp <= end && strchr(cset, *sp)) sp++; //查找字符串cset中首次出现字符*ep的位置 while(ep > start && strchr(cset, *ep)) ep--; len = (sp > ep) ? 0 : ((ep-sp)+1); //字符串的内存移动操作 if (sh->buf != sp) memmove(sh->buf, sp, len); sh->buf[len] = '\0'; //字符串的余下空间增长 sh->free = sh->free+(sh->len-len); sh->len = len; return s;} sds sdsrange(sds s, long start, long end) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); size_t newlen, len = sdslen(s); if (len == 0) return s; if (start < 0) { start = len+start; if (start < 0) start = 0; } if (end < 0) { end = len+end; if (end < 0) end = 0; } newlen = (start > end) ? 0 : (end-start)+1; if (newlen != 0) { if (start >= (signed)len) start = len-1; if (end >= (signed)len) end = len-1; newlen = (start > end) ? 0 : (end-start)+1; } else { start = 0; } if (start != 0) memmove(sh->buf, sh->buf+start, newlen); sh->buf[newlen] = 0; sh->free = sh->free+(sh->len-newlen); sh->len = newlen; return s;} void sdstolower(sds s) { int len = sdslen(s), j; for (j = 0; j < len; j++) s[j] = tolower(s[j]);} void sdstoupper(sds s) { int len = sdslen(s), j; for (j = 0; j < len; j++) s[j] = toupper(s[j]);} //对两个字符串进行比较int sdscmp(sds s1, sds s2) { size_t l1, l2, minlen; int cmp; l1 = sdslen(s1); l2 = sdslen(s2); minlen = (l1 < l2) ? l1 : l2;//返回短的 cmp = memcmp(s1,s2,minlen);//该函数返回一个指向目标存储区s1的指针。 if (cmp == 0) return l1-l2;//两者不相等，cmp=0 return cmp;} /* Split 's' with separator in 'sep'. An array * of sds strings is returned. *count will be set * by reference to the number of tokens returned. * * On out of memory, zero length string, zero length * separator, NULL is returned. * * Note that 'sep' is able to split a string using * a multi-character separator. For example * sdssplit("foo_-_bar","_-_"); will return two * elements "foo" and "bar". * * This version of the function is binary-safe but * requires length arguments. sdssplit() is just the * same function but for zero-terminated strings. */sds *sdssplitlen(char *s, int len, char *sep, int seplen, int *count) { int elements = 0, slots = 5, start = 0, j; //开设5字节的内存空间 //实际开设时会开设6字节，具体可以参看zmallo.c里的源代码 sds *tokens = zmalloc(sizeof(sds)*slots);#ifdef SDS_ABORT_ON_OOM if (tokens == NULL) sdsOomAbort();#endif if (seplen < 1 || len < 0 || tokens == NULL) return NULL; for (j = 0; j < (len-(seplen-1)); j++) { /* make sure there is room for the next element and the final one */ if (slots < elements+2) { sds *newtokens; slots *= 2; newtokens = zrealloc(tokens,sizeof(sds)*slots); if (newtokens == NULL) {#ifdef SDS_ABORT_ON_OOM sdsOomAbort();#else goto cleanup;#endif } tokens = newtokens; } /* search the separator */ if ((seplen == 1 && *(s+j) == sep[0]) || (memcmp(s+j,sep,seplen) == 0)) { //计算分割符以前的字符串的长度 tokens[elements] = sdsnewlen(s+start,j-start); if (tokens[elements] == NULL) {#ifdef SDS_ABORT_ON_OOM sdsOomAbort();//失败的情况下，如果定义了内存失败函数，将直接调用#else goto cleanup;//否则跳到cleanup函数，进行一个一个的释放#endif } elements++; start = j+seplen; j = j+seplen-1; /* skip the separator */ } } /* Add the final element. We are sure there is room in the tokens array. */ //分割串里面的最后一个字符串 tokens[elements] = sdsnewlen(s+start,len-start); if (tokens[elements] == NULL) {#ifdef SDS_ABORT_ON_OOM sdsOomAbort();#else goto cleanup;#endif } elements++; //传的是个引用，可以获取最终分割为多少个数组 *count = elements; return tokens;#ifndef SDS_ABORT_ON_OOM//如果没有定义分配失败的情况下，内存操作函数//将会一个一个的调用内存失败处理函数cleanup: { int i; for (i = 0; i < elements; i++) sdsfree(tokens[i]); zfree(tokens); return NULL; }#endif} 转载地址：http://ukorb.baihongyu.com/