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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include "sds.h"
#include "zmalloc.h"
// 根据字符串 init 及其长度 initlen 创建 sds,成功则返回 sdshdr 地址,失败返回 NULL
// O(N)
sds sdsnewlen(const void *init, size_t initlen) {
struct sdshdr *sh;
if (init) {
sh = zmalloc(sizeof(struct sdshdr) + initlen + 1); // 有值则不初始化内存,+1 是为 '\0' 预留
} else {
sh = zcalloc(sizeof(struct sdshdr) + initlen + 1); // 空字符串则 SDS 初始化为全零
}
if (sh == NULL) return NULL;
sh->len = initlen;
sh->free = 0; // 新 sds 不预留空闲空间
if (initlen && init)
memcpy(sh->buf, init, initlen); // 复制字符串 init 到 buf
sh->buf[initlen] = '\0'; // 以 \0 结尾
return (char *) sh->buf; // buf 部分即 sds
}
// 创建保存空字符串 "" 的 sds
sds sdsempty(void) {
return sdsnewlen("", 0);
}
// C 字符串转 sds
// O(N)
sds sdsnew(const char *init) {
size_t initlen = (init == NULL) ? 0 : strlen(init);
return sdsnewlen(init, initlen);
}
// 复制 sds
// O(N)
sds sdsdup(const sds s) {
return sdsnewlen(s, sdslen(s));
}
// 释放 sds 内存
// O(N)
void sdsfree(sds s) {
if (s == NULL) return;
zfree(s - sizeof(struct sdshdr)); // 同样左移寻址
}
// sds 更新后手动调整 len 的值,未使用可能废弃
// deprecated
void sdsupdatelen(sds s) {
struct sdshdr *sh = (void *) (s - (sizeof(struct sdshdr)));
int reallen = strlen(s);
sh->free += (sh->len - reallen);
sh->len = reallen;
}
// 清空 sds 为空字符串,但不释放 sds 空间,即惰性删除
// O(1)
void sdsclear(sds s) {
struct sdshdr *sh = (void *) (s - (sizeof(struct sdshdr)));
sh->free += sh->len; // 全部可用
sh->len = 0;
sh->buf[0] = '\0'; // 手动截断 buf
}
// 扩展 sds 空间增加 addlen 长度,进行内存预分配
// O(N)
sds sdsMakeRoomFor(sds s, size_t addlen) {
struct sdshdr *sh, *newsh;
size_t free = sdsavail(s);
size_t len, newlen;
if (free >= addlen) return s; // 无须扩展
len = sdslen(s);
sh = (void *) (s - (sizeof(struct sdshdr)));
newlen = (len + addlen); // 注意未把 free 算入
// 空间预分配策略:新长度在 (..., 1MB) 则成倍增长,[1MB, ...) 则每次仅增长 1 MB
if (newlen < SDS_MAX_PREALLOC)
newlen *= 2;
else
newlen += SDS_MAX_PREALLOC;
// 重分配
newsh = zrealloc(sh, sizeof(struct sdshdr) + newlen + 1);
if (newsh == NULL) return NULL;
newsh->free = newlen - len; // 更新 free 但不更新 len
return newsh->buf;
}
// 丢弃 sds 的 free 空闲空间
// O(N)
sds sdsRemoveFreeSpace(sds s) {
struct sdshdr *sh;
sh = (void *) (s - (sizeof(struct sdshdr)));
sh = zrealloc(sh, sizeof(struct sdshdr) + sh->len + 1); // free 空间会被系统自动回收
sh->free = 0;
return sh->buf;
}
// 返回系统为 sds 分配的全部内存字节数
size_t sdsAllocSize(sds s) {
struct sdshdr *sh = (void *) (s - (sizeof(struct sdshdr)));
// sds 头部长度 + 已存储字符串长度的空间大小 + 未使用的预分配空间大小 + '\0'
return sizeof(*sh) + sh->len + sh->free + 1;
}
/* 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
*
* 本函数在调用 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。
*
* 如果 incr 参数为负数,那么对字符串进行右截断操作。
* 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);
*/
// 单纯地将 len+=incr, free-=incr
void sdsIncrLen(sds s, int incr) {
struct sdshdr *sh = (void *) (s - (sizeof(struct sdshdr)));
assert(sh->free >= incr); // 确保 sds 空间足够
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);
s[sh->len] = '\0';
}
// 将 sds 扩充至指定长度,未使用的空间以 0 字节填充
sds sdsgrowzero(sds s, size_t len) {
struct sdshdr *sh = (void *) (s - (sizeof(struct sdshdr)));
size_t totlen, curlen = sh->len;
if (len <= curlen) return s; // 无需扩充
// 使用 realloc 分配的新内存取余是未初始化的
s = sdsMakeRoomFor(s, len - curlen);
if (s == NULL) return NULL;
// 将新分配的空间用 0 填充,防止出现无效值
sh = (void *) (s - (sizeof(struct sdshdr)));
memset(s + curlen, 0, (len - curlen + 1)); /* also set trailing \0 byte */
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
sds sdscatlen(sds s, const 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))); // 复制 t 中的内容到字符串后部
memcpy(s + curlen, t, len);
sh->len = curlen + len;
sh->free = sh->free - len;
s[curlen + len] = '\0';
return s;
}
// 追加字符串到 sds
sds sdscat(sds s, const char *t) {
return sdscatlen(s, t, strlen(t));
}
// 追加 sds 到 sds
sds sdscatsds(sds s, const sds t) {
return sdscatlen(s, t, sdslen(t));
}
// 将字符串的前 len 个字符复制到 sds 中,直接覆盖 sds 原有内容
sds sdscpylen(sds s, const char *t, size_t len) {
struct sdshdr *sh = (void *) (s - (sizeof(struct sdshdr)));
size_t totlen = sh->free + sh->len; // sds 总长度
// 若少于 len 则扩展
if (totlen < len) {
s = sdsMakeRoomFor(s, len - sh->len);
if (s == NULL) return NULL;
sh = (void *) (s - (sizeof(struct sdshdr)));
totlen = sh->free + sh->len;
}
memcpy(s, t, len); // 覆盖式复制
s[len] = '\0';
sh->len = len;
sh->free = totlen - len;
return s;
}
// 将 t 覆盖复制到 s 中
sds sdscpy(sds s, const char *t) {
return sdscpylen(s, t, strlen(t));
}
// 整数与 sds 互转的辅助函数
// 最小值为 -9223372036854775808 加上尾部 '\0' 长度为 21
#define SDS_LLSTR_SIZE 21
// 有符号长整型转字符串并保存至 s,返回其长度
int sdsll2str(char *s, long long value) {
char *p, aux;
unsigned long long v;
size_t l;
v = (value < 0) ? -value : value; // v 转为正数
p = s;
do {
*p++ = '0' + (v % 10); // 从高位到低位取数字,逐个转为 ASCII 数字字符
v /= 10;
} while (v);
if (value < 0) *p++ = '-'; // 恢复正负
l = p - s;
*p = '\0'; // 手动截断字符串
p--; // 跳过 '\0' 保留
// 对称交换反转 s 与 p 双指针
while (s < p) {
aux = *s;
*s = *p;
*p = aux;
s++;
p--;
}
return l; // 返回字符串长度
}
// 无符号长整型转字符串保存于 s,返回其长度
int sdsull2str(char *s, unsigned long long v) {
char *p, aux;
size_t l;
p = s;
do {
*p++ = '0' + (v % 10);
v /= 10;
} while (v);
l = p - s;
*p = '\0';
p--;
while (s < p) {
aux = *s;
*s = *p;
*p = aux;
s++;
p--;
}
return l;
}
// 长整型值转 sds
sds sdsfromlonglong(long long value) {
char buf[SDS_LLSTR_SIZE];
int len = sdsll2str(buf, value);
return sdsnewlen(buf, len);
}
// 将可变参数格式化到 sds 中
// 打印函数,被 sdscatprintf 所调用
// O(N^2)
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;
}
// 删除 sds 两端 cset 中的任意字符
sds sdstrim(sds s, const char *cset) {
struct sdshdr *sh = (void *) (s - (sizeof(struct sdshdr)));
char *start, *end, *sp, *ep;
size_t len;
sp = start = s;
ep = end = s + sdslen(s) - 1;
// 修剪, T = O(N^2)
while (sp <= end && strchr(cset, *sp)) sp++; // 裁剪左侧
while (ep > start && strchr(cset, *ep)) ep--; // 裁剪右侧
// 计算 trim 完毕之后剩余的字符串长度
len = (sp > ep) ? 0 : ((ep - sp) + 1);
// 左侧有裁剪则内存前移
if (sh->buf != sp) memmove(sh->buf, sp, len);
sh->buf[len] = '\0';
sh->free = sh->free + (sh->len - len);
sh->len = len;
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)
// 合法区间为 [0, sdslen(s) - 1]
// 索引可以是负数, sdslen(s) - 1 == -1
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; // 往回走
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(sh->buf, sh->buf + start, newlen);
sh->buf[newlen] = 0; // 0 和 '\0' 和 NULL 的 ASCII 值都是 0,是等价的
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
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
void sdstoupper(sds s) {
int len = sdslen(s), j;
for (j = 0; j < len; j++) s[j] = toupper(s[j]);
}
// 比较 sds
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); // 直接基于 mem* 内存操作函数
if (cmp == 0) return l1 - l2;
return cmp;
}
// 使用分隔符 sep 对 s 进行分割,返回一个 sds 字符串的数组,注意分隔符 sep 可以的是包含多个字符的字符串
// *count 会被设置为返回数组元素的数量
// 内存不足、字符串长度为 0 或分隔符长度为 0 等返回 NULL
// 函数接受 len 参数,是二进制安全的
sds *sdssplitlen(const char *s, int len, const char *sep, int seplen, int *count) {
int elements = 0, slots = 5, start = 0, j;
sds *tokens; // tokens 是子 sds 数组
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
// 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);
}
/* 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. */
// 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
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);
}
// 辅助函数,若 c 为十六进制符号的其中一个,返回 1
int is_hex_digit(char c) {
return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') ||
(c >= 'A' && c <= 'F');
}
// 辅助函数:将十六进制符号转换为 10 进制数
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) // 覆盖式更新
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
int main() {
struct sdshdr h;
printf("%zu\n", sizeof(h));
printf("%p\n", &h);
printf("%p\n", &h.len);
printf("%p\n", &h.free);
printf("%p\n", &h.buf);
char *sds = sdsnew("Redis");
char *free = sds - sizeof(int);
char *len = free - sizeof(int);
char *prefixSize = len - sizeof(size_t);
printf("used_memory: %zu\n", zmalloc_used_memory());
printf("prefix_size: %d\nlen: %d\nfree: %d\n", *prefixSize, *len, *free);
}
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