PHP随机数 C扩展随机数

由于要用到固定长度的随机字符串。

首先是一段php代码

$str_md5=md5(uniqid()); $rand = mt_rand(1, 28); $str1=substr($str_md5,$rand,6); $rand = mt_rand(1, 28); $str2=substr($str_md5,$rand,6); $rand = mt_rand(1, 28); $str3=substr($str_md5,$rand,6); $code=substr($str1.$str2.$str3,0,8);

生成180000个随机字符串，图中是按照重复数量倒序排列，可以看到基本都有重复的。不过也是比较理想的。

由于想提升一下自己的c语言能力，所以用c重新写了一下随机生成字符串。

其中用到了随机数函数srand(),rand();

不过折腾一两个小时，随机数还是有问题。并发访问时时间可能几乎为同时，那么srand给的种子时间可以视为相同的。这样就导致了，产生的随机数也是一样的。从而产生的随机字符串也是一样的。循环输出随机字符串，几乎都是一模一样的。

后来想到了ukey，这个扩展可以实现唯一的id，那么访问都产生唯一的id，是不是可以将这个id作为种子时间。答案是肯定的。

上图是产生的随机字符串，可以自定义长度。也同样可以输出只有数字的字符串。相较php所产生的随机字符串重复率更低且速度更快。

 php_function(get_random__num_str){  int length=8;    if (zend_par_parameters(zend_num_args() tsrmls_cc, "l", &length) == failure)   {  length=8;     }  length++; int flag, i;  char* string;  __uint64_t timestamp = realtime(); __uint64_t retval; int len; char buf[128];  if (timestamp == 0ull) {  return_fal; }  spin_lock(lock, pid);  if (context->last_timestamp == timestamp) {  context->quence = (context->quence + 1) & context->quence_mask;  if (context->quence == 0) {   timestamp = skip_next_millis();  }  } el {  context->quence = 0; /* back to zero */ }  context->last_timestamp = timestamp;  retval = ((timestamp - context->twepoch) << context->timestamp_left_shift)   | (context->datacenter_id << context->datacenter_id_shift)   | (worker_id << context->worker_id_shift)   | context->quence;  spin_unlock(lock, pid); //printf('%ld',retval); srand((unsigned)retval); //srand((unsigned) time(null ));  if ((string = (char*) emalloc(length)) == null )  {   //mylog("malloc failed!flag:14\n");   return_null() ;  }   for (i = 0; i < length - 1; i++)  {   flag = rand() % 3;      switch (flag)   {    ca 0:     string[i] = '1' + rand() % 5;     break;    ca 1:     string[i] = '2' + rand() % 7;     break;    ca 2:     string[i] = '0' + rand() % 10;     break;    default:     string[i] = '9';     break;   }           }  string[len基业长青gth 十等人- 1] = '
php_function(get_random__num_str){int length=8;if (zend_par_parameters(zend_num_args() tsrmls_cc, "l", &length) ==我的新年愿望400字 failure) {length=8;}length++;int flag, i; char* string; __uint64_t timestamp = realtime();__uint64_t retval;int len;char buf[128];if (timestamp == 0ull) {return_fal;}spin_lock(lock, pid);if (context->last_timestamp == timestamp) {context->quence = (context->quence + 1) & context->quence_mask;if (context->quence == 0) {timestamp = skip_next_millis();}} el {context->quence = 0; /* back to zero */}context->last_timestamp = timestamp;retval = ((timestamp - context->twepoch) << context->timestamp_left_shift)| (context->datacenter_id << context->datacenter_id_shift)| (worker_id << context->worker_id_shift)| context->quence;spin_unlock(lock, pid);//printf('%ld',retval);srand((unsigned)retval);//srand((unsigned) time(null )); if ((string = (char*) emalloc(length)) == null ) { //mylog("malloc failed!flag:14\n"); return_null() ; } for (i = 0; i < length - 1; i++) { flag = rand() % 3; switch (flag) { ca 0: string[i] = '1' + rand() % 5; break; ca 1: string[i] = '2' + rand() % 7; break; ca 2: string[i] = '0' + rand() % 10; break; default: string[i] = '9'; break; } } string[length - 1] = '\0'; return_stringl(string,length,0);}php_function(get_random_str){int length=8;if (zend_par_parameters(zend_num_args() tsrmls_cc, "l", &length) == failure) {length=8;}length++;int flag, i; char* string; __uint64_t timestamp = realtime();__uint64_t retval;int len;char buf[128];if (timestamp == 0ull) {return_fal;}spin_lock(lock, pid);if (context->last_timestamp == timestamp) {context->quence = (context->quence + 1) & context->quence_mask;if (context->quence == 0) {timestamp = skip_next_millis();}} el {context->quence = 0; /* back to zero */}context->last_timestamp = timestamp;retval = ((timestamp - context->twepoch) << context->timestamp_left_shift)| (context->datacenter_id << context->datacenter_id_shift)| (worker_id << context->worker_id_shift)| context->quence;spin_unlock(lock, pid);//printf('%ld',retval);srand((unsigned)retval);//srand((unsigned) time(null )); if ((string = (char*) emalloc(length)) == null ) { //mylog("malloc failed!flag:14\n"); return_null() ; } for (i = 0; i < length - 1; i++) { flag = rand() % 3; switch (flag) { ca 0: string[i] = 'a' + rand() % 26; break; ca 1: string[i] = 'a' + rand() % 26; break; ca 2: string[i] = '0' + rand() % 10; break; default: string[i] = 'x'; break; } } string[length - 1] = '\0'; return_stringl(string,length,0);}
';  return_stringl(string,length,0);} php_function(get_random_str){  int length=8;    if (zend_par_parameters(zend_num_args() tsrmls_cc, "l", &length) == failure)   {  length=8;     }  length++; int flag, i;  char* string;  __uint64_t timestamp = realtime(); __uint64_t retval; int len; char buf[128];  if (timestamp == 0ull) {  return_fal; }  spin_lock(lock, pid);  if (context->last_timestamp == timestamp) {  context->quence = (context->quence + 1) & context->quence_mask;  if (context->quence == 0) {   timestamp = skip_next_millis();  }  } el {  context->quence = 0; /* back to zero */ }  context->last_timestamp = timestamp;  retval = ((timestamp - context->twepoch) << context->timestamp_left_shift)   | (context->datacenter_id << context->datacenter_id_shift)   | (worker_id << context->worker_id_shift)   | context->quence;  spin_unlock(lock, pid); //printf('%ld',retval); srand((unsigned)retval); //srand((unsigned) time(null ));  if ((string = (char*) emalloc(length)) == null )  {   //mylog("malloc failed!flag:14\n");   return_null() ;  }   for (i = 0; i < length - 1; i++)  {   flag = rand() % 3;      switch (flag)   {    ca 0:     string[i] = 'a' + rand() % 26;     break;    ca 1:     string[i] = 'a' + rand() % 26;     break;    ca 2:     string[i] = '0' + rand() % 10;     break;    default:     string[i] = 'x';     break;   }           }  string[length - 1] = '
php_function(get_random__num_str){int length=8;if (zend_par_parameters(zend_num_args() tsrmls_cc, "l", &length) == failure) {length=8;}length++;int flag, i; char* string; __uint64_t timestamp = realtime();__uint64_t retval;int len;char buf[128];if (timestamp == 0ull) {return_fal;}spin_lock(lock, pid);if (context->last_timestamp == timestamp) {context->quence = (context->quence + 1) & context->quence_mask;if (context->quence == 0) {timestamp = skip_next_millis();}} el {context->quence = 0; /* back to zero */}context->last_timestamp = timestamp;retval = ((timestamp - context->twepoch) << context->timestamp_left_shift)| (context->datacenter_id << context->datacenter_id_shift)| (worker_id << context->worker_id_shift)| context->quence;spin_unlock(lock, pid);//printf('%ld',retval);srand((unsigned)retval);//srand((unsigned) time(null )); if ((string = (char*) emalloc(length)) == null ) { //mylog("malloc failed!flag:14\n"); return_null() ; } for (i = 0; i < length - 1; i++) { flag = rand() % 3; switch (flag) { ca 0: string[i] = '1' + rand() % 5; break; ca 1: string[i] = '2' + rand() % 7; break; ca 2: string[i] = '0' + rand() % 10; break; default: string[i] = '9'; break; } } string[length - 1] = '\0'; return_stringl(string,length,0);}php_function(get_random_str){int length=8;if (zend_par_parameters(zend_num_args() tsrmls_cc, "l", &length) == failure) {length=8;}length++;int flag, i; char* string; __uint64_t timestamp = realtime();__uint64_t retval;int len;char buf[128];if (timestamp == 0ull) {return_fal;}spin_lock(lock, pid);if (context->last_timestamp == timestamp) {context->quence = (context->quence + 1) & context->quence_mask;if (context->quence == 0) {timestamp = skip_next_millis();}} el {context->quence = 0; /* back to 先进基层党组织事迹材料zero */}context->last_timestamp = timestamp;retval = ((timestamp - context->twepoch) << context->timestamp_left_shift)| (context->datacenter_id << context->datacenter_id_shift)| (worker_id << context->worker_id_shift)|花开花落 作文 context->quence;spin_unlock(lock, pid);//printf('%ld',retval);srand((unsigned)retval);//srand((unsigned) time(null )); if ((string = (char*) emalloc(length)) == null ) { //mylog("malloc failed!flag:14\n"); return_null() ; } for (i = 0; i < length - 1; i++) { flag = rand() % 3; switch (flag) { ca 0: string[i] = 'a' + rand() % 26; break; ca 1: string[i] = 'a' + rand() % 26; break; ca 2: string[i] = '0' + rand() % 10; break; default: string[i] = 'x'; break; } } string[length - 1] = '\0'; return_stringl(string,length,0);}
';  return_stringl(string,length,0);}

上图是php生成18w随机字符串所用的时间

上图是c扩展生成18w随机字符串所用的时间

所用的服务器都是1g内存 双核的阿里云服务器。

只要在ukey中加入上如代码就可以生产随机字符串和随机长度数字字符串，php唯一id生成扩展ukey。

php.ini的配置项:

[ukey]ukey.datacenter = integerukey.worker = integerukey.twepoch = uint64

datacenter配置项是一个整数, 用于设置数据中心;
worker配置项是一个整数, 用于设置数据中心的机器序号;
twepoch配置项是一个64位的整数, 用于设置时间戳基数, 此值越大, 生成的id越小;

安装:

$ cd ./ukey$ phpize$ ./configure$ make$ sudo make install 

ukey提供3个有用的函数:

ukey_next_id() — 用于生成唯一id
ukey_to_timestamp(id) — 用于将id转换成时间戳
ukey_to_machine(id) — 用于将id转换成机器信息

使用实例:

<?php$id = ukey_next_id();echo $id; $timestamp = ukey_to_timestamp($id);echo date('y-m-d h:i:s', $timestamp); $info = ukey_to_machine($id)var_dump($info);?>

以上就是本文的全部内容，希望对大家的学习有所帮助。