Redis之4-字符串
2016-05-21 22:34
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sds.h文件
sds.c实现文件
/* SDSLib, A C dynamic strings library * * Copyright (c) 2006-2010, Salvatore Sanfilippo <antirez at gmail dot com> * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of Redis nor the names of its contributors may be used * to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #ifndef __SDS_H #define __SDS_H /* * 最大预分配长度 */ #define SDS_MAX_PREALLOC (1024*1024) #include <sys/types.h> #include <stdarg.h> /* * 类型别名,用于指向 sdshdr 的 buf 属性 */ typedef char *sds; /* * 保存字符串对象的结构 */ struct sdshdr { // buf 中已占用空间的长度 int len; // buf 中剩余可用空间的长度 int free; // 数据空间 char buf[]; }; /* * 返回 sds 实际保存的字符串的长度 * * T = O(1) */ static inline size_t sdslen(const sds s) { struct sdshdr *sh = (void*)(s-(sizeof(struct sdshdr))); return sh->len; } /* * 返回 sds 可用空间的长度 * * T = O(1) */ static inline size_t sdsavail(const sds s) { struct sdshdr *sh = (void*)(s-(sizeof(struct sdshdr))); return sh->free; } sds sdsnewlen(const void *init, size_t initlen); sds sdsnew(const char *init); sds sdsempty(void); size_t sdslen(const sds s); sds sdsdup(const sds s); void sdsfree(sds s); size_t sdsavail(const sds s); sds sdsgrowzero(sds s, size_t len); sds sdscatlen(sds s, const void *t, size_t len); sds sdscat(sds s, const char *t); sds sdscatsds(sds s, const sds t); sds sdscpylen(sds s, const char *t, size_t len); sds sdscpy(sds s, const char *t); sds sdscatvprintf(sds s, const char *fmt, va_list ap); #ifdef __GNUC__ sds sdscatprintf(sds s, const char *fmt, ...) __attribute__((format(printf, 2, 3))); #else sds sdscatprintf(sds s, const char *fmt, ...); #endif sds sdscatfmt(sds s, char const *fmt, ...); sds sdstrim(sds s, const char *cset); void sdsrange(sds s, int start, int end); void sdsupdatelen(sds s); void sdsclear(sds s); int sdscmp(const sds s1, const sds s2); sds *sdssplitlen(const char *s, int len, const char *sep, int seplen, int *count); void sdsfreesplitres(sds *tokens, int count); void sdstolower(sds s); void sdstoupper(sds s); sds sdsfromlonglong(long long value); sds sdscatrepr(sds s, const char *p, size_t len); sds *sdssplitargs(const char *line, int *argc); sds sdsmapchars(sds s, const char *from, const char *to, size_t setlen); sds sdsjoin(char **argv, int argc, char *sep); /* Low level functions exposed to the user API */ sds sdsMakeRoomFor(sds s, size_t addlen); void sdsIncrLen(sds s, int incr); sds sdsRemoveFreeSpace(sds s); size_t sdsAllocSize(sds s); #endif
sds.c实现文件
/* SDSLib, A C dynamic strings library * * Copyright (c) 2006-2012, Salvatore Sanfilippo <antirez at gmail dot com> * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of Redis nor the names of its contributors may be used * to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <ctype.h> #include <assert.h> #include "sds.h" #include "zmalloc.h" /* * 根据给定的初始化字符串 init 和字符串长度 initlen * 创建一个新的 sds * * 参数 * init :初始化字符串指针 * initlen :初始化字符串的长度 * * 返回值 * sds :创建成功返回 sdshdr 相对应的 sds * 创建失败返回 NULL * * 复杂度 * T = O(N) */ /* Create a new sds string with the content specified by the 'init' pointer * and 'initlen'. * If NULL is used for 'init' the string is initialized with zero bytes. * * The string is always null-termined (all the sds strings are, always) so * even if you create an sds string with: * * mystring = sdsnewlen("abc",3"); * * You can print the string with printf() as there is an implicit \0 at the * end of the string. However the string is binary safe and can contain * \0 characters in the middle, as the length is stored in the sds header. */ sds sdsnewlen(const void *init, size_t initlen) { struct sdshdr *sh; // 根据是否有初始化内容,选择适当的内存分配方式 // T = O(N) if (init) { // zmalloc 不初始化所分配的内存 sh = zmalloc(sizeof(struct sdshdr)+initlen+1); } else { // zcalloc 将分配的内存全部初始化为 0 sh = zcalloc(sizeof(struct sdshdr)+initlen+1); } // 内存分配失败,返回 if (sh == NULL) return NULL; // 设置初始化长度 sh->len = initlen; // 新 sds 不预留任何空间 sh->free = 0; // 如果有指定初始化内容,将它们复制到 sdshdr 的 buf 中 // T = O(N) if (initlen && init) memcpy(sh->buf, init, initlen); // 以 \0 结尾 sh->buf[initlen] = '\0'; // 返回 buf 部分,而不是整个 sdshdr return (char*)sh->buf; } /* * 创建并返回一个只保存了空字符串 "" 的 sds * * 返回值 * sds :创建成功返回 sdshdr 相对应的 sds * 创建失败返回 NULL * * 复杂度 * T = O(1) */ /* Create an empty (zero length) sds string. Even in this case the string * always has an implicit null term. */ sds sdsempty(void) { return sdsnewlen("",0); } /* * 根据给定字符串 init ,创建一个包含同样字符串的 sds * * 参数 * init :如果输入为 NULL ,那么创建一个空白 sds * 否则,新创建的 sds 中包含和 init 内容相同字符串 * * 返回值 * sds :创建成功返回 sdshdr 相对应的 sds * 创建失败返回 NULL * * 复杂度 * T = O(N) */ /* Create a new sds string starting from a null termined C string. */ sds sdsnew(const char *init) { size_t initlen = (init == NULL) ? 0 : strlen(init); return sdsnewlen(init, initlen); } /* * 复制给定 sds 的副本 * * 返回值 * sds :创建成功返回输入 sds 的副本 * 创建失败返回 NULL * * 复杂度 * T = O(N) */ /* Duplicate an sds string. */ sds sdsdup(const sds s) { return sdsnewlen(s, sdslen(s)); } /* * 释放给定的 sds * * 复杂度 * T = O(N) */ /* Free an sds string. No operation is performed if 's' is NULL. */ void sdsfree(sds s) { if (s == NULL) return; zfree(s-sizeof(struct sdshdr)); } // 未使用函数,可能已废弃 /* Set the sds string length to the length as obtained with strlen(), so * considering as content only up to the first null term character. * * This function is useful when the sds string is hacked manually in some * way, like in the following example: * * s = sdsnew("foobar"); * s[2] = '\0'; * sdsupdatelen(s); * printf("%d\n", sdslen(s)); * * The output will be "2", but if we comment out the call to sdsupdatelen() * the output will be "6" as the string was modified but the logical length * remains 6 bytes. */ void sdsupdatelen(sds s) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); int reallen = strlen(s); sh->free += (sh->len-reallen); sh->len = reallen; } /* * 在不释放 SDS 的字符串空间的情况下, * 重置 SDS 所保存的字符串为空字符串。 * * 复杂度 * T = O(1) */ /* Modify an sds string on-place to make it empty (zero length). * However all the existing buffer is not discarded but set as free space * so that next append operations will not require allocations up to the * number of bytes previously available. */ void sdsclear(sds s) { // 取出 sdshdr struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); // 重新计算属性 sh->free += sh->len; sh->len = 0; // 将结束符放到最前面(相当于惰性地删除 buf 中的内容) sh->buf[0] = '\0'; } /* Enlarge the free space at the end of the sds string so that the caller * is sure that after calling this function can overwrite up to addlen * bytes after the end of the string, plus one more byte for nul term. * * Note: this does not change the *length* of the sds string as returned * by sdslen(), but only the free buffer space we have. */ /* * 对 sds 中 buf 的长度进行扩展,确保在函数执行之后, * buf 至少会有 addlen + 1 长度的空余空间 * (额外的 1 字节是为 \0 准备的) * * 返回值 * sds :扩展成功返回扩展后的 sds * 扩展失败返回 NULL * * 复杂度 * T = O(N) */ sds sdsMakeRoomFor(sds s, size_t addlen) { struct sdshdr *sh, *newsh; // 获取 s 目前的空余空间长度 size_t free = sdsavail(s); size_t len, newlen; // s 目前的空余空间已经足够,无须再进行扩展,直接返回 if (free >= addlen) return s; // 获取 s 目前已占用空间的长度 len = sdslen(s); sh = (void*) (s-(sizeof(struct sdshdr))); // s 最少需要的长度 newlen = (len+addlen); // 根据新长度,为 s 分配新空间所需的大小 if (newlen < SDS_MAX_PREALLOC) // 如果新长度小于 SDS_MAX_PREALLOC // 那么为它分配两倍于所需长度的空间 newlen *= 2; else // 否则,分配长度为目前长度加上 SDS_MAX_PREALLOC newlen += SDS_MAX_PREALLOC; // T = O(N) newsh = zrealloc(sh, sizeof(struct sdshdr)+newlen+1); // 内存不足,分配失败,返回 if (newsh == NULL) return NULL; // 更新 sds 的空余长度 newsh->free = newlen - len; // 返回 sds return newsh->buf; } /* * 回收 sds 中的空闲空间, * 回收不会对 sds 中保存的字符串内容做任何修改。 * * 返回值 * sds :内存调整后的 sds * * 复杂度 * T = O(N) */ /* Reallocate the sds string so that it has no free space at the end. The * contained string remains not altered, but next concatenation operations * will require a reallocation. * * After the call, the passed sds string is no longer valid and all the * references must be substituted with the new pointer returned by the call. */ sds sdsRemoveFreeSpace(sds s) { struct sdshdr *sh; sh = (void*) (s-(sizeof(struct sdshdr))); // 进行内存重分配,让 buf 的长度仅仅足够保存字符串内容 // T = O(N) sh = zrealloc(sh, sizeof(struct sdshdr)+sh->len+1); // 空余空间为 0 sh->free = 0; return sh->buf; } /* * 返回给定 sds 分配的内存字节数 * * 复杂度 * T = O(1) */ /* Return the total size of the allocation of the specifed sds string, * including: * 1) The sds header before the pointer. * 2) The string. * 3) The free buffer at the end if any. * 4) The implicit null term. */ size_t sdsAllocSize(sds s) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); return sizeof(*sh)+sh->len+sh->free+1; } /* Increment the sds length and decrements the left free space at the * end of the string according to 'incr'. Also set the null term * in the new end of the string. * * 根据 incr 参数,增加 sds 的长度,缩减空余空间, * 并将 \0 放到新字符串的尾端 * * This function is used in order to fix the string length after the * user calls sdsMakeRoomFor(), writes something after the end of * the current string, and finally needs to set the new length. * * 这个函数是在调用 sdsMakeRoomFor() 对字符串进行扩展, * 然后用户在字符串尾部写入了某些内容之后, * 用来正确更新 free 和 len 属性的。 * * Note: it is possible to use a negative increment in order to * right-trim the string. * * 如果 incr 参数为负数,那么对字符串进行右截断操作。 * * Usage example: * * Using sdsIncrLen() and sdsMakeRoomFor() it is possible to mount the * following schema, to cat bytes coming from the kernel to the end of an * sds string without copying into an intermediate buffer: * * 以下是 sdsIncrLen 的用例: * * oldlen = sdslen(s); * s = sdsMakeRoomFor(s, BUFFER_SIZE); * nread = read(fd, s+oldlen, BUFFER_SIZE); * ... check for nread <= 0 and handle it ... * sdsIncrLen(s, nread); * * 复杂度 * T = O(1) */ void sdsIncrLen(sds s, int incr) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); // 确保 sds 空间足够 assert(sh->free >= incr); // 更新属性 sh->len += incr; sh->free -= incr; // 这个 assert 其实可以忽略 // 因为前一个 assert 已经确保 sh->free - incr >= 0 了 assert(sh->free >= 0); // 放置新的结尾符号 s[sh->len] = '\0'; } /* Grow the sds to have the specified length. Bytes that were not part of * the original length of the sds will be set to zero. * * if the specified length is smaller than the current length, no operation * is performed. */ /* * 将 sds 扩充至指定长度,未使用的空间以 0 字节填充。 * * 返回值 * sds :扩充成功返回新 sds ,失败返回 NULL * * 复杂度: * T = O(N) */ sds sdsgrowzero(sds s, size_t len) { struct sdshdr *sh = (void*)(s-(sizeof(struct sdshdr))); size_t totlen, curlen = sh->len; // 如果 len 比字符串的现有长度小, // 那么直接返回,不做动作 if (len <= curlen) return s; // 扩展 sds // T = O(N) s = sdsMakeRoomFor(s,len-curlen); // 如果内存不足,直接返回 if (s == NULL) return NULL; /* Make sure added region doesn't contain garbage */ // 将新分配的空间用 0 填充,防止出现垃圾内容 // T = O(N) sh = (void*)(s-(sizeof(struct sdshdr))); memset(s+curlen,0,(len-curlen+1)); /* also set trailing \0 byte */ // 更新属性 totlen = sh->len+sh->free; sh->len = len; sh->free = totlen-sh->len; // 返回新的 sds return s; } /* * 将长度为 len 的字符串 t 追加到 sds 的字符串末尾 * * 返回值 * sds :追加成功返回新 sds ,失败返回 NULL * * 复杂度 * T = O(N) */ /* Append the specified binary-safe string pointed by 't' of 'len' bytes to the * end of the specified sds string 's'. * * After the call, the passed sds string is no longer valid and all the * references must be substituted with the new pointer returned by the call. */ sds sdscatlen(sds s, const void *t, size_t len) { struct sdshdr *sh; // 原有字符串长度 size_t curlen = sdslen(s); // 扩展 sds 空间 // T = O(N) s = sdsMakeRoomFor(s,len); // 内存不足?直接返回 if (s == NULL) return NULL; // 复制 t 中的内容到字符串后部 // T = O(N) sh = (void*) (s-(sizeof(struct sdshdr))); memcpy(s+curlen, t, len); // 更新属性 sh->len = curlen+len; sh->free = sh->free-len; // 添加新结尾符号 s[curlen+len] = '\0'; // 返回新 sds return s; } /* * 将给定字符串 t 追加到 sds 的末尾 * * 返回值 * sds :追加成功返回新 sds ,失败返回 NULL * * 复杂度 * T = O(N) */ /* Append the specified null termianted C string to the sds string 's'. * * After the call, the passed sds string is no longer valid and all the * references must be substituted with the new pointer returned by the call. */ sds sdscat(sds s, const char *t) { return sdscatlen(s, t, strlen(t)); } /* * 将另一个 sds 追加到一个 sds 的末尾 * * 返回值 * sds :追加成功返回新 sds ,失败返回 NULL * * 复杂度 * T = O(N) */ /* Append the specified sds 't' to the existing sds 's'. * * After the call, the modified sds string is no longer valid and all the * references must be substituted with the new pointer returned by the call. */ sds sdscatsds(sds s, const sds t) { return sdscatlen(s, t, sdslen(t)); } /* * 将字符串 t 的前 len 个字符复制到 sds s 当中, * 并在字符串的最后添加终结符。 * * 如果 sds 的长度少于 len 个字符,那么扩展 sds * * 复杂度 * T = O(N) * * 返回值 * sds :复制成功返回新的 sds ,否则返回 NULL */ /* Destructively modify the sds string 's' to hold the specified binary * safe string pointed by 't' of length 'len' bytes. */ sds sdscpylen(sds s, const char *t, size_t len) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); // sds 现有 buf 的长度 size_t totlen = sh->free+sh->len; // 如果 s 的 buf 长度不满足 len ,那么扩展它 if (totlen < len) { // T = O(N) s = sdsMakeRoomFor(s,len-sh->len); if (s == NULL) return NULL; sh = (void*) (s-(sizeof(struct sdshdr))); totlen = sh->free+sh->len; } // 复制内容 // T = O(N) memcpy(s, t, len); // 添加终结符号 s[len] = '\0'; // 更新属性 sh->len = len; sh->free = totlen-len; // 返回新的 sds return s; } /* * 将字符串复制到 sds 当中, * 覆盖原有的字符。 * * 如果 sds 的长度少于字符串的长度,那么扩展 sds 。 * * 复杂度 * T = O(N) * * 返回值 * sds :复制成功返回新的 sds ,否则返回 NULL */ /* Like sdscpylen() but 't' must be a null-termined string so that the length * of the string is obtained with strlen(). */ sds sdscpy(sds s, const char *t) { return sdscpylen(s, t, strlen(t)); } /* Helper for sdscatlonglong() doing the actual number -> string * conversion. 's' must point to a string with room for at least * SDS_LLSTR_SIZE bytes. * * The function returns the lenght of the null-terminated string * representation stored at 's'. */ #define SDS_LLSTR_SIZE 21 int sdsll2str(char *s, long long value) { char *p, aux; unsigned long long v; size_t l; /* Generate the string representation, this method produces * an reversed string. */ v = (value < 0) ? -value : value; p = s; do { *p++ = '0'+(v%10); v /= 10; } while(v); if (value < 0) *p++ = '-'; /* Compute length and add null term. */ l = p-s; *p = '\0'; /* Reverse the string. */ p--; while(s < p) { aux = *s; *s = *p; *p = aux; s++; p--; } return l; } /* Identical sdsll2str(), but for unsigned long long type. */ int sdsull2str(char *s, unsigned long long v) { char *p, aux; size_t l; /* Generate the string representation, this method produces * an reversed string. */ p = s; do { *p++ = '0'+(v%10); v /= 10; } while(v); /* Compute length and add null term. */ l = p-s; *p = '\0'; /* Reverse the string. */ p--; while(s < p) { aux = *s; *s = *p; *p = aux; s++; p--; } return l; } /* Create an sds string from a long long value. It is much faster than: * * sdscatprintf(sdsempty(),"%lld\n", value); */ // 根据输入的 long long 值 value ,创建一个 SDS sds sdsfromlonglong(long long value) { char buf[SDS_LLSTR_SIZE]; int len = sdsll2str(buf,value); return sdsnewlen(buf,len); } /* * 打印函数,被 sdscatprintf 所调用 * * T = O(N^2) */ /* Like sdscatpritf() but gets va_list instead of being variadic. */ sds sdscatvprintf(sds s, const char *fmt, va_list ap) { va_list cpy; char staticbuf[1024], *buf = staticbuf, *t; size_t buflen = strlen(fmt)*2; /* We try to start using a static buffer for speed. * If not possible we revert to heap allocation. */ if (buflen > sizeof(staticbuf)) { buf = zmalloc(buflen); if (buf == NULL) return NULL; } else { buflen = sizeof(staticbuf); } /* Try with buffers two times bigger every time we fail to * fit the string in the current buffer size. */ while(1) { buf[buflen-2] = '\0'; va_copy(cpy,ap); // T = O(N) vsnprintf(buf, buflen, fmt, cpy); if (buf[buflen-2] != '\0') { if (buf != staticbuf) zfree(buf); buflen *= 2; buf = zmalloc(buflen); if (buf == NULL) return NULL; continue; } break; } /* Finally concat the obtained string to the SDS string and return it. */ t = sdscat(s, buf); if (buf != staticbuf) zfree(buf); return t; } /* * 打印任意数量个字符串,并将这些字符串追加到给定 sds 的末尾 * * T = O(N^2) */ /* Append to the sds string 's' a string obtained using printf-alike format * specifier. * * After the call, the modified sds string is no longer valid and all the * references must be substituted with the new pointer returned by the call. * * Example: * * s = sdsempty("Sum is: "); * s = sdscatprintf(s,"%d+%d = %d",a,b,a+b). * * Often you need to create a string from scratch with the printf-alike * format. When this is the need, just use sdsempty() as the target string: * * s = sdscatprintf(sdsempty(), "... your format ...", args); */ sds sdscatprintf(sds s, const char *fmt, ...) { va_list ap; char *t; va_start(ap, fmt); // T = O(N^2) t = sdscatvprintf(s,fmt,ap); va_end(ap); return t; } /* This function is similar to sdscatprintf, but much faster as it does * not rely on sprintf() family functions implemented by the libc that * are often very slow. Moreover directly handling the sds string as * new data is concatenated provides a performance improvement. * * However this function only handles an incompatible subset of printf-alike * format specifiers: * * %s - C String * %S - SDS string * %i - signed int * %I - 64 bit signed integer (long long, int64_t) * %u - unsigned int * %U - 64 bit unsigned integer (unsigned long long, uint64_t) * %% - Verbatim "%" character. */ sds sdscatfmt(sds s, char const *fmt, ...) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); size_t initlen = sdslen(s); const char *f = fmt; int i; va_list ap; va_start(ap,fmt); f = fmt; /* Next format specifier byte to process. */ i = initlen; /* Position of the next byte to write to dest str. */ while(*f) { char next, *str; size_t l; long long num; unsigned long long unum; /* Make sure there is always space for at least 1 char. */ if (sh->free == 0) { s = sdsMakeRoomFor(s,1); sh = (void*) (s-(sizeof(struct sdshdr))); } switch(*f) { case '%': next = *(f+1); f++; switch(next) { case 's': case 'S': str = va_arg(ap,char*); l = (next == 's') ? strlen(str) : sdslen(str); if (sh->free < l) { s = sdsMakeRoomFor(s,l); sh = (void*) (s-(sizeof(struct sdshdr))); } memcpy(s+i,str,l); sh->len += l; sh->free -= l; i += l; break; case 'i': case 'I': if (next == 'i') num = va_arg(ap,int); else num = va_arg(ap,long long); { char buf[SDS_LLSTR_SIZE]; l = sdsll2str(buf,num); if (sh->free < l) { s = sdsMakeRoomFor(s,l); sh = (void*) (s-(sizeof(struct sdshdr))); } memcpy(s+i,buf,l); sh->len += l; sh->free -= l; i += l; } break; case 'u': case 'U': if (next == 'u') unum = va_arg(ap,unsigned int); else unum = va_arg(ap,unsigned long long); { char buf[SDS_LLSTR_SIZE]; l = sdsull2str(buf,unum); if (sh->free < l) { s = sdsMakeRoomFor(s,l); sh = (void*) (s-(sizeof(struct sdshdr))); } memcpy(s+i,buf,l); sh->len += l; sh->free -= l; i += l; } break; default: /* Handle %% and generally %<unknown>. */ s[i++] = next; sh->len += 1; sh->free -= 1; break; } break; default: s[i++] = *f; sh->len += 1; sh->free -= 1; break; } f++; } va_end(ap); /* Add null-term */ s[i] = '\0'; return s; } /* * 对 sds 左右两端进行修剪,清除其中 cset 指定的所有字符 * * 比如 sdsstrim(xxyyabcyyxy, "xy") 将返回 "abc" * * 复杂性: * T = O(M*N),M 为 SDS 长度, N 为 cset 长度。 */ /* Remove the part of the string from left and from right composed just of * contiguous characters found in 'cset', that is a null terminted C string. * * After the call, the modified sds string is no longer valid and all the * references must be substituted with the new pointer returned by the call. * * Example: * * s = sdsnew("AA...AA.a.aa.aHelloWorld :::"); * s = sdstrim(s,"A. :"); * printf("%s\n", s); * * Output will be just "Hello World". */ sds sdstrim(sds s, const char *cset) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); char *start, *end, *sp, *ep; size_t len; // 设置和记录指针 sp = start = s; ep = end = s+sdslen(s)-1; // 修剪, T = O(N^2) while(sp <= end && strchr(cset, *sp)) sp++; while(ep > start && strchr(cset, *ep)) ep--; // 计算 trim 完毕之后剩余的字符串长度 len = (sp > ep) ? 0 : ((ep-sp)+1); // 如果有需要,前移字符串内容 // T = O(N) if (sh->buf != sp) memmove(sh->buf, sp, len); // 添加终结符 sh->buf[len] = '\0'; // 更新属性 sh->free = sh->free+(sh->len-len); sh->len = len; // 返回修剪后的 sds return s; } /* * 按索引对截取 sds 字符串的其中一段 * start 和 end 都是闭区间(包含在内) * * 索引从 0 开始,最大为 sdslen(s) - 1 * 索引可以是负数, sdslen(s) - 1 == -1 * * 复杂度 * T = O(N) */ /* Turn the string into a smaller (or equal) string containing only the * substring specified by the 'start' and 'end' indexes. * * start and end can be negative, where -1 means the last character of the * string, -2 the penultimate character, and so forth. * * The interval is inclusive, so the start and end characters will be part * of the resulting string. * * The string is modified in-place. * * Example: * * s = sdsnew("Hello World"); * sdsrange(s,1,-1); => "ello World" */ void sdsrange(sds s, int start, int end) { struct sdshdr *sh = (void*) (s-(sizeof(struct sdshdr))); size_t newlen, len = sdslen(s); if (len == 0) return; 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) { newlen = 0; } else if (end >= (signed)len) { end = len-1; newlen = (start > end) ? 0 : (end-start)+1; } } else { start = 0; } // 如果有需要,对字符串进行移动 // T = O(N) if (start && newlen) memmove(sh->buf, sh->buf+start, newlen); // 添加终结符 sh->buf[newlen] = 0; // 更新属性 sh->free = sh->free+(sh->len-newlen); sh->len = newlen; } /* * 将 sds 字符串中的所有字符转换为小写 * * T = O(N) */ /* Apply tolower() to every character of the sds string 's'. */ void sdstolower(sds s) { int len = sdslen(s), j; for (j = 0; j < len; j++) s[j] = tolower(s[j]); } /* * 将 sds 字符串中的所有字符转换为大写 * * T = O(N) */ /* Apply toupper() to every character of the sds string 's'. */ void sdstoupper(sds s) { int len = sdslen(s), j; for (j = 0; j < len; j++) s[j] = toupper(s[j]); } /* * 对比两个 sds , strcmp 的 sds 版本 * * 返回值 * int :相等返回 0 ,s1 较大返回正数, s2 较大返回负数 * * T = O(N) */ /* Compare two sds strings s1 and s2 with memcmp(). * * Return value: * * 1 if s1 > s2. * -1 if s1 < s2. * 0 if s1 and s2 are exactly the same binary string. * * If two strings share exactly the same prefix, but one of the two has * additional characters, the longer string is considered to be greater than * the smaller one. */ int sdscmp(const sds s1, const sds s2) { size_t l1, l2, minlen; int cmp; l1 = sdslen(s1); l2 = sdslen(s2); minlen = (l1 < l2) ? l1 : l2; cmp = memcmp(s1,s2,minlen); if (cmp == 0) return l1-l2; 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. * * 使用分隔符 sep 对 s 进行分割,返回一个 sds 字符串的数组。 * *count 会被设置为返回数组元素的数量。 * * On out of memory, zero length string, zero length * separator, NULL is returned. * * 如果出现内存不足、字符串长度为 0 或分隔符长度为 0 * 的情况,返回 NULL * * 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". * * 注意分隔符可以的是包含多个字符的字符串 * * This version of the function is binary-safe but * requires length arguments. sdssplit() is just the * same function but for zero-terminated strings. * * 这个函数接受 len 参数,因此它是二进制安全的。 * (文档中提到的 sdssplit() 已废弃) * * T = O(N^2) */ sds *sdssplitlen(const char *s, int len, const char *sep, int seplen, int *count) { int elements = 0, slots = 5, start = 0, j; sds *tokens; if (seplen < 1 || len < 0) return NULL; tokens = zmalloc(sizeof(sds)*slots); if (tokens == NULL) return NULL; if (len == 0) { *count = 0; return tokens; } // T = O(N^2) 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) goto cleanup; tokens = newtokens; } /* search the separator */ // T = O(N) if ((seplen == 1 && *(s+j) == sep[0]) || (memcmp(s+j,sep,seplen) == 0)) { tokens[elements] = sdsnewlen(s+start,j-start); if (tokens[elements] == NULL) goto cleanup; 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. */ tokens[elements] = sdsnewlen(s+start,len-start); if (tokens[elements] == NULL) goto cleanup; elements++; *count = elements; return tokens; cleanup: { int i; for (i = 0; i < elements; i++) sdsfree(tokens[i]); zfree(tokens); *count = 0; return NULL; } } /* * 释放 tokens 数组中 count 个 sds * * T = O(N^2) */ /* Free the result returned by sdssplitlen(), or do nothing if 'tokens' is NULL. */ void sdsfreesplitres(sds *tokens, int count) { if (!tokens) return; while(count--) sdsfree(tokens[count]); zfree(tokens); } /* * 将长度为 len 的字符串 p 以带引号(quoted)的格式 * 追加到给定 sds 的末尾 * * T = O(N) */ /* Append to the sds string "s" an escaped string representation where * all the non-printable characters (tested with isprint()) are turned into * escapes in the form "\n\r\a...." or "\x<hex-number>". * * After the call, the modified sds string is no longer valid and all the * references must be substituted with the new pointer returned by the call. */ sds sdscatrepr(sds s, const char *p, size_t len) { s = sdscatlen(s,"\"",1); while(len--) { switch(*p) { case '\\': case '"': s = sdscatprintf(s,"\\%c",*p); break; case '\n': s = sdscatlen(s,"\\n",2); break; case '\r': s = sdscatlen(s,"\\r",2); break; case '\t': s = sdscatlen(s,"\\t",2); break; case '\a': s = sdscatlen(s,"\\a",2); break; case '\b': s = sdscatlen(s,"\\b",2); break; default: if (isprint(*p)) s = sdscatprintf(s,"%c",*p); else s = sdscatprintf(s,"\\x%02x",(unsigned char)*p); break; } p++; } return sdscatlen(s,"\"",1); } /* Helper function for sdssplitargs() that returns non zero if 'c' * is a valid hex digit. */ /* * 如果 c 为十六进制符号的其中一个,返回正数 * * T = O(1) */ int is_hex_digit(char c) { return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F'); } /* Helper function for sdssplitargs() that converts a hex digit into an * integer from 0 to 15 */ /* * 将十六进制符号转换为 10 进制 * * T = O(1) */ int hex_digit_to_int(char c) { switch(c) { case '0': return 0; case '1': return 1; case '2': return 2; case '3': return 3; case '4': return 4; case '5': return 5; case '6': return 6; case '7': return 7; case '8': return 8; case '9': return 9; case 'a': case 'A': return 10; case 'b': case 'B': return 11; case 'c': case 'C': return 12; case 'd': case 'D': return 13; case 'e': case 'E': return 14; case 'f': case 'F': return 15; default: return 0; } } /* Split a line into arguments, where every argument can be in the * following programming-language REPL-alike form: * * 将一行文本分割成多个参数,每个参数可以有以下的类编程语言 REPL 格式: * * foo bar "newline are supported\n" and "\xff\x00otherstuff" * * The number of arguments is stored into *argc, and an array * of sds is returned. * * 参数的个数会保存在 *argc 中,函数返回一个 sds 数组。 * * The caller should free the resulting array of sds strings with * sdsfreesplitres(). * * 调用者应该使用 sdsfreesplitres() 来释放函数返回的 sds 数组。 * * Note that sdscatrepr() is able to convert back a string into * a quoted string in the same format sdssplitargs() is able to parse. * * sdscatrepr() 可以将一个字符串转换为一个带引号(quoted)的字符串, * 这个带引号的字符串可以被 sdssplitargs() 分析。 * * The function returns the allocated tokens on success, even when the * input string is empty, or NULL if the input contains unbalanced * quotes or closed quotes followed by non space characters * as in: "foo"bar or "foo' * * 即使输入出现空字符串, NULL ,或者输入带有未对应的括号, * 函数都会将已成功处理的字符串先返回。 * * 这个函数主要用于 config.c 中对配置文件进行分析。 * 例子: * sds *arr = sdssplitargs("timeout 10086\r\nport 123321\r\n"); * 会得出 * arr[0] = "timeout" * arr[1] = "10086" * arr[2] = "port" * arr[3] = "123321" * * T = O(N^2) */ sds *sdssplitargs(const char *line, int *argc) { const char *p = line; char *current = NULL; char **vector = NULL; *argc = 0; while(1) { /* skip blanks */ // 跳过空白 // T = O(N) while(*p && isspace(*p)) p++; if (*p) { /* get a token */ int inq=0; /* set to 1 if we are in "quotes" */ int insq=0; /* set to 1 if we are in 'single quotes' */ int done=0; if (current == NULL) current = sdsempty(); // T = O(N) while(!done) { if (inq) { if (*p == '\\' && *(p+1) == 'x' && is_hex_digit(*(p+2)) && is_hex_digit(*(p+3))) { unsigned char byte; byte = (hex_digit_to_int(*(p+2))*16)+ hex_digit_to_int(*(p+3)); current = sdscatlen(current,(char*)&byte,1); p += 3; } else if (*p == '\\' && *(p+1)) { char c; p++; switch(*p) { case 'n': c = '\n'; break; case 'r': c = '\r'; break; case 't': c = '\t'; break; case 'b': c = '\b'; break; case 'a': c = '\a'; break; default: c = *p; break; } current = sdscatlen(current,&c,1); } else if (*p == '"') { /* closing quote must be followed by a space or * nothing at all. */ if (*(p+1) && !isspace(*(p+1))) goto err; done=1; } else if (!*p) { /* unterminated quotes */ goto err; } else { current = sdscatlen(current,p,1); } } else if (insq) { if (*p == '\\' && *(p+1) == '\'') { p++; current = sdscatlen(current,"'",1); } else if (*p == '\'') { /* closing quote must be followed by a space or * nothing at all. */ if (*(p+1) && !isspace(*(p+1))) goto err; done=1; } else if (!*p) { /* unterminated quotes */ goto err; } else { current = sdscatlen(current,p,1); } } else { switch(*p) { case ' ': case '\n': case '\r': case '\t': case '\0': done=1; break; case '"': inq=1; break; case '\'': insq=1; break; default: current = sdscatlen(current,p,1); break; } } if (*p) p++; } /* add the token to the vector */ // T = O(N) vector = zrealloc(vector,((*argc)+1)*sizeof(char*)); vector[*argc] = current; (*argc)++; current = NULL; } else { /* Even on empty input string return something not NULL. */ if (vector == NULL) vector = zmalloc(sizeof(void*)); return vector; } } err: while((*argc)--) sdsfree(vector[*argc]); zfree(vector); if (current) sdsfree(current); *argc = 0; return NULL; } /* Modify the string substituting all the occurrences of the set of * characters specified in the 'from' string to the corresponding character * in the 'to' array. * * 将字符串 s 中, * 所有在 from 中出现的字符,替换成 to 中的字符 * * For instance: sdsmapchars(mystring, "ho", "01", 2) * will have the effect of turning the string "hello" into "0ell1". * * 比如调用 sdsmapchars(mystring, "ho", "01", 2) * 就会将 "hello" 转换为 "0ell1" * * The function returns the sds string pointer, that is always the same * as the input pointer since no resize is needed. * 因为无须对 sds 进行大小调整, * 所以返回的 sds 输入的 sds 一样 * * T = O(N^2) */ sds sdsmapchars(sds s, const char *from, const char *to, size_t setlen) { size_t j, i, l = sdslen(s); // 遍历输入字符串 for (j = 0; j < l; j++) { // 遍历映射 for (i = 0; i < setlen; i++) { // 替换字符串 if (s[j] == from[i]) { s[j] = to[i]; break; } } } return s; } /* Join an array of C strings using the specified separator (also a C string). * Returns the result as an sds string. */ sds sdsjoin(char **argv, int argc, char *sep) { sds join = sdsempty(); int j; for (j = 0; j < argc; j++) { join = sdscat(join, argv[j]); if (j != argc-1) join = sdscat(join,sep); } return join; } #ifdef SDS_TEST_MAIN #include <stdio.h> #include "testhelp.h" #include "limits.h" int main(void) { { struct sdshdr *sh; sds x = sdsnew("foo"), y; test_cond("Create a string and obtain the length", sdslen(x) == 3 && memcmp(x,"foo\0",4) == 0) sdsfree(x); x = sdsnewlen("foo",2); test_cond("Create a string with specified length", sdslen(x) == 2 && memcmp(x,"fo\0",3) == 0) x = sdscat(x,"bar"); test_cond("Strings concatenation", sdslen(x) == 5 && memcmp(x,"fobar\0",6) == 0); x = sdscpy(x,"a"); test_cond("sdscpy() against an originally longer string", sdslen(x) == 1 && memcmp(x,"a\0",2) == 0) x = sdscpy(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk"); test_cond("sdscpy() against an originally shorter string", sdslen(x) == 33 && memcmp(x,"xyzxxxxxxxxxxyyyyyyyyyykkkkkkkkkk\0",33) == 0) sdsfree(x); x = sdscatprintf(sdsempty(),"%d",123); test_cond("sdscatprintf() seems working in the base case", sdslen(x) == 3 && memcmp(x,"123\0",4) == 0) sdsfree(x); x = sdsnew("--"); x = sdscatfmt(x, "Hello %s World %I,%I--", "Hi!", LLONG_MIN,LLONG_MAX); test_cond("sdscatfmt() seems working in the base case", sdslen(x) == 60 && memcmp(x,"--Hello Hi! World -9223372036854775808," "9223372036854775807--",60) == 0) sdsfree(x); x = sdsnew("--"); x = sdscatfmt(x, "%u,%U--", UINT_MAX, ULLONG_MAX); test_cond("sdscatfmt() seems working with unsigned numbers", sdslen(x) == 35 && memcmp(x,"--4294967295,18446744073709551615--",35) == 0) sdsfree(x); x = sdsnew("xxciaoyyy"); sdstrim(x,"xy"); test_cond("sdstrim() correctly trims characters", sdslen(x) == 4 && memcmp(x,"ciao\0",5) == 0) y = sdsdup(x); sdsrange(y,1,1); test_cond("sdsrange(...,1,1)", sdslen(y) == 1 && memcmp(y,"i\0",2) == 0) sdsfree(y); y = sdsdup(x); sdsrange(y,1,-1); test_cond("sdsrange(...,1,-1)", sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0) sdsfree(y); y = sdsdup(x); sdsrange(y,-2,-1); test_cond("sdsrange(...,-2,-1)", sdslen(y) == 2 && memcmp(y,"ao\0",3) == 0) sdsfree(y); y = sdsdup(x); sdsrange(y,2,1); test_cond("sdsrange(...,2,1)", sdslen(y) == 0 && memcmp(y,"\0",1) == 0) sdsfree(y); y = sdsdup(x); sdsrange(y,1,100); test_cond("sdsrange(...,1,100)", sdslen(y) == 3 && memcmp(y,"iao\0",4) == 0) sdsfree(y); y = sdsdup(x); sdsrange(y,100,100); test_cond("sdsrange(...,100,100)", sdslen(y) == 0 && memcmp(y,"\0",1) == 0) sdsfree(y); sdsfree(x); x = sdsnew("foo"); y = sdsnew("foa"); test_cond("sdscmp(foo,foa)", sdscmp(x,y) > 0) sdsfree(y); sdsfree(x); x = sdsnew("bar"); y = sdsnew("bar"); test_cond("sdscmp(bar,bar)", sdscmp(x,y) == 0) sdsfree(y); sdsfree(x); x = sdsnew("aar"); y = sdsnew("bar"); test_cond("sdscmp(bar,bar)", sdscmp(x,y) < 0) sdsfree(y); sdsfree(x); x = sdsnewlen("\a\n\0foo\r",7); y = sdscatrepr(sdsempty(),x,sdslen(x)); test_cond("sdscatrepr(...data...)", memcmp(y,"\"\\a\\n\\x00foo\\r\"",15) == 0) { int oldfree; sdsfree(x); x = sdsnew("0"); sh = (void*) (x-(sizeof(struct sdshdr))); test_cond("sdsnew() free/len buffers", sh->len == 1 && sh->free == 0); x = sdsMakeRoomFor(x,1); sh = (void*) (x-(sizeof(struct sdshdr))); test_cond("sdsMakeRoomFor()", sh->len == 1 && sh->free > 0); oldfree = sh->free; x[1] = '1'; sdsIncrLen(x,1); test_cond("sdsIncrLen() -- content", x[0] == '0' && x[1] == '1'); test_cond("sdsIncrLen() -- len", sh->len == 2); test_cond("sdsIncrLen() -- free", sh->free == oldfree-1); } } test_report() return 0; } #endif
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