redis原始碼分析（二）、redis原始碼分析之sds字串
sds字串
Redis 只會使用 C 字串作為字面量， 在大多數情況下， Redis 使用 SDS （Simple Dynamic String，簡單動態字串）作為字串表示。
比起 C 字串， SDS 具有以下優點：
- 常數複雜度獲取字串長度。
- 杜絕緩衝區溢位。
- 減少修改字串長度時所需的記憶體重分配次數。
- 二進位制安全。
- 相容部分 C 字串函式。
根據傳統， C 語言使用長度為N+1的字元陣列來表示長度為 N 的字串，並且字元陣列的最後一個元素總是空字元 ‘\0’ 。
C 語言使用的這種簡單的字串表示方式， 並不能滿足 Redis 對字串在安全性、效率、以及功能方面的要求， 本節接下來的內容將詳細對比 C 字串和 SDS 之間的區別， 並說明 SDS 比 C 字串更適用於 Redis 的原因。
SDS又叫簡單動態字串，在Redis中預設使用SDS來表示字串。比如在Redis中的鍵值對中的鍵一般都是使用SDS來實現。首先需要說明的是在Redis中，字串不是用傳統的字串來實現，而是Redis自己構建了一個結構來表示字串。優點如下：
1、O(1)時間內獲取字串長度。常數複雜度獲取字串長度(依據其結構特性，只需要訪問其結構體成員len既可獲得字串長度)
2、杜絕緩衝區溢位，另外SDS還提供的一些API操作，是二進位制安全的(也就是不會因為空格等特殊字元而中斷字串)、不會溢位(API操作會檢查其長度)
3、減少了修改字串時帶來的記憶體重分配次數。
- 對於增長字串其採用的策略是檢查修改之後的長度大小，如果小於1024*1024，則分配2倍的修改後的長度+1
- 對於減少的字串其並不立即釋放空間，而是迴歸到alloc中去。（自動查閱redis記憶體分配與釋放策略）
typedef char *sds;//底層用於儲存字串的資料結構SDS
/* Note: sdshdr5 is never used, we just access the flags byte directly.
* However is here to document the layout of type 5 SDS strings. */
struct __attribute__ ((__packed__)) sdshdr5 {
//低三位儲存type，高5位儲存長度
unsigned char flags; /* 3 lsb of type, and 5 msb of string length */
char buf[];
};
struct __attribute__ ((__packed__)) sdshdr8 {
uint8_t len; /* used */
uint8_t alloc; /* excluding the header and null terminator */
unsigned char flags; /* 3 lsb of type, 5 unused bits */
char buf[];
};
struct __attribute__ ((__packed__)) sdshdr16 {
uint16_t len; /* used */
uint16_t alloc; /* excluding the header and null terminator */
unsigned char flags; /* 3 lsb of type, 5 unused bits */
char buf[];
};
struct __attribute__ ((__packed__)) sdshdr32 {
uint32_t len; /* used */
uint32_t alloc; /* excluding the header and null terminator */
unsigned char flags; /* 3 lsb of type, 5 unused bits */
char buf[];
};
struct __attribute__ ((__packed__)) sdshdr64 {
uint64_t len; /* used */
uint64_t alloc; /* excluding the header and null terminator */
unsigned char flags; /* 3 lsb of type, 5 unused bits */
char buf[];
};從程式碼中可以看出，SDS表示的字串是有SDS header和char*指標組成，而SDS的頭部主要由四部分組成：
len：SDS字串已使用的空間。 alloc：申請的空間，減去len就是未使用的空間，初始時和len一致。
flag：只使用了低三位表示型別，細化了SDS的分類，根據字串的長度的不同選擇不同的sds結構體，而結構體的主要區別是len和alloc的型別，這樣做可以節省一部分空間大小，畢竟在redis字串非常多，進一步的可以節省空間。
buf: 用了C的特性表示不定長字串。
除了sdshdr5之外，其他結構都是相似的。我們先看看sdshdr，它只有flags和buf成員，其中flag空間被C充分利用，其第三位儲存了SDS字串的型別.
#define SDS_TYPE_MASK 7 // 型別掩碼
#define SDS_TYPE_BITS 3
#define SDS_HDR_VAR(T,s) struct sdshdr##T *sh = (void*)((s)-(sizeof(struct sdshdr##T))); // 獲取header頭指標
#define SDS_HDR(T,s) ((struct sdshdr##T *)((s)-(sizeof(struct sdshdr##T)))) // 獲取header頭指標
#define SDS_TYPE_5_LEN(f) ((f)>>SDS_TYPE_BITS) // 獲取sdshdr5的長度,低三位儲存了type/*sds結構一共有五種Header定義，其目的是為了滿足不同長度的字串可以使用不同大小的Header，從而節省記憶體。
Header部分主要包含以下幾個部分：len、alloc、flags其中
len：表示字串真正的長度，不包含空終止字和alloc以及flag
alloc：表示字串的最大容量，不包含Header和最後的空終止字元和flag
flag：只用了3位表示sds的type 就是表示header的型別*/
// 五種header型別，flags取值為0~4
#define SDS_TYPE_5 0
#define SDS_TYPE_8 1
#define SDS_TYPE_16 2
#define SDS_TYPE_32 3
#define SDS_TYPE_64 4sdsnewlen函式 sds建立函式
/* 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) {
void *sh;
sds s;
// 根據initlen 求sds使用的結構體型別
char type = sdsReqType(initlen);
//下面是我在測試的時候新增的列印字串型別程式碼，原始碼中沒有
int type_t = type;
printf("sds.c------->sdsnewlen: the sds type is: [ %d ]\n", type_t);
/* Empty strings are usually created in order to append. Use type 8
* since type 5 is not good at this. */
//type5 不再使用 而是直接使用type8
if (type == SDS_TYPE_5 && initlen == 0) type = SDS_TYPE_8;
//sds使用的結構體的大小
int hdrlen = sdsHdrSize(type);
unsigned char *fp; /* flags pointer. */ //flag的第三位表示sds使用的結構體
//分配內層 大小是sds結構體的大小: hdrlen + buf的大小initlen + '\0'
sh = s_malloc(hdrlen+initlen+1);
//init為null的時候 直接初始化sh內容
if (!init)
memset(sh, 0, hdrlen+initlen+1);
//sh 分配失敗的情況直接返回null
if (sh == NULL) return NULL;
// s為資料部分的起始指標 指向buf地址指標
s = (char*)sh+hdrlen;
//fp指向flag flag的低三位表示sds使用的結構體型別
fp = ((unsigned char*)s)-1;
//根據sds使用的結構體型別 給結構體中的成員賦值
switch(type) {
case SDS_TYPE_5: {
// initlen << SDS_TYPE_BITS 把initlen的值儲存到flag的高5位中去 低三位儲存type的值
*fp = type | (initlen << SDS_TYPE_BITS);
break;
}
case SDS_TYPE_8: {
SDS_HDR_VAR(8,s);
sh->len = initlen;
sh->alloc = initlen;
*fp = type;
break;
}
case SDS_TYPE_16: {
SDS_HDR_VAR(16,s);
sh->len = initlen;
sh->alloc = initlen;
*fp = type;
break;
}
case SDS_TYPE_32: {
SDS_HDR_VAR(32,s);
sh->len = initlen;
sh->alloc = initlen;
*fp = type;
break;
}
case SDS_TYPE_64: {
SDS_HDR_VAR(64,s);
sh->len = initlen;
sh->alloc = initlen;
*fp = type;
break;
}
}
if (initlen && init)
//拷貝資料部分
memcpy(s, init, initlen);
// 與C字串相容
s[initlen] = '\0';
// 返回建立的sds字串指標
return s;
}sdsMakeRoomFor函式
函式原型：sds sdsMakeRoomFor(sds s, size_t addlen)
說明：實現擴充已有sds的可用空間為指定的大小，擴充規則是：當addlen的長度小於10241024時，則申請的空間是2(addlen+len)，否則擴充為1024*1024大小。
返回值:擴充後的sds物件
/* 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. */
sds sdsMakeRoomFor(sds s, size_t addlen) {
void *sh, *newsh;
size_t avail = sdsavail(s); //返回剩餘可用的空間。
size_t len, newlen;
char type, oldtype = s[-1] & SDS_TYPE_MASK; //獲取type
int hdrlen;
/* Return ASAP if there is enough space left. */
if (avail >= addlen) return s; //如果可用空間大於addlen直接返回舊的字串
len = sdslen(s); //求sds的長度
sh = (char*)s-sdsHdrSize(oldtype);
newlen = (len+addlen);
if (newlen < SDS_MAX_PREALLOC)
newlen *= 2;
else
newlen += SDS_MAX_PREALLOC;
//根據newlen調整sds的type
type = sdsReqType(newlen);
/* Don't use type 5: the user is appending to the string and type 5 is
* not able to remember empty space, so sdsMakeRoomFor() must be called
* at every appending operation. */
if (type == SDS_TYPE_5) type = SDS_TYPE_8;
//根據type獲取sds使用的結構體的長度
hdrlen = sdsHdrSize(type);
//若型別和原有型別一樣，則採用realloc分配空間，否則重新分配採用malloc函式分配空間
if (oldtype==type) {
newsh = s_realloc(sh, hdrlen+newlen+1);
if (newsh == NULL) return NULL;
s = (char*)newsh+hdrlen;
} else {
/* Since the header size changes, need to move the string forward,
* and can't use realloc */
newsh = s_malloc(hdrlen+newlen+1);
if (newsh == NULL) return NULL;
memcpy((char*)newsh+hdrlen, s, len+1); //把s中的字串拷貝到newsh指向的buf中去
s_free(sh);//釋放舊的sh空間
s = (char*)newsh+hdrlen; //s指向重新分配的字串
s[-1] = type; //指定newsds的type
sdssetlen(s, len); //設定新的字串的長度
}
sdssetalloc(s, newlen); //設定新的newsh的分配的空間長度
return s;
}sdscatlen :sds提供了字串的連線函式，用來連線兩個字串
//sds字串連線
sds sdscatlen(sds s, const void *t, size_t len) {
size_t curlen = sdslen(s);
//擴充套件s的空間
s = sdsMakeRoomFor(s,len);
if (s == NULL) return NULL;
// 連線新字串
memcpy(s+curlen, t, len);
// 設定連線後字串長度
sdssetlen(s, curlen+len);
s[curlen+len] = '\0';
return s;
}sds sdsempty(void); // 清空sds
sds sdsdup(const sds s); // 複製字串
sds sdsgrowzero(sds s, size_t len); // 擴充套件字串到指定長度
sds sdscpylen(sds s, const char *t, size_t len); // 字串的複製
sds sdscpy(sds s, const char *t); // 字串的複製
sds sdscatfmt(sds s, char const *fmt, ...); //字串格式化輸出
sds sdstrim(sds s, const char *cset); //字串縮減
void sdsrange(sds s, int start, int end); //字串擷取函式
void sdsupdatelen(sds s); //更新字串最新的長度
void sdsclear(sds s); //字串清空操作
void sdstolower(sds s); //sds字元轉小寫表示
void sdstoupper(sds s); //sds字元統一轉大寫
sds sdsjoin(char **argv, int argc, char *sep); //以分隔符連線字串子陣列構成新的字串sdsull2str 把一個long long的型別的數轉成字串
#include <iostream>
using namespace std;
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--;
}
// std::cout << s << std::endl;
return l;
}
int main()
{
char str[10]={0};
sdsll2str(str, 1234567);
std::cout << str << std::endl;
}整個sds.c檔案
/* SDSLib 2.0 -- A C dynamic strings library
*
* Copyright (c) 2006-2015, Salvatore Sanfilippo <antirez at gmail dot com>
* Copyright (c) 2015, Oran Agra
* Copyright (c) 2015, Redis Labs, Inc
* 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 <limits.h>
#include "sds.h"
#include "sdsalloc.h"
//根據sds的type 求sds使用的結構體大小
static inline int sdsHdrSize(char type) {
switch(type&SDS_TYPE_MASK) {
case SDS_TYPE_5:
return sizeof(struct sdshdr5);
case SDS_TYPE_8:
return sizeof(struct sdshdr8);
case SDS_TYPE_16:
return sizeof(struct sdshdr16);
case SDS_TYPE_32:
return sizeof(struct sdshdr32);
case SDS_TYPE_64:
return sizeof(struct sdshdr64);
}
return 0;
}
// 根據string的大小 求sds的結構體型別
static inline char sdsReqType(size_t string_size) {
printf("sds.c ---------> sdsReqType\n");
if (string_size < 1<<5)
return SDS_TYPE_5;
if (string_size < 1<<8)
return SDS_TYPE_8;
if (string_size < 1<<16)
return SDS_TYPE_16;
#if (LONG_MAX == LLONG_MAX)
if (string_size < 1ll<<32)
return SDS_TYPE_32;
#endif
return SDS_TYPE_64;
}
/* 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. */
//建立sds字串
sds sdsnewlen(const void *init, size_t initlen) {
void *sh;
sds s;
// 根據initlen 求sds使用的結構體型別
char type = sdsReqType(initlen);
//下面是我在測試的時候新增的列印字串型別程式碼，原始碼中沒有
int type_t = type;
printf("sds.c------->sdsnewlen: the sds type is: [ %d ]\n", type_t);
/* Empty strings are usually created in order to append. Use type 8
* since type 5 is not good at this. */
//type5 不再使用 而是直接使用type8
if (type == SDS_TYPE_5 && initlen == 0) type = SDS_TYPE_8;
//sds使用的結構體的大小
int hdrlen = sdsHdrSize(type);
unsigned char *fp; /* flags pointer. */ //flag的第三位表示sds使用的結構體
//分配內層 大小是sds結構體的大小: hdrlen + buf的大小initlen + '\0'
sh = s_malloc(hdrlen+initlen+1);
//init為null的時候 直接初始化sh內容
if (!init)
memset(sh, 0, hdrlen+initlen+1);
//sh 分配失敗的情況直接返回null
if (sh == NULL) return NULL;
// s為資料部分的起始指標 指向buf地址指標
s = (char*)sh+hdrlen;
//fp指向flag flag的低三位表示sds使用的結構體型別
fp = ((unsigned char*)s)-1;
//根據sds使用的結構體型別 給結構體中的成員賦值
switch(type) {
case SDS_TYPE_5: {
// initlen << SDS_TYPE_BITS 把initlen的值儲存到flag的高5位中去 低三位儲存type的值
*fp = type | (initlen << SDS_TYPE_BITS);
break;
}
case SDS_TYPE_8: {
SDS_HDR_VAR(8,s);
sh->len = initlen;
sh->alloc = initlen;
*fp = type;
break;
}
case SDS_TYPE_16: {
SDS_HDR_VAR(16,s);
sh->len = initlen;
sh->alloc = initlen;
*fp = type;
break;
}
case SDS_TYPE_32: {
SDS_HDR_VAR(32,s);
sh->len = initlen;
sh->alloc = initlen;
*fp = type;
break;
}
case SDS_TYPE_64: {
SDS_HDR_VAR(64,s);
sh->len = initlen;
sh->alloc = initlen;
*fp = type;
break;
}
}
if (initlen && init)
//拷貝資料部分
memcpy(s, init, initlen);
// 與C字串相容
s[initlen] = '\0';
// 返回建立的sds字串指標
return s;
}
/* Create an empty (zero length) sds string. Even in this case the string
* always has an implicit null term. */
//建立一個空的sds
sds sdsempty(void) {
return sdsnewlen("",0);
}
/* Create a new sds string starting from a null terminated C string. */
//建立sds
sds sdsnew(const char *init) {
size_t initlen = (init == NULL) ? 0 : strlen(init);
return sdsnewlen(init, initlen);
}
/* Duplicate an sds string. */
//dup一個sds
sds sdsdup(const sds s) {
return sdsnewlen(s, sdslen(s));
}
/* Free an sds string. No operation is performed if 's' is NULL. */
//釋放sds
void sdsfree(sds s) {
if (s == NULL) return;
s_free((char*)s-sdsHdrSize(s[-1]));
}
/* 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. */
//update sds的長度
void sdsupdatelen(sds s) {
int reallen = strlen(s);
sdssetlen(s, reallen);
}
/* Modify an sds string in-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. */
//清空sds的內容
void sdsclear(sds s) {
sdssetlen(s, 0);
s[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. */
//擴充套件sds的空間
sds sdsMakeRoomFor(sds s, size_t addlen) {
void *sh, *newsh;
size_t avail = sdsavail(s); //返回剩餘可用的空間。
size_t len, newlen;
char type, oldtype = s[-1] & SDS_TYPE_MASK; //獲取type
int hdrlen;
/* Return ASAP if there is enough space left. */
if (avail >= addlen) return s; //如果可用空間大於addlen直接返回舊的字串
len = sdslen(s); //求sds的長度
sh = (char*)s-sdsHdrSize(oldtype);
newlen = (len+addlen);
if (newlen < SDS_MAX_PREALLOC)
newlen *= 2;
else
newlen += SDS_MAX_PREALLOC;
//根據newlen調整sds的type
type = sdsReqType(newlen);
/* Don't use type 5: the user is appending to the string and type 5 is
* not able to remember empty space, so sdsMakeRoomFor() must be called
* at every appending operation. */
if (type == SDS_TYPE_5) type = SDS_TYPE_8;
//根據type獲取sds使用的結構體的長度
hdrlen = sdsHdrSize(type);
//若型別和原有型別一樣，則採用realloc分配空間，否則重新分配採用malloc函式分配空間
if (oldtype==type) {
newsh = s_realloc(sh, hdrlen+newlen+1);
if (newsh == NULL) return NULL;
s = (char*)newsh+hdrlen;
} else {
/* Since the header size changes, need to move the string forward,
* and can't use realloc */
newsh = s_malloc(hdrlen+newlen+1);
if (newsh == NULL) return NULL;
memcpy((char*)newsh+hdrlen, s, len+1); //把s中的字串拷貝到newsh指向的buf中去
s_free(sh);//釋放舊的sh空間
s = (char*)newsh+hdrlen; //s指向重新分配的字串
s[-1] = type; //指定newsds的type
sdssetlen(s, len); //設定新的字串的長度
}
sdssetalloc(s, newlen); //設定新的newsh的分配的空間長度
return s;
}
/* 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. */
//回收多餘的空間
sds sdsRemoveFreeSpace(sds s) {
void *sh, *newsh;
char type, oldtype = s[-1] & SDS_TYPE_MASK;
int hdrlen;
size_t len = sdslen(s);
sh = (char*)s-sdsHdrSize(oldtype);
type = sdsReqType(len);
hdrlen = sdsHdrSize(type);
if (oldtype==type) {
newsh = s_realloc(sh, hdrlen+len+1);
if (newsh == NULL) return NULL;
s = (char*)newsh+hdrlen;
} else {
newsh = s_malloc(hdrlen+len+1);
if (newsh == NULL) return NULL;
memcpy((char*)newsh+hdrlen, s, len+1);
s_free(sh);
s = (char*)newsh+hdrlen;
s[-1] = type;
sdssetlen(s, len);
}
sdssetalloc(s, len);
return s;
}
/* 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.
*/
//返回sds總的分配空間大小
size_t sdsAllocSize(sds s) {
size_t alloc = sdsalloc(s);
return sdsHdrSize(s[-1])+alloc+1;
}
/* Return the pointer of the actual SDS allocation (normally SDS strings
* are referenced by the start of the string buffer). */
//返回指向sds的字串指標
void *sdsAllocPtr(sds s) {
return (void*) (s-sdsHdrSize(s[-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.
*
* 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.
*
* Note: it is possible to use a negative increment in order to
* right-trim the string.
*
* 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:
*
* 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);
*/
//擴充套件sds的長度
void sdsIncrLen(sds s, int incr) {
unsigned char flags = s[-1];
size_t len;
switch(flags&SDS_TYPE_MASK) {
case SDS_TYPE_5: {
unsigned char *fp = ((unsigned char*)s)-1;
unsigned char oldlen = SDS_TYPE_5_LEN(flags);
assert((incr > 0 && oldlen+incr < 32) || (incr < 0 && oldlen >= (unsigned int)(-incr)));
*fp = SDS_TYPE_5 | ((oldlen+incr) << SDS_TYPE_BITS);
len = oldlen+incr;
break;
}
case SDS_TYPE_8: {
SDS_HDR_VAR(8,s);
assert((incr >= 0 && sh->alloc-sh->len >= incr) || (incr < 0 && sh->len >= (unsigned int)(-incr)));
len = (sh->len += incr);
break;
}
case SDS_TYPE_16: {
SDS_HDR_VAR(16,s);
assert((incr >= 0 && sh->alloc-sh->len >= incr) || (incr < 0 && sh->len >= (unsigned int)(-incr)));
len = (sh->len += incr);
break;
}
case SDS_TYPE_32: {
SDS_HDR_VAR(32,s);
assert((incr >= 0 && sh->alloc-sh->len >= (unsigned int)incr) || (incr < 0 && sh->len >= (unsigned int)(-incr)));
len = (sh->len += incr);
break;
}
case SDS_TYPE_64: {
SDS_HDR_VAR(64,s);
assert((incr >= 0 && sh->alloc-sh->len >= (uint64_t)incr) || (incr < 0 && sh->len >= (uint64_t)(-incr)));
len = (sh->len += incr);
break;
}
default: len = 0; /* Just to avoid compilation warnings. */
}
s[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. */
//初始化擴充套件部分的記憶體，確保沒有garbage
sds sdsgrowzero(sds s, size_t len) {
size_t curlen = sdslen(s);
if (len <= curlen) return s;
s = sdsMakeRoomFor(s,len-curlen);
if (s == NULL) return NULL;
/* Make sure added region doesn't contain garbage */
memset(s+curlen,0,(len-curlen+1)); /* also set trailing \0 byte */
sdssetlen(s, len);
return s;
}
/* 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. */
//將長度為len的c型別的字串連線到sds型別字串s的尾部
sds sdscatlen(sds s, const void *t, size_t len) {
size_t curlen = sdslen(s);
//擴充套件s的空間
s = sdsMakeRoomFor(s,len);
if (s == NULL) return NULL;
// 連線新字串
memcpy(s+curlen, t, len);
// 設定連線後字串長度
sdssetlen(s, curlen+len);
s[curlen+len] = '\0';
return s;
}
/* 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. */
//c 型別的字串t連線 sds型別字元s的尾部
sds sdscat(sds s, const char *t) {
return sdscatlen(s, t, strlen(t));
}
/* 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 t字串連線sds s的字串的尾部
sds sdscatsds(sds s, const sds t) {
return sdscatlen(s, t, sdslen(t));
}
/* Destructively modify the sds string 's' to hold the specified binary
* safe string pointed by 't' of length 'len' bytes. */
//將長度為len的字串連線到sds 字串尾部
sds sdscpylen(sds s, const char *t, size_t len) {
if (sdsalloc(s) < len) {
s = sdsMakeRoomFor(s,len-sdslen(s));
if (s == NULL) return NULL;
}
memcpy(s, t, len);
s[len] = '\0';
sdssetlen(s, len);
return s;
}
/* 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 length of the null-terminated string
* representation stored at 's'. */
#define SDS_LLSTR_SIZE 21
//將一個long long型別的陣列轉化為字串
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. */
//把一個long long型別的數轉成字串
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);
*/
sds sdsfromlonglong(long long value) {
char buf[SDS_LLSTR_SIZE];
int len = sdsll2str(buf,value);
return sdsnewlen(buf,len);
}
/* Like sdscatprintf() but gets va_list instead of being variadic. */
//型別c語言的vsnprintf
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 = s_malloc(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);
vsnprintf(buf, buflen, fmt, cpy);
va_end(cpy);
if (buf[buflen-2] != '\0') {
if (buf != staticbuf) s_free(buf);
buflen *= 2;
buf = s_malloc(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) s_free(buf);
return t;
}
/* 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 = sdsnew("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 = 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, ...) {
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 (sdsavail(s)==0) {
s = sdsMakeRoomFor(s,1);
}
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 (sdsavail(s) < l) {
s = sdsMakeRoomFor(s,l);
}
memcpy(s+i,str,l);
sdsinclen(s,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 (sdsavail(s) < l) {
s = sdsMakeRoomFor(s,l);
}
memcpy(s+i,buf,l);
sdsinclen(s,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 (sdsavail(s) < l) {
s = sdsMakeRoomFor(s,l);
}
memcpy(s+i,buf,l);
sdsinclen(s,l);
i += l;
}
break;
default: /* Handle %% and generally %<unknown>. */
s[i++] = next;
sdsinclen(s,1);
break;
}
break;
default:
s[i++] = *f;
sdsinclen(s,1);
break;
}
f++;
}
va_end(ap);
/* Add null-term */
s[i] = '\0';
return s;
}
/* 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,"Aa. :");
* printf("%s\n", s);
*
* Output will be just "Hello World".
*/
sds sdstrim(sds s, const char *cset) {
char *start, *end, *sp, *ep;
size_t len;
sp = start = s;
ep = end = s+sdslen(s)-1;
while(sp <= end && strchr(cset, *sp)) sp++;
while(ep > sp && strchr(cset, *ep)) ep--;
len = (sp > ep) ? 0 : ((ep-sp)+1);
if (s != sp) memmove(s, sp, len);
s[len] = '\0';
sdssetlen(s,len);
return s;
}
/* 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) {
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;
}
if (start && newlen) memmove(s, s+start, newlen);
s[newlen] = 0;
sdssetlen(s,newlen);
}
/* 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]);
}
/* 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]);
}
/* Compare two sds strings s1 and s2 with memcmp().
*
* Return value:
*
* positive if s1 > s2.
* negative 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.
*
* 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(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 = s_malloc(sizeof(sds)*slots);
if (tokens == NULL) return NULL;
if (len == 0) {
*count = 0;
return tokens;
}
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 = s_realloc(tokens,sizeof(sds)*slots);
if (newtokens == NULL) goto cleanup;
tokens = newtokens;
}
/* search the separator */
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]);
s_free(tokens);
*count = 0;
return NULL;
}
}
/* 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]);
s_free(tokens);
}
/* 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. */
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 */
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:
*
* foo bar "newline are supported\n" and "\xff\x00otherstuff"
*
* The number of arguments is stored into *argc, and an array
* of sds is returned.
*
* The caller should free the resulting array of sds strings with
* sdsfreesplitres().
*
* Note that sdscatrepr() is able to convert back a string into
* a quoted string in the same format sdssplitargs() is able to parse.
*
* 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'
*/
sds *sdssplitargs(const char *line, int *argc) {
const char *p = line;
char *current = NULL;
char **vector = NULL;
*argc = 0;
while(1) {
/* skip blanks */
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();
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 */
vector = s_realloc(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 = s_malloc(sizeof(void*));
return vector;
}
}
err:
while((*argc)--)
sdsfree(vector[*argc]);
s_free(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.
*
* For instance: sdsmapchars(mystring, "ho", "01", 2)
* will have the effect of turning the string "hello" into "0ell1".
*
* The function returns the sds string pointer, that is always the same
* as the input pointer since no resize is needed. */
sds sdsmapchars(sds s, const char *from, const char *to, size_t setlen) {
size_t j, i, l = sdslen(s);
for (j = 0; j < l; j++) {
for (i = 0; i < setlen; i++) {
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;
}
/* Like sdsjoin, but joins an array of SDS strings. */
sds sdsjoinsds(sds *argv, int argc, const char *sep, size_t seplen) {
sds join = sdsempty();
int j;
for (j = 0; j < argc; j++) {
join = sdscatsds(join, argv[j]);
if (j != argc-1) join = sdscatlen(join,sep,seplen);
}
return join;
}
/* Wrappers to the allocators used by SDS. Note that SDS will actually
* just use the macros defined into sdsalloc.h in order to avoid to pay
* the overhead of function calls. Here we define these wrappers only for
* the programs SDS is linked to, if they want to touch the SDS internals
* even if they use a different allocator. */
void *sds_malloc(size_t size) { return s_malloc(size); }
void *sds_realloc(void *ptr, size_t size) { return s_realloc(ptr,size); }
void sds_free(void *ptr) { s_free(ptr); }
#if defined(SDS_TEST_MAIN)
#include <stdio.h>
#include "testhelp.h"
#include "limits.h"
#define UNUSED(x) (void)(x)
int sdsTest(void) {
{
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)
printf("[%s]\n",x);
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(" x ");
sdstrim(x," x");
test_cond("sdstrim() works when all chars match",
sdslen(x) == 0)
sdsfree(x);
x = sdsnew(" x ");
sdstrim(x," ");
test_cond("sdstrim() works when a single char remains",
sdslen(x) == 1 && x[0] == 'x')
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)
{
unsigned int oldfree;
char *p;
int step = 10, j, i;
sdsfree(x);
sdsfree(y);
x = sdsnew("0");
test_cond("sdsnew() free/len buffers", sdslen(x) == 1 && sdsavail(x) == 0);
/* Run the test a few times in order to hit the first two
* SDS header types. */
for (i = 0; i < 10; i++) {
int oldlen = sdslen(x);
x = sdsMakeRoomFor(x,step);
int type = x[-1]&SDS_TYPE_MASK;
test_cond("sdsMakeRoomFor() len", sdslen(x) == oldlen);
if (type != SDS_TYPE_5) {
test_cond("sdsMakeRoomFor() free", sdsavail(x) >= step);
oldfree = sdsavail(x);
}
p = x+oldlen;
for (j = 0; j < step; j++) {
p[j] = 'A'+j;
}
sdsIncrLen(x,step);
}
test_cond("sdsMakeRoomFor() content",
memcmp("0ABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJABCDEFGHIJ",x,101) == 0);
test_cond("sdsMakeRoomFor() final length",sdslen(x)==101);
sdsfree(x);
}
}
test_report()
return 0;
}
#endif
#ifdef SDS_TEST_MAIN
int main(void) {
return sdsTest();
}
#endif
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