Fix implementation of getting random string (#726)

src/utils/string.cpp

@@ -3,8 +3,9 @@
 #include <sstream>
 #include <string>
 #include <vector>
-#include <stdlib.h>
-#include <time.h>
+#include <cstdlib>
+#include <ctime>
+#include <random>
 
 #include "string.h"
 #include "map_extra.h"
@@ -57,25 +58,20 @@ void split(std::vector<std::string_view> &result, std::string_view s, char separ
 
  while (i != s.size())
  {
- int flag = 0;
- while(i != s.size() && flag == 0)
+ while(i != s.size())
  {
- flag = 1;
  if(s[i] == separator)
  {
  ++i;
- flag = 0;
  break;
  }
  }
 
- flag = 0;
  string_size j = i;
- while(j != s.size() && flag == 0)
+ while(j != s.size())
  {
  if(s[j] == separator)
  {
- flag = 1;
  break;
  }
  ++j;
@@ -141,7 +137,7 @@ std::string toUpper(const std::string &str)
 void processEscapeChar(std::string &str)
 {
  string_size pos = str.find('\\');
- while(pos != str.npos)
+ while(pos != std::string::npos)
  {
  if(pos == str.size())
  break;
@@ -191,7 +187,7 @@ void processEscapeCharReverse(std::string &str)
 
 int parseCommaKeyValue(const std::string &input, const std::string &separator, string_pair_array &result)
 {
- string_size bpos = 0, epos = input.find(',');
+ string_size bpos = 0, epos = input.find(separator);
  std::string kv;
  while(bpos < input.size())
  {
@@ -200,9 +196,9 @@ int parseCommaKeyValue(const std::string &input, const std::string &separator, s
  else if(epos && input[epos - 1] == '\\')
  {
  kv += input.substr(bpos, epos - bpos - 1);
- kv += ',';
+ kv += separator;
  bpos = epos + 1;
- epos = input.find(',', bpos);
+ epos = input.find(separator, bpos);
  continue;
  }
  kv += input.substr(bpos, epos - bpos);
@@ -213,9 +209,9 @@ int parseCommaKeyValue(const std::string &input, const std::string &separator, s
  result.emplace_back(kv.substr(0, eqpos), kv.substr(eqpos + 1));
  kv.clear();
  bpos = epos + 1;
- epos = input.find(',', bpos);
+ epos = input.find(separator, bpos);
  }
- if(kv.size())
+ if(!kv.empty())
  {
  string_size eqpos = kv.find('=');
  if(eqpos == std::string::npos)
@@ -328,12 +324,12 @@ std::string getUrlArg(const std::string &url, const std::string &request)
  while(pos)
  {
  pos = url.rfind(pattern, pos);
- if(pos != url.npos)
+ if(pos != std::string::npos)
  {
  if(pos == 0 || url[pos - 1] == '&' || url[pos - 1] == '?')
  {
  pos += pattern.size();
- return url.substr(pos, url.find("&", pos) - pos);
+ return url.substr(pos, url.find('&', pos) - pos);
  }
  }
  else
@@ -410,23 +406,24 @@ bool isStrUTF8(const std::string &data)
 std::string randomStr(int len)
 {
  std::string retData;
- srand(time(NULL));
- int cnt = 0;
- while(cnt < len)
+ std::random_device rd;
+ std::mt19937 gen(rd());
+ std::uniform_int_distribution<> dis(0, 61);
+ for(int i = 0; i < len; i++)
  {
- switch((rand() % 3))
+ int r = dis(gen);
+ if (r < 26)
  {
- case 1:
-  retData += ('A' + rand() % 26);
-  break;
- case 2:
- retData += ('a' + rand() % 26);
-  break;
- default:
-  retData += ('0' + rand() % 10);
- break;
+  retData.push_back('a' + r);
+ }
+ else if (r < 52)
+ {
+ retData.push_back('A' + r - 26);
+ }
+ else
+ {
+ retData.push_back('0' + r - 52);
  }
- cnt++;
  }
  return retData;
 }
@@ -451,7 +448,7 @@ int to_int(const std::string &str, int def_value)
 
 std::string join(const string_array &arr, const std::string &delimiter)
 {
- if(arr.size() == 0)
+ if(arr.empty())
  return "";
  if(arr.size() == 1)
  return arr[0];