#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"

//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
}

初始化字符串

//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NULLif (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0else 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);
}

字符串基本操作

/** 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_OOMif (newsh == NULL) sdsOomAbort();
#elseif (newsh == NULL) return NULL;
#endif//新的余下空间newsh->free = newlen - len;return newsh->buf;
}

字符串拼接操作

//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_OOMif (buf == NULL) sdsOomAbort();
#elseif (buf == NULL) return NULL;
#endifbuf[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;
}

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;
}

获取指定范围里的字符串

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;
}

将字符串中的所有字符均转为小写的形式

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

将字符串中所有字符均转为大写的形式

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

字符串比较

//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=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;//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_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)) {//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_OOMsdsOomAbort();//失败的情况下，如果定义了内存失败函数，将直接调用
#elsegoto 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_OOMsdsOomAbort();
#elsegoto 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
}