文章目錄

• • 初始化字符串
  • 字符串基本操作
  • 字符串拼接操作
  • other
  • 獲取指定范圍里的字符串
  • 將字符串中的所有字符均轉為小寫的形式
  • 將字符串中所有字符均轉為大寫的形式
  • 字符串比較
• other

#define SDS_ABORT_ON_OOM#include "sds.h" #include <stdio.h> #include <stdlib.h> #include <stdarg.h> #include <string.h> #include <ctype.h> #include "zmalloc.h" //內存出錯函數**封裝的一個報錯函數 static void sdsOomAbort(void) {//發生內存錯誤時向標準輸出設備輸出出錯信息fprintf(stderr,"SDS: Out Of Memory (SDS_ABORT_ON_OOM defined)\n");abort();//出錯時直接終止程序 }

初始化字符串

//新建一個字符串，并將其初始化，初始化時，取init字符串中initlen個字符 sds sdsnewlen(const void *init, size_t initlen) {struct sdshdr *sh;//創建字符串存儲空間，多創建一個1，是因為C語言中的字符串//均有一個\0結束符sh = zmalloc(sizeof(struct sdshdr)+initlen+1); #ifdef SDS_ABORT_ON_OOM//如果內存分配失敗的情況下，直接終止程序的運行if (sh == NULL) sdsOomAbort(); #else//如果內存分配失敗的情況下，返回NULLif (sh == NULL) return NULL; #endif//記錄內存空間的實際使用量sh->len = initlen;//記錄內存空間的余下多少sh->free = 0;if (initlen) {//如果設置了init的情況下，復制initlen個字符if (init) memcpy(sh->buf, init, initlen);//否則將內存全部置為0else memset(sh->buf,0,initlen);}//結尾字符,C語言中字符串均以\0結尾sh->buf[initlen] = '\0';return (char*)sh->buf; }//生成一個空字符串,調用newlen()函數，開辟0個長度 sds sdsempty(void) {return sdsnewlen("",0); }/** 生成一個新字符串* init表字生成新字符串時要拷貝進來的東西* 計算傳進來的字符串長度，然后調用sdsnewlen()函數*/ sds sdsnew(const char *init) {size_t initlen = (init == NULL) ? 0 : strlen(init);//傳入 init的值，init的長度//返回的是//返回sdshdr這個結構體的return (char*)sh->buf;字符串長度return sdsnewlen(init, initlen); }

字符串基本操作

/** 獲取字符串的長度* 字符串的長度是存放在sdshdr結構中的len里面*/ size_t sdslen(const sds s) {struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr)));return sh->len; }/** 對字符串進行復制*/ sds sdsdup(const sds s) {return sdsnewlen(s, sdslen(s)); }/** 釋放字符串*/ void sdsfree(sds s) {if (s == NULL) return;zfree(s-sizeof(struct sdshdr)); }/** 返回字符串中還有多少空間可以使用*/ size_t sdsavail(sds s) {struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr)));return sh->free; }/** 更新字符串的長度*/ void sdsupdatelen(sds s) {struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr)));int reallen = strlen(s);sh->free += (sh->len-reallen);sh->len = reallen; }/** 給字符串增加長度*/ static sds sdsMakeRoomFor(sds s, size_t addlen) {struct sdshdr *sh, *newsh;size_t free = sdsavail(s);size_t len, newlen;//如果余下空間還足夠的話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);//內存分配失敗的情況下進行處理 #ifdef SDS_ABORT_ON_OOMif (newsh == NULL) sdsOomAbort(); #elseif (newsh == NULL) return NULL; #endif//新的余下空間newsh->free = newlen - len;return newsh->buf; }

字符串拼接操作

//進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; }//同樣進行字符串的拼接操作 sds sdscat(sds s, char *t) {return sdscatlen(s, t, strlen(t)); }//進行字符串的copy,會覆蓋掉原字符串 sds sdscpylen(sds s, char *t, size_t len) {struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr)));//字符串s代表的字符串的總共長度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; }//同樣也是進行字符串的copy //也會覆蓋掉原字符串 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_OOMif (buf == NULL) sdsOomAbort(); #elseif (buf == NULL) return NULL; #endifbuf[buflen-2] = '\0';//c語言中的可變參數的循環遍歷va_start(ap, fmt);vsnprintf(buf, buflen, fmt, ap);va_end(ap);if (buf[buflen-2] != '\0') {zfree(buf);buflen *= 2;continue;}break;}//對字符串進行拼接t = sdscat(s, buf);zfree(buf);return t; }

other

//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;//字符串的開始位置sp = start = s;//字符串的結束位置ep = end = s+sdslen(s)-1;//查看字符串cset中首次出現字符*sp的位置while(sp <= end && strchr(cset, *sp)) sp++;//查找字符串cset中首次出現字符*ep的位置while(ep > start && strchr(cset, *ep)) ep--;len = (sp > ep) ? 0 : ((ep-sp)+1);//字符串的內存移動操作if (sh->buf != sp) memmove(sh->buf, sp, len);sh->buf[len] = '\0';//字符串的余下空間增長sh->free = sh->free+(sh->len-len);sh->len = len;return s; }

獲取指定范圍里的字符串

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; }

將字符串中的所有字符均轉為小寫的形式

void sdstolower(sds s) {int len = sdslen(s), j;for (j = 0; j < len; j++) s[j] = tolower(s[j]); }

將字符串中所有字符均轉為大寫的形式

void sdstoupper(sds s) {int len = sdslen(s), j;for (j = 0; j < len; j++) s[j] = toupper(s[j]); }

字符串比較

//對兩個字符串進行比較 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);//該函數返回一個指向目標存儲區s1的指針。if (cmp == 0) return l1-l2;//兩者不相等，cmp=0return cmp; }

other

/* 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;//開設5字節的內存空間//實際開設時會開設6字節，具體可以參看zmallo.c里的源代碼sds *tokens = zmalloc(sizeof(sds)*slots); #ifdef SDS_ABORT_ON_OOMif (tokens == NULL) sdsOomAbort(); #endifif (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_OOMsdsOomAbort(); #elsegoto cleanup; #endif}tokens = newtokens;}/* search the separator */if ((seplen == 1 && *(s+j) == sep[0]) || (memcmp(s+j,sep,seplen) == 0)) {//計算分割符以前的字符串的長度tokens[elements] = sdsnewlen(s+start,j-start);if (tokens[elements] == NULL) { #ifdef SDS_ABORT_ON_OOMsdsOomAbort();//失敗的情況下，如果定義了內存失敗函數，將直接調用 #elsegoto cleanup;//否則跳到cleanup函數，進行一個一個的釋放 #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個字符串tokens[elements] = sdsnewlen(s+start,len-start);if (tokens[elements] == NULL) { #ifdef SDS_ABORT_ON_OOMsdsOomAbort(); #elsegoto cleanup; #endif}elements++;//傳的是個引用，可以獲取最終分割為多少個數組*count = elements;return tokens;#ifndef SDS_ABORT_ON_OOM //如果沒有定義分配失敗的情況下，內存操作函數 //將會一個一個的調用內存失敗處理函數 cleanup:{int i;for (i = 0; i < elements; i++) sdsfree(tokens[i]);zfree(tokens);return NULL;} #endif }

總結

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